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Night School Past Course Details
Night School 14: Fundamentals of Stability
Written and Presented by Members of the Structural Stability Research Council (SSRC)
Summer 2017 Course
The high-strength and stiffness-to-weight ratios of structural steels make them ideal design materials. Throw a consideration for economy into the mix, and the result often includes relatively slender members and systems in which structural stability is of primary concern. In fact, a quick review of any steel specification will convince you of the need to know at least the fundamentals. With this in mind, this 8-session, 12-hour course will present an overview of the behavior of compression, flexural and beam-column members as well as an introduction to system stability. In addition, the behavior and design of bracing intended to resist such failure modes will be presented.
Note - this is the same program as Night School 2, from 2013.
This lecture will begin with a brief overview of the 8-lecture course. The behavior of compression members will then be covered. The assumptions in the solution to the Euler column problem will be used as a basis for systematically moving from the theoretical solution presented in 1759 to the modern day methods of design and analysis of compression members. Emphasis will be placed on the effects of material yielding accentuated by the presence of residual stresses, initial imperfections, and end conditions. The flexural buckling strength of members without slender elements will be covered and ultimately presented in the form of column curves.
Initially, an overview of flexural, torsional, and flexural-torsional resistance of individual column members will be provided. Emphasis then will be placed on defining and assessing the AISC LRFD and ASD strengths of various structural shapes, including wide flange, round and square HSS, cruciform, equal and unequal single and double leg angles, WT, channel, and built-up shapes.
Using an approach similar to that employed in Session 1, this lecture will begin by presenting and dissecting the solution to the differential equation that defines the elastic lateral torsional buckling (LTB) strength of beams. Related flexural and torsional concepts, including the benefits of warping resistance, will be briefly reviewed. The assumption of elastic behavior will then be relaxed to define the inelastic LTB and plastic moment capacities of flexural members. The strength of beams without slender elements will be covered and ultimately presented in the form of beam resistance curves.
This lecture will focus on the design of flexural members for the pertinent stability limit states. Solutions for the effects of moment gradient and load position will be covered including moment gradient factors for a variety of common design situations. This lecture will include material pertinent to both rolled sections as well as built-up members. Efficient use of the design aids in the AISC manual will be addressed as well as methods for the preliminary sizing of built-up girders.
This lecture will begin with a review of basic concepts related to the stability of structural systems. With an eye towards design, the difference between a bifurcation or critical load analysis and the loss in stiffness due to second-order effects and material yielding, as the maximum resistance of physical structures is approached, will be emphasized. The lecture will conclude with an overview of the direct analysis and effective length methods.
This lecture will begin with an overview of the fundamental stability behavior of beam-column members. The discussion then will focus on the background to and use of beam-column interaction equations in the AISC Specification Section H1.3 for compact I-section members loaded in major-axis bending within the plane of a frame. Efficient and economical design of rolled W-section beam-columns using the AISC Manual Section 6 design aids will be addressed. The session will close with a focus on advanced procedures, sanctioned within the commentary of the AISC Specifications, that allow the designer to account for substantial increases in the strength of WT and other singly-symmetric beam-column members.
This lecture will focus on the fundamental behavior related to bracing of compression and flexural members. The dual criteria of stiffness and strength will be covered. The effects of imperfections on brace forces will be addressed, along with the impact of connection flexibility and cross-sectional distortion on the effectiveness of the bracing. An overview of the different classifications of bracing including relative, nodal, continuous, and lean-on bracing will be provided.
This lecture will emphasize the design requirements for column and beam systems. Several design examples will be provided that demonstrate the effective use of the AISC Specification Appendix 6 provisions. These examples will include relative, nodal, and lean-on applications. The uses of the provisions covered in the specification appendix as well as modifications covered in the specification commentary will be addressed.
Quiz and Attendance records
Quiz 1: 1. a, 2. c, 3. a, 4. e, 5. b, 6. c, 7. e, 8. d, 9. b, 10. d
Quiz 2: 1. c, 2. c, 3. e, 4. d, 5. b, 6. b, 7. d, 8. a, 9. e, 10. b
Quiz 3: 1. e, 2. d, 3. c, 4. a, 5. e, 6. d, 7. b, 8. b, 9. b, 10. c
Quiz 4: 1. a, 2. a, 3. d, 4. b, 5. c 6. d, 7. d, 8. c, 9. b, 10. b
Quiz 5: 1. d, 2. e, 3. d, 4. e, 5. c, 6. e, 7. e, 8. b, 9. g, 10. b
Quiz 6: 1. d, 2. e, 3. e, 4. b, 5. c, 6. b. 7. c, 8. a, 9. d, 10. c
Quiz 7: 1. c, 2. d, 3. c, 4. b, 5. d, 6. b, 7. d, 8. c, 9. d, 10. a
Quiz 8: 1. b, 2. e, 3. a, 4. b, 5. a, 6. b, 7. b, 8. b, 9. a, 10. a
Final Exam: 1. e, 2. a, 3. c, 4. e, 5. c, 6. a, 7. d, 8. e, 9. b, 10. d, 11. b, 12. d, 13. b, 14. b, 15. a, 16. a, 17. c, 18. b, 19. b, 20. d, 21. a, 22. b, 23. b, 24. a
Night School 13: Design of Industrial Buildings
Written and Presented by James M. Fisher and Jules Van de Pas
Winter 2017 Course
This Night School consists of eight 90 minute lessons. Each lesson consists of approximately 75 minutes of discussion followed by a question and answer period. The lessons are split between the design of buildings without overhead cranes and those structures with light duty and heavy duty overhead cranes. Critical design issues and design approach techniques are discussed. Calculations are presented in a manner that serve as a teaching tool for engineers. A complete design example (anchor rods to roofing) of a 50-ton overhead crane building is illustrated.
In Lesson 1, loads as required by IBC 2015 and ASCE 7-10 are discussed as well as owner established design criteria. Advantages and disadvantages of various roof and wall systems are presented. Serviceability issues and other design considerations are discussed in detail for roof and wall types. Expansion joint requirements and details for expansion joints for both buildings without overhead cranes and those with overhead cranes are presented. Member selection guidelines for optimum design are discussed.
Lesson 2 focuses on roof and bay optimization. Design considerations for roof trusses are discussed. Connection considerations, permanent, and erection bracing for roof trusses are presented. Economic issues pertaining to: span-to-depth ratios, location of splice points, use of tee chords, the advantages of LRFD, use of high strength steels, web arrangements, and the value of repetition of member sizes are all discussed. Design considerations for: Block Shear and Shear Rupture, Orientation of Wide Flange Chords, Slip Critical Joints, Seat Connections, and Splices are discussed. Additional information not covered in Lesson 1 on optimum member selection, and details for the support of hanging loads and roof top units are provided. An interactive Spreadsheet tool is demonstrated for selecting optimum bay layout. Roof diaphragm details and design requirements are also discussed.
Lesson 3 deals with lateral load resisting systems which includes, roof horizontal bracing systems, braced frames, and rigid frames. Economical choices for the lateral load system are discussed. Moment connections details for connecting Joist Girders to columns are provided along with practical suggestions for the maximum moment resistance for each detail. Three examples are given, these include a braced frame using LRFD and ASD, and a rigid frame using ASD. The braced frame examples include the design of the roof diaphragm. The rigid frame example includes a “hand calculation” of a moment connection as well as a demonstration of a Spreadsheet solution.
Lesson 4 sets the stage for a complete building design for a two bay 50-ton overhead crane building. The project description and design criteria including all loads and serviceability requirements are discussed. Preliminary design procedures and calculations are provided for the runway girders, columns, and roof members beginning with the determination of required eave height based upon the owner’s requirement for the crane hook height. A discussion on the various choices for column types and the preliminary design hints for each is provided. A weight comparison between 30 ft. and 40 bay spacing is also provided.
Lesson 5 includes the design of a typical 30-foot-long crane runway girder and an analysis for a typical frame in the example building. A crane girder design procedure is demonstrated, including the evaluation of strength and serviceability limit states. Examples of proper details for minimizing fatigue effects for crane runway girders are presented. Development of the frame loads, including seismic loads, and the selection of the seismic force resisting system are discussed. Second order analysis methods and calculations for estimating second order effects are presented.
Lesson 6 incorporates the results of the frame analysis discussed in lesson 5 to demonstrate the design of the building columns, crane columns, and moment connections. The AISC Manual beam column tables are used for the design of the beam columns to illustrate their use. The design of the Ordinary Moment Frame connection of a Joist Girder to the building column is provided. The development of the specification for the Joist Girders, for the example building, using the Steel Joist Institute’s Technical Digest 11 is also discussed. The design of the column anchor rods is provided including evaluation of limit states according to ACI 318 Chapter 17. Discussion of the recommendations of AISC Design Guide 1 are included in the example, as well as, the calculation for the thickness of the column base plate.
Lesson 7 begins with the design of a 60-foot-long crane runway girder, the backup girder, and the horizontal lacing which connects the backup beam to the runway girder. The design of the longitudinal bracing system is then presented including the roof longitudinal bracing, and the building longitudinal bracing. The loads and forces acting on the bracing members and struts are developed, the members selected, and typical details are discussed. The crane bumper force calculation is provided and the crane longitudinal bracing design is shown. The design of the end wall bracing is also provided. Connection details for the braces are provided.
Lesson 8 is the final lesson and the final design of the 50-ton overhead crane building design example is presented. The final roof and wall design is presented with a discussion relative to the design of standing seam roofs and to membrane roofs. Advantages and disadvantages of standing seam roofs are presented. Design concerns for metal roof deck and open web joists relative to mechanical membrane roofs subjected to wind uplift forces are presented. Proper specifications for open web joists subjected to gravity, uplift and roof ponding are discussed. Design procedures for cold-formed girts are presented along with wind column design. Lateral bracing calculations for the Ordinary Moment Frame (OMF) columns and beams are performed and discussed.
Quiz and Attendance records
Quiz 1: 1. d, 2. b, 3. b, 4. a, 5. d, 6. c, 7. a, 8. c, 9. d, 10. b
Quiz 2: 1. b, 2. d, 3. b, 4. b, 5. d, 6. b, 7. a, 8. c, 9. b, 10. b
Quiz 3: 1. b, 2. d, 3. a, 4. b, 5. c, 6. c, 7. a, 8. d, 9. d, 10. c
Quiz 4: 1. c, 2. c, 3. a, 4. c, 5. d, 6. b, 7. c, 8. b, 9. c, 10. d
Quiz 5: 1. a, 2. a, 3. b, 4. e, 5. b, 6. c, 7. c, 8. g, 9. b, 10 d
Quiz 6: 1. d, 2. d, 3. a, 4. b, 5. b, 6. d, 7. b, 8. c, 9. a, 10. e
Quiz 7: 1. c, 2. b, 3. e, 4. c, 5. f, 6. b, 7. a, 8. b, 9. b, 10. b
Quiz 8: 1. b, 2. c, 3. d, 4. a, 5. b, 6. b, 7. c, 8. c, 9. a, 10. d
Final Exam: 1. c, 2. b, 3. b, 4. c, 5. d, 6. a, 7. a, 8. c, 9. a, 10. d, 11. d, 12. a, 13. a, 14. c, 15. d, 16. a, 17. b, 18. a, 19. d, 20. b, 21. b, 22. e, 23. d, 24. d