New Modular Precast Concrete Bridge System

Alan Bromage, the head of civil engineering at The Concrete Centre has revealed that he believes the development of a new modular precast concrete bridge system could offer an alternative to steel-composite construction for medium-span bridges.

The bridge consists of precast concrete shell units that are precast off site. Once on site, the units are assembled, stressed together and in-situ concrete placed. It combines the best features of precast concrete and in-situ concrete into one single solution for bridges with a span of 15-50m.

The use of precast shell units allows the in-situ concrete to be poured into small bays. This eliminates most of the issues associated with early-age thermal and restraint effects. The internal prestressing of the deck from end-to-end allows an efficient use of materials whilst making the deck fully integral with bankseat abutments. This reduces future maintenance costs by eliminating all bearings and expansion joints.

The modular precast approach can be adapted to suit a wide range of bridge sites and project programme demands. Its flexibility is such that it can be constructed by the use of incremental launching, lifting using mobile cranes or transporters or by using a temporary gantry.

The system is also suitable for a wide range of highway bridge layouts. Varying span lengths, carriageway widths, horizontal and vertical curvatures and skew can be readily accommodated by the match-cast shell units. The modular precast system is adaptable to varying span requirements as the depth of the precast shells can be changed to allow different spans to be achieved.

The use of modular precast concrete construction offers designers a well-engineered and economic solution that will see concrete as the preferred option for bridges.

For further information and a comprehensive list of companies who offer concrete services, please visit our website at http://www.buildingregister.com