Limit Behavior of Stone Arch Bridges

Abstract

According to Heyman's extension of limit design to masonry structures, the safety of stone arches is a purely geometrical matter, considering that it is almost always possible to assess that mean compressive stresses are low even in structures showing several cracks. Safety of stone arches require the load's thrust line to be anywhere within the arch profile. Different issues must be faced when considering dead and traveling loads. In the first case, a minimum thickness can be defined so as to contain the line of thrust. Considering traveling loads, the goal is to define a load factor such to turn the structure into a mechanism. In this paper, iterative methods to find the minimum thickness under dead loads and the collapse mechanism and load factor when acting also live loads are proposed. The results of a comprehensive numerical investigation are shown, which can be easily used in the safety check of stone arches.