The UK has tended to build most of its bridges using composite steel construction. But consultant Benaim has discovered good reason to build many bridges using modular precast concrete units.
'The modular bridge system combines the best features of steel-composite, precast beam, in-situ and segmental schemes into a solution that can deliver the highest value at the majority of bridge locations, ' says a report written by Benaim for the Concrete Bridge Development Group (see page 17).
Benaim has pioneered the system in Ireland, most recently on a road bridge over the River Shannon.
'The concept has been created especially to suit new overbridges across live carriageways, ' says Benaim director Simon Bourne.
He adds that building concrete bridges has all the benets of steel-composite schemes - high speed; low cost; increased workforce safety; factory production and quality; reduced trafc management and high sustainability - but that the result is 'signicantly more elegant, efcient and robust'.
The modular concrete bridge is similar to conventional segmental concrete, using 2.5m long units with longitudinal holes for prestressing tendons.
The units have also been detailed to allow them to be lifted in, cantilevered or launched incrementally.
Bourne adds: 'The precast modular scheme is cheaper and faster to erect than similar steelcomposite options.
'However, the next step is to get it used in the UK, with the hope that it could eventually be the optimum choice for bridges between 15m and 50m.'