A simply supported beam 30 ft long is prestressed by a straight tendon that carries an effective force of 233 kips. The rectangular beam is 10 in....

A simply supported beam 30 ft long is prestressed by a straight tendon that carries

an effective force of 233 kips. The rectangular beam is 10 in. wide and 20 in. deep

and the eccentricity of the prestressing force is 4 in. 

A. Calculate the maximum mid-span service moment the beam can support for

the allowable stresses listed in the table below:

Compressive Stress (psi) Tensile Stress (psi)

2,700 0

3,600 0

2,700 580

3,600 580

B. Draw a neat sketch to indicate the location of the center of the compression

force and its distance from the tensile force. What conclusions can you draw? 

C. Repeat parts A and B but for the maximum service moment but at a location

distant 25 in. from the support.