PROBLEM 1: (30points) The section of a column is shown below. The bl-300 mm, b2= 180 mm, d1= 250 mm, d2= 350 mm, fc-28 MPa, fy- 414 MPa. A). Determine the location of the centroid of the gross concrete area measured from y-axis. B). Determine the location of the plastic section of the column measured from the y-axis. Neglect the area of concrete occupied by the steel. C). Determine the factored moment Mu due to a factored load Pu= 3200 KN applied 400 mm from the y-axis. Assume that the column is reinforced such that plastic centroid is 290 mm from the y-axis. Use ACI Specifications. 6-20 mm ba 4-28 mm de 84 mm