Chapter 4 Member Forces in Planar Trusses() and Space Frameworks(构架) Instructor: Sun, Fei-fei Spet, 15th, 2014, 月大学 土工程学院 11 TONGI UNIVERSITY COLLEGE OF CVI ENGINEERING 4.1 Planar truss（平面桁架） structures upper chord members (上弦杆) verticals (竖杆) diagonals(斜杆) lower chord members (下弦杆) (a) gusset(节点板) plate weld (焊缝) 一 2 (b) (c)
4.2 Idealizations for planar trusses typical panel (a) p floor beams 4.3 Variations in planar truss configuration (a) (b) B D simple simple truss truss A C E
4.4 Truss joint(结点)identification and member force representation R=x食=（ 同源大学 土本工程学院 4.5 Sign convention(符号规定) and member force representation joint A joint B A B T (a) joint A joint B A B (b) 同©大学 土本工程学院 6
4.6 Strategy for planar truss analysis E 60 kips XED ED FED FEC Method of joints (结点法) 60 kips 一FFE 20 15 Method of sections 士示红程学院 (截面法) 4.7 Condition equations Hinge.M=0 0 d Hinge.M=0 Hinge.Mez=0 Parallel members,P O in panel be a
4.9 Numerical truss analysis problems D 0 E 6o kips B A 0 M 0 K 0 0 0 Bars with zero force. (零杆) 0 180 kips 120 kips 9 4.9 Continued 60 kips 60 kips ←一FE 15 4 20 60kips4 C 15 (b) 3@15'=45 (a) -80 60 kips- 80kips +26.7 s0 2679 +80 XED YED FED +80 +80 60 kips +26.7 80 FEC 80 kips 80kips (c) (d)
4.9 Continued 30 G F 24 kips 48 kips 48 kips 24 kips 48 kips 201—200—20° 20 (a) (b) R 16 kips +16 6 144 kips 12 6 d36 4 30 48 12 36 360 +2 84 -144 kips FGF 64 24 kips 48 kips 24 kips 48 kips 48 kips 120 kips 20 20° (e) (d) 4.10 Complex planar trusses复杂平面桁架) (a) (b) 同©大学 目 土亦工程学院 12
4.11 nonplanar truss-type space frameworks b 13 d 4.12 Variations in framework configurations 14
4.13 Joint identification,member force notation,and sign convention(符号规定) _=- L利财功 -x自.份2周 Member衫cu x=食。月-z食 Member length = --x目-周 工-食=目。-食 同停大学 土床工程学院 15 4.15 Analysis of truss-type space frameworks 5m R 50kN 16