Maximum Bending Moment

Simply Supported Beam with Support Added at Midspan to Prevent Excessive Deflection

Situation
A simply supported beam has a span of 12 m. The beam carries a total uniformly distributed load of 21.5 kN/m.
1.   To prevent excessive deflection, a support is added at midspan. Calculate the resulting moment (kN·m) at the added support.

A.   64.5 C.   258.0
B.   96.8 D.   86.0

2.   Calculate the resulting maximum positive moment (kN·m) when a support is added at midspan.

A.   96.75 C.   108.84
B.   54.42 D.   77.40

3.   Calculate the reaction (kN) at the added support.

A.   48.38 C.   161.2
B.   96.75 D.   80.62

 

Solution to Problem 457 | Moving Loads

Problem 457
A truck and trailer combination crossing a 12-m span has axle loads of 10, 20, and 30 kN separated respectively by distances of 3 and 5 m. Compute the maximum moment and maximum shear developed in the span.
 

Solution to Problem 456 | Moving Loads

Problem 456
Three wheel loads roll as a unit across a 44-ft span. The loads are P1 = 4000 lb and P2 = 8000 lb separated by 9 ft, and P3 = 6000 lb at 18 ft from P2. Determine the maximum moment and maximum shear in the simply supported span.
 

Solution to Problem 455 | Moving Loads

Problem 455
A tractor weighing 3000 lb, with a wheel base of 9 ft, carries 1800 lb of its load on the rear wheels. Compute the maximum moment and maximum shear when crossing a 14 ft-span.