WORLD FOR CIVIL

Statics & Strength of Materials

Topic 5.6b - Problem Assignment 2 - Bending Stresses

For the following problems use a maximum allowable bending stress of 1500 psi. for wood, 25,000 psi. for steel and 6000 psi. for concrete.

1. A W10x21 steel cantilever beam is 8 feet long. Determine the maximum point load that a the beam can carry at its end without exceeding the allowable bending stress. (5630 lb.)

2. Find the maximum point load that a 14 foot long steel W24x84 can carry at its midpoint without exceeding the allowable bending stress. The beam is simply supported at its ends. (117,260 lb.)

3. Find the maximum point load that a 30 foot long steel W30x108 can carry at its midpoint without exceeding the allowable bending stress. The beam is simply supported at its ends. (83.330 lb.)

4. Determine the minimum section modulus needed for a 14 foot beam to carry a uniformly distributed load of 160 pounds per foot. The beam is simply supported at its ends. Select the appropriate wood beam to carry this load.(31.4 in³, 2" x 10" selection may depend on table used)

5. A parking ramp floor is supported by horizontal concrete beams. The horizontal concrete beams are supported at the quarter points, that is 1/4 of the beam length in from each end. The beams are designed to carry a uniformly distributed load of 5000 pounds per foot and are 72 feet long. Determine the minimum section modulus for the beams.(1620 in³)

6. Find the minimum section modulus for the parking ramp in problem 5 if the beams are supported at their ends. (6480 in³)