Substructures

All bridges have foundations and abutments, while most have piers, columns, pylons or towers which where they are located below the deck level are collectively known as the substructure. The wide variety of substructures commonly used range from piled to spread footing, bankseats to embedded abutments, cantilevering piers to fully integral structures. Substructures also bring together structural and geotechnical engineering interacting to support the rest of the bridge. To do justice to all aspects of substructure would require a much lengthier script than we have room for here, but this chapter endeavours to introduce the basic principles in scheming up, designing and constructing the substructure for a bridge. Guidance is given on selecting suitable structural arrangements for the foundations, abutments and piers along with the geotechnical parameters used in their design.