Question

The portion of structure shown represents the upper part of a power transmission line tower. For the given loading, determine 1. Whether there are any O-force members; 2. The force in each of the members located above HJ. State whether each member is in tension or compression. 1.60 m 2.21 m 2.21 m F 10.60 m 10.60 m 1.2 kN 1.20 m 1.2 kN L 10.60 m 10.60 m +2.97 m 1.2 kN 1.20 m 1 IN P 10.60 m 10.60 m 1.2 kN 1.2 KN

Answer 1

Solution: foee body : Joint A: FAB FAC 2.29 FAB FAC 1:2 1-2 KN 2.21 J-2 2.23 1.2 2.23 L0.6 fAB FAc FAB = 2.29 kn CT)- 1:2KN. fAc = 2.29 KN + Toree body: Joint f: foF FEE Fof 1.2 KN 229 2-21 2.2.9 1:2 2.29 2.1 12KN 2-29 = 2.29 KN (T) + Fof Fer. 1-2KN. FEF = 2-29 KN (C)+ + foee body: Joint D : FBR 2.29 EN FBD D 2.21 l0.6 2.29 FDE FDE 2.29 KN %3D FBD 2.29 d.6 2.21 fof=2.9KN FDE feD 2.2) KN (T) FOE O:600 KN (c)+ %3D fRo= 2-21KN > free body: Joint B : 2.21 0'6 2.29 fre =229KN 2.21 -x2-29 =0 2.29 FaE * Fes + 2:21 KN - Fec FBE O.6 x2.29 =0 2.29 +1Efy =0 : -Facxo- for =-0: 600KN :. For = 0: 60OKN (C) BC

foee body:Joint c: Fsc = 0.600kN + Ef = o 2.21 2.21 -× 2.29 =O Jo.6 2.29 FAC 2.29 FeE =2.29 KN. FEE = -2. 2) KN. FcE (c) +- = 2.2) KN fCH + 1E fy : O:6 Fon O.600KN - X2.29 = o 2.29 FoM 1.200 KN fCH 1-2 KN CC) - foee body : Joint E pE = 0-600 kN .ΣE ο fer= 2-29 KN Jo.6 FRE =0 2.21 Fes =2 2IEN 2.21 - X2.29- EH 2.21 2-29 FEM FEH +1Σ 0.6 - FEs - o:600 - 2.29 X 2-29 -O =0 1.200 KN %3D EJ FEJ = -1:200 KN +- (C)