GATE Civil Engineering (CE) 2023 Shift 1 Solved Paper

Consider the pin-jointed truss shown in the figure (not to scale). All members have the same axial rigidity, AE. Members QR, RS, and ST have the same length L. Angles QBT, RCT, SDT are all 90°. Angles BQT, CRT, DST are all 30°. The joint T carries a vertical load P. The vertical deflection of joint T is k$\frac{\mathit{P}\mathit{L}}{\mathit{A}\mathit{E}}$. What is the value of k?