1.A concrete mix with a 3-inch slump, w/c ratio of 0.50, and sand with a fineness modulus of 2.4 contains 1700 lb/yd^3 of coarse aggregate. Compute the required weight of coarse aggregate per cubic yard. To adjust the mix so as to increase the compressive strength, the water-to-cement ratio is reduced to 0.45. Will the quantity of coarse aggregate increase, decrease, or stay the same?
2.How many 3?4-inch diameter rivets are required to transmit 55,000 lb from the two angles to the gusset plate if the allowable shear stress in the rivets is 15,000 psi? Assume each rivet carries the same amount of load.