Load Effects of ASR-induced Expansion in Reinforced Concrete and Their Consequences for Structural Assessment

This paper describes the structural effects of ASR expansion in reinforced structures. It proposes models and procedures for calculating the strains in the concrete caused by the reinforcement, the load effects in statically indeterminate structures and the cross-sectional capacities. Three models are described to include variations of the ASR expansion in a section. Model 1 for constant or linearly varying ASR expansion, Model 2 for an expansion variation in different parts of a cross-section and Model 3 for a particular case of different expansion in subsections of the cross-section. The models are exemplified by calculations based on input data from one relevant bridge, the 70 years old Elgeseter bridge in Trondheim, Norway. This is done to illustrate various aspects of the calculation methods and show the structural consequences of the ASR expansion. The results correlate with the bridge's observed structural behavior and assumed expansion. This paper also illustrates the importance of coordinating inspection, material testing and structural strength analysis to obtain reliable assessment.