Extending the Life of Masonry and Concrete Arch Bridges

A large number of existing bridges need to be rehabilitated or widened due to the increased traffic and/or loading requirements that have arisen since their original entry into service and most of these are masonry or plain concrete arches. A great effort has been undertaken in the last decades to develop structural methods to predict the ultimate capacity of masonry and concrete arches but there is a need to interpretate the results obtained (ultimate load) in terms of a safety level. A procedure is presented for estimating the safety level of masonry or concrete arch bridges. The safety is measured in terms of the reliability index which is obtained using the results of the ultimate capacity analysis of the arch and of the traffic loads. Some techniques for the rehabilitation and widening of existing bridges are also presented here, including several case studies.