Question

3. (30 points) A space truss is shown. a. Determine the force in member BE. b. Determine the force in member AB. Note: Although this truss is indeterminate, a solution is possible due to symmetry of geometry and loading.

Answer 1

- joints. for we can solve the problem using method of In this care, support reactions are not required determining the member force consider sand A Force acting at jant A are shown below Free H EFZ 20 za om S PAR (am) -620. FAB 6462 EN (1) Į GAN x 78620 5620 fac [ 3) - Fad () 20 FACE FAD - 1 Ergo FAC ( 4 ) + FAD (4) - 6,462 ( 12 ) 20. O fact FAD= 3 - from ③ , 2PAC = 3 FACa 115 kn smFAD Sm 3m 1. FAC= FAO= 115 kn

Consider a jont B forcer acting at B are shown below oort O Poesia y Enzo Foc (as) - Foo () zo 57 Pre Relea ñ FAB6.98 10 = 6,462 KN FBC = FB2 - 0 E Fzzo Feel 5) + fool 5 s) - 6,462 (5/12) 20 fect rep = 61462% Sport e vog FBct FBO = 7.397 from B, 2 FBC = 7.397 FBC = 3,7 kn (c) FBc = FBO = 3,7 kn (c) $530 25300 () + 6.462 ( lama) - Foc zo FBE = 418kN (1) I Force in member BE, FBE = 4,8 kN (1) force in member AB, FAB= 6.462 kN (T)