simple beam

Problem
A concentrated load P is carried at midspan by a simply supported 4-m span beam. The beam is made of 40-mm by 150-mm timber screwed together, as shown. The maximum flexural stress developed is 8.3 MPa and each screw can resist 890 N of shear force.
 

1.   Determine the spacing of screws at A.
2.   Determine the spacing of screws at B.

Problem
A wooden log is to be used as a footbridge to span 3-m gap. The log is required to support a concentrated load of 30 kN at midspan. If the allowable stress in shear is 0.7 MPa, what is the diameter of the log that would be needed. Assume the log is very nearly circular and the bending stresses are adequately met. Neglect the weight of the log.
 

A downward concentrated load of magnitude 1 unit moves across the simply supported beam AB from A to B. We wish to determine the following functions:

• reaction at A
• reaction at B
• shear at C and
• moment at C

when the unit load is at a distance x from support A. Since the value of the above functions will vary according to the location of the unit load, the best way to represent these functions is by influence diagram.
 

Problem 906
For the 2-in. by 6-in. wooden beam shown in Fig. P-906. Determine the normal stress at A and B. Are these the points of maximum normal stress? If not, where are they located and what are their values?
 

Problem 905
A wooden beam 100 mm by 200 mm, supported as shown in Figure P-905, carries a load P. What is the largest safe value of P is the maximum stress is not to exceed 10 MPa?
 

Problem 861
For the beam shown in Fig. P-861, determine the value of EIδ at 2 m and 4 m from the left support.
 

Problem 1007
A uniformly distributed load of 300 lb/ft (including the weight of the beam) is simply supported on a 20-ft span. The cross section of the beam is described in Problem 1005. If n = 20, determine the maximum stresses produced in the wood and the steel.
 

Problem 1003
A simply supported beam 4 m long has the cross section shown in Fig. P-1002. It carries a uniformly distributed load of 20 kN/m over the middle half of the span. If n = 15, compute the maximum stresses in the wood and the steel.