Manufacture r Of Architectur al And Commercial Grade Windows, Curtain Walls, Entrances, And Storefronts EFCO UNIVERSITY 2008 VSEC Seminar March 26, 27 2008 Virginia Beach, VA Richmond, VA David DeSutter, P.E. Director of Engineering and Customer Service EFCO Corporation Mitch Snead The Snead Company
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VSEC Seminar March 26, 27 2008 Virginia Beach, VA Richmond, VA David DeSutter, P.E.
VSEC Seminar March 26, 27 2008 Virginia Beach, VA Richmond, VA David DeSutter, P.E. Director of Engineering and Customer Service EFCO Corporation Mitch Snead The Snead Company. VSEC Seminar March 26, 27 2008 Virginia Beach, VA Richmond, VA - PowerPoint PPT Presentation
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Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
VSEC SeminarMarch 26, 27 2008
Virginia Beach, VA
Richmond, VA
David DeSutter, P.E.
Director of Engineering and Customer Service
EFCO Corporation
Mitch Snead
The Snead Company
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
VSEC SeminarMarch 26, 27 2008
Virginia Beach, VA
Richmond, VA
Better Communication = Better Overall Structure
Pondering Point:
During a “design event,” the typical commercial “window” will fail due to either improper anchorage or under-designed surrounding
conditions.
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
VSEC SeminarMarch 26, 27 2008
•Curtain Wall vs. Storefront (General, Construction, Connection and Anchors)
•Accurate span information (dimensions), location of appropriate anchors! $$$$
•Aluminum Association ASD/LRFD
Goal: Transfer all wind forces to MWFRS
WL Reactions: 200 lbf to 3,500 lbf per anchor is typical
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
Snow Considerations
•Flat Roof Snow Loads + Drift Surcharge on Bladed Sunshades is (?)
•Mullion Attachment Typical for Sunshades
Goal: Transfer all snow forces to curtain wall system, then to MWFRS
Effect of Snow on Reactions: Little effect to MWFRS
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
Seismic Considerations
•Racking of CW – Engineer of Record Must Provide Calculated Interstory Drift!
•Controlled “Fallout” is the Standard (Fallout in ASCE 7)
Ps
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
Seismic Considerations
•Shear Forces per ASCE 7
• Calculate Fp = .4ap(Sds)Wp/(Rp/Ip) (1+2(z/h))
• Fp= Seismic force acting at centroid of mullion, with load evenly distributed along length of mullion
– Fp acts the same as the wind load
– Varies for perimeter anchors
– Determine Deflection, Stress of frame member
– Can be problematic for intermediate
wind load anchors
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
Seismic Considerations
•Racking of CW
•Shear Forces per ASCE 7
Goal: Transfer all seismic forces to MWFRS
Seismic Reactions: Usually 50% of WL (200 lbf to 3,500 lbf per anchor is typical), but in-plane along weak axis
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
Thermal/Vertical Movement Considerations
•CW Mullions Buckle Easily
•Must Account for all Vertical Movement (Thermal + Building Movement) $$$$
•Must Maintain Integrity of Perimeter Sealant Joint and Satisify Architectural Aesthetics
•Sealant Joint RoT = ½ x Joint Width (Compression/Tension)
•“Standard” System (no “Bells & Whistles”) good for +/- ¼” to ½” +/-!!
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
Thermal/Vertical Movement Considerations
Total VM = Thermal + LL + CS + Creep + DL
Thermal
Glass contact controls
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
Thermal/Vertical Movement Considerations3 3 33333333
33
33
33
2 2
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
Thermal/Vertical Movement Considerations
HL94
STV2STV2STV2
STK4 STK4
WN
E0
WN
E0
WE
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WN
E0
WV80STC0
5959
6345
S
ARCH./G.C. NOTE:COPING AT THIS LOCATION WILL SEE POSSIBLE3/4" OF MOVEMENT DUE TO THE THERMALEXPANSION OF VERTICAL MULLION. PLEASECONFIRM AS ACCEPTABLE.
Thermal + Slab Movement
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall Performance
Wind, Snow, Seismic/Drift, Thermal/VM, Impact and Blast
•CW/SF Manufacturer’s Design Considerations (What We Need)
•CW/SF Manufacturer’s Design Considerations (What We Get)
•CW/SF Manufacturer’s Design Considerations (What We Assume)
•CW Analysis, Rules of Thumb
•Reference Information
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Wind Considerations
1. Appropriate Code [No code or conflicting wind speeds – ie. 3 second gust wind speeds with fastest mile code]
2. Appropriate Exposure and Wind Speed [Conflicting wind speeds]
3. Accurate Span Information [“Like pulling teeth”]
4. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [You be the judge - Plywood, 20 ga. Stud, face brick, masonry/concrete w/o edge distance are problematic]
Manufacturers Bid Documents:
1. Take-off from installer
2. Plans (Architecturals, limited Structurals) and Specs
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Wind Considerations
3. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [Is this lintel able to handle the wind loads?.]
200# - 3,500#
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Wind Considerations
3. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [Can this masonry handle these loads? If so, it is very difficult for the CW anchor to hit the center of the cell.]
200# - 3,500#
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Wind Considerations
3. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [No doubt the concrete can handle the wind loads, but maintaining edge distance is impossible w/o customization.]
200# - 3,500#
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Snow Considerations
1. Appropriate Code [Code is identified 50% of time.]
2. Appropriate Ground Snow Load [Ground snow load is specified in some cases, drift surcharge is rarely, if ever specified…]
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Seismic/Drift Considerations
1. Appropriate Code [Typical spec: “Curtain wall system must be designed to resist appropriate seismic forces and displacements…..”]
2. Must, Must, Must have calculated interstory drift. [See above.]
3. Must have Design Spectral Response Acceleration (Sds) variable to calculate seismic shear (ASCE 7, Section 9.4.1.2) [This is rarely, if ever provided in specifications]
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Thermal/VM Considerations
1. Total Vertical Deflection per Floor (not the Allowable by Code!) [Sometimes we get the LL, column shortening and creep as a maximum for all floors, all spans. Most of the time, spec reads: “…curtain wall system must be designed to accommodate deflections including, but not limited to live load, dead load, column shortening, creep and thermal expansion and contraction of the curtain wall system assuming a temperature differential of 180 deg F…”]
2. Is the Total Vertical Deflection “Up and Down” or Different? [Rarely get different values for “up” and “down,” see above]
3. (The CW Manufacturer Will Add in the Thermal Movements)
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Impact Considerations
1. Appropriate Code (for DP) [No code or conflicting wind speeds – ie. 3 second gust wind speeds with fastest mile code]
2. Appropriate Wind Speed (Local Codes May Override Model BC) [Conflicting wind speeds]
3. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [You be the judge…]
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Get
Blast Considerations
1. Charge and Standoff Distance or Blast Load and Impulse for “Blast Design” (DoD is prescriptive) [Rarely if ever specified…]
2. Appropriate Perimeter Condition (Structure) for Short Duration Blast Loads! [Our opinion is the perimeter structure is generally ignored for windows and CW for blast projects …]
10,000# +
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
VSEC SeminarMarch 26, 27 2008
•Curtain Wall vs. Storefront (General, Construction, Connection and Anchors)
•CW/SF Manufacturer’s Design Considerations (What We Need)
•CW/SF Manufacturer’s Design Considerations (What We Get)
•CW/SF Manufacturer’s Design Considerations (What We Assume)
•CW Analysis, Rules of Thumb
•Reference Information
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Wind Considerations
1. Appropriate Code [No code or conflicting wind speeds – ie. 3 second gust wind speeds with fastest mile code] [Assume latest ASCE 7.]
2. Appropriate Exposure and Wind Speed [Conflicting wind speeds] [Assume an Exposure Cat. (usually “C”) and wind speed based on map.]
3. Accurate Span Information [“Like pulling teeth”] [“Quote and qualify” then hope for the best and plan for the worst]
4. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [You be the judge - Plywood, 20 ga. Stud, face brick, masonry/concrete w/o edge distance are problematic] [Assume that condition will support loads, assume architect passes info to engineer of record.]
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Wind Considerations
3. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [Plywood, 20 ga. Stud, face brick, masonry/concrete w/o edge distance and lintels.] [Assume that condition will support loads, address water concern, redesign anchor as necessary, assume architect passes info to engineer of record.]
200# - 3,500#
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Wind Considerations
3. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [Plywood, 20 ga. Stud, face brick, masonry/concrete w/o edge distance and lintels.] [Assume that condition will support loads, redesign anchor as necessary, assume architect passes info to engineer of record.]
200# - 3,500#
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Wind Considerations
3. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [Plywood, 20 ga. Stud, face brick, masonry/concrete w/o edge distance and lintels.] [Assume that condition will support loads, redesign anchor as necessary, assume architect passes info to engineer of record.]
200# - 3,500#
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Snow Considerations
1. Appropriate Code [Code is identified 50% of time.] [Assume ASCE 7]
2. Appropriate Ground Snow Load [Ground snow load is specified in some cases, drift surcharge is rarely, if ever specified…] [Assume ground snow loads in ASCE 7, use best judgment on drift surcharge.]
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Seismic/Drift Considerations
1. Appropriate Code [Typical spec: “Curtain wall system must be designed to resist appropriate seismic forces and displacements…..”] [Assume ASCE 7, but……..]
2. Must, Must, Must have calculated interstory drift. [See above.] [Assume that our “standard” performance for fallout is less than the calculated interstory drift, communicate to architect, assume that this information is passed to Engineer of Record. This information is rarely provided.]
3. Must have Design Spectral Response Acceleration (Sds) variable to calculate seismic shear (ASCE 7, Section 9.4.1.2) [This is rarely, if ever provided in specifications] [Make a call to customer/architect. Thus far, this information is almost always provided.]
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Thermal/VM Considerations
1. Total Vertical Deflection per Floor (not the Allowable by Code!) [Sometimes we get the LL, column shortening and creep as a maximum for all floors, all spans. Most of the time, spec reads: “…curtain wall system must be designed to accommodate deflections including, but not limited to live load, dead load, column shortening, creep and thermal expansion and contraction of the curtain wall system assuming a temperature differential of 180 deg F…”] [Assume that our standard system as quoted will meet the requirement - bad assumption. Hard splice everywhere possible to minimize moving joints. Use realistic F.]
2. Is the Total Vertical Deflection “Up and Down” or Different? [Rarely get different values for “up” and “down,” see above] [Assume same “up” and “down” deflections.]
3. (The CW Manufacturer Will Add in the Thermal Movements) […using “realistic” F…]
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Impact Considerations
1. Appropriate Code (for DP) [No code or conflicting wind speeds – ie. 3 second gust wind speeds with fastest mile code] [Use ASCE 7.]
2. Appropriate Wind Speed (Local Codes May Override Model BC) [Conflicting wind speeds] [Use ASCE 7 wind speed map.]
3. Appropriate Perimeter Condition (Structure) for “Higher” DP Regions [You be the judge…] [Assume that condition will support loads, assume architect passes info to engineer of record.]
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
Curtain Wall PerformanceWhat We (Manufacturers) Assume
Blast Considerations
1. Charge and Standoff Distance or Blast Load and Impulse for “Blast Design” (DoD is prescriptive) [Rarely if ever specified…]
2. Appropriate Perimeter Condition (Structure) for Short Duration Blast Loads! [Our opinion is the perimeter structure is ignored…] [Assume that condition will support loads, design anchor and connection accordingly, assume architect passes info to engineer of record. Bad assumption in the case below…]
10K – 20K
Manufacturer
Of
Architectural
And
Commercial
Grade
Windows,
Curtain Walls,
Entrances,
And
Storefronts
EFCO UNIVERSITY 2008
VSEC SeminarMarch 26, 27 2008
•Curtain Wall vs. Storefront (General, Construction, Connection and Anchors)