Structural Assessment of Reinforced-Concrete Arch Underpasses Subjected to Vehicular Overloads

Abstract

In most countries, the maximum dimensions and weights of vehicles that circulate on national roads and highways are legally regulated. However, several economic activities imply the circulation of exceptional vehicles or overloads, raising concerns not only about road surface deterioration but also about the structural safety of the bridges that are to be crossed. In a previous publication, the authors proposed a methodology for permit checking of vehicular overloads applicable to girder bridge decks that involves a comparison of code design-load effects with those resulting from the special vehicle being analyzed. The software developed therein [Bridge Investigation for Special Trucks (BIST)] performs a structural safety analysis of the bridges that are to be crossed, providing simplified safety factors associated with a particular overload, based on which the permit decision is made. This paper presents an update of the BIST software that extends the permit-checking methodology to underpass arch bridges. The first part of the paper describes the general methodology of BIST and its application to RC underpass arch bridges. Extension of the methodology involved the development of two- and three-dimensional finite-element (FE) models of a wide range of arch underpasses that were validated and calibrated based on full-scale experimental tests and the assumption of a set of proper conservative simplifications. The second part of the paper presents a study carried out to evaluate the conservativeness and accuracy of the method proposed by comparing the safety factors provided by BIST with those obtained from numerical models of real arch underpasses subjected to a wide range of real vehicular overloads. The safety factors provided by the BIST software were always conservative and reasonably accurate, thereby validating the methodology proposed and enabling fast, economical, and safe permit decision making.