Question

Q1. Consider a truss shown in Fig.1. Joint A sits on a pin support and I on a roller support. () Determine the forces on members CD, FG and Hl, using two different methods (a) and (b). Identify the forces as Tension or Compression. (ii) Determine the member that carries maximum tension. (a) method of Joints, and (b) method of Sections 200 kN 200 kN 200 kN 200 kN 200 kN 4 m 3 m -5 m Fig.1 Truss

Answer 1

Draw the free body diagram of the joint B. 200 KN BD BA BD FR200 KN Draw the free body diagram of the joint A. FAR AD AC 0. 500 kN

AC /25+ 9 25 +49 AC 300 AC /25 +9 0.5 14Че +0.8 14F,D-_300 AD 25 +49 FAC 435.568 kN FAD643.6 kN Draw the free body diagram of the joint D. 200 kN DB DA DC DF DB DA FD-0+-643.6x 25 +49 FD-374.085 kN

200+F cos F0 200-643.6x F 323.72 kN Draw the free body diagram of the joint C. DA DC IX DC CF CE 4 3 m AC

AC 435.568 cE25+1 0.98Fcz +0.78FcF-373.5 25 +16 25+9 323.72+0.626FF0.2FCE 435.568(0.5145) 0.626FcF +0.2FC -99.62 FoF376.69 kN 680.935 kN The given truss is a svmmetric structure. he forces in the members are also symmetric as follows: FC 323.72 kN (Tensile) Fr 376.69 kN (Compressive) F 643.6 kN (Compressive FG CF HI AD