It has been estimated that about 350 arch highway bridges will require repair, strengthening or replacement every year. Of these it is estimated that 230 will be repaired or strengthened and 120 replaced. The average annual cost of this work is of the order of #20 million, excluding traffic delay costs (1993 prices). There is considerable scope for cost savings by selecting strengthening methods which are both cost effective and minimise disruption to traffic. There are a number of strengthening methods available. However there is a lack of quantitiative information on the increase in load bearing capacity they provide. This paper describes a programme of research that is being undertaken by TRL to address this problem. The tests carried out to date have shown that strengthening techniques such as grouting (where ring separation has occurred), saddling, sprayed concrete or reinforcment can significantly increase the load carrying capacity of an arch. Analytical methods are being developed to model the techniques being used and to enable the increase in strength of in-situ structures to be determined.
Samenvatting