Question

2. Determine the force in members CD, HI, and CH of the truss, and state if the members are in tension or compression. (15 points) K J H G 8 ft Α. B C D E F -6 ft 6 ft 6 ft 6 ft 6 ft 900 lb 1500 lb 900 lb 1500 lb 900 lb

Answer 1

Solution Given, d I I G Y eft B E F k oft off oft oft Gft. goolb goolb 15oolb 1500 lb goolb Cut the section at 1-1 Take right side at 1-1 Equillibirium the RHS of 1-1 THE -I G for 0 8ft tve fo L- f a oft D E 6ft oft 1500lb goolb goolb Pn gecoh CD = 6ft HD = 8ft CH=√ Cg2+ HD2 = N62782 (H=rloo loft CORO = HD CH B =

{fy =0 FcH. Coso - 900 - 1500 - 900 =0 - for X 8 3300 To fcH = -4 125 lb ve xign implies that com pussion force) For = 4125 lb compression EMA=0 (moment about point His zero) - Fox at 150086 +90 x 12 tue) 8 for = 19800 fed - = -2475 lb OR Fd = 2475 lb compression EM=0 (moment about point c is zero) the FHI XB + goox6 +1500X12 + 900 x 18 = 0 8 FHI 39600 FH I = 4950 lb Tencion

Member	Force	Nature
CD	2475 lb	Compression
HI	4950 lb	Tension
CH	4125 lb	Compression