Old concrete slab bridges. Can they carry modern traffic loads?

As part of an investigation to assess more accurately the performance of concrete slab bridges, six slab bridges were subjected to truck load tests. In addition, two spans of a five span continuous bridge were subjected to several tests, including testing to collapse. The elastic response of concrete slab bridges was studied. It is concluded that old concrete slab bridges possess significant reserve capacity and that yield line analysis can effectively be utilized to accurately predict the strength of these bridges.