Bridge strengthening by conversion to network arch: design criteria and economic validation

Abstract

The study presents a new strengthening methodology in bridges over river beds affected by scour and erosion at piers. The proposal is part of an innovative concept, implementing a structural change of the original bridge, without the need to strengthen the substructure, thanks to the construction of an upper arch with network and vertical hangers. The vertical hangers are responsible to lift the deck from the piers, generating a single span (simply supported tied arch). The study describes the construction phases, considering the conditions and difficulties in their implementation due to multi-objective targets and additional boundary conditions and requirements. Additionally, it gives a description of the structural behaviour and a layout of each element, to use as criteria or guideline for future applications of the method. Finally, a validation is made through a comparative analysis in a Chilean bridge, between a traditional method of strengthening by additional piling in the foundations and the proposal here presented. Additionally to the feasibility of application, the example shows that the new solution is cheaper.