Impact of Drying on Structural Performance of Reinforced Concrete Shear Walls

Hiroshi Sasano, Ippei Maruyama, Akihiro Nakamura, Yoshihito Yamamoto, Masaomi Teshigawara

Journal of Advanced Concrete Technology, 16, 210-232, 2018

The aim of this study is to experimentally investigate the effect of drying on a shear wall, and to clarify the mechanism of the changes in the structural performance due to drying. Two sufficiently hydrated wall specimens are prepared. Then, one is loaded without drying, while the other is tested after sufficient drying until the shrinkage of concrete reaches an equi-librium state. The results show a reduction in the initial stiffness and little change in the ultimate shear strength in the dry specimen, in spite of an increase in the compressive strength. Reproduction numerical analysis using Rigid Body Spring-network Model (RBSM) coupled with a truss network model for moisture transport is conducted, and an ac-ceptable agreement is confirmed in the ultimate strength and the crack patterns. From the numerical results, it is revealed that two factors are balanced in the ultimate shear strength after drying in this experiment: 1) an increase in the com-pressive strength due to aging (material scale), and 2) a strength reduction due to lateral strain, which is evaluated using the formula suggested by Vecchio and Collins (1986) (member scale). This indicates that the wall reinforcement ratio and concrete shrinkage have the influence on the ultimate strength through increasing/decreasing the number of cracks and the crack width.

The influence of drying shrinkage on stiffness, strength and deformability of reinforced concrete members is of great interest, particularly when assessing the resistance of concrete structures to severe loading, such as earthquakes. This paper presents experimental results for shear walls subjected reversed cyclic loading, after exposure to different drying conditions to evaluate the effects of such drying. Numerical modeling of the test results elucidates mechanisms that contribute to test specimen behaviors. The model explicitly accounts for the structural behavior, moisture content, and their basic coupling. The comparisons between the experimental and modeling results are excellent. The experimental results are valuable and the modeling component of the research provides important insights into the observed behaviors. (Reviewer A)