Segmental Aerial Structure Retrofit and Load Testing

Load testing of three retrofitted segmental rail-transit aerial structures, to verify their structural adequacy prior to exposing them to the revenue traffic, is described. An overview of the retrofit is provided, followed by a discussion of the scope and findings of the load testing program. The testing was performed in two stages. First the spans were subjected to static load testing, prior to the revenue operations. Later, the findings of the static load testing program were verified by a dynamic testing phase, performed with the revenue trains crossing the spans. A very good correlation between the results of the two phases of the testing was confirmed, indicating that under the action of moving trains the segmental aerial structures were continuing to behave in an elastic, resilient and monolithic manner. The testing program resulted not only in an efficient and successful evaluation of the retrofitted spans, it also yielded a very useful insight into the static and dynamic behavior of segmental aerial structures.