next up previous
Next: About this document

Consider the structure shown below. Assume that the beams shown are constructed of a very light material so that their weight can be ignored for the purposes of this problem. Using the laws of statics, calculate the stress in each beam of the structure.

If you are not familiar with the laws of statics, hereis all you need to know:

  1. The bridge is obviously not moving -- hence the term static -- so the forces on each junction must add up to zero.
  2. Using trigonometry it is possible to decompse any force acting on any junction into the sum of forces in the x and y directions.
  3. Considering the forces acting on all the junctions yields a linear system of equations which can be solved simultaneously.
  4. The stress on any beam can be obtained from the forces acting on the junctions to which its ends belong.

Juris Steprans
Mon Apr 21 13:11:44 EDT 1997