A rectangular reinforced concrete beam has a width of 300 mm and an effective depth of 450 mm to centroid of the tension bars. The beam is reinforced with six 32 mm ɸ tension bars placed in two layers with the outer layer having a depth of 478 mm, and two 28 mm ɸ compression bars with centroid 65 mm from the extreme concrete fiber. Use the 2010 NSCP, fc’= 34.5 MPa and fy = 345 MPa. Assume that the concrete displaced by the compression steel shall not be neglected and that the compression steel yields. Det. the following: 19. The balanced steel ratio if the beam is singly reinforced. a. 0.04607 b. 0.03555 c. 0.02721 d. 0.03672 20. The maximum steel ratio for a singly-reinforced section in tension control. a. 0.03555 b. 0.04607 c. 0.03672 d. 0.02721 21. The maximum steel ratio for a doubly-reinforced section in tension control. a. 0.02721 b. 0.03672 c. 0.03555 d. 0.04607
A rectangular reinforced concrete beam has a width of 300 mm and
an effective depth of 450 mm to centroid of the tension bars. The
beam is reinforced with six 32 mm ɸ tension bars placed in two
layers with the outer layer having a depth of 478 mm, and two 28
mm ɸ compression bars with centroid 65 mm from the extreme concrete
fiber. Use the 2010 NSCP, fc’= 34.5 MPa and fy = 345 MPa. Assume
that the concrete displaced by the compression steel shall not be
neglected and that the compression steel yields. Det. the following:
19. The balanced steel ratio if the beam is singly reinforced.
a. 0.04607 b. 0.03555
c. 0.02721 d. 0.03672
20. The maximum steel ratio for a singly-reinforced section in
tension control.
a. 0.03555 b. 0.04607
c. 0.03672 d. 0.02721
21. The maximum steel ratio for a doubly-reinforced section in
tension control.
a. 0.02721 b. 0.03672
c. 0.03555 d. 0.04607
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