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.
 

Problem 583
A rectangular beam 6 in. wide by 10 in. high supports a total distributed load of W and a concentrated load of 2W applied as shown in Fig. P-583. If f_b ≤ 1500 psi and f_v ≤ 120 psi, determine the maximum value of W.
 

Problem 582
Find the cross-sectional dimensions of the smallest square beam that can be loaded as shown in Fig. P-582 if f_v ≤ 1.0 MPa and f_b ≤ 8 MPa.
 

Problem 581
A laminated beam is composed of five planks, each 6 in. by 2 in., glued together to form a section 6 in. wide by 10 in. high. The allowable shear stress in the glue is 90 psi, the allowable shear stress in the wood is 120 psi, and the allowable flexural stress in the wood is 1200 psi. Determine the maximum uniformly distributed load that can be carried by the beam on a 6-ft simple span.
 

Problem 580
A rectangular beam of width b and height h carries a central concentrated load P on a simply supported span of length L. Express the maximum f_v in terms of maximum f_b.
 

To determine the load capacity or the size of beam section, it must satisfy the allowable stresses in both flexure (bending) and shear. Shearing stress usually governs in the design of short beams that are heavily loaded, while flexure is usually the governing stress for long beams. In material comparison, timber is low in shear strength than that of steel.
 

Problem 577
A plywood beam is built up of 1/4-in. strips separated by blocks as shown in Fig. P-577. What shearing force V will cause a maximum shearing stress of 200 psi?
 

Problem 576
Rework Prob. 575 assuming that the web is 200 mm instead of 160 mm.
 

Problem 575
Determine the maximum and minimum shearing stress in the web of the wide flange section in Fig. P-575 if V = 100 kN. Also, compute the percentage of vertical shear carried only by the web of the beam.