Evolution and Current Developments in the Construction of Prefabricated Voussoir Bridges.

The development of the technique of prefabricated voussoir bridges during the past years has been made possible by the progress achieved in various fields which are developed and include the improvement of the joint between arch stones by the adoption of multi-notch joints where the adhesive plays a less important part; the increase in the cross dimensions of the voussoirs as well as in their unit weight, which reduces the number of joints, as well as the diversification of the forms, which can lead to the elimination of the cross prestress; and the improvement of the methods of placing and of the design of the lifting rigs; the study of these different factors is supplemented and illustrated by the presentation of two recent works.