Experimental Study on Flexural Behavior of Reinforced Concrete Walls

Abstract

Design codes prescribe equations for the ultimate state design of RC walls with flange walls as boundary elements. These codes consider part of the length of the flange wall as a width that will effectively resist lateral loads. However, wall damage and the accuracy of the effective width used in the calculations have not been sufficiently discussed. Therefore, a loading test is carried out at Yokohama National University on two 1/3 scale specimens in order to evaluate the strength, damage, energy dissipation, and behavior of RC structural walls in flexure. One specimen without flange walls and one with flange walls are tested. The strength and response of each specimen are described, and the prediction accuracy of the design flexural strengths given by design codes ACI, Eurocode, and AIJ are examined. Experimental strain data are used to describe the behavior of the flange wall in order to understand the mechanism and to confirm the accuracy of the effective width prescribed by the design codes in terms of tension and compression. The result of the experimental study reveals that design prescriptions given by ACI, Eurocode, and AIJ guidelines can conservatively estimate the flexural strength for RC walls without flanges, but they underestimate the flexural strength for flanged walls. This underestimation is due to a lack of knowledge of the mechanism that develops at the flange. It is not possible to determine a specific value for flexural effective width. However, according to the results of calculations, a portion larger than the width proposed by the aforementioned design codes serves to resist the stresses imposed by lateral loads. Therefore, it is confirmed that the flange width is underestimated by the design codes, and it increases with the imposed drift level. The stress distribution at the flange in the out-of-plane direction is found not to be uniform, a fact that is at odds with design assumptions.