Steel plate at the top is held by 3 columns. The cross section area for each column is 400 cm and its length is 200 cm. Before the load applied on top of the plate, due to mistake in production the middle column is made 1 mm short. If the module of elasticity for the columns are 30GPa and allowable stress equals to 20MPa, determine the maximum allowable load "P" on top of the steel plate. (35 points)