Multiscale analysis of shrinkage-induced performance degradation of shear wall and application to structural analysis

Abstract

Shrinkage-induced cracks reduce the stiffness of concrete structures. Shear walls are more sensitive to drying shrinkage than other members because of their fully restricted condition and large surface areas exposed to air. This study examines how concrete structural performance is affected by shrinkage due to moisture loss via hydration or dissipation by applying multiscale integrated finite element analysis. First, a cyclic shear loading test on shear wall specimens subjected to drying in a previous study was reproduced. Based on the reproduction analysis model, parametric analysis was conducted, focusing on the member scale, mix proportion, and surface treatment of concrete. Shrinkage-induced cracks reduced member stiffness, and the effects of the member scale on drying speed were shown. The dominance of autogenous shrinkage in the case of high-strength concrete was also observed. The sealing of the concrete surface effectively prevented moisture dissipation, but moisture supply from ambient air was also blocked when the humidity inside the concrete was low. Thus, a proper surface protection method should be selected considering water consumption via hydration. Finally, the use of equivalent material properties for considering initial damage due to shrinkage was proposed as a simple way to account for drying effects in structural analyses.