The indeterminate structure rig (Figure 1) consists of three pin-jointed members made of the same type of steel. The top member is at 45 to the vertical. The middle member is horizontal and the bottom member is at an angle of 60 to the vertical; the bottom member is 1m long between pins. The outside diameter of the steel tubes is 25.4 mm and the wall thickness is 1.2 mm. Young's Modulus of the steel tubes of the rig is 210GPa. B 45 C 45 A 90 30 60 F x Load (kN) Strain gauge 1 & 2 (top member) 1 42.5 Figure 1: Test rig used (left) and schematic drawing of the frame of the rig (right) Theoretical analysis: using the analytical method calculate the horizontal and vertical displacements of point A and the internal forces in each member of the structure if a load of 6 kN is applied vertically, as shown in Figure 1. Average strain in micro-strain (=10^-6 strain) Strain gauge 3 & 4 (middle member) Strain gauge 5 & 6 (bottom member) -41 2.5 2 23456 125 -1-5 -3 -815 -119-5 164 h- 208 -5 -158 -2015 251 -6 -243-5