A reinforced concrete beam has a simple span of 4.5 m and carries a dead load of 20 kN/m and live load of 35 kN/m. Steel covering is 75 mm. Using f’c= 28 MPa and fy = 415 MPa. Determine the maximum moment due to the factored loads. Determine the least dimensions of the beam using the maximum allowable reinforcement

A simply supported rectangular beam of length L has a width of b and an effective depth of d. Compression steel bars are placed at a distance d' from the extreme concrete compressive fiber. The beam supports service dead loads of wD and wl, respectively. Use fc'= 28 MPa and fy = 420 MPa. For the reinforcements, use 4 20 mm tension steel bars and 4 10 mm compression steel bars. b= 390 mm d= 615 mm d'= 165 mm L= 5.85 m Wd= 27.79 kN/m WI= 32. 25 KN/m Questions 1. Calculate the height of the neutral axis measured from the extreme compression fiber. 2. Calculate the strength reduction factor for the given beam. B. Calculate the design moment for the given beam.

The section of a Super-T prestressed concrete girder is shown below. The girder is simply supported on a span of 7.0 m and are pre-tensioned with total initial force of 825 kN from low-relaxation strands. The girder supports a total dead load of 2 kPa and live load of 6 kPa. There is a loss of prestress of 0.2 at service loads. Assume "-" for compression and "+" for tension. Hint: Assume tributary width is equal to flange width. Properties of the section: A = 100,000 mm2 INA = 940 x 106 mm4 All measurements in the drawings are in millimeters. 1. What is the stress, in MPa, at the top fibers of the girder at end span due to initial prestressing force only? 2. What is the stress, in MPa, at the bottom fibers of the girder at midspan due to initial prestressing force only? 3. What is the stress, in MPa, at the top fibers of the girder at end span due to prestressing force and service loads? 4. What is the stress, in MPa, at the bottom fibers of the girder at midspan due to prestressing…