Question

Supports at A and B are pins. Find a) AD, b) CD, c) DE and d) BC bars. 1 kip = 1000 lb. P kips 12 ft 8 ft 1910 10 ft Sft -

Answer 1

tano = 4 0 = 38-6598 tang=y Ax 12f4 L Vo p. 14ft O ㅏ d u $= 21.80140 Bx = Reaction force at B Axes horizontal Reachon - force at A Ay = Vertical Reaction force at A consider joint B Be B loft . t fsst 7 FBC Equating verhcal forces FBc smo=0 FBC =0 force en BC BXEBET - kips Conside FAC joint a FCO Equating force by property (for parallel forces ) Fco=FBc , FAC = FCE [Fro= o kips] force in co FBC FCE

Consider joint F, FOF loos Equating horzontal forces FDF Coso + F-EF COOO=0 FDE = -FEF Equaling vertical forces FDE BIN O - P + FEF 8mo For sino - FEF Sino =P 2 FDF sino = p For = sin 38-6598 FOR = 0.800 3%5P keps consider joint D, A FAR Equating horzontal forces No FAD Coro - FDF COOO Foro FDE FAD Cox 21.801430.80039 P co0 38.6598 FDE FAD= 0.6731450 / force an AD keps

Equating vertical forces FAD sin 0 = FDF SMO + Fed Bin 0 + FDE FDE = FAD sind - For smo = 0,67314581121.8014 – 0,80039081n38-6598 FRE= –.0.25% kep FDE=0.25P kip compression force un DE