Question

Answer the following questions for each cross-section below using the Equivalent Rectangular Stress Block (Whitney Stress Block) for compressive stresses in the concrete. (72 total points) A. What is the nominal moment capacity of the beam (Ma)? [6 points) B. What is the distance from the top of the beam to the neutral axis (c)? [2 points] C. Assuming the concrete reaches a strain of 0.003, what is the strain in the extreme tension layer of reinforcing steel? Draw the strain and stress diagrams, specifically labeling e, a, d, di, the compressive stress in the concrete, the tensile stress in the steel, the resultant compressive force, and the resultant tensile force. [8 points) D. Would failure of the beam be considered tension-controlled, compression-controlled, or in the transition region? What is the resistance factor ()? 12 points) Which cross section has the max nominal moment capacity considering the strength reduction factor M2 2 points 2. 1. 32" (12)#7 (4) W5 1-7/8"! 18" 2 2-1/2,-60,000 psi 5,000 ps 60,000 psi 18" 16 4 16* 2-1/4-1 (5)#7 (3)#11 2-1/2-1 (5) #10 3" (5)#11 2-1/2- f 3,500 pi ,60,000 psi f8,000 psi 60,000 psi

Answer 1

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