Question

Using the method of joints, determine the force in each member of the truss shown. State whether each member is in tension or compression.

7 kN 24 kN 7 kN B с А 0.8 m DO E F 8 kN -1.5 m- -1.5 m

Answer 1

22 KN FKN FRN B C 0.8m a རང] 120 SAN * > * 1.5m 1.5m Ateb-1: Determine Reactions {fy zo Rothy & 7+24+7 +8 ROTRE 46 KN Moment about a & Moto t RfX3 = (Bxrs) (24x15) + (7x3) RE & 23 KN Ro=46-23 225 KN

At Tant A YKN Ety FAO 7+ Foco FAO FADE - KN FAD FAN compression Seint e FAO fов Etyo you for FADT FOR sind tro co Ro -7+ FAX 0-8 + 23-0 27 17 you FOR = -34 KN 15 FDB = 34 KN I compression Efco FOB Cosa + FoE =0 -34X 1.5 + FDE =0 FOR = 30 KM Tension

At Joint E FO Ety=0 E FEE TEER & S KN Tension FED 8KN Efnzo FED FEE & 30 KN FER 30KN/ Tension. so by symmetry For = FAD FAD = FRN For 7KN/ compression > FBE = FBD - 34 KN [ For = 34 KN Combustion → TAB = FBC

At Joint B 244N FAB FBC 8 FBD For Errco FABI FRD Cosa = For cosa + F.BC This FAB = FBC =0