Rigid bar abc is supported by a pin at bracket a and by tie rod (1). tie rod (1) has a diameter of 7 mm, and it is supported by double-shear pin connections at b and d. the pin at bracket a is a single-shear connection. the pin at b is 8 mm in diameter. assume a = 540 mm, b = 270 mm, h = 340 mm, and θ= 55°. if the normal stress in tie rod (1) cannot exceed 180 mpa and the shear stress in pin b cannot exceed 130 mpa, determine the maximum load pmax that can be supported by the structure.