J A El-Rimawi (J.A.El-Rimawi@lboro.ac.uk) .
(Answer: Reactions RB=250 , RC=50 ; Member forces: AD,DG=141.42(T); AB,BG =100(C); GH=100(T); BE,EH=212.13(C); HF,FC=70.71(C),BC=50(T); and zero.)
Calculate the reactions by careful choice of three equations of equilibrium and the equation of condition. Hence find the force in members BD and DC.
(Answer: VA= VG =75 ; HA = - HG = 12.5® , FBD = 19.3 (T); FDC= 45.7 (C))
Check the vertical reactions by taking moments about the z-axis through B. All the horizontal reactions should be zero.
Check the forces in members AB, AC and AD by resolving at joint A along each axis; each equation should sum to zero. Express the force of each member along an axis as a ratio of its projected to actual length (the lengths of members AB, AC and AD are 7.07, 10.49 and 7.55 m).
(Answer: FAB = 6.4; FAC = 4.9; FAD = 4.2 (all C)).