Blank.indd 1 2/11/2010 8:51:01 AMdocshare01.docshare.tips/files/16927/169276645.pdf · 2016-12-24 · Visit STRUCTURE magazine online at STRUCTURE® (Volume 17, Number 4). ISSN 1536-4283.

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STRUCTURE magazine April 2010

Visit STRUCTURE magazine on-line atwww.structuremag.org

Visit STRUCTURE magazine on-line at www.structuremag.org

Visit STRUCTURE magazine online atwww.STRUCTUREmag.org

STRUCTURE® (Volume 17, Number 4). ISSN 1536-4283. Publications Agreement No. 40675118. Owned by the National Council of Structural Engineers Associations and published in cooperation with CASE and SEI monthly by C3 Ink. The publication is distributed free of charge to members of NCSEA, CASE and SEI; the non-member subscription rate is $65/yr domestic; $35/yr student; $125/yr foreign (including Canada). For change of address or duplicate copies, contact your member organization(s). Any opinions expressed in STRUCTURE magazine are those of the author(s) and do not necessarily refl ect the views of NCSEA, CASE, SEI, C3 Ink, or the STRUCTURE Editorial Board.

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KPFF Consulting Engineers Page 4

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Advertiser Index free information from advertisers

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C O N T E N T S

Publication of any article, image, or advertisement in STRUCTURE® magazine does not constitute endorsement by NCSEA, CASE, SEI,

C3 Ink, or the Editorial Board. Authors, contributors, and advertisers retain sole responsibility for the content of their submissions.

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Northrop-Grumman Building R6, Redondo Beach, CA, a post-tensioned concrete building using shrinkage-compensating cement to solve difficult restraint-to-shortening problems. Built over 40 years ago, the building has required no unusual maintenance or repairs, and continues to perform well today. See more on this building in our feature on page 18.

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Columns

Features

Departments

In every Issue

on the Cover

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18 Shrinkage-Compensating Concrete in Post-Tensioned BuildingsBy Kenneth B. Bondy, S.E., FACIRestraint to shortening (RTS) is a major concern for designers of post-tensioned concrete buildings. It can cause unsightly cracking in floor systems and restraining elements (columns and walls). One proven method for solving RTS problems has been in use for over 40 years and yet it is not well known. Shrinkage-compensating concrete has been successfully used to construct large, jointless elevated slabs in post-tensioned concrete structures since the 1960s.

7 EditorialThe Benefits of Networking

By Douglas Ashcraft, P.E., S.E.

8 Structural DesignPost-Tensioned Slabs on Ground

By Bryan Allred, S.E.

12 Practical SolutionsHeavily Loaded Strap Footings

By Truly Guzman, P.E. M.Sc

16 InSightsEducational Art

By Duane Ellifritt, Ph.D., P.E.

34 Structural ForumWe Need to Work Together or Risk Being Torn Apart

By Barry Arnold, S.E., SECB

23 Risk ManagementManaging the Risks of BIM

By Joseph M. Ales Jr., Ph.D., S.E.

4 Advertiser Index26 Resource Guide

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ChairJon A. Schmidt, P.E., SECB

Burns & McDonnellKansas City, MO

[email protected]

Executive EditorJeanne M. Vogelzang, JD, CAE

NCSEAChicago, IL

[email protected]

Craig E. Barnes, P.E., SECBCBI Consulting, Inc.

Boston, MA

Richard Hess, S.E., SECBHess Engineering Inc.

Los Alamitos, CA

Mark W. Holmberg, P.E.Heath & Lineback Engineers, Inc.

Marietta, GA

Editorial BoardBrian J. Leshko, P.E.

HDR Engineering, Inc.Pittsburgh, PA

John A. Mercer, P.E.Mercer Engineering, PC

Minot, ND

Brian W. MillerAISC

Davis, CA

Mike C. Mota, P.E.CRSI

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Evans Mountzouris, P.E.The DiSalvo Ericson Group

Ridgefield, CT

Matthew Salveson, Ph.D., P.E. Dokken Engineering

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Greg Schindler, P.E., S.E.KPFF Consulting Engineers

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Stephen P. Schneider, Ph.D., P.E., S.E.Kramer Gehlen & Associates, Inc.

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John “Buddy” Showalter, P.E.AF & PA/American Wood Council

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Editorial

7

The Benefits of NetworkingBy Douglas Ashcraft, P.E., S.E.Chair, Council of American Structural Engineers (CASE)

Leaders of CASE, CAMEE, Small Firms, COPS, Land Development, and Design Professionals Coalitions continue to work together to develop strategies for showing other firms the many benefits of joining ACEC and one of the design coalitions. Among the many benefits identified, one keeps coming up as having the most value. The ability to network with other design professionals and discuss issues that affect the business of engineering is seen as an invaluable benefit of becoming a member of ACEC and CASE.Something that CASE tried this past January shows great promise in

letting others see what CASE is about and provide incentive to join. CASE held its Winter Meeting in Houston in January. We contacted the leadership of the Houston/Gulf Coast Chapter of The Structural Engineers Association of Texas (SEAoT) and asked them if we could join them for their regular monthly meeting. They agreed, and CASE supplied the program.The program consisted of round table discussions about four different

issues affecting the risk profile of structural engineering firms today. Each discussion was led by a knowledgeable leader in the industry from different firms around the country. The four topics included Building Information Modeling, LEED and Sustainable Design, Integrated Project Delivery, and Collecting Fees without Counter-Claims. Attendees were asked to choose any of the four topics, and I was amazed to see each table fairly equally populated.Kurtis Young, a principal in the Houston office of Walter P Moore,

led a discussion about the benefits and risks of engaging in projects that are delivered by the Integrated Project Delivery model. Kurt explained that the Owner, Architect and Builder are all parties to the same agreement, in which they agree to cooperate in the best interest of the project and to not sue each other. All parties to the contract have specific responsibilities and are held accountable by an Executive Leadership committee, consisting of senior management from the three major stakeholders.There were several at the table that had experience with this type of

contract. They explained that profit for the designer and builders is at risk, being tied up in the construction contingency for the project. If the project is delivered for less than the budget, everyone receives more profit than anticipated. However, if some of the contingency is spent on over-budget items, everyone’s profit suffers. All agreed that the key issue for success is working with partners with which you have had experience and can trust to perform.

Dirk Kestner, a project manger from the Austin office of Walter P Moore and a LEED Accredited Professional, started the conversation about the risks associated when an owner wishes the project to be LEED certified. Many areas of LEED point accumulation are out of the purview of structural engineers, and the SE’s role is somewhat limited. That does not mean there is no risk for structural engineers nor does it mean that SE’s should not get involved with the design team early to help move the sustainable discussion along. Designers should never allow there to be a guarantee for a particular LEED level in the contract; there are many issues associated with construction that can impact the project’s ability to become LEED certified. Many new products and procedures will present themselves as sustainable and appropriate for LEED certification. Designers should take appropriate actions to verify those claims before allowing their use.Building Information Modeling promises to enhance collaboration

and condense information. David Odeh of Odeh Engineers led a group in discussing the contractual risks that must be addressed with BIM. Before a model is begun, the purpose for its creation must be agreed upon. Ownership and control of the model must be addressed in the contract. The question of what constitutes a standard of care with a new technology needs to be answered to properly assign risk among the parties.Most engineering firms spend an inordinate amount of time

managing accounts receivable. David Collings of Ames and Gough, the Chair of CASE’s Insurance Engagement Committee, helped the group discuss ways in which design firms can collect what is owed without getting sued in the process. Project managers should be engaged with clients and held accountable for overdue collections. Some firms take overdue amounts off the bottom line, to give PM’s incentive to be proactive in collecting fees. Be sure there are no valid reasons based on your performance for not getting paid; but, if not, aggressive actions such as stopping work may be necessary. Let the order to stop work come from higher up, so as to not endanger the PM’s relationship with the client. Getting a Promissory Note signed is a good way to ensure collections and makes it easier to get a judgment against the client in case of non-payment.Everyone agreed that the evening of networking between local

engineers and members of CASE, from diverse locations and firm size, was a great success. Look for a CASE meeting near you, and help us as CASE tries to reach out to a larger audience.▪

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Post -Tensioned Slabs on GroundPart 2: Specific Design ConsiderationsBy Bryan Allred, S.E.

The January 2010 issue of Structure Magazine contained a general overview of the design and construction of post-tensioned slab on ground foundations. This article will focuses on specific engi-neering items that occur when designing these types of foundations. As described previously, post-tensioned slabs on grade are primarily designed to support residen-tial and light industrial construction that is on expansive or compressible soil. The foundations can be designed per the Post-Tensioning Institute (PTI) method to be a ribbed or uniform thickness foundation.

Ribbed FoundationsA typical ribbed foundation will have

a 5-inch thick slab, with interior and exterior footings that extend from one end of the foundation to the other (Figure 1). The layout of the footings (ribs) will give it an exaggerated waffle slab appearance if it could be viewed from the soils perspective. Due to their depth, the footings will provide the vast majority of the foundations section modulus and moment of inertia, which are the key parameters in limiting the flexural stresses and deflections. Although it may be economically advantageous to have a few very deep footings to generate the same elastic section properties, the performance of the foundation may suffer with large gaps between ribs. The PTI method limits the maximum spacing of footings to be 15 feet, and requires the spacing of adjacent footings to be 20% of each other. The spacing limitations are intended to have the footings close enough such that the foundation can respond as having a consistent stiffness across its cross section, rather than having localized areas of large stiffness that are connected by a relatively thin slab. In typical structures, the footings are around 10 to 12 feet on center in each direction. A tighter rib spacing will also minimize footing depth and width. In the author’s opinion, the footings should be located under the lateral system and the load bearing elements (walls, post or columns). In addition to providing vertical and lateral support for the structure, the footings location will be linked to the architectural plans which will minimize dimensional discrepancies in the between the structural and architectural drawings.

The footing width and depth will depend on the specific site conditions and the load of the structure, but they are typically around 18 to 24 inches deep (including the slab thickness) and 12 inches wide. Footings that are wider than 14 inches can be constructed, but the width is limited to 14 inches for the numerical design.Footings of different depths can be

used, but the ratio of largest to smallest must be kept within 1.2. This is most typically seen where deeper footings are used on the perimeter due to larger post loads/hold downs forces, or specific embed-ment requirements of the soils report. Although the foundation will benefit from deeper footings, the code limits the numerical design to the 1.2 ratio. Using very deep exterior footings to generate section proprieties that satisfy stress lim-its, such that interior footings are not required or are very shallow, is not the intent of the methodology.Instead of adding ribs for bearing wall

loads, the PTI method contains a pro-cedure for the slab to act as a footing. A typical post-tensioned 5-inch slab with a compressive strength of 3000 psi and a precompression force of 50 pounds per square inch (code minimum) can support a 1,900 pound per linear foot bearing wall. This capacity can be increased with thicker slabs, higher strength concrete or a larger precompression force from the strands. In most residential construction, footings are

not required to support the bearing wall loads. The potential to have the slab act as a footing is also useful in home remodels or tenant improvements, since the require-ment for new footings can be minimized. The same philosophy can be used for the slab to resist post loads. For most code compliant designs, a post-tensioned slab can comfortably resist 1,000 pounds of load for each inch of thickness.For typical single family home con-

struction, the tendons in a ribbed system are approximately 3 to 4 feet on center in each direction. This spacing allows easier installation and inspection while minimizing the potential of field person-nel damaging the strands or pushing them off their supports. In addition, the relatively large spacing typically provides sufficient room for plumbing and other penetrations without modification to the tendons. The spacing of the tendon is not required to be placed at a specific spacing. Variations in the tendon locations, to avoid penetrations, re-entrant corners or hold downs, are permitted provided the spacing between adjacent strands is less than 6 feet. If a spacing of 6 feet is required, additional rebar may be required for crack control and continuity of the foundation.The number of strands is primarily af-

fected by the desired precompression force and the sub grade friction resistance. For the same site conditions and con-struction, a larger footprint foundation

Figure 1: Ribbed Post-Tensioned Foundation.

will have more tendons since the sub grade friction force increases with size. The code minimum precompression of 50 psi is calcu-lated at the middle of the foundation, where the affect of sub grade friction is the largest. For larger foundations, there will most likely be a substantial difference between the pre-compression force at the edge of the foundation compared to the middle.The tendons in the majority of post-

tensioned foundations are located in the center of the slab and run flat from anchor to anchor. Care should be taken by the contractor and deputy inspector to eliminate localized kinks (vertical and horizontal) in the strands when they extend over footings or where they are curved to avoid penetrations. The strands are intended primarily to provide a precom-pression force throughout the foundation to reduce flexural tension stresses. They are not designed as tension reinforcement that con-forms to the moment diagram as they would in elevated slab and beam design. The design of these foundations is based solely on allowable stresses, so placing the tendons at different locations of the slab will not provide in any benefit in the design. Balance loads created by vertically draping the tendons aren’t re-quired since the structure is supported by the soil. In addition, since the expansive soil movement can occur in both vertical directions,

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April 2010 STRUCTURE magazine April 2010

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not required to support the bearing wall loads. The potential to have the slab act as a footing is also useful in home remodels or tenant improvements, since the require-ment for new footings can be minimized. The same philosophy can be used for the slab to resist post loads. For most code compliant designs, a post-tensioned slab can comfortably resist 1,000 pounds of load for each inch of thickness.For typical single family home con-

struction, the tendons in a ribbed system are approximately 3 to 4 feet on center in each direction. This spacing allows easier installation and inspection while minimizing the potential of field person-nel damaging the strands or pushing them off their supports. In addition, the relatively large spacing typically provides sufficient room for plumbing and other penetrations without modification to the tendons. The spacing of the tendon is not required to be placed at a specific spacing. Variations in the tendon locations, to avoid penetrations, re-entrant corners or hold downs, are permitted provided the spacing between adjacent strands is less than 6 feet. If a spacing of 6 feet is required, additional rebar may be required for crack control and continuity of the foundation.The number of strands is primarily af-

fected by the desired precompression force and the sub grade friction resistance. For the same site conditions and con-struction, a larger footprint foundation

Figure 1: Ribbed Post-Tensioned Foundation.

Figure 2: Uniform Thickness Post-Tensioned Foundation.

will have more tendons since the sub grade friction force increases with size. The code minimum precompression of 50 psi is calcu-lated at the middle of the foundation, where the affect of sub grade friction is the largest. For larger foundations, there will most likely be a substantial difference between the pre-compression force at the edge of the foundation compared to the middle.The tendons in the majority of post-

tensioned foundations are located in the center of the slab and run flat from anchor to anchor. Care should be taken by the contractor and deputy inspector to eliminate localized kinks (vertical and horizontal) in the strands when they extend over footings or where they are curved to avoid penetrations. The strands are intended primarily to provide a precom-pression force throughout the foundation to reduce flexural tension stresses. They are not designed as tension reinforcement that con-forms to the moment diagram as they would in elevated slab and beam design. The design of these foundations is based solely on allowable stresses, so placing the tendons at different locations of the slab will not provide in any benefit in the design. Balance loads created by vertically draping the tendons aren’t re-quired since the structure is supported by the soil. In addition, since the expansive soil movement can occur in both vertical directions,

load balancing may help in one condition while hurt the system in the other. Even though load balancing is the primary benefit of post-tensioning in elevated slab and beam design, it should play no part in the design of these ground supported foundations. In some extreme edge lift cases, specific tendons are anchored at the mid-depth of the slab and immediately draped to the bottom of the

footing, where they extend across the foundation until they are draped back up at the other end of the foundation. This profile will create a “downturned” force that is intended to coun-teract the force of the soil moving “upwards”. This type of design is primarily done in Texas where they have very large edge lift condi-tions. Even with expansive soils, everything is larger in Texas.

continued on next page



Uniform ThicknessThe uniform thickness option is designed

by converting the section properties of the code compliant design ribbed foundation to a single thickness slab. The conversion is intended for the slab only, and does account for the presence of exterior footings. Using the section properties of the exterior footing to minimize the uniform slab thickness is not the intent of the PTI method or the building code. Without interior footings, the slab alone will be required to provide the stiffness and strength to resist expansive and compressible soil movement. Perimeter footings are often requirements of the soils report or to resist large post or hold down loads, but since their stiffness cannot effectively be distributed over the entire foundation, their influence is to be ignored in the conversion.Typical uniform thickness slabs are in the 8

to 12 inch range (Figure 2, page 9) and have been used to support up to 5 stories of wood frame construction. They typically have more concrete when compared to a ribbed foundation, so more tendons are required to provide the required precompression. Without interior footings, deepened sections of concrete may be required to resist large post loads or shear wall hold downs. Depending on slab thick-ness, localized footings are often used under the lateral system to satisfy the allowable soil pressure due to overturning.Regardless of the slab thickness, the tendons

are still located and anchored in the middle of slab. This layout can create slabs with 5 to 6 inches of cover from the strands to the top of the concrete. Although this would not be permitted in elevated slabs, there is no additional top rebar required in these types of foundations. Some engineers will place a grid of rebar or mesh in the top of the slab, but this is not a requirement of the PTI method and may be done simply for crack control. In the larger foundation plates, tendons can have a required spacing of 12 to 24 inches on center. To maximize the distance between strands, the tendons can be grouped into bundles of twos or threes. The bundled strands are placed side by side, are typically tied together, and use

the same chairs or dobies for support. They are separated near the slab edge or stressing location to allow for the installation of the individual anchors. In addition, this practice will minimize having a series of tendons that are varying lengths if the slab edge has an angled or saw tooth configuration.

Cost a FactorFor engineers and contractors that are new to

post-tensioned foundations, a common question is what type of foundation is best suited for my project? As in most situations in construc-tion, the contractor’s price is typically the deciding factor. With the ribbed system, more trenching is required, and this has been a cost and time issue for some contractors. In addi-tion, the ribs require maintenance during the placement of the reinforcing and the vapor retarded. Portions of the soil may drop into the trench during construction, affecting the foot-ing depth and covering the rebar with dirt. The uniform thickness foundations will have less trenching but more material costs in concrete and tendons. If you are dealing with methane issues, the uniform thickness slab option is typically preferred since it’s more economical to install the barrier relatively flat rather than extending it through a series of overlapping footings. In the author’s experience, most single family homes are constructed with a ribbed foundation, while multi-level apartment/condominium projects are designed with a uniform thickness system.

CorrosionFor post-tensioned slabs on grade, the soils

report should include information regard-ing the corrosiveness or the chloride content of the site. For corrosive sites, encapsulated tendons (Figure 3) are used to further protect the strand, anchor and wedges from deteriora-tion. The strand, anchor and wedges are the same between the standard and encapsulated system; only the sheathing and the anchor covering is changed. The anchor assembly is encased in a watertight connection between the strand, sheathing, anchor and wedges.

Standard encapsulated systems are hydrostati-cally tested to verify water tightness. For this reason, tears in the sheathing, regardless of length need, to be repaired and anchors that arrive on site in a damaged condition need immediate attention. Sealing the encapsulated system after the tendons have been exposed to an aggressive environment will only lock the corrosive elements into the system, increasing the likelihood of damage. Unlike the sulfate table in ACI 318, there is no corresponding corrosive chart that identifies when encapsulated tendons should be used. Per the PTI recom-mendations, if the soils report lists moderate or above chloride content or if the report lists the site as corrosive to ferrous metals (or other similar language), encapsulated tendons should be specified on the structural drawings.

ShrinkageTo minimize shrinkage cracks, it is critical

that the tendons are stressed as soon as pos-sible. The PTI design manual recommends the tendons be stressed within 10 days of placing the concrete. The precompression from the strands is the primary crack control reinforcement in the foundation. The sooner the strands are stressed, the sooner the slab can resist the tensile stresses generated from the shrinkage of the concrete. These foundations will typically have very little rebar, so until the tendons are stressed, the concrete is essentially un-reinforced and prone to cracking. To further resist shrinkage cracking, some engineers will saw cut the slab within the first 24 hours after placing the concrete (Figure 4). The depth and spacing of the saw cuts will vary depending on the slab thickness so the tendons will not be damaged during construction. In addi-tion, the saw cuts need to be specified such that the continuity of the slab is not signifi-cantly impacted.▪

Figure 4: Saw Cuts on a Uniform Thickness Foundation.

Figure 3: Encapsulated Tendon with a Pocket Former.

Bryan Allred is a license structural engineer and Vice President of Seneca Structural Engineering Inc. in Laguna Hills CA. He can be reached via email at [email protected].


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Heavily Loaded Strap FootingsDesign, Detailing and BehaviorBy Truly Guzman, P.E. M.Sc

In dense urban environments where ev-ery inch of construction is precious and needs to be maximized, it is usual for footings or pile caps supporting exterior columns to be moved inside property lines. This in turn creates an eccentric load on these elements. In the city of New York, especially in the borough of Manhattan, where high capacity bed-rock can be found at reasonably shallow depths, it is common to support tall buildings on isolated footings bearing on rock. Strap footings are usually the most efficient mechanism to remove ec-centricity from exterior footings and to accomplish a more uniform distribution of bearing pressure. A strap footing consists of two spread

footings linked together by a strap beam. Its design is based on the assumption that this beam is not in contact with the bear-ing stratum such that no soil pressure is exerted on the beam itself. The means used to provide this pressure-relieving mechanism varies; some engineers indicate polystyrene between the beam and the bearing soil, others prefer simply to show a gap, and still others prescribe a tapered beam. Most of the time, verifying that this requirement has been satisfied dur-ing construction is not considered crucial. Moreover, in many cases the responsibility for inspecting and controlling this detail is not clear or can easily be neglected. The question arises: How important is it to relieve this pressure from the strap beam in order for it to behave as designed? In other words, can this pressure be neglected for all practical purposes?

Case StudyAn example is shown in Figure 1, where

a strap footing was designed to support a 27-story building bearing on rock with a bearing capacity of 25 tons per square foot.By performing a simple conventional

rigid static analysis and assuming that the strap beam is not in contact with the rock, the resulting design moment and shear for the beam are 4,600 kips-feet and 235 kips respectively. A 6-foot-deep, 4-foot-wide beam is chosen as the design section. In most cases, the depth of the strap beam is controlled either by the depth of footing required to avoid

punching shear failure or by the maxi-mum amount of flexural reinforcement allowed. Typically, minimum or no shear reinforcement is required.If the beam is constructed by placing

concrete directly against the rock, it is apparent that the pressure imposed on the beam will be a direct function of the width of the beam. In theory, if the beam is of infinitesimally small width but has a comparable bending stiffness to the original beam, the results should be similar. In order to determine the stage

at which the resulting moments and shears become similar, with and without bearing pressure exerted on the beam, the author carried out a series of numerical analy-ses. The model had compression-only spring elements with a subgrade reaction modulus of 800 pounds per cubic inch to represent the rock under the footings, and two-thirds of this value for the rock under the grade beam in order to account for shape effects. Since no tension was allowed on the

springs, the strap beam was able to “relax”

Figure 1: Moment and Shear Diagrams on a Strap Footing.

continued on page 14

C-PracSol-Guzman-April10.indd 1 3/22/2010 9:04:23 AM

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STRUCTURE magazine April 2010 STRUCTURE magazine

in the areas with less pressure and even lose contact with the rock where required – a more realistic condition than the simple rigid anal-ysis could simulate. The width of the beam varied from the original 48 inches down to 6 inches with 5 intermediate widths, while keeping the moment of inertia constant. In addition, a numerical analysis assum-ing no pressure on the beam with the same variations in width served as a basis for comparison with the original analytical results.The increments on moment and shear at the critical section as a

function of beam width are plotted in Figures 2a, 2b and 2c.It is clear from the results that when no pressure is allowed, the

moments and shears stay constant as the width changes. On the other hand, when pressure is allowed, the moments and shears increase con-siderably with width. For the original 48-inch-wide beam, an increase of about 73% in moment and about 400% in shear can be observed. As expected, when the width of the beam is the smallest, the difference between the no-pressure and with-pressure analyses is small, as well. Nevertheless, even for the 6-inch-wide beam, the difference in shear is still considerable at about 65% while the difference in moment goes down to about 3% .The variation exhibited in soil pressure is also expected – when the

area in contact with the soil is considerable, the total load is distributed over a broader area creating less overall soil pressure.A small parametric study illustrates how the relationship between total

area of footing and total area of strap beam affects the increase in forces on the beam. The variation shown in Figure 3 can be interpreted as mostly linear.

ConclusionResults indicate that when a strap footing is used as part of a founda-

tion system, a detail that allows for pressure to be relieved from the strap footing is necessary on construction documents. Without it, a considerable un-foreseen load path could be created that may result in the failure of the strap beam followed by overstress of the soil/rock under the eccentric footing. It is also important to emphasize the need for fi eld enforcement and control of these requirements.The author recommends the two options

shown in Figure 4 in order to avoid fi eld mistakes. It is also good to emphasize that if Option 1 is chosen, a low-density, low-modulus polystyrene must be specified. The thickness should be slightly greater than the maximum expected settlement of the footings. Furthermore, if the contractor prefers to perform a non-monolithic pour, construction joint keys must be oriented as indicated. Option 2 has the advantage of saving concrete, with the drawback of more labor-intensive formwork. Of course, there is always the alternative of explicitly accounting for the pressure on the beam at the design stage, rather than neglecting it. However, it is obvious from the results of this study that this can be an ineffi cient and uneconomical solution.▪

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Figure 2a: Variation in Moments (kips-ft).Figure 2b: Variation in Shear (kips).

Figure 2c: Variation in Soil Pressure (kips per square foot).

Figure 3: Area of Footings vs. Area of Strap Beam.

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in the areas with less pressure and even lose contact with the rock where required – a more realistic condition than the simple rigid anal-ysis could simulate. The width of the beam varied from the original 48 inches down to 6 inches, with 5 intermediate widths, while keeping the moment of inertia constant. In addition, a numerical analysis assum-ing no pressure on the beam, with the same variations in width, served as a basis for comparison with the original analytical results.The increments on moment and shear at the critical section as a

function of beam width are plotted in Figures 2a, 2b and 2c.It is clear from the results that when no pressure is allowed, the

moments and shears stay constant as the width changes. On the other hand, when pressure is allowed, the moments and shears increase con-siderably with width. For the original 48-inch-wide beam, an increase of about 73% in moment and about 400% in shear can be observed. As expected, when the width of the beam is the smallest, the difference between the no-pressure and with-pressure analyses is small, as well. Nevertheless, even for the 6-inch-wide beam, the difference in shear is still considerable at about 65%, while the difference in moment goes down to about 3% .The variation exhibited in soil pressure is also expected – when the

area in contact with the soil is considerable, the total load is distributed over a broader area, creating less overall soil pressure.A small parametric study illustrates how the relationship between total

area of footing and total area of strap beam affects the increase in forces on the beam. The variation shown in Figure 3 can be interpreted as mostly linear.

ConclusionResults indicate that when a strap footing is used as part of a founda-

tion system, a detail that allows for pressure to be relieved from the strap footing is necessary on construction documents. Without it, a considerable un-foreseen load path could be created that may result in the failure of the strap beam, followed by overstress of the soil/rock under the eccentric footing. It is also important to emphasize the need for field enforcement and control of these requirements.The author recommends the two options

shown in Figure 4 in order to avoid field mistakes. It is also good to emphasize that if Option 1 is chosen, a low-density, low-modulus polystyrene must be specified. The thickness should be slightly greater than the maximum expected settlement of the footings. Furthermore, if the contractor prefers to perform a non-monolithic pour, construction joint keys must be oriented as indicated. Option 2 has the advantage of saving concrete, with the drawback of more labor-intensive formwork. Of course, there is always the alternative of explicitly accounting for the pressure on the beam at the design stage, rather than neglecting it. However, it is obvious from the results of this study that this can be an inefficient and uneconomical solution.▪

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Figure 2b: Variation in Shear (kips).

Figure 3: Area of Footings vs. Area of Strap Beam.

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Truly Guzman, P.E., M.Sc, is a Project Engineer with GACE consulting engineers pc in New York City, and member of the in-house quality control committee. Previously he was a teacher/research assistant at the City College of New York (CCNY). Truly can be reached at [email protected].

C-PracSol-Guzman-April10.indd 3 3/19/2010 12:51:21 PM

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Educational ArtA Sculpture That Teaches!By Duane Ellifritt, Ph.D., P.E.

There are probably 40 or 50 ways to join two pieces of steel together. Some are more economical than others and, while stu-dents are not expected to graduate with the knowledge possessed by fabricators and engineers with years of experience, they should have a rudimentary knowledge of the most common kinds of connec-tions. Thus, my job each semester was to try to teach them how to design a few simple connections. Unfortunately, the exercise often ended in frustration.Beginning steel design is basically two-

dimensional; members are reduced to lines that intersect other members at points, or nodes. Even in 3-dimensional analysis, members are still lines meeting at points. After determining the forces in all those lines, actual members can be selected that can efficiently resist those forces. Students rarely have a problem with this; well, the good ones, anyway.But it is those points – connecting one

member to another – that give most stu-dents trouble. Connections are graphically 3-dimensional in nature, even in a two-dimensional analysis. Given two orthogo-nal views with all the bolts and welds, one should be able visualize them – or so I always thought.How could I help students see a 3-D

connection when looking at 2-D diagrams on a page? Field trips are always helpful, if you happen to be lucky enough to have a steel-framed building going up nearby, in a stage where the steel is still exposed. In a small town like Gainesville, that is not always the case. And even if you can find an appropriate structure, you have to transport the students there, coordinate with the contractor, have the students sign “no liability” forms, get hard hats and safety glasses and arrange the time for a tour. Add to this the owner’s reluctance to allow students to climb over a structure that presents all kinds of physical hazards and potential liability and it becomes a real chore to organize and carry out a field trip.My next idea was to build models of

various connections and bring them into the classroom. I didn’t get very far with this because, at full scale and with real steel, they would be too heavy to carry around. Okay, we can mount them on wheels, I thought,

and roll them into class at the right time. But where to keep them when they were not in use? The logistics of this scheme were not realistic.In the spring of 1985, I had an epiphany:

I would create a sculpture for the campus that would do double duty as a work of art and serve as a teaching tool. It would feature all kinds of steel members and the most common kinds of connections. That would solve all the problems inherent in my other solutions. It would be right outside the Civil Engineering building (no transportation involved) and students could examine it at their own conve-nience. Since it would be rooted to one site, there would be no storage problem. It was a perfect solution! But how could I sell such an idea to the University ad-ministration? The Chairman of Civil Engineering and the Dean of the Engi-neering College both gave it their blessing, but I also had to convince the University Facilities Planning Committee.I spent several months designing what I

believed to be an optimum arrangement of pieces and connections, all radiating outward from a central free-standing column. I then made four elevation views of the structure, and a color isometric rendering that would mean something to a Committee of non-engineering types. I included a light sketch of the Civil Engineering building in the background, showing my idea of where the sculpture could be located in a prominent spot.

After I made my presentation to the Committee, there were a lot of questions, some about whether this could be con-sidered “art” or not, but mostly about safety and the University’s liability. After much discussion, the Assembly agreed to allow me to erect the sculpture, but in an alternate location on the south side of Weil Hall behind an electrical substa-tion, virtually hidden from public view. I wasn’t happy, but at least I had approval to build it.I had developed, over my years in

industry, some contacts with steel fabricators, so I approached one of them, Steel Fabricators, Inc. in Ft. Lauderdale, about making my sculp-ture. They agreed, but needed some fabrication drawings which I did not have. I had only my conceptual drawings of how I had envisioned the finished product would look. In order to fabricate, a separate drawing is required for each piece, showing where holes are to be punched, tabs to be welded, angles to be attached, etc. Fortunately, an engineering firm who was on our Board of Visitors, Kun-Young Chui and Associates from Valdosta, Georgia agreed to make the shop drawings for me.The next hurdle was the founda-

tion. Building a foundation meant digging a hole, but one just doesn’t go out and start digging on a Uni-versity campus! I had to apply for a “dig permit” from the Building and Grounds department and have the underground utilities located. Then I could set some stakes and

The original steel teaching sculpture, erected at the University of Florida in 1986. Courtesy of Jeff Post.

Dr. Ellifritt pointing out the various connections on his sculpture to students. Courtesy of Ron Franklin of Engineering Publications.

get students to help with the digging, placing reinforcing, and pouring concrete.The fabrication of the sculpture was

completed in October. Steel Fab loaded it onto a flat-bed trailer and transported it to the campus, where they engaged a mobile crane to lift the piece from their trailer and set it on the anchor bolts. I had set the bolts myself, so

University of Western Ontario. Courtesy of Duane Ellifritt.

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17

After I made my presentation to the Committee, there were a lot of questions, some about whether this could be con-sidered “art” or not, but mostly about safety and the University’s liability. After much discussion, the Assembly agreed to allow me to erect the sculpture, but in an alternate location on the south side of Weil Hall behind an electrical substa-tion, virtually hidden from public view. I wasn’t happy, but at least I had approval to build it.I had developed, over my years in

industry, some contacts with steel fabricators, so I approached one of them, Steel Fabricators, Inc. in Ft. Lauderdale, about making my sculp-ture. They agreed, but needed some fabrication drawings which I did not have. I had only my conceptual drawings of how I had envisioned the finished product would look. In order to fabricate, a separate drawing is required for each piece, showing where holes are to be punched, tabs to be welded, angles to be attached, etc. Fortunately, an engineering firm who was on our Board of Visitors, Kun-Young Chui and Associates from Valdosta, Georgia agreed to make the shop drawings for me.The next hurdle was the founda-

tion. Building a foundation meant digging a hole, but one just doesn’t go out and start digging on a Uni-versity campus! I had to apply for a “dig permit” from the Building and Grounds department and have the underground utilities located. Then I could set some stakes and

The original steel teaching sculpture, erected at the University of Florida in 1986. Courtesy of Jeff Post.

get students to help with the digging, placing reinforcing, and pouring concrete.The fabrication of the sculpture was

completed in October. Steel Fab loaded it onto a flat-bed trailer and transported it to the campus, where they engaged a mobile crane to lift the piece from their trailer and set it on the anchor bolts. I had set the bolts myself, so

was a little tense during this operation, but the base plate slipped over the bolts quite easily.Shortly after the installation, I gave a brief

discussion of my creation at a national steel meeting and several professors approached me and asked if I was willing to share the plans with them. I was frankly flattered to be asked and made them available to anyone who wanted them. A few universities, like the U. of Toronto and the U. of Houston built a copy and sent me pictures.A few years later, the American Institute of

Steel Construction heard of this and thought it was a great teaching tool and would be a good device for establishing relations between engineering schools and steel fabricators. I was approached by Fromy Rosenberg, AISC’s Director of Education, about their taking over the plans and promoting it as a teaching tool. I gave permission to use my idea and AISC took the plans, scaled the structure down to around eight feet high (my sculpture was 14 feet high), changed some of the connections, and began a vigorous campaign to get more of them built on college campuses.This effort has been hugely successful, and as

of this date (early 2010) there are 135 of these sculptures on campuses within the United States, with an additional 18 in Canada, 5 in Mexico and one in India.▪

Duane Ellifritt is Professor Emeritus of Civil Engineering at the University of Florida. He is an accomplished artist in his own right and some of his work can be viewed at www.ellifritt.com. He may be contacted at [email protected].

University of Western Ontario. Courtesy of Duane Ellifritt.

Virginia Tech. Courtesy of Dr. Thomas M. Murray.

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Shrinkage-Compensating Concrete in Post-Tensioned Buildings A Four-Building Survey – Part One By Kenneth B. Bondy, S.E., FACI

Restraint to shortening (RTS) is a major concern for designers of post-tensioned concrete buildings. It can cause unsightly cracking in

floor systems and restraining elements (columns and walls). Although the total volume change in post-tensioned concrete buildings is not very different than it is in non-prestressed buildings (shrinkage is the biggest contributor in both), post-tensioned buildings shorten differently than non-prestressed buildings and present unique RTS problems.In non-prestressed buildings, the total concrete volume change con-

sists of the sum of many closely spaced cracks that develop between the ends of the floor system, each with relatively small width. The ends stay roughly in the same position in which they were originally placed. Restraint forces are minimal because the many distributed cracks relieve stress in the floor system and the connected columns and walls.In a post-tensioned building, however, the prestressing force fully

or partially closes cracks which develop in the floor system, and the ends tend to move inwards. This movement is resisted by restraining members, and can generate large forces that produce severe cracking in the floor system and in the walls and columns. Typical solutions to mitigate RTS cracking have included joinery details (expansion joints, pour strips and slip joints) and added non-prestressed reinforcement to distribute cracking. These measures, while effective, are expensive, cumbersome, and can impact resource usage and construction time.There is another proven method for solving RTS problems that has

been used for over 40 years, yet it is not well known and deserves wider recognition. Shrinkage-compensating concrete has been successfully used to construct large, jointless elevated slabs in post-tensioned

concrete structures since the 1960s. Made with ASTM C845 Type K cement, the concrete expands slightly during the first seven days of curing, after which it undergoes a normal amount of drying shrinkage, for net volume change closely approaching zero.For the short period of time after placement when shrinkage-

compensating concrete expands, growth of the floor system is restrained by connected members. Restraint forces are minimal because the stiffness of the restraining members is not fully developed. After expansion, normal drying shrinkage begins and restraint forces decrease with time, approaching zero as the magnitude of the shrinkage approaches the initial expansion. Long-term volume change is greatly reduced, permitting the elimination of, or greatly increased spacing between, expansion joints and pour strips.This article, in two parts, presents case studies of four projects on

which shrinkage-compensating concrete was used. Two of these projects were built more than 40 years ago; one has been in service for 12 years, and one is new, completed just 19 months before this writing. On two of the projects (the newest and one of the oldest) measurements of volume change versus time were made. In this first part, the two oldest buildings are described. The other two buildings surveyed will be presented in a second article to be published in a future issue of STRUCTURE®. These four projects demonstrate the effective use of shrinkage-compensating concrete to mitigate RTS cracking in post-tensioned concrete buildings.

Santa Monica Parking Structure #2In the late 1960s, the city of Santa Monica, CA, built six municipal

parking structures. All were designed by the structural engineering firm T.Y. Lin and Associates, Van Nuys, CA, where I was employed and did some structural work (seismic load analysis) on several of them, including Structure #2 discussed here.Each building was designed for eight elevated levels; four to be built

initially, with the capacity for an additional four levels to be added as the need for parking increased. Floors were framed with monolithic cast-in-place post-tensioned lightweight concrete using one-way slabs spanning to clearspan beams (Figure 1). Plan dimensions are approximately 150 feet (three beam spans) by 200 feet (9 slab spans.) One slab construction

joint was used, running in the short direction at roughly the third point of the long direction (some of the upper floors used two construction joints). There were no pour strips.Of particular note is Structure #2, located at 1235 2nd Street. The

original four levels (370 cars capacity) were built in 1968, with Type K shrinkage-compensating concrete in the floor systems. Around 1980, an additional four levels were added using conventional portland cement concrete. A series of pins were set into the original deck so that measurements of strain in the slab concrete could be made. These measurements were made at the following points in time:

• Prior to post-tensioning (first seven days after placing concrete)• During and immediately after slab post-tensioning (seventh and

eighth day after placing concrete)• At intervals for the subsequent five years

The total shortening strain measured five years after concrete place-ment was 0.00034 in./in. In the same study, total shortening strain in a similarly framed industrial building in Pasadena, CA, built using lightweight concrete with Type II portland cement, was measured at 0.00112 in./in., more than three times higher.I inspected the entire floor area of Structure #2 in November, 2009,

41 years after completion of the lower four floors. I carefully observed the areas most susceptible to cracking: the four corners, two with stair/elevator shafts and two without, the ends of the central longitudinal concrete shearwalls, and the areas around the girder framing at each turn-around aisle.I measured a total of 80 lineal feet of cracks in the lower four floors

built with shrinkage-compensating concrete. All of this cracking was on the first elevated slab in the northeast and southwest corners of the building, near the two elevator/stair shafts. The orientation of cracking was consistent with RTS, aggravated not only by the shafts, but by the proximity of a length of basement wall in each location. The largest crack width I measured was 3/32 inch and the longest crack length was about 18 feet. The cracks were visible at the top and bottom of the slab (when both were accessible), and I saw no evidence of efflorescence at the bottom of any crack, suggesting there was no significant moisture penetration. The southeast and northwest corners of the first elevated slab, lacking shafts and basement wall conditions, were crack free.I saw no cracking in any structural member (slab, beam, girder,

concrete shearwall, masonry shearwall or column) anywhere else in the lower four floors. I observed some minor spalling between the edge of the slab and the masonry wall at the northeast stairshaft at a few levels. Most experienced observers would rate the condition of these lower floors as excellent, with less than 100 lineal feet of cracking in about 120,000 square feet of elevated deck. This is particularly impressive considering the structure has been extensively loaded and unloaded with automobiles on a daily basis for over 40 years. It has also experienced two major earthquakes of Richter 6.0 or larger (San Fernando in 1971 and Northridge in 1994).

Buildings M5 and R6 (plan view). These two buildings required elevated concrete decks with no control joints or pour strips. Shrinkage-compensating concrete was successfully used to cast all floor members. The buildings continue to perform well more than 40 years later. Courtesy of CTS Cement Mfg.

South Elevation Building R6 – Looking Down 439-foot Length at Plaza Level. Courtesy of Phillip Yee of Northrop-Grumman.

Figure 1: Beam and Slab Framing (4th Level).

F-Bondy-April10.indd 1 3/19/2010 9:48:20 AM


concrete structures since the 1960s. Made with ASTM C845 Type K cement, the concrete expands slightly during the first seven days of curing, after which it undergoes a normal amount of drying shrinkage, for net volume change closely approaching zero.For the short period of time after placement when shrinkage-

compensating concrete expands, growth of the floor system is restrained by connected members. Restraint forces are minimal because the stiffness of the restraining members is not fully developed. After expansion, normal drying shrinkage begins and restraint forces decrease with time, approaching zero as the magnitude of the shrinkage approaches the initial expansion. Long-term volume change is greatly reduced, permitting the elimination of, or greatly increased spacing between, expansion joints and pour strips.This article, in two parts, presents case studies of four projects on

which shrinkage-compensating concrete was used. Two of these projects were built more than 40 years ago; one has been in service for 12 years, and one is new, completed just 19 months before this writing. On two of the projects (the newest and one of the oldest) measurements of volume change versus time were made. In this first part, the two oldest buildings are described. The other two buildings surveyed will be presented in a second article to be published in a future issue of STRUCTURE®. These four projects demonstrate the effective use of shrinkage-compensating concrete to mitigate RTS cracking in post-tensioned concrete buildings.

Santa Monica Parking Structure #2In the late 1960s, the city of Santa Monica, CA, built six municipal

parking structures. All were designed by the structural engineering firm T.Y. Lin and Associates, Van Nuys, CA, where I was employed and did some structural work (seismic load analysis) on several of them, including Structure #2 discussed here.Each building was designed for eight elevated levels; four to be built

initially, with the capacity for an additional four levels to be added as the need for parking increased. Floors were framed with monolithic cast-in-place post-tensioned lightweight concrete using one-way slabs spanning to clearspan beams (Figure 1). Plan dimensions are approximately 150 feet (three beam spans) by 200 feet (9 slab spans.) One slab construction

joint was used, running in the short direction at roughly the third point of the long direction (some of the upper floors used two construction joints). There were no pour strips.Of particular note is Structure #2, located at 1235 2nd Street. The

original four levels (370 cars capacity) were built in 1968, with Type K shrinkage-compensating concrete in the floor systems. Around 1980, an additional four levels were added using conventional portland cement concrete. A series of pins were set into the original deck so that measurements of strain in the slab concrete could be made. These measurements were made at the following points in time:

• Prior to post-tensioning (first seven days after placing concrete)• During and immediately after slab post-tensioning (seventh and

eighth day after placing concrete)• At intervals for the subsequent five years

The total shortening strain measured five years after concrete place-ment was 0.00034 in./in. In the same study, total shortening strain in a similarly framed industrial building in Pasadena, CA, built using lightweight concrete with Type II portland cement, was measured at 0.00112 in./in., more than three times higher.I inspected the entire floor area of Structure #2 in November, 2009,

41 years after completion of the lower four floors. I carefully observed the areas most susceptible to cracking: the four corners, two with stair/elevator shafts and two without, the ends of the central longitudinal concrete shearwalls, and the areas around the girder framing at each turn-around aisle.I measured a total of 80 lineal feet of cracks in the lower four floors

built with shrinkage-compensating concrete. All of this cracking was on the first elevated slab in the northeast and southwest corners of the building, near the two elevator/stair shafts. The orientation of cracking was consistent with RTS, aggravated not only by the shafts, but by the proximity of a length of basement wall in each location. The largest crack width I measured was 3/32 inch and the longest crack length was about 18 feet. The cracks were visible at the top and bottom of the slab (when both were accessible), and I saw no evidence of efflorescence at the bottom of any crack, suggesting there was no significant moisture penetration. The southeast and northwest corners of the first elevated slab, lacking shafts and basement wall conditions, were crack free.I saw no cracking in any structural member (slab, beam, girder,

concrete shearwall, masonry shearwall or column) anywhere else in the lower four floors. I observed some minor spalling between the edge of the slab and the masonry wall at the northeast stairshaft at a few levels. Most experienced observers would rate the condition of these lower floors as excellent, with less than 100 lineal feet of cracking in about 120,000 square feet of elevated deck. This is particularly impressive considering the structure has been extensively loaded and unloaded with automobiles on a daily basis for over 40 years. It has also experienced two major earthquakes of Richter 6.0 or larger (San Fernando in 1971 and Northridge in 1994).

The upper four floors, added at a later date without the use of shrinkage-compensating concrete, contain some widely distributed random cracks, most of them visible on the top level. Of particular interest is a very noticeable crack running in the north-south direction on the top (9th) level at the north end of the building, in the exterior slab span along the grid line separating the west and center aisles. This crack is about 15 feet long, visible at the top and bottom of the slab, measuring 1/16 inch wide at the top and hairline at the bottom. A similar crack is visible in the asymmetrical location near the southeast corner, but smaller with a measured width of 1/32 inch at the top of the slab. I did not observe this crack at the same location on any other floor. The crack at the top level may have been aggravated by temperature effects since it is fully exposed to the environment, but the presence of this crack on a floor built with conventional concrete, and its absence on lower floors built with shrinkage-compensating concrete with more severe RTS conditions, suggests that shrinkage-compensating concrete made the difference.The plan dimensions and restraint conditions of this building are

modest. The slab-to-wall joinery details were typical for the time and were the same as those normally used in buildings with conventional concrete. Nonetheless, the unusually good condition of the lower four floors of this building can be, in my opinion, attributed to the use of shrinkage-compensating concrete.

TRW Buildings M5 and R6, Redondo Beach, California

In 1968, the TRW Corporation (now Northrop-Grumman) added two new buildings to its complex in Redondo Beach, CA. One was for manufacturing (called M5), the other for research (R6). Atlas Prestressing Corp. in Southern California, my employer at the time, provided consulting services for the design of the post-tensioned floor system to the Architect/Engineer, Albert C. Martin & Associates (now A.C. Martin Partners), and furnished and installed the post-tensioning tendons and non-prestressed reinforcing steel in both buildings for the general contractor, Swinerton & Walberg. I was personally involved in both the design and construction of these buildings.Each building has three stories, a large first floor plaza level, a second

floor, and a roof. The second floors and roofs of the buildings are identical in plan dimension, each 199 feet x 363 feet. The first floors of each building are adjacent, separated by an expansion joint, and orthogonal dimensions are very large: for M5, 422 feet x 243 feet; for R6, 439 x 407 feet. All construction was cast-in-place post-tensioned concrete with unbonded tendons. Column spacing was large, with typical bay sizes of 40 feet x 64 feet. Floor system framing was a one-way slab (shallow

South Elevation Building R6 – Looking Down 439-foot Length at Plaza Level. Courtesy of Phillip Yee of Northrop-Grumman.

Santa Monica Parking Structure #2.

Figure 1: Beam and Slab Framing (4th Level).



pan joists in R6 for extra stiffness) spanning be-tween beams located on and midway between column lines. The intermediate beam was supported by a girder spanning between col-umns. Seismic framing for both buildings was provided by moment-resistant beam-column frames in both directions.Aside from the large plan dimensions, these

buildings presented major challenges for the designers in the mitigation of RTS cracking:

• Other than the joint separating the two Plaza Levels, no other expansion joints were permitted by the owner due to the highly sensitive precision research and manufacturing equipment that would be housed in both buildings.

• Temporary separation joints, such as pour strips, were ruled out by the contractor because of the difficulty of passing them through heavily reinforced beams and girders.

• Axial prestress compression was high, slightly above 300 psi in each direction, thus aggravating the effects of axial shortening.

• Lightweight concrete was used in the floor systems, further increasing the effects of axial shortening and creep because of the reduced modulus of elasticity.

• Columns below the Plaza level were large (37 inches square with 16-#14 vertical bars) providing significant restraint to floor shortening.

Considering these difficult conditions, a de-cision was made by the designers to use Type K shrinkage-compensating concrete for all floor members in both buildings.The use of shrinkage-compensating concrete

was highly successful in the TRW buildings. Recently, more than forty years after con-struction, I had the opportunity to observe the buildings, in the presence of Northrop-Grumman facilities personnel. The structural condition of the observable portions of the floor system and columns was excellent, virtu-ally crack-free after four decades of continuous service. Northrop-Grumman facilities personnel (Jimmy Guerrero, P.E., Facilities Project Manager, and Phillip Yee, Facilities Risk Manager), who have worked onsite at this facility for years, report that the structural per-formance of the buildings has been excellent

and they have required no unusual mainte-nance or repairs over their entire service lives.

ConclusionRTS is one of the two biggest problems faced

by the post-tensioning industry (the other being tendon corrosion). Looking back over the growth of post-tensioned concrete for 5 decades, and the early efforts to solve the shortening problems, it seems that the use of shrinkage-compensating concrete could have made the solution to the RTS problem easier.The two buildings discussed in this article

clearly demonstrate the utility of shrinkage-compensating concrete to solve RTS problems. Their long-term performance is testimony to the durability of this technology. They show (as we shall also see in the second part of this article) that when properly mixed, placed, fin-ished and cured, it can substantially eliminate pour strips, and with due consideration of temperature effects, can realistically increase the maximum length between expansion joints to approximately 500 feet, with equiva-lent or superior performance.▪

The author gratefully acknowledges the staff of CTS Cement Manufacturing, Inc., whose products include KSC shrinkage-compensating cement, and in particular its president, my old friend Ed Rice, for their assistance with this article.

The shortening strain study measurements referenced in this article are from: Liljestrom, W. P. and Polivka, M., A Five-Year Study of the Dimensional Stability of Shrinkage-Compensating Lightweight Concrete Used in Post-Tensioned Slabs, American Concrete Institute, Special Publica-tion SP-38-13, January 1, 1973, pp. 273-288.

Kenneth B. Bondy, S.E., FACI, is the current President of the Post-Tensioning Institute (PTI) and was, in 2005, inducted into the PTI Hall of Fame, “Legends of Post-Tensioning”. He serves on numerous ACI committees. He has been widely published on a variety of design issues concerning concrete and post-tensioning. Mr. Bondy can be reached via www.kenbondy.com.

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Risk ManageMentrisk management topics for structural engineers


Managing the Risks of BIMBy Joseph M. Ales Jr., Ph.D., S.E.

The future of Building Information Management (BIM) is now. With the in-

creasing acceptance of BIM in the architectural-engineering-construction (AEC) industry, it has moved past the buzzword phase and has hit, and likely passed, the all important “tipping point.” Though you may still be resistant to the idea of having to “waste” time modeling your work in 3D, at some point in the very near future you will not have an option. Making such a disruptive change in your production process can be scary.

Is BIM Required on Your Project?

More than likely, the answer to this question is no. Though everyone seems to be talking about BIM, the application of the process on any given project is probably voluntary. The more forward-thinking and larger design firms have transitioned to using BIM software for production, and may or may not request their sub-consultants to do the same. In these situations, the end product, which will be paper contract documents, will be arrived at by “doing BIM”, but more as a glorified drafting tool than as the application of a new production paradigm. In this case, are there any legal concerns or additional risks that come into play by using BIM? Assuming you have a properly trained staff who can produce good quality paper documents, probably not. There are, however, many sophisticated owners, and large public entities, such as the states of Texas and Wisconsin, that now require BIM for their projects. In cases where BIM is required on a project, a careful reading of the criteria for implementation on the project is necessary, and review by an attorney familiar with BIM contract language is strongly recommended.What about those cases where the design

team would like to take full advantage of the BIM production process, and not just use it as a “glorified drafting tool?” Are there any docu-ments or standards that provide a framework for this situation? Fortunately, yes. Two of the more commonly used documents are:

1) AGC ConsensusDOCS 301 BIM Addendum, created by the Associated General Contractors (AGC) of America. The primary purpose of this document is to fill the void left by typical standard form agreements, which inadequately, or do not at all,

address BIM. This document covers areas such as definitions, information management, the BIM execution plan, risk allocation, intellectual property rights, and collaboration.

2) AIA E202-2008 Building Information Modeling Protocol, created by the American Institute of Architects (AIA). The purpose of this document is to provide a framework for determining model content, model usage, and model element responsibility.

Whether these documents are adopted as for-mal contract exhibits or, more informally, are adopted to provide internal team guidance on a project, they are excellent tools in managing the risks associated with implementing the relatively new technology called BIM.

What Are The Owner/Client Expectations?

Most structural engineers have probably heard at one time or another that we have the amazing ability to design everything “with the push of a button.” That is, we have this amazing soft-ware that just designs everything for us, with minimal thought and effort on our part. That same ability has migrated to the world of BIM, where those with just enough knowledge to be dangerous make the assumption that the design team can produce a perfectly coordinated set of documents by using BIM. And that we can do it for the same fee, or preferably a smaller fee, because BIM makes our job easier. Waving around pieces of paper with a bunch of legalese does not replace the need to manage the ex-pectations of your client. The champions of BIM (of which I am one) do a great job of expounding on the promise and advantages of BIM…not so much on the challenges and obstacles to implementing it. Obviously, there is a need to properly educate and manage the expectations of your client.

Standard of CareConsider the following scenario. You have just

won a large and complex building project. You and the architect use BIM software to produce the contract documents, as you have made the leap from the world of 2D. You do not, how-ever, spend much time discussing how BIM will be implemented, and do not make use of any standard BIM documents to help define

model content or responsibilities. Your contract documents are produced and, as is typical with most projects, changes occur, RFI’s cover your desk, and change orders are produced – nothing that hasn’t occurred on thousands of projects before. And the owner says, But wait, don’t you ‘do BIM?’ You know about clash detection (which in the mind of the owner is the same as BIM). Why didn’t you run clash detection and avoid all these problems? Why, I do believe you are violating the Standard of Care! Though this is a hypothet-ical situation at the moment, it may not be in the near future.

What Are The Requirements Of The Deliverables?

If you are asked to implement BIM on a project, one of your first questions should be, “What are the deliverables?” A set of contract documents is likely and expected. That means the extraction of 2D views from your model, which will require you to do enough modeling to accurately represent your structure on plan, and perhaps in section or elevation. Is clash detection going to be performed on this proj-ect? If so, those kickers and gusset plates and sloped slabs that were either typical details or annotations for your contract documents, now need to be in the model. Are you going to turn this over to a fabricator so shop drawings can be produced? Oh, boy. That means connection plates, anchor bolts, edge angles, rebar, etc. Your scope on a project is directly related to the deliverables required. These deliverables impact the schedule, determine your staffing requirements, dictate the expertise required of your staff, and of course affect your fee.

Who Owns What?In the world of 2D CAD, the ownership of

the documents was pretty straight-forward (for the purposes of this discussion, we are not referring to intellectual property rights). The architect created his plans and details, the structural engineer and MEP engineer likely traced over and copied the architectural backgrounds to initially create their drawings, and there was really no discussion or issues related to the ownership of the various “lines” in the CAD files. With the implementation of BIM, these fairly clear-cut distinctions be-come quite blurred. In the ideal BIM world,


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the architect creates and owns “architectural” objects, the structural engineer creates and owns “structural” objects, and the MEP engi-neer creates and owns the “MEP” objects. On the face, it appears easy to distinguish between model element ownership. As the structural engineer, I am going to determine the thickness of the slab, the reinforcement required, and I will specify any other parameters related to the design. The architect, however, is probably going to establish the slab edge, where penetrations are required (with input from the MEP), and what slopes may be required. Considering all this, who owns the slab? If it is determined that I own the slab, I am liable for the cost that may be incurred for a slab edge that is improperly located? Establishing the owner-ship of model elements at the start of a project, perhaps through the use of the E202 BIM protocol, will help to establish clear divisions of ownership.Moving from the element level to the model

level, is there such thing as ownership of the BIM model? Well, that depends on how many BIM models there are. In most projects im-plementing BIM, it is likely there are several BIM models, typically one for each discipline. These separate and distinct models can then be linked together to form a single “federated model.” The distinct models that are provided by the various disciplines cannot be altered in the federated model, and each model creator retains ownership of his model. A common use of a federated model is for clash detection. There is no one “owner” of a federated model. At some point in the future, a truly integrated model will become a reality, in which all parties do their work in a single model.

What Are The Technical Challenges That Affect

Your Risk?In addition to the issues of model ownership

that are evident in this process, an organization must be aware of various technical challenges that create risk so that it may implement mitigation measures. Some technical issues to highlight are interoperability, software limita-tions, and fi le storage and transfer limitations. The ability to interoperate between various software platforms provides engineers and companies with visions of grandeur. The con-cept of your analysis fi les driving the engineering deliverables, providing a platform for creating a more effi cient and accurate product, is too much for any company to ignore. While the technology exists to perform these types of tasks, organizations should try to move deliberately and cautiously in its implementation. The in-teroperability bells and whistles marketed by the software venders are never quite as seamless

as the brochures indicate. Don’t believe every-thing the software vendors tell you.Defi ne some specifi c goals to integrate your

software processes. Then ask yourself the tough questions. What do you want to accomplish with the integration of various software tools? Does the software have the ability to do this out of the box? Can an application program-ming interface (API) be developed to perform the interoperation in a manner consistent with your desires and, if so, do you have the person-nel available and capable to develop, maintain, trouble shoot, and effi ciently roll out the tools. Reasonable fi rst steps would be to research the software limitations, test run some of the standard applications, evaluate their usefulness and implement on a small scale. Then use the successful applications in ways that will that will add value to your process.Also understand that a variety of information

technology (IT) issues may need to be evalu-ated. The data fi les produced by some BIM software can get very large. The size of these fi les may require you to rework project fi le size limits, corporate storage capacity, upgrade hardware, and improve backup capabilities. The opportunity to share this data upstream and downstream to various parties will pres-ent itself. While working through the legal ramifi cations of this activity is equally impor-tant, be prepared to implement data transfer systems that are robust enough to handle large fi le transfers.

Reduce Your Risk with Proper Implementation

When the decision is made to implement BIM, consideration must be given to the train-ing required. While individual staff research is

important, a focused plan on the fi rm wide training effort is mandatory. This can be challenging, as the development of this plan affects all aspects of the project production. Managers will need to be trained to under-stand software capabilities, technicians will need to be trained in the effi cient use of the software, and engineering staff will often times be caught in the middle between the production issues of the technicians and the grand vision of the managers and marketing personnel. Managing expectations is critical to making sure this process in implemented at the right pace.Organizations will often go through the fol-

lowing experiences during the integration of BIM into their production process:

• Cautious investigation• Trial and Error on a small level• Recognition of value• The big sale on the big project…

then reality strikes• Implementation of standards• BIM effi ciency

The order of these events may vary from organization to organization, but BIM effi ciency is likely never to come before the implementa-tion and transition of corporate standards. This process needs to be considered and worked into the plan. While time consuming, it will aid in transitioning your organization from the 2D world into an effi cient 3D BIM practice. An-other issue that organizations will grapple with is the quality of the product. A concerted effort and investment can be required to get the new software to produce drawings that appear the same as your old deliverables. Sometimes it is wise to consider alternatives in the product output. It may be less time consuming to con-sider a change in the standard output and tailor it to what the software can do, rather than

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implement the strict performance guidelines developed during the CAD era.

ConclusionThe decision to implement BIM at your

fi rm is not one to be taken lightly. You will need to make the transition if you are to re-main competitive in the AEC industry. Either your clients will be demanding that you make the change, or the projects that you typically bid on will require BIM as part of the contract. As with any new technology,

Joseph M. Ales Jr., Ph.D., S.E., is a Principal and Managing Director of the Los Angeles offi ce of Walter P Moore. He is the vice-chair of the Joint SEI-CASE Committee on Building Information Modeling and is the chair of Walter P Moore’s BIM Implementation Task Force. Joe can be reached at [email protected].

there will be resistance to the change and trepidation at the disruptive nature of your production process. Though the process will not be easy, you can take several steps to re-duce your risks as you embark on the imple-mentation and on-going use of BIM. Most of these steps are simple common sense, such as defi ning and knowing your scope, managing the expectations of your client, developing a properly trained staff, make use of standard BIM agreements, and getting the advice of an attorney for projects requiring

BIM. For more information on building infor-mation modeling, please visit www.seibim.org for useful links and documents.▪

2010 ENGINEERED WOOD PRODUCTS GUIDEa defi nitive listing of wood product manufacturers and their product lines

Company Product DescriptionAmerican Wood CouncilPhone: 202-463-2766Email: [email protected]: www.awc.org

Codes and Standards AWC develops internationally recognized building codes and standards for engineered wood products. Asso

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Southern Pine CouncilPhone: 504-443-4464Email: [email protected]: www.southernpine.com

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The Southern Pine Council (SPC) is a joint promotional body supported by members of the Southern Forest Products Association (SFPA) and the Southeastern Lumber Manufacturers Association (SLMA). Both associations represent manufacturers of Southern Pine lumber. SPC is the leading source of information about Southern Pine products for design/build professionals.

WoodWorks SoftwarePhone: 800-844-1275 Email: [email protected]: www.woodworks-software.com

WoodWorks® SoftwareWoodWorks® – produced by the Canadian Wood Council with technical guidance from the American Wood Council of the American Forest & Paper Association. Quickly design light-frame or heavy timber structures based on 2005 edition of the AF&PA’s National Design Specifi cation® (NDS®) for Wood Construction.

Simpson Strong-TiePhone: 925-560-9000Email: [email protected]: www.strongtie.com

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Cascade Consulting Associates, Inc.Phone: 800-279-1353Email: [email protected]: www.strucalc.com

StruCalc™ 8.0 for WindowsSoftware solution for the design and analysis of beams, columns, joists, rafters and footings using solid sawn lumber, steel and tube steel, structural composite, glulams, fl itch beams, and I-joists. Includes full AISD 13th Edition Steel Calculations, hip beams, stud walls, and many other exciting features.

Hoover Treated Wood Products, Inc.Phone: 800-531-5558Email: [email protected]: www.frtw.com

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iLevel by WeyerhaeuserPhone: 888-453-8358Email: [email protected]: www.iLevel.com

iLevel Shear BraceA prefabricated, engineered wood panel with more predictable and consistent performance than site-built shear walls, the iLevel Shear Brace has high allowable loads at narrow widths of 12" and 24". It can be used in multi-story applications and can be fi eld trimmed for custom heights.

RISA TechnologiesPhone: 949-951-5815Email: [email protected]: www.risa.com

RISAFloorRISAFloor and RISA-3D for wood design – Create 3D models of your entire structure and get full design of wood walls (with and without openings), fl exible wood diaphragms, dimension lumber, glulams, parallams, LVL’s, joists and more. Custom databases for species, hold-downs-and panel nailing offer total fl exibility.

Southern Pine Council See above information

TrimJoist CorporationPhone: 800-844-8281Email: [email protected]: www.trimjoist.com

TrimJoist™

TrimJoist is the combination of an open web fl oor truss and a trimmable wood-I-joist, bringing the best features of each together to form a trimmable fl oor truss. As the name indicates, it can be trimmed on the construction site for a custom fi t.

Universal Forest ProductsPhone: 574-532-6102Email: [email protected]: www.ufpi.com

Open Joist™

Speed of installation and superior load-bearing strength have made Open Joist™ a preferred choice for building designs that require longer joist spans or wider joist spacing and reduced framing costs. Open Joist features an open web design for quick and easy installation of mechanical systems.

WheelerPhone: 800-328-3986Email: [email protected]: www.wheeler-con.com

Timber BridgesWheeler specializes in the design and supply of custom engineered timber bridges for recreation and vehicular applications.

Not listed? Visit www.STRUCTUREmag.org/guides.aspx and opt-in to our email reminder list.Listings are provided as a courtesy. STRUCTURE® magazine is not responsible for errors.


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NCSEA Winter Institute, Coronado, CAMarch 12-13, 2010

NCSEA’s Winter Institute attendees took advantage of a great opportunity to learn from the experts about seismic design in steel, masonry, concrete and wood, as well as nonstructural components and systems, SFSI, and performance-based design.

Friday afternoon, March 12, provided a unique learning opportunity, when attendees visited the Charles Pankow Structures Laboratory and the Robert and Natalie Englekirk Structural Engineering Center at UCSD, which hosts the NEES Large Outdoor High-Performance Shake Table, a blast simulator and two soil pits for performing soil-foundation studies.

28

The New Structural ExamNCEES Raises the Bar

The National Council of Examiners for Engineering and Surveying (NCEES) is introducing a new 16-hour Structural PE examination. The current Structural I (SE I) and Structural II (SE II) exams will

be replaced by the new exam starting in April 2011. Therefore, the current exams will be offered for the last time in October 2010.Currently, NCEES offers three different structural engineering

exams: the 4-hour structural module of the Civil PE exam, the 8-hour SE I exam, and the 8-hour SE II exam. In addition, California and Washington administer an 8-hour, state-specific Structural III (SE III) exam. Oregon also uses the exam developed by Washington. There are at least eight different combinations of these exams that various jurisdictions use to qualify structural engineers for licensure.NCEES adopted the Model Law Structural Engineer (MLSE)

designation in 2004 as a guideline to a national standard for minimum competence for structural engineering licensure. To qualify for the MLSE, a candidate must meet specific education and experience requirements and pass 16 hours of structural engineering exams. The exams can be a combination of SE I and SE II, a combination of SE II and an 8-hour state-specific exam, or a 16-hour state-specific exam taken prior to 2004.As a result of all this, there have been questions and confusion

about requirements to become a licensed structural engineer from state to state. In 2006, NCEES established the Struc-tural Exam Task Force (SETF) to address these issues. The SETF recommended the development of a new 16-hour exam for structural engineering licensure, to be designed in such a manner that its content and format would be acceptable to all jurisdictions that already offer such licensure. The SETF also recommended maintaining a structural module of the Civil PE exam and discontinuing the use of the 8-hour SE I exam for P.E. licensure. In August 2007, the SETF’s recommenda-tions were officially adopted at the NCEES Annual Meeting in Philadelphia, Pennsylvania.To determine the new exam’s content, NCEES formed a

committee composed of structural engineers from all states that require 16 hours of exams for structural engineering licensure, as well as from many other states that do not. The committee developed a survey that was sent to licensed structural engineers to determine the knowledge areas most relevant to current professional practice. The committee subsequently reviewed the results of the survey and developed the exam specification accordingly. Most of the committee members are now involved in the preparation, assembly and review, and scoring of the new exam.The test will be offered in two components on successive days.

The 8-hour Vertical Forces (Gravity/Other) and Incidental Lateral component will be offered on Friday, and the 8-hour Lateral Forces (Wind/Earthquake) component will be offered on Saturday. The morning sessions will consist of 40 multiple-choice questions covering a comprehensive range of structural engineering topics. The afternoon sessions will have four one-hour essay questions and focus more closely on a single area of practice in structural engineering. Examinees will have to choose

either buildings or bridges and work the same topic area both days. The two 8-hour components may be taken and passed in different exam administrations.At the 2009 NCEES Annual Meeting, a motion was passed

to change the NCEES Model Law and Model Rules to in-clude a 5-year window for passing both components. Once the candidate passes one component, whether Vertical Forces or Lateral Forces, the candidate will have 5 years to pass the second component. If the candidate does not pass both the components within the 5-year window, the candidate will have to retake the first component again. Currently, it is up to the state licensing boards to amend their rules in order for these changes to take effect.The implementation of the new 16-hour exam will affect

currently licensed engineers, as well as individuals taking the test for the first time, since several licensing boards have indicated that they are adopting the new exam as a requirement to become licensed as a structural engineer. However, other licensing boards will require passage of only the 8-hour Civil exam with the structural module, in order to practice structural engineering in those states as a P.E.The licensing board in Washington has indicated that it plans

to discontinue its use of their state-specific exam in favor of the new 16-hour exam. Other states, such as California, are also considering this option. This will be beneficial to examinees that do not live in these states, because they will now be able to have the new exam proctored in their own state or a nearby state, reducing travel time and expenses. Washington will offer its state SE III exam for the last time in October 2011. After that date, the only way to become licensed as a structural engineer in Washington and Oregon will be to take the new 16-hour exam, even if the person has previously passed the SE II exam. Therefore, engineers who practice structural engineering will want to plan ahead and check with the local licensing boards in the states where they practice.The new 16-hour NCEES Structural exam is raising the bar

for the structural engineering profession and has the poten-tial to improve consistency in requirements among the various jurisdictions that have implemented separate licensure. This development appropriately reflects the unique and important responsibility that structural engineers have, for protecting the safety, health, and welfare of the public, no matter where their projects are located.A more detailed version of this article is posted on the NCSEA

website (www.NCSEA.com).

By Peter Vaccaro, [email protected]

Call for EntriesNCSEA 2010 Excellence in Structural Engineering Awards Program

Next NCSEA Webinar April 20Wind Design using the 2009 IBCPresented by Don Scott

Don Scott, Chairman of NCSEA’s CAC Wind Engineering Subcommittee, has been with PCS Structural Solutions since 1982 and became a Principal in 1986. He has led many of the firm’s educational, commercial, institutional and private projects for new and renovated construction and has authored and co-authored many technical publications on wind. He is also Vice Chairman of the ASCE 7 Wind Load Committee (since 1996), shaping future IBC provisions for wind design and Chairman of the SEAW Wind Load Committee.

The cost is $250 per internet connection. Several people may attend for one connection fee. This course will award 1.5 hours of continuing education, with a $5 fee for each continuing education certificate requested. The times will be 10:00 Pacific, 11:00 Mountain, 12:00 Central, and 1:00 Eastern. Register at www.ncsea.com. Approved in All 50 States.Diamond

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NCSEA announces the 13th annual Excellence in Structural Engineering Awards Program. Up to three Excellence in Structural Engineering Awards will be presented in each of the following eight categories: New Buildings under $10M, New Buildings $10M to $30M, New Buildings $30M to $100M, New Buildings over $100M, New Bridge and Transportation Structures, International Structures, Forensic/Renovation/Retrofit/Rehabilitation Structures, and Other Structural Design Projects. In each category, one of the three projects will be cho-sen as an Outstanding Project.

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NCSEA Winter Institute, Coronado, CAMarch 12-13, 2010

NCSEA’s Winter Institute attendees took advantage of a great opportunity to learn from the experts about seismic design in steel, masonry, concrete and wood, as well as nonstructural components and systems, SFSI, and performance-based design.

Friday afternoon, March 12, provided a unique learning opportunity, when attendees visited the Charles Pankow Structures Laboratory and the Robert and Natalie Englekirk Structural Engineering Center at UCSD, which hosts the NEES Large Outdoor High-Performance Shake Table, a blast simulator and two soil pits for performing soil-foundation studies.

Professor Jose Restrepo had just returned from Chile and added some new slides to his presentation.

29

either buildings or bridges and work the same topic area both days. The two 8-hour components may be taken and passed in different exam administrations.At the 2009 NCEES Annual Meeting, a motion was passed

to change the NCEES Model Law and Model Rules to in-clude a 5-year window for passing both components. Once the candidate passes one component, whether Vertical Forces or Lateral Forces, the candidate will have 5 years to pass the second component. If the candidate does not pass both the components within the 5-year window, the candidate will have to retake the fi rst component again. Currently, it is up to the state licensing boards to amend their rules in order for these changes to take effect.The implementation of the new 16-hour exam will affect

currently licensed engineers, as well as individuals taking the test for the fi rst time, since several licensing boards have indicated that they are adopting the new exam as a requirement to become licensed as a structural engineer. However, other licensing boards will require passage of only the 8-hour Civil exam with the structural module, in order to practice structural engineering in those states as a P.E.The licensing board in Washington has indicated that it plans

to discontinue its use of their state-specifi c exam in favor of the new 16-hour exam. Other states, such as California, are also considering this option. This will be benefi cial to examinees that do not live in these states, because they will now be able to have the new exam proctored in their own state or a nearby state, reducing travel time and expenses. Washington will offer its state SE III exam for the last time in October 2011. After that date, the only way to become licensed as a structural engineer in Washington and Oregon will be to take the new 16-hour exam, even if the person has previously passed the SE II exam. Therefore, engineers who practice structural engineering will want to plan ahead and check with the local licensing boards in the states where they practice.The new 16-hour NCEES Structural exam is raising the bar

for the structural engineering profession and has the poten-tial to improve consistency in requirements among the various jurisdictions that have implemented separate licensure. This development appropriately refl ects the unique and important responsibility that structural engineers have, for protecting the safety, health, and welfare of the public, no matter where their projects are located.A more detailed version of this article is posted on the NCSEA

website (www.NCSEA.com).

By Peter Vaccaro, [email protected]

Call for EntriesNCSEA 2010 Excellence in Structural Engineering Awards Program

Next NCSEA Webinar April 20Wind Design using the 2009 IBCPresented by Don Scott

Don Scott, Chairman of NCSEA’s CAC Wind Engineering Subcommittee, has been with PCS Structural Solutions since 1982 and became a Principal in 1986. He has led many of the fi rm’s educational, commercial, institutional and private projects for new and renovated construction and has authored and co-authored many technical publications on wind. He is also Vice Chairman of the ASCE 7 Wind Load Committee (since 1996), shaping future IBC provisions for wind design and Chairman of the SEAW Wind Load Committee.

In this webinar, Mr. Scott will review the development of the Alternate Wind Load Provisions of the 2009 International Building Code (IBC), to allow the user to understand the proper application of these provisions for building design. The limitations of the procedure will also be reviewed, to give guidance to the user as to when these provisions are valid and when the provisions of ASCE 7-05 are required to be used.

The cost is $250 per internet connection. Several people may attend for one connection fee. This course will award 1.5 hours of continuing education, with a $5 fee for each continuing education certifi cate requested. The times will be 10:00 Pacifi c, 11:00 Mountain, 12:00 Central, and 1:00 Eastern. Register at www.ncsea.com. Approved in All 50 States.Diamond

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Entries are due July 9, and awards will be presented at the Hyatt Regency on the Hudson in Jersey City, NJ on October 2, at the conclusion of the NCSEA Annual Conference. Winning projects will be featured in future issues of STRUCTURE®

magazine. For awards program rules and eligibility, as well as entry forms, see the Call for Entries on the NCSEA website: www.ncsea.com.

NCSEA announces the 13th annual Excellence in Structural Engineering Awards Program. Up to three Excellence in Structural Engineering Awards will be presented in each of the following eight categories: New Buildings under $10M, New Buildings $10M to $30M, New Buildings $30M to $100M, New Buildings over $100M, New Bridge and Transportation Structures, International Structures, Forensic/Renovation/Retrofi t/Rehabilitation Structures, and Other Structural Design Projects. In each category, one of the three projects will be cho-sen as an Outstanding Project.

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ErrataSEI posts up-to-date errata information for our publications at www.SEInstitute.org. Click on

“Publications” on our menu, and select “Errata.” If you have any errata that you would like to submit,

please email it to Jim Rossberg at [email protected].▪

30

Survey of Structural Engineering (SE) and Building Information Modeling (BIM)This is the third year of a respected and internationally rec-

ognized survey on the topic of Building Information Modeling (BIM) in the profession of Structural Engineering. The sur-vey considers several key areas of BIM in the profession that include firm demographics, structural system definitions, interoperability, implementation, and the direction the tech-nology should take in structural engineering. It also provides an important opportunity to collectively voice our opinion on the topic of this technology and our profession. Please take a few moments to participate in the online survey by visiting www.seibim.org/survey2010.htm.The survey is a collaborative effort of the Joint Structural

Engineering Institute (SEI) – Council of American Struc-tural Engineers (CASE) Committee on Building Information Modeling (BIM) and the Structural Engineers Association of Texas (SEAoT) Information Technology (IT) Committee on BIM. The results of the 2010 third annual survey will be presented at the Structures Congress this spring in Orlando, Florida. For questions or comments on the survey, please visit www.seibim.org/survey.htm.

2010 Structures Congress with NASCC the Steel ConferenceMaking Connections

May 12-15, 2010Gaylord Palms Convention Center

Orlando, Florida

For the first time ever, the leading programs for those involved in the design and construction of buildings and bridges will all be held under one roof. And with the uncertain economy, the combined conferences are happening at a propitious moment – now you can pay one low fee of just $390 (SEI and AISC members) and have your choice of more than 200 seminars, network with colleagues and potential clients, and visit the industry’s largest exhibit hall.Technical sessions cover the full gamut of structural design,

ranging from serviceability issues to the seismic design of bridges and from wind effects to legal issues. There also are special sessions for those involved in construction, including steel fabricators, erectors, and detailers.See the SEI Website at www.seinstitute.org for information on

the Structures Congress Technical Sessions, Advance Program, and the Schedule at a Glance.For complete conference information and the NASCC sessions,

please visit www.aisc.org/nascc.

SEI/ASCE Structural Seminars and WebinarsSEI/ASCE offers a full range of structural seminars which

qualify for CEUs and take place each month across the nation. For a list of upcoming seminars see our website at:

www.asce.org/conted/seminars/seminar.cfm?cat=7Webinars are live, interactive continuing education programs

which can be attended without leaving your office. Not only will these practice-oriented programs help you stay current, but they also help you earn Professional Development Hours toward Professional Engineer license renewal. All that’s required is a computer with high-speed Internet access and a speakerphone. For additional information on upcoming webinars and to register, visit www.asce.org/webinar/list.

Upcoming titles for April and May 2010 include:

Wednesday, April 7, 2010Deterioration and Repair of Concrete

Tuesday, April 13, 2010Foundations for Metal Building Systems

Friday, April 16, 2010Reinforced Masonry: Design and Construction

Monday, April 19, 2010Renovation of Slabs on Grade

Wednesday, April 21, 2010Wind and Seismic Retrofit of Wood-Framed Buildings

Tuesday, April 27, 2010Design of Masonry Shear Walls

Thursday, April 29, 2010Strengthening Concrete Buildings

Monday, May 3, 2010Designing and Procuring Pre-Engineered Buildings

Thursday, May 6, 2010Best Practices in Design and Renovation of Masonry Veneer

Tuesday, May 11, 2010Design of Wood Connections

Wednesday, May 12, 2010Strengthening Structural Steel Beams

Tuesday, May 18, 2010Design of Wood Diaphragms and Shear Walls

Friday, May 21, 2010Deciphering Building Code Provisions for Structural Renovation

Monday, May 24, 2010Overview of Seismic Design for Buildings According to ASCE 7-10

Tuesday, May 25, 2010Practical Design of Bolted and Welded Steel Connections

Wednesday, May 26, 2010Investigation and Repair of Wood Structures

Thursday, May 27, 2010Lessons From Failures of Pre-Engineered Buildings

ACI-SEI Joint Committee 343 on Concrete Bridge Design

The joint ACI-SEI Committee 343 on Concrete Bridge Design is working on updating and developing several ACI documents related to concrete bridges, as follows:

ACI 358.1R-03: Analysis and Design of Reinforced and Prestressed-Concrete Guideway StructuresA sub-committee of Committee 343, headed by Bruce Kates,

has worked to develop a draft of this revised document that has been balloted by the committee. It is expected that the document will be jointly approved by the ACI and SEI, and will be published in summer 2010.

ACI 343R-95: Analysis and Design of Reinforced Concrete Bridge StructuresSeveral sub-committees continue to work in developing

individual chapters of this revised document, as follows: Preliminary Design (headed by Claudia Pulido), Analysis (headed by Sameh Badie), Loads (headed by Andrej Nowak), and Design (headed by Riyadh Hindi). The state-of-the-art guideline will be completed in 2011.

New Document: Bridge Deck DesignThis new document is being developed to include various

existing and new concrete bridge deck design methodologies. The pros and cons of the methods will be included. The guideline will be completed in 2011.

Professional Development Hours (PDHs)Earn up to 27 PDHs by attending technical

sessions and short courses.

Registration is open – register today!

Hotel Information:Gaylord Palms Hotel & Convention Center6000 West Osceola ParkwayKissimmee, FL 34746407-586-2000Hotel reservations through the NASCC website: www.aisc.org/nascc.

Schedule for Committee Meetings at the 2010 Structures Congress Available on Website

The schedule for committee meetings during the 2010 Structures Congress in Orlando, Florida has been posted on-line. The schedule will be updated weekly and will also appear in the final Congress program. There are close to 60 meetings scheduled between Wednesday, May 12 and Saturday, May 15. To view the schedule, visit our website at www.seinstitute.org.

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Survey of Structural Engineering (SE) and Building Information Modeling (BIM)This is the third year of a respected and internationally rec-

ognized survey on the topic of Building Information Modeling (BIM) in the profession of Structural Engineering. The sur-vey considers several key areas of BIM in the profession that include firm demographics, structural system definitions, interoperability, implementation, and the direction the tech-nology should take in structural engineering. It also provides an important opportunity to collectively voice our opinion on the topic of this technology and our profession. Please take a few moments to participate in the online survey by visiting www.seibim.org/survey2010.htm.The survey is a collaborative effort of the Joint Structural

Engineering Institute (SEI) – Council of American Struc-tural Engineers (CASE) Committee on Building Information Modeling (BIM) and the Structural Engineers Association of Texas (SEAoT) Information Technology (IT) Committee on BIM. The results of the 2010 third annual survey will be presented at the Structures Congress this spring in Orlando, Florida. For questions or comments on the survey, please visit www.seibim.org/survey.htm.

2010 Structures Congress with NASCC the Steel ConferenceMaking Connections

May 12-15, 2010Gaylord Palms Convention Center

Orlando, Florida

For the first time ever, the leading programs for those involved in the design and construction of buildings and bridges will all be held under one roof. And with the uncertain economy, the combined conferences are happening at a propitious moment – now you can pay one low fee of just $390 (SEI and AISC members) and have your choice of more than 200 seminars, network with colleagues and potential clients, and visit the industry’s largest exhibit hall.Technical sessions cover the full gamut of structural design,

ranging from serviceability issues to the seismic design of bridges and from wind effects to legal issues. There also are special sessions for those involved in construction, including steel fabricators, erectors, and detailers.See the SEI Website at www.seinstitute.org for information on

the Structures Congress Technical Sessions, Advance Program, and the Schedule at a Glance.For complete conference information and the NASCC sessions,

please visit www.aisc.org/nascc.

2011 SEI/ASCE Student Structural Design CompetitionThe Structural Engineering Institute of ASCE sponsors a struc-

tural design competition for universities. Innovative projects demonstrating excellence in structural engineering are invited for submission.Awards include cash prizes and an opportunity to present win-

ning designs at the 2011 SEI Structures Congress in Las Vegas, Nevada, April 14-16, 2011Deadline for Submissions: June 30, 2010For competition guidelines, entry form and a poster to promote

the competition, visit: www.SEInstitute.org.

Committee NewsACI-SEI Joint Committee 343 on

Concrete Bridge DesignThe joint ACI-SEI Committee 343 on Concrete Bridge Design

is working on updating and developing several ACI documents related to concrete bridges, as follows:

ACI 358.1R-03: Analysis and Design of Reinforced and Prestressed-Concrete Guideway StructuresA sub-committee of Committee 343, headed by Bruce Kates,

has worked to develop a draft of this revised document that has been balloted by the committee. It is expected that the document will be jointly approved by the ACI and SEI, and will be published in summer 2010.

ACI 343R-95: Analysis and Design of Reinforced Concrete Bridge StructuresSeveral sub-committees continue to work in developing

individual chapters of this revised document, as follows: Preliminary Design (headed by Claudia Pulido), Analysis (headed by Sameh Badie), Loads (headed by Andrej Nowak), and Design (headed by Riyadh Hindi). The state-of-the-art guideline will be completed in 2011.

New Document: Bridge Deck DesignThis new document is being developed to include various

existing and new concrete bridge deck design methodologies. The pros and cons of the methods will be included. The guideline will be completed in 2011.

Progressive Collapse CommitteeThe SEI Committee on Progressive Collapse has a subcommittee

tasked with compiling references and other pertinent research information related to the topic of disproportionate collapse. To date, a Wiki website has been established, and we are looking for additional contributions to the information that has already been added. Please take a moment to review the information already included on the Wiki and add any contributions you feel are appropriate. The following information can be used to access the Wiki:The WIKI link is www.disproportionatecollapse.com/wikiLogin to input articles to the Wiki: USERID = guestPassword = structure

ASCE Seismic Rehabilitation of Existing Building Committee

The ASCE Seismic Rehabilitation of Existing building committee reconvened on December 9, 2009, after a three year hiatus, to initiate the process of updating ASCE 31 and 41 within the next three years. It is being chaired by Chris Poland of Degenkolb Engineers. The committee agreed to reorganize itself into an ASCE 7 style structure comprised of regular members and affiliate members, and operate using an executive committee and subcommittees. Those interested in getting involved with the committee should contact Robert Pekelnicky ([email protected]), who is serving as committee vice-chair and secretariat.ASCE 31 and 41 are national consensus standards dealing

with the seismic evaluation and upgrade of existing buildings, respectively. Both are rooted in a performance-based design philosophy, giving engineers greater control over the evaluation and upgrade process than traditional code-based design methods do. Also, because they deal specifically with existing buildings which have structural elements of varying ductility and robustness, the standards provide guidance on how to evaluate those types of elements and also incorporate those elements with new, ductile elements into an upgrade design. The committee welcomes ideas for updates, revisions, and new material. Please contact Robert Pekelnicky if you have anything you wish the committee to consider.

Schedule for Committee Meetings at the 2010 Structures Congress Available on Website

The schedule for committee meetings during the 2010 Structures Congress in Orlando, Florida has been posted on-line. The schedule will be updated weekly and will also appear in the final Congress program. There are close to 60 meetings scheduled between Wednesday, May 12 and Saturday, May 15. To view the schedule, visit our website at www.seinstitute.org.

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CASE Risk Management Convocation Comes into Orlando Next MonthThe CASE Risk Management Convocation will be held in conjunction with the first-ever combined Structures Congress/North

American Steel Construction Conference at the Gaylord Palms Convention Center in Orlando, Florida, May 12–15, 2010. The Structural Engineering Institute of ASCE (SEI) and the American Institute of Steel Construction (AISC) are joining forces in 2010 to host this first-ever combined event. Registration will open very soon and will be handled at AISC’s website: www.aisc.org. A preliminary program is available for viewing at SEI’s website www.seinstitute.org.The following CASE Convocation sessions are scheduled to take place on Friday, May 14:

6:45 am – 8:00 am CASE Breakfast: Changes to AISC Code of Standard Practice – What SE’s Need to Know

Speaker: David B. Ratterman, Secretary and General Counsel, AISC

The AISC Code of Standard Practice has served as a specification guideline and statement of custom and usage in the fabricated structural steel industry since approximately 1921. The Code is regularly updated and maintained by a balanced committee of industry professionals; approximately one-third of the Code Committee is comprised of practicing structural engineers. Mr. Ratterman is a graduate engineer and counsel to the Code Committee. He will discuss the relationship of the Code to the practice of structural engineering.

8:00 am – 9:30 am Steel Design Dos & Don’ts – A Construction Friendly PerspectiveSpeakers: Carol Drucker, Drucker Zaidel; Other Speakers TBA

This session will be led by a licensed structural engineer specializing in connection design who will comment on the document quality as it relates to potential risk management issues for the structural engineer of record. Often, problems in steel design are not so apparent until after the job has been awarded and is in detailing, fabrication or erection. Small oversights can have big impact and may cause delays or additional costs. Potential issues are avoidable by understanding structural steel systems and their connections. This seminar will address different aspects of lateral system design, main member design, connection design and avoidable problems. Actual examples from real projects will be highlighted and discussed. The session will include discussion from a steel detailer and a steel fabricator related to the associated construction costs and/or change orders resulting from document quality and clarity.

1:45 pm – 3:15 pm A Day in the Life of a Project ManagerSpeakers: John Aniol, Walter P Moore; Corey Matsuoka, SSFM International

Follow a structural project manager as he struggles through a day filled with risk and discovers tools to help him mitigate those risks. Some of the tools he will discover will cover communication, corporate culture, planning and prevention, education, scope and contracts, construction documents and construction.

3:30 pm – 5:00 pm Managing Expectations and Risks During the Steel Detailing ProcessSpeakers: Glenn Bishop, LBYD, Birmingham AL; Will Ikerd, RLG Engineers, Dallas, TX

The AISC Code of Standard Practice provides two options for structural steel connections, either fully detailed by the engineer or selected and completed by the detailer. After much discussion, AISC is considering adding a third option for connection: design by a specialty structural engineer retained by the fabricator. This session will explore the needs and expectations of both the engineer and the fabricator for each of these three options. Also discussed will be how these expectations might change in the BIM world.

CASE to Conduct Code Complexity Panel Discussion at NASCC in Orlando

ACEC Annual Convention Takes On Economic, Business Challenges Facing FirmsAcross the board, ACEC’s 2010 Annual Convention and

Legislative Summit will address current business conditions and opportunities. To be held in Washington, D.C., April 25-28, the Convention will feature more than two dozen top-tier business sessions tackling pressing management concerns, including how to restore firm growth and win projects in a changing and highly competitive marketplace. Procurement officers from key federal agencies – including NASA, U.S. Army Corps of Engineers, General Services Administration, State Department, Department of Veteran’s Affairs, and Department of Energy – will describe new contracting opportunities. Gregory Ip, U.S. economics editor for The Economist magazine, will provide a market forecast. Leaders of three of the nation’s largest engineering firms will discuss current and future industry challenges. The group includes Robert Uhler, chairman and CEO of MWH Global; Leonard Rodman, chairman, president and CEO of Black & Veatch; and George Pierson, CEO of Parsons Brinckerhoff. A Bentley Systems-sponsored panel on cyber-engineering will feature CIOs from AECOM, Jacobs Engineering, Malcolm Pirnie, and WSP Flack & Kurtz. CEO Roundtables, organized by firm size, will address

operational issues affecting firms. For more information go to www.acec.org.

ACEC Business Course Identifies Contract “Red Flags”ClosingtheDealWithA/E/CContracts:RecognizePitfalls,NegotiateWinnersMay20 -21,SanFrancisco

Identify and demystify “red-flag contract provisions,” acquire the skills and principles of toe-to-toe negotiating to maintain professional standards and protect your business. Learn the differences between custom contracts and model contracts, the pitfalls, and how to negotiate to win-win agreements. Closing the Deal With A/E/C Contracts: Recognize Pitfalls, Negotiate Winners is an in-depth course designed to meet the contract needs of engineers, architects, contractors, project managers, contracting officers, specifiers, and those responsible for procuring construc-tion or design services. Presented by a faculty of experts with

In addition to the CASE Risk Management Convocation in Orlando next month at the 2010 Structures Congress, CASE is conducting a program on the business impacts and risks associated with code complexity at the North American Steel Construction Conference (NASCC). As reported earlier, the Structures Congress and the NASCC are combining their events for the first time. Code Complexity – Risks and Cost to the Profession, and how this issue is affecting the “bottom line”, will feature a panel discussion moderated by Edward W. Pence, Jr, Stroud,

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April 2010STRUCTURE magazine 33

CASE Risk Management Convocation Comes into Orlando Next MonthThe CASE Risk Management Convocation will be held in conjunction with the first-ever combined Structures Congress/North

American Steel Construction Conference at the Gaylord Palms Convention Center in Orlando, Florida, May 12–15, 2010. The Structural Engineering Institute of ASCE (SEI) and the American Institute of Steel Construction (AISC) are joining forces in 2010 to host this first-ever combined event. Registration will open very soon and will be handled at AISC’s website: www.aisc.org. A preliminary program is available for viewing at SEI’s website www.seinstitute.org.The following CASE Convocation sessions are scheduled to take place on Friday, May 14:

6:45 am – 8:00 am CASE Breakfast: Changes to AISC Code of Standard Practice – What SE’s Need to Know

Speaker: David B. Ratterman, Secretary and General Counsel, AISC

The AISC Code of Standard Practice has served as a specification guideline and statement of custom and usage in the fabricated structural steel industry since approximately 1921. The Code is regularly updated and maintained by a balanced committee of industry professionals; approximately one-third of the Code Committee is comprised of practicing structural engineers. Mr. Ratterman is a graduate engineer and counsel to the Code Committee. He will discuss the relationship of the Code to the practice of structural engineering.

8:00 am – 9:30 am Steel Design Dos & Don’ts – A Construction Friendly PerspectiveSpeakers: Carol Drucker, Drucker Zaidel; Other Speakers TBA

This session will be led by a licensed structural engineer specializing in connection design who will comment on the document quality as it relates to potential risk management issues for the structural engineer of record. Often, problems in steel design are not so apparent until after the job has been awarded and is in detailing, fabrication or erection. Small oversights can have big impact and may cause delays or additional costs. Potential issues are avoidable by understanding structural steel systems and their connections. This seminar will address different aspects of lateral system design, main member design, connection design and avoidable problems. Actual examples from real projects will be highlighted and discussed. The session will include discussion from a steel detailer and a steel fabricator related to the associated construction costs and/or change orders resulting from document quality and clarity.

1:45 pm – 3:15 pm A Day in the Life of a Project ManagerSpeakers: John Aniol, Walter P Moore; Corey Matsuoka, SSFM International

Follow a structural project manager as he struggles through a day filled with risk and discovers tools to help him mitigate those risks. Some of the tools he will discover will cover communication, corporate culture, planning and prevention, education, scope and contracts, construction documents and construction.

3:30 pm – 5:00 pm Managing Expectations and Risks During the Steel Detailing ProcessSpeakers: Glenn Bishop, LBYD, Birmingham AL; Will Ikerd, RLG Engineers, Dallas, TX

The AISC Code of Standard Practice provides two options for structural steel connections, either fully detailed by the engineer or selected and completed by the detailer. After much discussion, AISC is considering adding a third option for connection: design by a specialty structural engineer retained by the fabricator. This session will explore the needs and expectations of both the engineer and the fabricator for each of these three options. Also discussed will be how these expectations might change in the BIM world.

CASE to Conduct Code Complexity Panel Discussion at NASCC in Orlando

ACEC Outreach Leads to String of QBS VictoriesACEC, working in close coordination with ACEC/Kansas

and the Joint Forces National Guard, secured another victory last month for Qualifications-Based Selection (QBS). This is the latest in a series of successful interventions by ACEC in recent months that have led to federal agencies bringing their procurement policies into compliance with the Brooks Act. The latest victory occurred when a Member Firm notified ACEC/Kansas of an apparent Brooks Act violation in a National Guard RFP. Kansas alerted the national headquarters, which contacted the Guard to raise the issue and reinforce the benefits of QBS both for taxpaying citizens and for the overall public safety. Kansas National Guard procurement officials were very responsive to ACEC’s concerns, not only fixing the problem contract but offering to work with the Council to educate their managers on A/E procurements. Scott Heidner, Executive Director of ACEC/Kansas, underscored the significance of this offer, saying “Making sure they comply with Brooks moving forward is the lasting success.” ACEC has successfully intervened on behalf of Member Firms a dozen times since last summer with DOD agencies, FEMA, GSA and other federal agencies to promote QBS and full compliance with the Brooks Act. In many cases, procurement officials were unaware of the benefits offered by QBS and its required application.

ACEC Annual Convention Takes On Economic, Business Challenges Facing FirmsAcross the board, ACEC’s 2010 Annual Convention and

Legislative Summit will address current business conditions and opportunities. To be held in Washington, D.C., April 25-28, the Convention will feature more than two dozen top-tier business sessions tackling pressing management concerns, including how to restore firm growth and win projects in a changing and highly competitive marketplace. Procurement officers from key federal agencies – including NASA, U.S. Army Corps of Engineers, General Services Administration, State Department, Department of Veteran’s Affairs, and Department of Energy – will describe new contracting opportunities. Gregory Ip, U.S. economics editor for The Economist magazine, will provide a market forecast. Leaders of three of the nation’s largest engineering firms will discuss current and future industry challenges. The group includes Robert Uhler, chairman and CEO of MWH Global; Leonard Rodman, chairman, president and CEO of Black & Veatch; and George Pierson, CEO of Parsons Brinckerhoff. A Bentley Systems-sponsored panel on cyber-engineering will feature CIOs from AECOM, Jacobs Engineering, Malcolm Pirnie, and WSP Flack & Kurtz. CEO Roundtables, organized by firm size, will address

operational issues affecting firms. For more information go to www.acec.org.

ACEC Business Course Identifies Contract “Red Flags”ClosingtheDealWithA/E/CContracts:RecognizePitfalls,NegotiateWinnersMay20 -21,SanFrancisco

Identify and demystify “red-flag contract provisions,” acquire the skills and principles of toe-to-toe negotiating to maintain professional standards and protect your business. Learn the differences between custom contracts and model contracts, the pitfalls, and how to negotiate to win-win agreements. Closing the Deal With A/E/C Contracts: Recognize Pitfalls, Negotiate Winners is an in-depth course designed to meet the contract needs of engineers, architects, contractors, project managers, contracting officers, specifiers, and those responsible for procuring construc-tion or design services. Presented by a faculty of experts with

years of industry experience, the course will update attendees’ knowledge in critical contract areas including:

• Controversial contract provisions, from every angle• The elements of good negotiating and errors to avoid• The latest revisions to the most-used contracts• Recent court rulings involving construction contracts• Protecting the bottom line: how profits can be won or lost

in negotiations For details and to register contact LaCreshea Makonnen at

ACEC at [email protected] or 202-347-7474.

In addition to the CASE Risk Management Convocation in Orlando next month at the 2010 Structures Congress, CASE is conducting a program on the business impacts and risks associated with code complexity at the North American Steel Construction Conference (NASCC). As reported earlier, the Structures Congress and the NASCC are combining their events for the first time. Code Complexity – Risks and Cost to the Profession, and how this issue is affecting the “bottom line”, will feature a panel discussion moderated by Edward W. Pence, Jr, Stroud,

Pence and Associates with three practicing structural engineers who are responsible for the operation of their respective firms. The panelists include James C. Parker, Simpson, Gumpertz & Heger; Art Johnson, KPFF Consulting Engineers; and Jaime Vasquez, Walter P Moore and Associates, Inc.

CASE News April10.indd 2 3/19/2010 9:56:27 AM

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Structural Forum is intended to stimulate thoughtful dialogue and debate among structural engineers and other participants in the design and construction process. Any opinions expressed in Structural Forum are those of the author(s) and do not necessarily reflect the views of NCSEA, CASE, SEI, C 3 Ink, or the STRUCTURE® magazine Editorial Board.

34

We Need to Work Together or Risk Being Torn ApartBy Barry Arnold, S.E., SECB

Engineers, as a whole, are an impressive collection of the best and brightest graduates coming out of our universities. Their ability to think deeply and focus their attention on problems, analyze a variety of possible solutions, and find a viable answer is unparalleled. Engineers’ minds are geared toward critical thinking and problem solving. We have reason to be proud – as long as our pride does not get in the way of a greater good.That fact was brought out when I ar-

rived early for an important meeting with a client. Alone in the large conference room, I busied myself making notes and answering e-mails. A few minutes later, I was joined by a woman and her male assistant. They sat at the far end of the room talking loudly so that their con-versation could easily be overheard. The exchange went like this:“Did you know there’ll be twelve engi-

neers in the meeting today?” the woman stated somberly, with an apprehensive quality in her voice.“Twelve! Oh no! We’ll never get anything

done,” was her companion’s lament.After a labored pause, the woman de-

clared, “All engineers do is argue about what and who is right, all the while look-ing for someone to blame when things go wrong and devising a strategy to get more credit than they deserve when the project’s a success.”The man stated, “Big egos, huh?“The worst!” replied the lady without let-

ting a second go to waste. She quickly followed up the comment, saying, “Work-ing with engineers is a lot like herding cats. They all tend to go in the same general direction, but all at different speeds, in-different to those around them, and each with their own agenda.”Having heard enough, I went to my

companions and introduced myself as a structural engineer. I was hoping for a look of surprise or guilt, or some minor act of repentance in the form of a retrac-tion of their gross generalizations. All I received was a look of sympathy.I believe what hurt the most was the fact

that, to a large degree, the lady was correct.As a group, structural engineers are very

fragmented across a number of superfluous

lines. We compare and contrast ourselves against those around us based on:

• Education: Ivy Leaguer schools vs. state universities;

• Degree: PhD vs. MS vs. BS;• Office Size: Large vs. medium vs.

small vs. working out of your house;• Office Location: East coast vs. west

coast vs. no coast;• Project Size: Big vs. medium vs.

small; and,• Pending Disasters: Earthquake vs.

hurricanes vs. floods vs. tornados vs. ice storms, etc.

As structural engineers, our primary goal and purpose is to hold paramount the health, safety and welfare of the public. Everything else is secondary – and likely of little consequence.Psychologists tell us that we create these

artificial boundaries as a means of pro-moting our own self-worth. It is the same old routine that is practiced on playgrounds across America today: “I did this… (fill in the blank)… and you didn’t; therefore, I’m better.” The logic is

erroneous – seriously flawed, in fact – and detrimental to the health and vitality of a state-level SEA, as well as NCSEA, CASE and SEI at the national level.It is vital that our professional organiza-

tions not become fragmented over petty differences. As a group of peers, we must respect input and advice from all of our members, along with non-member en-gineers and other interested parties. You do not need to watch very many nature programs on television to realize that a fragmented herd is easily hunted. The goal of the predator is to frighten, sepa-rate and ultimately cull the heard. When we as individuals distance ourselves from our professional organizations, we lose in two important areas: We are not able to support the goals, objectives and growth of those groups; and, we cannot reap the rewards, opportunities and benefits that membership offers.

Take, for example, a member structural engineer who will not attend local mem-bership meetings because a particular competitor, to whom they lost a project, might be in attendance. This is unfortu-nate and counterproductive. Although it is always disappointing to see someone else receive work that we were actively seeking, this alone should never preclude us from participating in and contributing to an organization to which both parties belong. We can and should still work together for our common interests, keep-ing our eyes on the big picture instead of getting sidetracked by hard feelings over a short-term setback.As individual structural engineers acting

alone, we will not be able to progress much in promoting the causes of our profession. You may make some headway, but it will be painfully slow and will usu-ally have little lasting effect. By contrast, as a contributing member of your SEA, CASE and/or SEI, your impact will be significant, substantial and long-term; you can help establish goals and define objectives that may guide the profession for many years to come. You can set stan-dards and make improvements that will benefit the membership and society today and for generations into the future.One fact remains certain: If we do not

work together as a collection of valued and respected peers, we will certainly be torn apart, leaving the growth and value of the profession in question. Together we need to focus on the biggest possible picture, solve the most pressing problems, and chart a course to achieve the worthy goals of our professional organizations. The work is easier and more swiftly accomplished when everyone supports these organizations by providing input and assistance.▪

Barry Arnold, S.E., SECB, is a Vice President at ARW Engineers in Ogden, Utah. He is a Past President of the Structural Engineers Association of Utah (SEAU), serves as the SEAU Delegate to NCSEA, and is a member of the NCSEA Licensing Committee. Barry can be reached at [email protected].

“All engineers do is argue about what and

who is right,...”

C-StructForum-Arnold-April10.indd 1 3/19/2010 9:57:23 AM

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