Realistic shear assessment and novel strengthening of existing concrete bridges

Research Organisation	University of Bath, Architecture & Civil Engineering
Principle Investigator	T.J. Ibell

Description

Every concrete bridge in the United Kingdom is due to be assessed for its flexural and shear strength as part of the U. K. Bridge Assessment Programme. To prevent unnecessary demolition or repair of adequate concrete bridges, the analytical techniques adopted must be realistic and accurate. Such methods should be plasticity-based, so that the actual behaviour of the concrete bridge at collapse is considered.

Previous work by the Principal Investigator has resulted in the development of a 3-D plastic shear assessment analysis technique, which successfully considers the actual shear collapse mechanism of the bridge. Many thousands of concrete bridges (particularly those related to railways) consist of prestressed concrete rectangular beams, prestressed together transversely to aid lateral distribution of load. The extent to which such distribution acts is unclear and many such bridges are prone to shear assessment failure.

Initially, this project will implement a 3-D plasticity-based shear assessment technique for such bridges, and determine exactly what the shear capacity of such bridges is through testing. Thereafter, the project will consider the possible shear strengthening of such concrete bridges using vertically-embedded steel and/or FRP bars, rather than external FRP sheets which cannot be used due to inaccessibility of the bean webs.

Such a technique has been tested to feasibility stage on small-scale beam specimens at the University of Bath in a pilot study, with very encouraging results. Such a project will provide bridge owners with a realistic shear assessment tool and, in the event of real lack of shear strength, a practical method for shear strengthening.

Funding body	EPSRC
Ref. Number	GR/S18144/01
Amount	(UK £) 150017.00
Start	01 June 2003
End	31 May 2006
Status	Research project is underway