1. The floor of the office building is made of 4-in.-thick lightweight concrete. If the office floor is a slab having a length of 20 ft and width of 15 ft, determine the total fag concentrated load. Q-2: The Prestressed concrete girder is made from plain stone concrete and four 3/4-in. cold- form steel reinforcing rods. Determine the dead weight of the girder per foot of its length by neglecting the weight of steel reinforcement. 8 in. 6 in. 20 in. 6 in. 8 in. 4 in. 6 in. in. Q-3: The floor system used in a school classroom consists of a 6-in. reinforced stone concrete slab. Calculate and sketch the loading that acts along the side girder ABCDE. Use a=7.5ft and b=20ft