Arches

The other day I had to design a bridge which had the most efficient design. The bridges design efficiency was determined to be the bridge that has the smallest bending moments when it has a number of different forces acting as a uniform distribution load upon it.

There were 3 different types of designs put under inspection:

1. Sine Wave
2. Parabola
3. Circular Arc

It was determined that the parabola design was the most efficient as it had the lowest bending moments upon it, which were all in the positive direction. The sine wave being second most efficient and the circular arc being least efficient.

It is interesting to note however, that the sine wave and circular arc both have two points of contraflexure acting as thirds upon the design. However the bending moments went from negative-positive-negative and positive-negative-positive respectively.