flexural stress

Problem 594
A distributed load of w_o lb/ft is applied over a middle 6 ft of a simply supported span 12 ft long. The beam section is that in Prob. 593, but used here so that the 8-in dimension is vertical. Determine the maximum value of w_o if f_b ≤ 1200 psi, f_v ≤ 120 psi, and the screws have a shear strength of 200 lb and a pitch of 2 in.
 

Problem 593
A box beam, built up as shown in Fig. P-593, is secured by screws spaced 5 in. apart. The beam supports a concentrated load P at the third point of a simply supported span 12 ft long. Determine the maximum value of P that will not exceed f_v = 120 psi in the beam or a shearing force of 300 lb in the screws. What is the maximum flexural stress in the beam?
 

Problem 592
A wide flange section is formed by bolting together three planks, each 80 mm by 200 mm, arranged as shown in Fig. P-592. If each bolt can withstand a shearing force of 8 kN, determine the pitch if the beam is loaded so as to cause a maximum shearing stress of 1.4 MPa.
 

Problem 590
A box beam carries a distributed load of 200 lb/ft and a concentrated load P as shown in Fig. P-590. Determine the maximum value of P if f_b ≤ 1200 psi and f_v ≤ 150 psi.
 

Problem 589
A channel section carries a concentrated loads W and a total distributed load of 4W as shown in Fig. P-589. Verify that the NA is 2.17 in. above the bottom and that I_NA = 62 in⁴. Use these values to determine the maximum value of W that will not exceed allowable stresses in tension of 6,000 psi, in compression of 10,000 psi, or in shear of 8,000 psi.
 

Problem 588
The distributed load shown in Fig. P-588 is supported by a wide-flange section of the given dimensions. Determine the maximum value of w_o that will not exceed a flexural stress of 10 MPa or a shearing stress of 1.0 MPa.
 

Problem 587
A beam carries two concentrated loads P and triangular load of 3P as shown in Fig. P-587. The beam section is the same as that in Fig. P-577 on this page. Determine the safe value of P if f_b ≤ 1200 psi and f_v ≤ 200 psi.
 

Problem 586
The distributed load shown in Fig. P-586 is supported by a box beam having the same cross-section as that in Prob. 585. Determine the maximum value of w_o that will not exceed a flexural stress of 10 MPa or a shearing stress of 1.0 MPa.
 

Problem 585
A simply supported beam of length L carries a uniformly distributed load of 6000 N/m and has the cross section shown in Fig. P-585. Find L to cause a maximum flexural stress of 16 MPa. What maximum shearing stress is then developed?
 

Problem 584
A wide-flange section having the dimensions shown in Fig. P-584 supports a distributed load of w_o lb/ft on a simple span of length L ft. Determine the ratio of the maximum flexural stress to the maximum shear stress.