prestressed concrete beam has the following characteristics: a width of 300mm overall depth of 600mm prestressing tendons are placed at a distance “e” below the NA of the beam the applied prestressing force is P in kN there is 15% loss of prestress 2. Find P in KN when the compressive stresses at the top and bottom of the beam are 2MPa and 12MPa, respectively.

Column AB is made from high strength pre-cast concrete and reinforced with four in. diameter A-36 steel rods. The allowable normal stress for the high strength concrete and the steel are (allow)con = 2.4 ksi and (allow)st = 24 ksi, respectively. The modulus of elasticity for high strength concrete is 4.2 × 10³ ksi and for A-36 steel is 29 x 10³ ksi. (Figure 1) Figure 10 ft 9 in. H 9 in. Section a-a Part A Determine the magnitude of the maximum allowable floor loading P. Express your answer to three significant figures and include the appropriate units. Pmax = Submit 04 μA Provide Feedback Value Request Answer Units ?

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.