Building Design - The Intelligent Approach

Transcription

1 Building Design - The Intelligent Approach Copyright 2017 Steel Joist Ins@tute. All Rights Reserved. Presented by: James M. Fisher

2 Learning Objec;ves Selec&ng the serviceability criteria for the horizontal framing members Selec&ng the lateral dri7 criteria Selec&ng the structural system, i.e. braced frames, moment frames, shear walls Determining the type of connec&ons to use Designing connec&ons or establishing their design criteria Checking that the design has been correctly transferred onto the construc&on documents Project Specifica&ons 2

3 Building Design - The Intelligent Approach 3

4 Building Design - The Intelligent Approach Purpose: The purpose of this discussion is to inform engineers how to frame buildings, so the most cost effec&ve structure is achieved. 4

5 Building Design - The Intelligent Approach As a designer of structural steel buildings, you are a part of a team: The team of Engineers, Fabricators, Detailers, Erectors, and Material Suppliers. A smart building is one in which the building performs well, and the team members and the owner are all sa&sfied with the result. This generally occurs when all team members make a profit on the project, and the building owner believes he or she paid a fair price for the structure. 5

6 Building Design - The Intelligent Approach A smart building can only be accomplished with quality construc&on documents and coopera&on among the team members. Remember that design is not a success un&l construc&on is complete and the structure func&ons properly. 6

7 What are you going to do when first given a design project? Think about the Big Picture Think Through the Design Problem(s) Think Through the Design Solu&on(s) 7

8 Design Approach Select the serviceability criteria for the horizontal framing members. Select the lateral dri7 criteria. Determine the fire protec&on criteria. Determine any loss preven&on requirements such as Factory Mutual (FM) Global requirements. 8

9 Design Approach Select the direc&on of roof drainage (primarily for single story structures). Select the structural system, i.e. braced frames, moment frames, shear walls. Determine the loads on the structure. Determine the type of connec&ons to use. 9

10 Design Approach Select the members to be used for the lateral load system. Select member sizes based on the dri7 criteria, other serviceability criteria and material availability. Select member sizes that make the connec&ons work. Perform analysis to check conformance with dri7 criteria. 10

11 Design Approach Check member sizes for strength. Design connec&ons or establish design criteria. Draw plans and details to an appropriate scale. Check to make sure that the design has been correctly transferred onto the construc&on documents. Finalize Project Specifica&ons 11

12 Preliminary Design Geometrical Considera&ons Member Selec&on Guidelines Lateral Load Resis&ng Systems 12

13 Geometrical Considera;ons Bay size Bay propor&ons Member selec&on (Joists, Joist Girders, Structural Steel) Short spans (HSS, Channels) Direc&on of main members vs. secondary members Girts and Wind Columns Diaphragm Geometry Length to width ra&os 13

14 Bay Size Square Bays Generally Least Cost If Rectangular Span the Girders in the Short Direc&on Replica&on Replica&on of joists and beam sizes reduces cost of detailing, fabrica&on, and erec&on. Carefully review computer results to obtain replica&on. 14

15 Member Selec;on Guidelines Deck Joists and Joist Girders Structural Steel Beams Columns 15

16 Deck Selec;on Guidelines SDI Recommended Spans FM Global and other Insurance Requirements Standing Seam Roofs 16

17 SDI Recommended Spans 2 - Hr Fire Rat - ing 1 - Hr Fire Rat - ing 3.5 LWC Above Flutes Deck Gage Deck Depth NWC Above Flutes Deck Gage Deck Depth LWC Above Flutes Deck Gage Deck Depth NWC Above Flutes Deck Gage Deck Depth

18 FM Global Data for Roof Deck 18

19 Standing Seam Roofs 19

20 Design Tools Roof Framing (SJI and AISC) Floor Framing Non Composite Joists (SJI) Composite Joists (SJI) Non Composite Beams (AISC) Composite Beams (AISC) 20

21 Bay and Member Selec;on Guidelines See SJI Steel Tools, hbps://steeljoist.org See AISC Steel Tools, hbp:// 21

22 Roof Framing Analysis Tool - Demonstra;on 22

23 Beams and Columns 23

24 Rules of Thumb* Depth of Roof Joists = 0.5*Length Depth of Floor Joists = 0.6*Length Depth of Composite Beams = 0.55*Length Where Length is feet and depth is inches Composite Beams Number of Studs req d for full composite ac&on = 1.25*Wt * Rules of Thumb for Steel Design, John L. Ruddy and Socrates A. Ioannides, AISC NASCC,

25 Lateral Load Resis;ng Systems Rigid Frames Roof Bracing Diaphragms 25

26 Rigid Frames 26

27 SJI Tools for Moment Connec;ons Joist Girder Moment Connec&ons to the Strong Axis of Wide Flange Columns Joist Girder Moment Connec&ons to the Strong Axis of Wide Flange Columns - Intermediate Levels Joist Girder Moment Connec&ons to the Weak Axis of Wide Flange Columns Joist Girder Moment Connec&ons to HSS Columns - Top Plate Joist Girder Moment Connec&ons to HSS Columns - Knife Plates Joist Girder Moment Connec&ons to Strong Axis of WF Columns - Knife Plates 27

28 Moment Connec;on - Top Plate 28

29 Moment Connec;on - Top Plate 29

30 Rigid Frame Moment Connec;ons Tool - Demonstra;on REFERENCE MANUAL AND PROGRAM USAGE GUIDE Joist Girder Moment Connections to the Strong Axis of Wide Flange Columns Version 1.0 Steel Joist Institute 234 W. Cheves Street Florence, SC Phone: (843)

31 Roof Bracing 31

32 Roof Diaphragms 32

33 Roof Diaphragm Key Plan Use 36/4 with 1 Side Lap Screw Use 36/7 with 2 Side Lap Screws 33

34 Means of Fastening Welding Power Driven Fasteners Self Driven Screws Bubon Punching 34

35 Advantages of Screws and Power Driven Fasteners Easy to Install with Unskilled Labor Clean Neat Appearance Dependable 35

36 Disadvantages of Screws and Power Driven Fasteners Capacity Cost 36

37 Deck Determina&on of Forces Selec&on of Deck Type and Fastening Steel Deck Ins&tute (SDI) ICC-ES Reports Evalua&on of Deflec&ons Analysis of Chord Forces Force Transfer Details 37

38 Connec;ons Chord Forces Shear Transfer 38

39 Chord Forces The Engineer of Record Must Indicate the Chord Force Requirements on the Contract Documents 39

40 Chord Forces The specifying professional shall provide the nominal loads and load combina&ons as s&pulated by the applicable code under which the structure is designed and shall provide the design basis, ASD or LRFD. The specifying professional shall calculate and provide the magnitude and loca&on of ALL JOIST and JOIST GIRDER LOADS. This includes all special loads (dri7 loads, mechanical units, net upli7, axial loads, moments, structural bracing loads, or other applied loads) which are to be incorporated into the joist or Joist Girder design. Type and magnitude of end moments and/or axial forces at the joist and Joist Girder end supports shall be shown on the structural drawings... SJI Code of Standard Prac&ce 6.1(a) 40

41 Diaphragm Chord F F 41

42 Joist Chord Bending M F e F 42

43 Joist Tie Plate Top Chord of Joist 43

44 Joist Tie Angles Top Chord of Joist 44

45 Shear Transfer Methods Deck Support Angles Joist Seat Rollover Shear Collectors Transfer to Shear Walls Across Expansion Joists Abachment to Ver&cal Bracing with Joist Girder 45

46 Deck Support Angle Continuous Angle Field Weld or Screw Deck to Angle per Roof Diaphragm Requirements 46

47 Joist Seat Rollover v /

48 Deck Support Angle and Joist Seat Rollover 48

49 Shear Collector K-Series Joist ROOF DECK PER SIDE LAP DIAPHRAGM 5/8" DIA. REQUIREMENTS HSS 2 1/2 X 2 1/2 X 3/16 CENTER BETWEEN JOISTS (NOT BY JOIST MANUFACTURER) JOIST GIRDER 49

50 Shear Collector LH-Series Joist ROOF DECK 3/16 " 5/8" DIA. PER SIDE LAP DIAPHRAGM REQUIREMENTS 5" CHANNEL C5 x 6.7 CENTER BETWEEN JOISTS (NOT BY JOIST MANUFACTURER) JOIST GIRDER 50

51 Shear Transfer to Masonry DECK ATTACHED TO LEDGER TO TRANSFER SHEAR FORCE CONCRETE FILLED BOND BEAM CMU WALL LEDGER ANGLE ANCHOR TO WALL (NOT BY JOIST MANUFACTURER) DECK JOIST CAMBER TO BE SPECIFIED TO MATCH LEDGER 51

52 Precast Insert SLOTTED INSERT SECTION A A DECK NOT SHOWN FOR CLARITY T-STRAP (NOT BY JOIST MANUFACTURER) 52

53 Constructability Think Constructability Throughout the Design Process 53

54 Constructability Issues Minimize the number of anchor rods per column. Provide permanent bracing that can be used as temporary bracing. Make sure that all beams can be brought into place without interference or having to spread columns apart. Provide adjustability in your design. Consider mill and fabrica&on tolerances by using shims and oversize or slobed holes where required. Check that tolerances do not accumulate, causing fit up problems. 54

55 Constructability Issues Check to see that the tolerances specified match your expecta&ons of the final product. Make sure that there is adequate access for welding and bol&ng. Check that beams do not have to be severely coped, i.e. deep members framing into shallow members. Eliminate overhead welding. Have realis&c specifica&ons that match your actual intent and design requirements. 55

56 Constructability Issues Use materials that are readily available. Minimize the amount of loose material for details. Provide straight forward connec&ons that can be erected without added temporary provisions. Check for camber differences on adjacent members. Make sure members have sufficient width for elements bearing on them. 56

57 Constructability Issues Run can&lever beams over column tops whenever possible, for safety in erec&on. Have steel deck span all in the same direc&on. Don t use moment base columns bearing on concrete piers. Avoid moment connec&ons into the weak axis of columns. 57

58 Fabricator/Detailer The fabricator wants you to provide a design that will permit the material to flow con&nuously through the shop. This means that your design should not require welding to a column or beam, if the design also requires the drilling or punching of holes in the same member. Drill and punch lines are different lines than the welding lines. It costs money to transfer a column or beam from one line to another. The material will not flow through the shop if such transfer must be made. Fabricators and detailers suggest the following to achieve a successful design: 58

59 Fabricator/Detailer Use standard AISC connec&ons: single plate shear connec&ons and single angle connec&ons. Use field bolted moment connec&ons. Keep the design simple. Provide understandable plans. Minimize changes. Release mill orders and detailing only when complete. And if not complete inform the architect, contractor and fabricator of the areas which are not yet complete. 59

60 Fabricator/Detailer Repeat member sizes whenever possible (least weight is not least cost). Show all reac&ons on the drawings: axial, shear, moment, and transfer forces. Answer the detailer s ques&ons promptly, i.e., REALLY FAST. Approve shop drawings in a &mely manner. 60

61 Erector Minimize the amount of loose material for field installa&on. Use maximum prac&cal column lengths (2 or 3-story with splices 4 7. above the floor). When possible, provide permanent bracing in the design that can also be used as temporary bracing. Keep the design simple, provide readily understandable plans. 61

62 Learn From the Team Members Listen to the fabricator, the detailer, the erector, and the material suppliers. They have prac&cal knowledge gained in their day-to-day experiences of puqng together many projects. This knowledge can be instrumental in achieving a good design. 62

63 THANK YOU Copyright 2017 Steel Joist All Rights Reserved. Presented by: James M. Fisher