3. The concrete column is reinforced using four steel reinforcing rods, each having a diameter of 25 mm. Determine the stress in the concrete and the steel if the column is subjected to an axial load of 1200 kN. Est = 200 GPa, 1200 kN Ec = 25 GPa. 300 mm 300 mm

PROBLEM TO SOLVE: 600 mm 400 mm 6-25mm diam. 90 mm Using fc' = 28 MPa, Mmax = +320 kNm Determine the following: a. Cracking Moment (kNm) b. Compressive Stress felt by concrete (MPa) c. Tension Stress felt by the tension bars (MPa) d. Moment of Inertia under critical condition e. Demand Capacity Ratio of Concrete under Compression Stress f. Compression force on concrete (kN) g. Distance of the compression concrete force from the neutral axis (mm)

A prestressed concrete beam of rectangular section 300mm wide and 600mm deep is prestressed by 5 pieces of 8mm high tensile wires at 500mm from the top and 15 pieces of 8mm diameter high tensile wires at 83 mm from the bottom. The initial stress in the wires is 1200 MPa. Estimate the loss of stress in the bottom wires due to elastic shortening of concrete. Assume modular ratio = 6.

If column AB is made from high strength pre-castconcrete and reinforced with four 20 mm diameter A-36steel rods, determine the maximum allowable floorloadings P. The allowable normal stress for the highstrength concrete and the steel are (ϭallow)con = 18 MPaand (ϭallow)st= 170 MPa, respectively.