Comparative study of geometrical properties and preliminary design proposal for concrete arch bridges

The present research is based on the construction of a comprehensive and descriptive database of 58 concrete arch bridges (38 roadways and 20 railways) built in Spain during the last century. The collected information includes geometrical and mechanical data that are used to find out the main relations among different dimensions and parameters of the structures, further assembled to derive specific trends. These information have been combined with data collected by other relevant authors involved in the same issue as Salonga, Gauvreau and Manterola. In this way, a wider dataset has been obtained for bridges with similar features, allowing to have more reliable results. In particular, 112 arch bridges covering a span range from 12 to 384 meters have been employed to investigate relations of a variety of parameters. These are both geometrical, such as flatness, arch and girder dimensions, system bending stiffness, slenderness, effective slab thickness, and mechanical, as dimensionless axial force. Moreover, these empirical relations have been studied and applied to the Tiemblo bridge situated in Avila, Spain, designed by Fhecor, in 1999, whose technical drawings were kindly given by the Designer and the co-supervisor of this work. In this way, a finite element model of the bridge was built to carry more detailed analysis on this type of structures, with the aim to understand the influence of each engineering choices adopted during conceptual design process. Based on the data collected in the database presented in this work, the authors have proposed a sound procedure for the preliminary design of roadway arch bridges with fixed supports and variable cross-section. Then, a comparison between the results obtained from this procedure and the real data collected into the dataset has been performed, specifically, in terms of dimensionless axial force ν. The aim of this work is to find a methodology which, although its simplicity, represents a conservative procedure for the preliminary design of arch bridges. The authors are aware that the methodology does not include a complete analysis of the bridges, but the procedure proposed may represent a first approach to the design of such bridges.