Pratt Truss, Howe Truss and Warren Truss

Question

What are the differences among Pratt Truss, Howe Truss and Warren Truss?

Answer 1

Warren truss includes a chain of isosceles triangles or equilateral triangles. Verticals are added for Warren Truss to enlarge the span length of the truss bridge.

Pratt truss is characterized by having its diagonal members slanted down towards the middle of the bridge span. In such structural arrangement when subjected to external loads tension is created in diagonal members at the same time the vertical members deal with compressive forces. Thinner and lighter steel or iron can be used as materials for diagonal members so that a more efficient structure can be enhanced.

The structure of Howe truss is the opposite to that of Pratt truss in which the diagonal members are slanted in the direction opposite to that of Pratt truss. Hence, it is not economical to use steel members to handle compressive force.