Toward Macro-Modeling of Alkali-Silica Reaction-Affected Structures

Although much attention has been directed toward modeling alkali-silica reaction (ASR) since its first deleterious effects on concrete structures were identified 75 years ago, there remain many unresolved issues. Among them, according to CSA A864-00, is that conventional methods of analysis become invalid for the assessment of ASR-affected structures due to the induced anisotropy with regards to the mechanical properties of concrete. To address this need, an alternative procedure for nonlinear analysis of ASR-affected reinforced concrete structures is presented, implemented within the framework of finite-element programs developed for the analysis of membrane and three-dimensional structures. Reinforced concrete is treated as an orthotropic material based on a smeared rotating crack model within the context of a total-load secant-stiffness macro-modeling approach. Verification is provided through analyses of reinforced concrete beams with behavior governed by either flexural or shear mechanisms. Keywords: alkali-silica reaction; analysis; assessment; finite element; nonlinear analysis; reinforced concrete; structures.