Rams Beam

DAA037950-1/0001

RAM SBeamTM

Manual

Version 4.0 October 2008

Bentley Systems, Inc 2744 Loker Avenue West, Suite 103

Carlsbad, CA 92010 Telephone: (760) 431-3610 Toll Free: (800) 726-7789

Fax: (760) 431-5214

TRADEMARK NOTICE Bentley and the "B" Bentley logo are registered or non-registered trademarks of Bentley Systems, Incorporated. RAM SBeam, RAM Structural System, RAM Manager, RAM Modeler, RAM Steel, RAM Frame, RAM Foundation and RAM Concrete are registered or non-registered trademarks of Bentley Systems, Incorporated. All other marks are the property of their respective owners. COPYRIGHT NOTICE Copyright (c) 2008 Bentley Systems, Incorporated. All Rights Reserved. Including software, file formats, and audiovisual displays; may only be used pursuant to applicable software license agreement; contains confidential and proprietary information of Bentley Systems, Incorporated and/or third parties which is protected by copyright and trade secret law and may not be provided or otherwise made available without proper authorization. ACKNOWLEDGEMENTS Includes Adobe(R) PDF Library technology. Portions Copyright (c) Adobe Systems, Inc. Objective Grid C++ Library Copyright Rogue Wave Software, Inc. Virtual Print Engine (VPE) Copyright IDEAL Software Portions Copyright Microsoft Corporation RESTRICTED RIGHTS LEGENDS If this software is acquired for or on behalf of the United States of America, its agencies and/or instrumentalities ("U.S. Government"), it is provided with restricted rights. This software and accompanying documentation are "commercial computer software" and "commercial computer software documentation," respectively, pursuant to 48 C.F.R. 12.212 and 227.7202, and "restricted computer software" pursuant to 48 C.F.R. 52.227-19(a), as applicable. Use, modification, reproduction, release, performance, display or disclosure of this software and accompanying documentation by the U.S. Government are subject to restrictions as set forth in this Agreement and pursuant to 48 C.F.R. 12.212, 52.227-19, 227.7202, and 1852.227-86, as applicable. Contractor/Manufacturer is Bentley Systems, Incorporated, 685 Stockton Drive, Exton, PA 19341-0678. Unpublished - rights reserved under the Copyright Laws of the United States and International treaties.

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Preface RAM SBeam is a powerful and versatile program for the design of steel beams. Using one of several design codes, RAM SBeam can select the optimum beam size or check the adequacy of existing construction. The program provides rapid evaluation and comparison between various beams under various load conditions. RAM SBeam has a user interface unparalleled for simplicity and ease of use, while providing a very powerful design capability. This results in substantial time savings for the Engineer and a more economical design for the client. The User should become thoroughly familiar with the documentation and gain a thorough understanding of the program. This will allow the User to analyze members more rapidly and correctly. As a professional, the Engineer is ultimately responsible for the design of the structure. RAM SBeam is a tool to aid in that endeavor; it cannot replace sound engineering judgment. Features:

Composite Beam Design and Investigation Non-composite Beam Design and Investigation Cantilevers Braced or Unbraced Compression Flange ASD, LRFD, Canadian, British or Eurocode design English, SI, and Metric Units Rolled and Built-up Shapes Foreign and Domestic Steel Tables Web Opening Design Beam Self-weight Automatically Included Load Diagrams Shear, Moment, and Deflection Diagrams User Control of Design Criteria and Parameters

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Disclaimer The software and related documentation, including this documentation, are protected by both United States copyright law and international treaty provisions. Any unauthorized copying or reproduction is strictly prohibited and subject to civil and criminal penalties. Please refer to the License Agreement (EULA) for authorization to make a backup copy of the software. You may not sell this software or documentation or give copies of them to anyone else. Except as expressly warranted in the License Agreement (EULA), Bentley Systems, inc. disclaims all warranties, expressed or implied, including but not limited to implied warranties or merchantability and fitness for a particular purpose, with respect to the software, the accompanying written materials, and any accompanying hardware. All results should be verified to the users satisfaction. The contents of these written materials may include technical inaccuracies or typographical errors and may be revised without prior notice.

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RAM SBeam Table of Contents 1 Introduction ................................................................................................................. 1 2 Installation and Defaults.............................................................................................. 3

2.1 Introduction .......................................................................................................... 3 2.2 Installing RAM SBeam ........................................................................................ 3 2.3 RAM SBeam Directories ..................................................................................... 3 2.4 Criteria and Property Defaults.............................................................................. 4

3 Using RAM SBeam..................................................................................................... 5 3.1 Invoking RAM SBeam......................................................................................... 5 3.2 Starting a Design .................................................................................................. 5 3.3 File Management.................................................................................................. 5 3.4 Criteria.................................................................................................................. 6 3.5 Beam................................................................................................................... 14 3.6 Loads .................................................................................................................. 17 3.7 Process................................................................................................................ 20 3.8 Reports ............................................................................................................... 24 3.9 View ................................................................................................................... 25 3.10 Exiting RAM SBeam ......................................................................................... 25 3.11 Keyboard Commands......................................................................................... 26

4 Technical Notes ......................................................................................................... 27 4.1 Steel Design Codes............................................................................................. 27 4.2 Member Loads.................................................................................................... 28 4.3 Composite Beam Design.................................................................................... 30 4.4 Non-Composite Beam Design............................................................................ 38 4.5 Design Yield Strength ........................................................................................ 41 4.6 Material Properties ............................................................................................. 42 4.7 Cross Section Classification............................................................................... 42 4.8 Cantilevers.......................................................................................................... 43 4.9 Unbraced Length ................................................................................................ 44 4.10 Deflection ........................................................................................................... 49 4.11 Camber ............................................................................................................... 50 4.12 Shear................................................................................................................... 50 4.13 Optimization....................................................................................................... 51 4.14 Size and Depth Limitation.................................................................................. 51 4.15 User-defined Rolled and Built-up Shapes.......................................................... 52 4.16 Vibration Analysis.............................................................................................. 52 4.17 Web Openings .................................................................................................... 54

5 RAM SBeam Output ................................................................................................. 59 5.1 Beam Design - Allowable Stress Design (AISC ASD 9th) ............................... 59 5.2 Beam Design AISC 360-05 (ASD & LRFD) and LRFD 3rd ......................... 65 5.3 Beam Design CAN/CSA-S16-01 .................................................................... 67 5.4 Beam Design BS 5950 .................................................................................... 72 5.5 Beam Design Eurocode................................................................................... 79 5.6 Load Diagram..................................................................................................... 81 5.7 Shear, Moment and Deflection Diagrams .......................................................... 82

6 RAM Structural System............................................................................................. 83

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Appendix A: RAM SBeam Tables................................................................................ 85 A.1 Metal Deck Tables ............................................................................................. 85 A.2 Metal Deck Table File Format ........................................................................... 86 A.3 Master Steel Tables ............................................................................................ 87 A.4 Master Steel Table File Format.......................................................................... 88 A.5 Design Steel Tables............................................................................................ 93 A.6 Beam Design Steel Table Format....................................................................... 95

Appendix B: Bison Precast Units ................................................................................. 99 B.1 Deck Properties .................................................................................................. 99 B.2 Criteria................................................................................................................ 99 B.3 Technical Notes................................................................................................ 100 B.4 Contact ............................................................................................................. 102

Appendix C: Steel and Synthetic Fibres ..................................................................... 103 C.1 Modeling .......................................................................................................... 104 C.2 Deck Table ....................................................................................................... 104 C.3 Composite Beam Design.................................................................................. 104 C.4 Beam Design Report ........................................................................................ 106

Introduction

1 RAM SBeam v4.0

1 Introduction RAM SBeam is a powerful program for the design of composite or non-composite beams in strict accordance with several steel code design requirements. RAM SBeam allows any combination of point, trapezoidal, and uniform loads, and can be used to select optimum design for new construction or to check adequacy of existing construction. Member sizes and stud information selected by the program can be easily overridden by the user if necessary, and alternate designs can be investigated. The Windows-based graphical user interface provides the designer with a design tool of unmatched ease of use. Data entry is simplified and intuitive, and data can be entered or modified in any order. Chapter 2 explains the Installation procedures. Chapter 3 is a reference for all commands in the RAM SBeam program. Chapter 4 provides a detailed description of the output. Chapter 5 describes the technical and theoretical concepts employed by the program. Chapters 4 and 5 may be reproduced for submission to the Building Department. Chapter 6 is a brief discussion of the powerful, state of the art program called the RAM Structural System, a more comprehensive software system from which RAM SBeam was derived. If you like the design power, capabilities, and usability of RAM SBeam, you should investigate the information on the RAM Structural System. Appendix A describes the design tables used by the program. Appendix B explains how Bison Precast Units, available in the UK, can be used in RAM SBeam for composite beam design. Appendix C explains how steel and synthetic fibres, available in the UK, can be used with Kingspan, Corus and Tegral decks in RAM SBeam for composite beam design. With RAM SBeam, an Engineer can quickly design and refine the design of composite and non-composite beams. The result is a substantial savings of time as well as a more economical design.

Introduction

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Installation and Defaults

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2 Installation and Defaults

2.1 Introduction

The RAM SBeam Setup program will install RAM SBeam and will setup all the files necessary for the program to run properly. The RAM SBeam Setup Program will prompt for the name of the directories where the program and associated files are to be installed. The program will automatically install with certain defaults set. As described in Section 2.4 the engineer can permanently modify the default settings from within the RAM SBeam program.

2.2 Installing RAM SBeam

To install RAM SBeam, do the following:

Download the installation program from the Bentley SELECT server. Run the downloaded file. This will install the installation program on the hard

drive, and the auto-run program will open an installation window. Select Install RAM SBeam.

A dialog indicating the various directories that need to be created for RAM SBeam will be displayed. Any or all of these directory names and their paths can be changed. To do this simply access the item to change and input the new path and directory name or use the browse button to locate an existing folder. Refer to Section 2.3 of this chapter for greater detail regarding directory names. Click NEXT and a dialog will be displayed in which the default design code and default units are set. The Cancel button causes the setup program to exit.

2.3 RAM SBeam Directories

RAM SBeam will create the following three directories unless they are specified otherwise by the user during installation. PROG: Contains the executable file RAMSBeam.exe, the Help file

RAMSBeam.chm, and the Manual file RAMSBeam.pdf. The default directory is C:\Program Files\Bentley Engineering\RAMSBEAM\PROG. Note: Users of the RAM Structural System or other RAM utility programs may have already established the PROG directory on their computer. RAM SBeam can be installed in the PROG directory that already exists.

Installation and Defaults

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TABLES: Contains the deck and steel beam design tables used by the program. The

tables used by RAM SBeam are the same tables used by the RAM Structural System. The default directory is C:\Program Files\Bentley Engineering\RAMSBEAM\TABLES.

DATA: Contains the output data files of individual beam runs created when the Save

command is invoked. The default directory C:\Program Files\Bentley Engineering\RAMSBEAM\DATA.

2.4 Criteria and Property Defaults

Initial Default Criteria are set during the installation process. The user can modify any default values at any time. To modify a default value:

Invoke the Criteria menu command containing the default to be set. Specifying the new default value. Select the Save as Default option. Select OK and exit from the dialog box.

Some material property items can likewise be set as defaults in the Beam Span Definition command and the Beam Composite command. The specified values will now be the default values whenever the program is run. It is recommended that all of the defaults be thus specified and modified immediately after installing the program, if necessary, prior to proceeding with any designs. Care should be taken to specify all criteria on all tabs of all of the commands, and it should be done in the order that the commands appear in the menus in the program.

Using RAM SBeam

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3 Using RAM SBeam RAM SBeam allows the engineer to evaluate or optimize composite and non-composite steel beams. The following is an overview of the RAM SBeam program and a brief discussion of its use. More information on specific RAM SBeam commands is available in the on-line help.

3.1 Invoking RAM SBeam

RAM SBeam is invoked by selecting the RAM SBeam icon through the Start menu or by double-clicking on the RAM SBeam icon in the designated program folder. Once invoked, the RAM SBeam screen will appear displaying the Bentley Systems, Inc. logo.

3.2 Starting a Design

Upon invoking RAM SBeam, the program is ready to accept data. It is NOT necessary to create a new file before beginning a design. Criteria items and the beam span information can be specified, followed by the data related to composite properties, loads, etc., as explained below.

3.3 File Management

3.3.1 New When File - New is selected after data has been input, all data previously entered is reset to the defaults, and any loads are cleared out. Therefore File - New should only be invoked if the data to be entered is substantially different from the data for the beam just entered, when it is easier to re-input all of the information for a next beam to be designed rather than to modify the data that is different from the previous beam. Generally it will be easier to modify the previous data than to start over by selecting File - New.

3.3.2 Open To open a file that was previously saved by RAM SBeam:

Select the File Open command and select the desired file from the list. All of the criteria, geometry, and design information will be restored from that file.

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3.3.3 Save To save a file:

Select the File Save or the File Save As command and specify the file name. This will save all of the current criteria settings, beam geometry, loads, etc. If the beam size has been specified as a user-specified size (rather than as an optimum size), the size and studs will be saved as well.

3.3.4 Job Information A Job Name and Comments can be entered by invoking the File Job Information command. This text will appear on the reports generated in the Reports command. This command is also automatically invoked whenever one of the Reports is created.

3.3.5 Print In addition to the standard reports available in the Reports menu, the File Print Screen command is available to print out the current view on the main screen. File Print Preview can be used to preview what is going to be printed, and File Print Setup can be used to modify printer settings for that printout. Note that File Print Setup only affects the printout of the view on the main screen; it does not affect the settings used for the printing of the standard reports.

3.4 Criteria

Various criteria can be specified for each design. These allow the engineer to specify options and values resulting in designs that conform to the design philosophy of the engineer. The criteria are divided into five categories: General, Design, Deflection, Camber and Web Openings. If the default values are acceptable for the current design session, it is not necessary to explicitly select these menu items. The default criteria can be modified by the user by invoking the desired Criteria command, specifying the desired criteria values, and then selecting the Save as Default option. Subsequent designs will be performed using these new default criteria settings unless modified.

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3.4.1 General

Units: RAM SBeam can accept input and provide output in English (US Imperial), SI or Metric units. The units can be changed at any time during the design process by selecting the Units tab on the Criteria - General command. The capability to change units at any time is useful in the case where a job requires the production of designs in units in which the engineer is unaccustomed to working. A beam can be modeled and designed in a familiar system of units. Once the design is completed to the satisfaction of the engineer the units can be changed for the final output reports.

Tables: When inputting the composite beam data the deck type must be specified. The data for the deck type is taken from the deck table selected in the Tables tab of the Criteria General command. Decks commonly used in the U.S. are listed in RAMDECKS.DCK. Decks commonly used in Canada are listed in RAMCAN.DCK. Decks commonly used in the U.K. are listed in RAMUK.DCK. Decks commonly used in Australia are listed in RAMAS.DCK. When selecting member sizes the program selects sizes from the Design Table selected in the Tables tab of the Criteria General command. The Design Table lists the sizes to be considered, ordered by economy (least weight). The section properties of those sizes are listed in the corresponding Master Table. It is important to note that when a Design Table is specified, it is necessary to also specify a Master Table that includes the section properties for all of the sizes listed in the Design Table. Several Design and Master Tables are included. They can be customized (sizes reordered and regrouped, undesirable shapes deleted, etc.) or new tables created. See Appendix A for more information. Sizes commonly used in the U.S. are listed in RAMAISC.BMS, and the corresponding Master Table is RAMAISC.TAB. Sizes commonly used in Canada are listed in RAMCAN.BMS, and the corresponding Master Table is RAMCAN.TAB. Sizes commonly used in the U.K. are listed in RAMUK.BMS, and the corresponding Master Table is RAMUK.TAB. Sizes commonly used in Australia are listed in RAMAS.BMS, and the corresponding Master Table is RAMAS.TAB.

3.4.2 Design

Code: The steel design specifications of several codes have been implemented. The design code to be used for design can be selected on the Code tab of the Criteria Design Criteria command. Options include AISC 360-05 ASD and LRFD, AISC ASD 9th Edition, with or without the requirements of Supplement #1, AISC LRFD 3rd Edition, Canadian CAN/CSA-S16-01, BS 5950 : 1990 or BS 5950 : 2000, and Eurocode ENV provisions.

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The appearance of and options available in some of the other Criteria commands are affected by the design code selected here.

Studs: The user is given considerable control over the design of composite beams with respect to shear studs. Stud criteria can be specified on the Studs tab of the Criteria Design Criteria command. Care should be taken to avoid specifying conflicting criteria values, resulting in no beam size being capable of satisfying all of the criteria simultaneously. Each code has limits on the minimum and maximum percent of full composite that is allowed, but more stringent values can be specified. If the values specified by the user are less stringent than the code requirements, the user-specified values will be ignored in design. The number of rows of studs that can be placed down the length of the beam are dependent upon the flange width, flange thickness, spacing requirements of the studs, and staggering of the studs. The program considers these in the selection of the beam size. The maximum number of rows allowed can be limited by the user. The width of beam required to accommodate the studs is dependent upon the edge distance and center-to-center spacing requirements of the design code used and on the stud configuration (staggered or aligned). The program does not investigate any of these requirements individually, rather it bases the allowable number of rows on the minimum flange width values specified by the user. The minimum flange width required for two rows of studs and for three rows of studs can be specified, and should account for the above mentioned conditions. During optimization, the beam size being investigated will be rejected if multiple rows of studs are required and its flange width is less than the minimum width specified for that number of studs. The maximum allowable center-to-center spacing of the studs, measured along the length of the beam, is specified by the code. A more stringent spacing may be specified. This option should be used cautiously, however, to avoid unintended results. Remember that for skewed beams the distance between ribs measured along the length of the beam is increased. Too small values of Spacing may conflict with the actual rib spacing. Studs are usually placed on a beam such that they are uniformly distributed except in the case of girders, which often require a higher density of studs between the point of zero moment and the point where the beam frames in. These stud configurations are referred to by the program as Uniform Distribution and Segmented Distribution, respectively. If the Optimum Distribution option is selected the program will use either the Uniform or Segmented Distribution, as appropriate for the beam being designed. If the Uniform Distribution option is selected, the program will always base the design on a uniform stud distribution, ensuring that the uniform distribution called for has a density of studs

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sufficient to satisfy every individual segment of the girder. This option generally results in a greater number of studs, but simplifies the stud callout and placement. Generally if the composite beam does not have a sufficient number of studs to satisfy the minimum stud requirements of the code, the beam should be designed as a non-composite beam. Normally the Use Bare Beam section properties option should be selected in order to enforce this requirement. When investigating existing conditions when there are insufficient studs, however, it is sometimes desired to see how close the beam is to satisfying the minimum percent composite requirements and what the corresponding composite design results are. This can be accomplished by selecting the Use Composite section properties option. Note that this option should be used carefully because it allows the analysis of beams that violate the minimum percent composite requirements of the code. Also note that this option is ignored when the beam size is being Optimized, it is only allowed when the beam size is being Analyzed (investigated). For AISC 360-05 a Stud Placement option that affects the calculation of Rp (See Section 4.3.4) is available. In AISC 360-05 Section I3.2c, emid-ht is defined as distance from the edge of the stud shank to the steel deck web, measured at mid-height of the deck rib, and in the load bearing direction of the stud (in the direction of maximum moment for a simply supported beam) Design Defaults: The terminology used and the options available in the Design Defaults tab of the Criteria Design Criteria command vary, depending on the Code selected. A number of options can be specified that affect the calculation of the unbraced length, or distance between braced points of the compression flange. If the Check Unbraced Length option is not selected, the program will assume that both the top and bottom flanges of the beam are fully braced for the entire length of the beam. It is not recommended to deselect this option unless the beam is truly fully braced. There are differing design philosophies regarding the effect of the point of inflection on the bracing conditions of the compression flange. The Consider Point of Inflection option is discussed in greater detail in Section 4.9. The stiffness of profiled steel deck varies based on the direction it is spanning. Hence its ability to brace the top flange of the beam may vary as well. For the design of the precomposite condition of composite beams, the ability of the deck to brace the top flange can be indicated with the Deck Perpendicular to Beam Braces Flange and Deck Parallel to Beam Braces Flange options. These options have no impact on the bracing of the bottom flange, which by default is assumed to be unbraced unless specified otherwise. Addition bracing information can be specified using the Beam Bracing command, see Section 3.5.3.

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Steel Material: The Steel Material tab is available when CAN/CSA-S16-01 is selected as the design code. The steel material type (Table 6-3 from CISC Handbook, Seventh Edition) must be specified. The designated steel material type is combined with the nominal yield strength to determine the steel grade and the design yield strength of the section. For example, a section of type W with a nominal Fy of 350N/mm2 is assigned a steel grade of 350W. A nominal Fy of slightly less than 350 will result in a steel grade of 300W. Specifying a nominal Fy and material type that has no matching steel grade will result in a design yield strength of 0.0 and no grade assignment. Vibration: The Vibration tab is available when BS 5950 is selected as the design code. A simplified method of determining the acceptability of a composite beam for vibration has been implemented based on the beams frequency. Different frequency limits can be set for both short span and long span beams. The transition span length between short span and long span is specified by the user. The frequency is calculated by a simplified method using the following equation:

Fz = 18/sqrt (deflection) where the deflection is based on the full composite section using the short term modular ratio under Dead Load and 10% of the Live Load. Ig may be increased 10% to account for increased stiffness of the beam under dynamic loading, such as for the effects of continuity. If the size fails the specified limit, a larger size will be used when optimizing beam sizes. A value of 0.0 specified for the minimum frequency means that there is no minimum limit on the frequency; specify 0.0 if the simplified vibration approach is not to be used. Steel Section Options: The Steel Section Options tab is available when BS 5950 is selected as the design code. Hollow Sections can either be designated as Hot-Rolled or Cold-Formed. This designation affects the classification of the cross section (see table 12 in BS5950-1:2000), and the web shear interaction as described in H.3 of BS5950-1:2000. This selection has no impact on BS5950-1:1990. The Distance top-of-section to axis of restraint option applies to beams which are fully braced at the top flange. The dimension entered is used in calculating the lateral torsional buckling capacity of beams with fully restrained tension flange (hogging region) per 4.3.5.3c and Annex G.2. of BS5950-1:2000. This selection has no impact on BS5950-1:1990.

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IBS 5950-1:2000 has changed the method in which the lateral torsional bending capacity of beams is calculated. In certain circumstances, where the tension flange of a beam is fully braced and the compression flange unbraced, the height of the restraint to the tension flange affects the bending capacity of the member (See BS 5950-1:2000 4.3.5.3c, Annex G.1. and G.2.). This will typically affect the design of cantilever or continuous members in the zone where the unbraced lower flange is in compression. The engineer can stipulate the distance from the top-of-flange (tension flange), to the center of the restraint of that flange. Bison PC Units: The Bison PC Units tab is available when BS 5950 is selected as the design code. The program can perform composite beam design using Bison precast units for the slab. On the Bison PC Units tab some items can be specified by the user, other items are shown for informational purposes only to show the values that the program will be using in the design of composite beams with the Bison Precast units. The gap between planks at the supporting beam is determined based on the beam flange width, the required Bearing Width of the plank, the Slab Tolerance and the Construction Tolerance. The beam design will be rejected if the resulting gap width is less than 30mm, and a wider beam will be selected. A gap of at least 30mm is necessary in order to fit the studs between the precast units. The gap value is also used in the determination of the effective flange width. Bearing Width is the required width of bearing of the precast unit on the beam flange. Slab Tolerance is the manufacture tolerance of the precast unit. Construction Tolerance is the manufacture and construction tolerance of the steel beam. Information regarding the transverse reinforcement and the precast units is also displayed to indicated the values that will be used by the program. These values can not be modified by the user. See Appendix B for more information on the design of composite beams with Bison Precast Units. Eurocode Factors: The Eurocode Factors tab is available when Eurocode is selected as the design code. A number of factors used in the Eurocode may vary from country to country. Their values are specified in the individual countrys National Application Document (NAD). The user may specify these values as appropriate. The dialog that is displayed is divided into four frames each of which is described briefly below.

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Partial Safety Factors: Load factors for load combination generation and member resistance factors for adjusting member capacity. Composite Beam Design: Factors used in the design of composite beams. Psi: Psi vec is used in the calculation of bending capacity, Meff, when lateral torsional buckling is being considered. Design fy: Indicate whether the design fy should be reduced according to the member thickness as described in the Eurocode. Beam Lateral Torsional Buckling (Zg=0): Specify whether loads applied along the length of the section are applied at the top flange or at the shear center. The selected option will impact the magnitude of Mcr per Annex F of ENV 1993-1-1:1992 by setting Zg=0 if the load is applied at the shear center.

3.4.3 Deflection Deflection criteria can be set independently for Composite Unshored, Composite Shored, and Non-Composite beams. L/d indicates a minimum span-to-deflection ratio, delta indicates an absolute maximum deflection value. A value of "0" indicates no limit for that condition. The Total Deflection value calculated and used by the program when comparing against the deflection limit will include the benefit of camber, if any. The Deflection tab is available when CAN/CSA is selected as the design code. Parameters used in the calculation of Long Term and Shrinkage deflection are specified there.

3.4.4 Camber Camber criteria can be set independently for Composite and Non-composite beams. If no camber is desired, select the Do Not Camber option. If the Camber Except When option is selected, no camber will be specified if the beam falls within any of the limits specified. Note that the values for Weight greater than and Depth greater than should not be 0.0, otherwise all beam sizes will exceed those limits and no camber will be specified.

3.4.5 Web Openings Openings in the webs of I-shaped steel beams can be specified in the Beam Web Openings command. This data includes location, shape and size of the opening. During optimization or analysis of the beam, the effects of the web openings on the beam are considered. If necessary, the program will design stiffeners above and below the openings. The criteria for the stiffeners can be specified in the Criteria Web Openings command.

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Specify the yield strength of the stiffener plates. Specify the minimums and increments of the dimensions of the stiffener plates. The program will select stiffeners, when necessary, that are sized as required but that are at least the minimum size specified. The sizes are rounded up to the multiple of the increment specified.

Figure 3-1

Horizontal web stiffeners, when required, are always placed in pairs, one above the opening and one below the opening. Those pairs of stiffeners may be place on one side of the web only, or on both sides of the web, as required. Stiffeners placed on only one side of the web are often acceptable and more economical. They are not always desirable, however, because they cause the beam to be asymmetrical (which can be a problem in cases of long unbraced lengths). The program will investigate the design of web openings with stiffeners on one side of the web if that option is selected, otherwise it will not. It may be more economical to use deeper, heavier beams rather than adding stiffeners. If neither option to allow stiffeners is selected, the program will optimize to the beam size that does not require stiffeners at the openings. On the other hand, if depth of beam is a concern, lighter, shallower beams may be acceptable if stiffeners are allowed. See Section 3.5.4 for information on specifying the geometry and location of web openings.

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3.5 Beam

The physical geometry and material properties of the beam are specified in the commands available in the Beam menu. A wide range of conditions can be specified and designs obtained.

3.5.1 Span Definition The program can design simple span beams, and simple span beams with cantilevers on either or both ends. The span and cantilever lengths are specified in the Beam Span Definition command.

The beam shape and steel yield strength are also specified. Allowable shapes include hot rolled or built-up I-sections, channels, and square and rectangular hollow sections. Beams may be either Composite or Non-composite. If non-composite the user can specify whether or not the top flange is continuously braced or not (as may be provided by roof or floor deck). The flange bracing conditions can be further specified or modified using the Beam Bracing command. Two sets of design constraints can be specified, Size Restrictions and Span/Depth Limit. Size restrictions on the depth and width can be specified by selecting the Use option and then selecting the checkbox or checkboxes associated with the restrictions desired. The values specified are taken as absolute dimensions, not nominal dimensions. The minimum beam depth can also be controlled by specifying a value for Maximum Span/Depth Ratio. When selecting optimized sizes the program selects members that are at least deep enough to satisfy this criteria. This is a common rule-of-thumb, not a Code requirement. Common values are 20 to 24. Note that you must use consistent units ft/ft or m/m. A value of 0.0 indicates no limit.

3.5.2 Composite The decking information in the Beam Composite command must be input for beams specified as Composite in the Beam Span Definition command, but is not necessary otherwise.

In order to calculate the effective flange width, the distance to adjacent beam or edge must be specified. The adjacent condition can be explicitly specified as either an edge or a beam. The effects of skewed framing and openings should be considered when determining the values specified here; the values for the controlling conditions should be specified Stud properties are specified. Beams may be either shored or unshored (propped or unpropped). If shored, select the Beam is Shored option.

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Concrete and steel deck properties are specified. These values may differ on one side of the beam (Left) versus the other side (Right). Deck Orientation impacts the flange bracing in the precomposite design and it affects the stud capacity and spacing. The choices of steel decks available for Deck Type are dependent upon the Deck Table selected on the Tables tab in the Criteria General command. The data specified for one side can be copied and pasted into the data cells for the other side using the copy and paste commands described in Section 3.11.1. See Section 4.3 for more information on Composite beam design. When the deck is skewed with respect to the beam and the angle between the deck and the beam is very small, there may be very few ribs crossing the beam in which to put studs. It is sometimes impossible to fit the number of studs required for minimum composite action due to the long spacing between ribs. In actual construction practice, the required number of studs can be forced to fit either by splitting the deck forming a concrete haunch down the length of the beam or by cutting or flattening the ribs as necessary to place the studs. The user can indicate that the spacing of the ribs is to be ignored, allowing the program to design those beams as composite beams. This is done by selecting the Ignore rib spacing when determining stud spacing option on the Ignore Rib Spacing tab in the Beam Composite command. When overriding the rib spacing the engineer can designate that the deck is either Split or Altered. The selected option has an impact on the design as described in Section 4.3.4.

3.5.3 Bracing The braced condition of the compression flange is affected by a number of items specified in various locations in the program. Composite beams are assumed to be fully braced on the top flange for the composite condition, but for the

precomposite condition the bracing is dictated by the direction of deck specified in Beam Composite and whether or not the options Deck Perpendicular to Beam Braces Flange and Deck Parallel to Beam Braces Flange on the Design Defaults tab of the Criteria Design command were selected. When Concentrated loads are specified using the Loads Load Cases command, options are given to indicate whether or not the top flange and/or the bottom flange are braced at those locations (as may be the case when the concentrated load is caused by a beam framing in). For special conditions not covered by these features, additional bracing conditions can be specified using the Beam Bracing command. Brace points in addition to those specified for the concentrated loads can be specified as Additional Brace Points in the Beam Bracing command. The distance, measured from the left end of the beam, and options to indicate that the top and/or the bottom flange are braced at that point are specified.

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Segments along the beam for which the deck does not provide adequate bracing of the top flange, such as a beam cutting through an opening, can be specified as Additional Unbraced Segments in the Beam Bracing command. The distance from the beginning to the end of the unbraced segment, measured from the left end of the beam, is specified. This only affects the top flange, and takes precedence over the deck bracing options selected on the Design Defaults tab of the Criteria Design command. Flange bracing is shown graphically in the main window. The segments of the top flange that are continuously braced are shown with a red line along the side of the flange. Discreet brace points are indicated with a yellow triangle next to the specified flange.

3.5.4 Web Openings The location and geometry of web openings are specified with the Beam Web Openings command.

Figure 3-2

The location of the web opening is specified as the Distance from the selected end of the beam segment (cantilever or span) to the center of the opening. The i-end indicates the left end and the j-end indicates the right end of the beam span. H is the height of a rectangular opening, B is the length of a rectangular opening. Diam is the diameter of a circular opening.

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Figure 3-3

Web openings are generally centered at the mid-depth of the beam, but they can be specified as being offset. The offset is specified by the user as the distance from the top of the beam to the top, center or bottom of opening. Any number of openings can be added. To add an opening, specify the opening geometry and location in the Beam Web Openings command, and select Add. The opening will be added to the list of openings. Once openings are added they can be modified or deleted. To modify the opening information, select the opening from the list, make the desired changes, and select Change. To delete an opening, select the opening from the list and select Delete. Web opening geometry and location can also be modified after the beam has been designed using the Modify command in the Process Beam Design command. See Section 3.7.1. Note that web openings are only valid for I-Section beams and can only be modeled on such beams. If the shape of the beam with an opening already modeled is changed from an I shape to a Rectangular HS or Channel, the program will issue a warning about the web openings; they will be ignored during the design. After web openings have been entered they are shown on the beam on the main screen.

3.6 Loads

3.6.1 Specifying Loads Loads on the beam are specified using the Loads Load Cases command. Loads can be any combination of Uniform, Partial Uniform, Trapezoidal and Concentrated.

Loads have four components: Dead Load, Construction Dead Load, Live Load and Construction Live Load. Construction Dead Load and Construction Live Load are only

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relevant for unshored (unpropped) Composite beams and are the loads applied to the bare beam prior to composite action; they do not need to be specified for non-composite or shored composite beams. The Dead Load is the total dead load, while the Construction Dead Load is that portion of the Dead Load that is applied to the precomposite condition. Live Loads should already be reduced as allowed by various codes for Live Load Reduction; no reduction is performed by the program. After the loads have been specified they are displayed on the main screen. The total load values (Dead plus Live) are shown.

3.6.2 Uniform To specify the Uniform load on the beam, select the Uniform Load tab on the Loads Load Cases command and specify the load values. The Uniform load extends across the entire beam length. An option to have the beam self-weight automatically included with the loads is also available.

3.6.3 Partial Uniform To specify Partial Uniform loads on the beam, select the Partial Uniform Load tab on the Loads Load Cases command and specify the load values. Any number of Partial Uniform loads can be specified. Partial Uniform loads only load the portion of the beam specified and have a non-varying magnitude. CDL refers to Construction Dead Load and CLL refers to Construction Live Load as explained above. Start refers to the distance from the left end of the beam to the beginning of the load and End refers to the distance from the left end of the beam to the end of the load. When there are multiple loads, the loads can overlap. See Section 3.11.1 for information on copying, pasting and deleting data in this dialog box.

3.6.4 Trapezoidal Load To specify Trapezoidal loads on the beam, select the Trapezoidal Load tab on the Loads Load Cases command and specify the load values. Any number of Trapezoidal loads can be specified. Trapezoidal loads only load the portion of the beam specified and have a varying magnitude (trapezoidal or triangular shape).

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CDL refers to Construction Dead Load and CLL refers to Construction Live Load as explained above. For each trapezoidal load, specify the magnitudes that occur on the Left end of the load and that occur on the Right end of the load, as well as the Distance to the Right or Left end of the load, accordingly. Distance is measured from the left end of the beam to the beginning or end of the load. When there are multiple loads, the loads can overlap. See Section 3.11.1 for information on copying, pasting and deleting data in this dialog box.

3.6.5 Concentrated To specify Concentrated loads on the beam, select the Concentrated Load tab on the Loads Load Cases command and specify the load values. Any number of Concentrated loads can be specified. CDL refers to Construction Dead Load and CLL refers to Construction Live Load as explained above. For each concentrated load, specify the magnitudes as well as the Distance to the load. Distance is measured from the left end of the beam to the load. When there are multiple loads, the loads can overlap. Note that compression flange bracing options are included with the concentrated load information because of the relationship of flange bracing and concentrated loads: concentrated loads are frequently caused by another beam framing in which provides bracing to the compression flange. By specifying the bracing information here, it is not necessary to repeat the bracing information using the Beam Bracing command. To specify that the point of the concentrated load is to be considered as a top flange or bottom flange brace point, select the Braces Top Flng and/or Braces Bot Flng options as appropriate. See Section 3.11.1 for information on copying, pasting and deleting data in this dialog box.

3.6.6 Clear Loads The Loads Clear Loads command can be used to clear all of the loads specified on the beam. This command is useful when designing multiple beams where the load on one beam is significantly different than the loads on the previous beam such that it is easier to re-enter the loads rather than to modify the previous loads.

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3.7 Process

3.7.1 Beam Design (Ctrl+D) Selecting the Process Beam Design command will cause the beam to be designed automatically for its optimum size based on the steel table and design criteria specified by the user. The View/Update dialog box will then appear.

This is a very powerful function that allows you to perform the following tasks:

Inspect the Beam Size and Stud Configuration selected by the program. Modify the currently selected beam size, stud configuration, Fy (fy, py),

Composite/Non-composite Flag or web opening configuration and Re-analyze or Re-optimize.

View and print the full output for the beam design. View and print the shear, moment and deflection diagrams for the beam. View and print the load diagram. Save the design.

In the View/Update dialog box, the following additional information is displayed for informational purposes only:

The Steel Code Selections. The Length of the Beam and the support locations. The Decking orientation on the beam (for composite beams). Size Restriction on the beam, if any.

You may modify any of the following design parameters:

Beam Size Shape Fy (fy, py) Composite/Non-composite Flag Stud Configuration Web Opening configuration and stiffener design

Upon entering the View/Update dialog box, the beam size optimization algorithm is performed or, in the case of beams for which a size was previously saved or frozen, the analysis algorithm is performed. The selected beam size is displayed along with the design parameters. The Optimize button invokes the beam size optimization algorithm after changes have been made to the design parameters. Because the purpose of this function is to select the optimum beam size and stud configuration, the currently selected beam size and stud configuration will be disregarded.

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The Analyze button uses the design parameters established in the dialog box to perform a beam analysis of the currently specified size. The Analyze feature is activated when the beam size, Fy (fy, py), web opening geometry or, for composite beams, the composite flag or stud configuration is modified. Either Optimizing or Analyzing a beam enables the Save Design button. When a design is saved it is tagged as a User Size. (Note: Save Design does not perform the same function as File Save, which saves the data to a file.) After a beam is tagged as a User Size, the program will no longer perform the optimization algorithm for that beam. Instead, the User Size and Stud Configuration will be analyzed for the Strength and Deflection Criteria. The beam will remain tagged as a User Size until that flag is cleared by the user. This can be done by using the Process Clear Design command. Changes to design criteria, geometry or loading WILL NOT clear the user size flag. If these types of changes are made, the user should clear the User Size flag if the optimum beam configuration is desired. If a user-selected beam fails the stress or deflection check, a warning is issued, but the design is still allowed. It is the then engineer's responsibility to determine whether or not to ignore the design warnings and allow an overstressed or over-deflected condition on user-specified member sizes. To try a different Beam Size:

Select the desired size in the Beam Size list box. The Analyze button will be enabled. Selecting the Analyze button will cause the design checks to be run. If the beam fails, a message will appear warning the user of the failure.

To try a different Fy (fy, py):

Enter the new Fy into the Fy edit box. Selecting the Optimize button will cause the program to select the optimum beam size using the newly specified Fy. Selecting the Analyze button will cause the program to check the current beam size using the newly specified Fy.

To change the Composite/Non-composite Flag:

Select the desired Composite or Non-composite Option. Note that Composite will be disabled if the user specified the Non-composite option in the Span Data. Selecting the Optimize button will cause the program to select the optimum beam size using the newly specified Composite/Non-composite flag. Selecting the Analyze button will cause the program to check the current beam size using the newly specified Composite/Non-composite flag.

To change Stud Configuration:

If the beam is composite, the stud configuration will be shown for both Segmented and Uniform Stud Distribution (see Section 4.3.4 for an explanation of the stud distribution). The user may update the stud design by changing between

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Uniform and Segmented, or by entering the desired number of studs in the Actual edit boxes.

The Analyze button will be enabled. Selecting the Analyze button will cause the

program to check the current beam size with the new stud configuration. If the beam fails either check, a message will appear warning the user of the failure.

To change Web Opening configuration or Stiffener design:

If web openings have been defined using the Beam Web Openings command, the web opening information and stiffener design will be shown. If the opening fails, that will be indicated as well.

To modify the web opening information select the Modify command. In the

Modify Web Opening dialog box the location, shape and size of the opening can be modified. Select the opening from the list, make the desired changes, and select the Change button. To return to the View/Update dialog box, select OK. If the geometry of the opening is thus modified and the Optimize command invoked, the program will re-optimize the beam and web stiffeners, if needed, using the modified opening geometry. The stiffener design can also be modified similarly. If the Analyze command is invoked after the opening geometry or stiffener design has been modified, the program will check that design (rather than optimizing the design) and give Design Warnings, if any.

To view the design results:

Select the View Results command to see the Beam Design report. You may scroll through this window to observe the actual design of the beam based on the currently selected beam parameters. See Section 3.8.1 for a description of the controls available in the report viewer.

To view the beam loads:

Select the View Loads command to see the Load Diagram report, showing a display of the beam loads. Load magnitudes are also listed. See Section 3.8.1 for a description of the controls available in the report viewer.

To view Shear, Moment and Deflection diagrams:

Select the View Diagrams command to cause the Shear, Moment, Deflections window to appear.

Move the cursor across the beam to see the shear, moment and deflections at any point. The values are listed on the right-hand portion of the screen.

Select the desired load combination and load cases to be viewed. Obtain a printout of diagrams by invoking the Print command. Exit out of the view by selecting Cancel.

To exit the the View/Update dialog box, select Save Design to save the current design or select Cancel to discard any changes made to any of the design parameters. The program

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will then return to the main screen, and any of the previously entered data can then be modified and a new design performed.

3.7.2 Clear Design The Process Clear Design command clears any User-specified size that has been assigned using the Save Design command of the Process Beam Design command or the Process Freeze Design command.

3.7.3 Freeze Design The Process Freeze Design command performs the same function as the Save Design command in the Process Beam Design command. It tags the size as a User-specified size, which the program will subsequently use regardless of any changes made to the criteria, geometry, loads, etc. If the Process Beam Design command is subsequently invoked the program will analyze that beam size rather than selecting the optimum size. That size will also be saved to a file with the rest of the beam data if the File Save command is invoked.

3.7.4 Design Error Messages A number of design error and design warning messages are given when the conditions are encountered during design. When a user-specified size fails the deflection criteria, is overstressed, or exceeds the allowable capacities, error messages are given accordingly. When the concrete is overstressed in a composite beam using ASD, the program issues a Concrete Overstressed message. In this case the program has selected a beam size which works stress-wise without contribution from the composite action, but which may require composite action to meet deflection criteria. The user can then choose to either ignore the message or else change the beam to non-composite. When the program is unable to add sufficient studs to create a beam that is at least the code-required minimum percent of full composite, the program issues a message saying, Cannot fit enough studs for 25% composite action (or whatever the code minimum is). This is generally caused by the beam being sharply skewed with respect to the direction of deck, by a narrow beam flange, or by a large concentrated load near the support. In this case the program has selected a beam size that works as a non-composite beam, assuming the same bracing conditions as for a composite beam, and calls for zero studs. The user can then choose to either ignore the message or else change the beam to non-composite. Alternatively, the user can specify that the program is to ignore the rib spacing when determining the number of studs that will fit by using the Ignore Rib Spacing command described in Section 3.5.2.

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3.8 Reports

Two reports are available from the Reports menu: Beam Design and Load Diagram. Details on the information included in these reports are given in Chapter 5. When Reports Beam Design or Reports Load Diagram is invoked, the Job Information dialog box appears allowing a Job Name and Comments to be entered. This text appears on the reports. There are four options for the destination of the report. Reports can be printed, viewed on-screen, saved as a text file, or saved as a Viewer file. The current selection is indicated with a check mark next to the Reports menu item. The Reports Printer command causes the reports to go directly to the printer. The Reports Screen command causes the report to appear on-screen. Several commands are available for scaling, zooming, scrolling, etc.:

Select the Print button on the toolbar to obtain a printout of the report. Set the scale with the Set Scale or Show Full Page buttons on the toolbar. Zoom in or out with the Zoom buttons on the toolbar or with the left and right

mouse buttons. Scroll down the page with the scroll bars on the right. Scroll from page to page with the Go To buttons on the toolbar. Select the Close Preview button on the toolbar to close.

The Reports Text File command causes the report to be saved as an unformatted comma-delimited file (.csv), suitable for opening in a text editor or Excel or other spreadsheet programs. The Reports Viewer File command causes the report to be saved in the Virtual Print Engine file format (.vpe). These files can be opened with the report viewer program, VPEView.exe, which is distributed with the program and installed in the Program directory with the other program executables. This is convenient for electronically transmitting the reports.

3.8.1 Report Preferences The format and appearance of the reports can be modified and specified by the user using the Reports Report Preferences command. Margins, paper size, text font and styles, and default destination can be specified.

A Company logo can be included in the upper left-hand corner of each page of the reports if this option is selected. The RAM logo is distributed with the program, but this can be replaced with a logo of the users company if desired. The logo to be shown must be

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contained in a .bmp or .jpg graphics file named logo.bmp or logo.jpg and placed in the same directory as the RAM SBeam program executables (the RAM Program subdirectory). The size of the bitmap is irrelevant, as it will be scaled appropriately.

3.9 View

The main screen graphically shows the beam, bracing conditions, web openings and loads. The view can be controlled if necessary by selecting or deselecting View Brace Points, View Web Openings and View

Loads. There are also buttons on the toolbar corresponding to each of these commands. The size of the text shown on the graphic can be increased or decreased using the text size buttons on the toolbar. There are two pre-set views. View Rotate to Perspective will show the beam in a perspective view (which is the default view), View Rotate to Profile will show the beam in profile. There are buttons on the toolbar corresponding to these commands. The view

can be rotated into any position using the arrow keys on the keyboard.

The view can be zoomed in or out using the View Zoom In and the View Zoom Out commands. There are buttons on the toolbar corresponding to these commands. Also, the + key can be used to zoom in and the key can be used to zoom out.

The view can be printed using the File Print Screen command.

3.10 Exiting RAM SBeam

To exit the RAM SBeam program, select the File -Exit command or click on the Close button (the X button) on the right end of the title bar.

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3.11 Keyboard Commands

3.11.1 Copy, Paste and Delete Some dialog boxes (most notably the Uniform, Trapezoidal and Concentrated load tabs in Loads Load Cases) feature a spreadsheet-like interface. In these spreadsheets, several common keyboard commands are available.

Copy (Control-c) To copy data in a cell or group of cells, select those cells (by clicking and dragging the cursor across them) and then press Control-c (press the Control key and the c key simultaneously). To copy data in an entire line of cells, select the row by clicking on the left-most cell or the column by clicking on the top-most cell and then press Control-c.

Paste (Control-v) To paste (insert) data copied from a cell or group of cells, select the first cell into which that data is to be copied and then press Control-v. To paste (insert) data copied from an entire line of cells, select the row by clicking on the left-most cell or the column by clicking on the top-most cell and then press Control-v.

Delete (Control-x or Delete key) To delete data from a cell or group of cells, select those cells (by clicking and dragging the mouse across them) and then press Control-x or the Delete key. To delete data from an entire line of cells, select the row by clicking on the left-most cell or the column by clicking on the top-most cell and then press Control-x or the Delete key.

Selecting Multiple Rows or Columns Multiple adjacent rows can be selected either by clicking on the first cell of the first row and dragging the cursor to the first cell of the last row, or by clicking on the first cell of the first row and while holding down the Shift key selecting the first cell of the last row. Multiple columns can similarly be selected. Note that nonadjacent rows or columns can be similarly selected using the Control key, rather than the Shift key.

3.11.2 Graphics See Section 3.9 for keyboard commands that can be used to control the view of the beam graphic on the main window.

3.11.3 Design The Process Beam Design command can be invoked by pressing Control-d (press the Control key and the d key simultaneously).

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27 RAM SBeam v4.0

4 Technical Notes In the design of a structure a great number of decisions must be made. What is acceptable to one engineer may not be acceptable to another. It is crucial that the user understands the decisions and assumptions being made by the RAM SBeam program. If these are not appropriate for the specific conditions of a particular building, the user should augment or replace the results from RAM SBeam with those of some other tool. The purpose of the Technical Notes is to explain the assumptions and methodology of the RAM SBeam. Every effort has been made to include a discussion of significant decisions and assumptions made by the program. Generally, if there is any question as to how the RAM SBeam handles any particular condition, a beam can be quickly entered and analyzed, and the results verified with the appropriate hand calculations.

4.1 Steel Design Codes

RAM SBeam incorporates the requirements of several U.S. and international steel design specifications. These specifications include: Specification for Structural Steel Buildings - (March 9, 2005), ANSI/AISC 360-05 ASD (Allowable Strength Design) and ANSI/AISC 360-05 LRFD (Load Resistance Factored Design) published by the American Institute of Steel Construction in Manual of Steel Construction (13th Edition). Specification for Structural Steel Buildings - Allowable Stress Design and Plastic Design (June 1, 1989), published by the American Institute of Steel Construction in Manual of Steel Construction - Allowable Stress Design (9th Edition). The requirements of Supplement No. 1 (December 17, 2001) are also included as an option. Load and Resistance Factor Design Specification for Structural Steel Buildings (December 27, 1999), published by the American Institute of Steel Construction in Manual of Steel Construction - Load and Resistance Factor Design (3rd Edition). Limit States Design of Steel Structures, CAN/CSA-S16-01, including Update No. 1 and Update No. 2, published by the Canadian Institute of Steel Construction. Structural use of steelwork in building, BS 5950 : Part 1, Code of practice for design in simple and continuous construction: hot rolled sections (1990). Structural use of steelwork in building, BS 5950 : Part 1, Code of practice for design: rolled and welded sections (2000), published by the British Standards Institute.

Technical Notes

RAM SBeam v4.0 28

Structural use of steelwork in building, BS 5950 : Part 3, Section 3.1, Code of practice for design of simple and continuous composite beams (1990), published by the British Standards Institute. Eurocode 3 - Design of Steel Structures, Prestandard ENV 1993-1-1, published by the European Committee for Standardization in Design of Steel Structures (Eurocode 3). Eurocode 4 - Design of Composite Steel and Concrete Structures, Prestandard ENV 1994-1-1, published by the European Committee for Standardization in Design of Composite Steel and Concrete Structures (Eurocode 4). In the RAM SBeam program, its outputs and throughout the remainder of this manual, these are referred to as AISC 360 ASD, AISC 360 LRFD, ASD, LRFD, CAN/CSA-S16-01, BS 5950 and Eurocode respectively.

4.2 Member Loads

4.2.1 Load Properties A load consists of a Dead Load, a Construction Dead Load, a Live Load and a Construction Live Load. A note regarding terminology: Repeated reference is made throughout the program and the documentation to Live Loads. In some codes these loads are referred to as Imposed Loads. The Dead Load is the total dead load such as slab, deck, partitions, miscellaneous, etc. It should include slab self-weight, as the program does not include this automatically. The beam self-weight will be automatically included if that option is selected on the Uniform Load tab in the Loads Load Cases command. The Construction Dead Load, or Pre-composite Dead Load, is a temporary condition load and is that portion of the Dead Load that is applied to the beam prior to composite action. It must be less than or equal to the Dead Load. This value is only used when designing unshored (unpropped) composite beams and need not be specified for non-composite beams or shored (propped) composite beams. This is in addition to the Construction Live Load described below. The Live Load is the total live load appropriate for the particular building based on the applicable Building Code and use of the building. Live Loads should be reduced for Live Load Reduction if applicable; the program does not perform any Live Load Reduction. The Construction Live Load is a temporary load that is applied to the beam prior to composite action. It represents the temporary load due to workers and equipment on the bare beam prior to composite action. This load is combined with the Construction Dead

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29 RAM SBeam v4.0

Load when investigating the pre-composite beam. Its magnitude is independent of the Live Load value. This value is used only when designing unshored (unpropped) composite beams and need not be specified for non-composite beams or shored (propped) composite beams.

4.2.2 Positive Loads, Negative Loads, and Skip Loading On the output, loads are referred to as Positive or Negative. A Positive load is a downward acting load while a Negative load is an upward acting load. The program keeps track of Positive and Negative loads independently. On the output, moments and reactions are labeled Maximum Positive and Maximum Negative. If there is no Negative value, it is listed as 0.0 or not shown at all. If there is no Positive value, it is listed as 0.0 or not shown. As required by some Codes, when a beam is cantilevered at one or both ends the program skip loads the Live load on adjacent spans and alternating spans such as to create the maximum moments, deflections, and reactions. Not only does the program skip load the Live loads, it applies the Positive and Negative loads on alternating spans such that the worst conditions are calculated. Note that the Live loads are skip loaded regardless of the Code selected. The following skip load condition is performed to calculate the maximum positive moment (top flange in compression):

Negative Live Loads on Cantilevers and Positive Live Loads on Span The following skip load condition is performed to calculate the maximum negative moment (bottom flange in compression):

Positive Live Loads on Cantilevers and Negative Live Loads on Span The following skip load conditions are performed to calculate the maximum shear force:

Positive Live Loads on Left Cantilever, and Negative Live Loads on Span and Right Cantilever

Positive Live Loads on Left Cantilever and Span, and Negative Live Loads on

Right Cantilever

Negative Live Loads on Left Cantilever, and Positive Live Loads on Span and Right Cantilever

Negative Live Loads on Left Cantilever and Span, and Positive Live Loads on

Right Cantilever

Technical Notes

RAM SBeam v4.0 30

If there are no Negative Live Loads, a value of 0.0 is applied to the particular cantilever or span in the above conditions. Similarly for Positive Live Loads. The Construction Live Load is similarly skip loaded. Dead Load is not skip loaded; the full dead load is applied to all spans and cantilevers. Where BS 5950 and Eurocode require the investigation of the interaction of moment and shear effects, each unbraced segment of the beam is checked for the maximum shear (with associated moment) and the maximum moment (with associated shear) using the skip loading conditions which produce the maximum moment, and for the maximum shear (with associated moment) using the skip loading conditions which produce the maximum shear.

4.3 Composite Beam Design

4.3.1 Calculating Effective Flange Width The effective flange width is automatically calculated for the specified Code based on the distance to edge or adjacent beam specified in the Beam Composite command. When calculating the effective flange width for BS 5950 for a simple beam with a cantilever, Lz = L3 0.3L4, but Lz 0.7L3 (see Figure 3 therein). When the slab spans at an angle with respect to the beam, be is based on an interpolation which is a function of sin2 and the values from Clause 4.6(a) and Clause 4.6(b). When calculating the effective flange width for the Eurocode for a simple beam with a cantilever, l0 = L3 0.3L4, but l0 0.7L3 (see Figure 4.3 therein).

4.3.2 Deck Orientation The orientation of the deck relative to the beam is an important consideration in composite design. There are special Code requirements for deck perpendicular to the member versus parallel to the member. Based on the angle values specified in the Beam Composite command the program applies the appropriate provisions. If the orientation is within 10 degrees of being parallel, the program assumes that the orientation is parallel. In ASD design when the deck is parallel to the beam, the concrete within the deck flutes is used in calculating the total horizontal shear Vh and the composite section properties Itr and Str (the Ad2 term is used but the Ixx term, the moment of inertia of the concrete in the flute around its own centroid, is ignored). If the angle between the beam and the deck orientation is greater than 10 degrees the concrete within the flutes is ignored. In all other Codes, the concrete within the flutes is ignored in all cases.

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31 RAM SBeam v4.0

4.3.3 Effect of Slab and Deck Change Generally a beam will only carry one type of deck with a single orientation. However, occasionally the slab properties, deck properties, and/or deck orientation change along a beam. This change can occur either down the axis of the beam (see Figure 4-1) or else at some point along the beam. The Codes do not specifically address these situations. RAM SBeam Design conforms to rules outlined in the following sections.

Figure 4-1

Change in Deck Orientation When the orientation of the deck is different on one side of the beam than the other, for the purpose of calculating the allowable shear values for the studs the deck is considered to be oriented in the direction of the deck that is non-parallel to the beam. This is conservative. If the deck on either side is parallel to the beam, the number of studs allowable in a single row along the beam will be limited to:

L / (6 * StudDiam) per I3.2d(6) of AISC 360-05, I4 of AISC ASD 9th Edition or I5.6 of AISC LRFD 3rd Edition or Clause 17.7.2.4 of CAN/CSA-S16-01, or

L / (5 * StudDiam) per Clause 6.4.2(3) of Eurocode 4 or Clause 5.4.8.4.1 of BS 5950, where L is the Span length, and StudDiam is the nominal stud diameter. If the deck on either side is perpendicular to the beam, the maximum stud spacing will be limited to that permitted by the specified Code.

Change in Slab Properties When the properties of the slab are different on one side of the beam than the other, the section properties of the composite section are calculated using the different slab properties for each side.

Technical Notes

RAM SBeam v4.0 32

4.3.4 Shear Stud Connectors The program calculates the number of studs required, accounting for the locations of maximum moments and zero moments and special distributions required due to the presence of concentrated, or point, loads. It calculates the studs required for a uniform distribution along the entire length of the beam as well as for a segmented distribution where the segments are defined by the locations of the point loads. If there are no point loads on a member there will only be one segment. In this case the number of studs required for segmented distribution and uniform distribution will be identical. When determining the number of studs required for a uniform distribution, the highest stud density required in any segment is determined and then placed along the full beam length. The program automatically defaults to a uniform distribution of studs unless fewer total studs are required by using the segmented distribution. If there are more than four point loads, the program always defaults to uniform stud distribution. Segments are determined based on the location of the point loads. If a segment is so short that no studs could be placed within it, it is combined with the adjacent segment. If the point of maximum moment occurs at a point other than at the location of a point load, the number of studs in that segment is based on the greater of the densities required on either side of the maximum moment. This is also the case for beams with no point loads. If the point of zero moment occurs at a point other than the support, the number of studs between the support and the point of zero moment is based on the density of studs required in the segment adjacent to the point of zero moment. The point of zero moment used is that which corresponds to the load combination that produced the maximum moment. For AISC 360-05, LRFD 3rd, Eurocode, CAN/CSA-S16-01, or BS 5950, when calculating the studs required between any concentrated load and the point of zero moment, a more exact approach is incorporated whereby the number of studs is based on that required to generate the moment capacity necessary to satisfy the actual design moment at the point of the concentrated load. This is done in lieu of the more simplified approach of calculating the studs based on ratios of the moments allowed by some codes. Cantilevers are not considered as a segment nor are studs called out on cantilevers since the concrete on a cantilever is generally not in compression. Even when there is an uplift load at the end of the cantilever resulting in compression in the concrete on the cantilever, the cantilever beam is not designed as a composite section. In the View/Update dialog box the user can change the number of studs in each segment. When the program does an analysis using the user-specified studs, it only checks the

Technical Notes

33 RAM SBeam v4.0

composite section against the maximum moment; it does not check for adequate number of studs at each point load. In other words, when optimizing the size and studs the program ascertains that the stud requirements at each point load, in addition to the point of maximum moment, are satisfied, but when analyzing a user-specified size and stud configuration the program only checks to determine if the stud requirements are met at the point of maximum moment. Thus the user may, without getting an explicit warning, specify a distribution of studs that satisfies the requirements for the maximum moment but does not satisfy the additional requirements for the stud distribution due to point loads. However, the lack of adequate studs will be apparent by comparing the number of studs indicated as required for partial composite (Partial) with the number of studs specified by the user (Actual). The number of studs specified should always equal or exceed the number of studs that the program shows for Partial. These values are shown in both the View/Update dialog box as well as the Beam Design output. The program indicates the number of studs required for full composite action as well as minimum partial composite action. The number of studs shown for Partial composite action represents the greater of the number required for moment capacity at points of maximum moment and point loads, minimum percent of full composite, or maximum allowable stud spacing. If the number of studs required to produce full composite action exceeds the maximum number of studs that can be placed along the beam, the values shown for full composite are limited to that maximum number, and the output will indicate Max rather than Full. This is based on the minimum stud spacing for deck parallel to the beam, and three studs per flute otherwise. If the number of studs specified by the user exceeds the number shown for full composite, the additional studs are ignored. Additionally, the number of studs shown for full composite does not reflect minimum stud requirements, while the number of studs shown for partial composite does. Thus it is possible in some cases for the number of studs shown for partial composite to exceed the number of studs shown for full composite. An example of this is a girder loaded with equal loads at the third points; RAM SBeam will indicate that no studs are required in the middle segment for full composite but that some (minimum studs) are required for partial composite. It should be noted that consistent with the Code requirements, in calculating the properties Seff and Ieff of partially composite beams the value of Cf (for AISC 360-05 ASD, AISC 360-05 LRFD and LRFD 3rd) or Vh (for ASD 9th) is the total horizontal shear from the appropriate equations and is not the value limited by the number of studs that can be placed. There is a provision in the AISC Codes which states, Unless located directly over the web, the diameter of studs shall not be greater than 2-1/2 times the thickness of the flange to which they are welded. The other codes have a similar provision. The program checks this provision before selecting a member size requiring multiple rows of studs. If the provision is not met, the program will select a larger size. In the case of CAN/CSA-S16-01, the program will not select a beam whose flange thickness is less than 2-1/2 times the stud diameter. There is a provision in the AISC Codes which states, The minimum center-to-center spacing of stud connectors shall be ... 4 diameters transverse to the longitudinal axis of

Technical Notes

RAM SBeam v4.0