Department of Architecture and Civil Engineering

Shear capacity and strengthening of longitudinally and laterally-prestressed concrete bridges

At a glance

Funding body: EPSRC, £150,000; Network Rail, £10,000
Principal investigator: Tim Ibell
Co-investigator: Antony Darby
Researcher: Pierfrancesco Valerio
Industry partners: Parsons Brinckerhoff, Network Rail
Dates: 2003 - 2006


In the UK, Network Rail owns hundreds of concrete bridges which consist of longitudinally-pretensioned rectangular beams laterally post-tensioned together to form a 'plate' bridge. Such bridge decks routinely fail shear assessments due to uncertainty surrounding the lateral distribution of load.

This project aimed to provide Network Rail with a rational approach to shear assessment of such structures. This was achieved through extensive testing of such structures, together with application of upper- and lower-bound plasticity approaches. A rational, accurate and useable tool was produced.

Further, in cases where shear strengthening was still deemed necessary, a 'deep embedment' shear strengthening method was developed whereby vertical FRP bars are resined into holes drilled into the bridge from the soffit. This technique is practical and successful.