For a rectangular beam and having the following given information: (Time: 20 minutes) 55 in Aps 4 in 35 in 1. Ultimate
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For a rectangular beam and having the following given information: (Time: 20 minutes) 55 in Aps 4 in 35 in 1. Ultimate
1. Ultimate bending moment, Mu = 1200 k-ft 2. Compressive strength of concrete, f'c = 5.5 ksi 3. The ultimate strength of prestressing steel, fpu = 270 ksi 4. Minimum concrete cover from the bottom fiber to the centroid of the prestressing steel = 4 in. 5. fpy/fpu = 0.76 6. Tendons are bonded Strictly based on ultimate strength requirements;
Strictly based on ultimate strength requirements; a. 10 Grades Determine the required area of the prestressing steel, Aps. b. 5 Grades Check the criterion for the maximum reinforcement that ensures the section of the maximum moment remains under-reinforced using the AASHTO LRFD Code provisions for tension-controlled, compression-controlled, or transition members. State whether the section is tension-controlled, compression- controlled, or transition. C. 5 Grades Determine the maximum allowable area of the prestressing steel for this beam to ensure that the section of the maximum moment remains under- reinforced using the AASHTO LRFD Code provisions. Then determine the corresponding nominal bending moment, Mn. Hint: for axº + bx + c = 0; x = -b + b2 - 4 (a)(C) 2a