The effect of cracking on the response and design of diaphragm walls and adjacent buildings

Abstract

The development of the bending moment corresponding to the maximum tensile stress the concrete accommodated (relatively low with reference to the capacity of the wall) produces cracking initiation. Despite the fact that concrete cracking significantly affects the diaphragm wall response by provoking substantial decrease in its stiffness, it is often disregarded or is introduced by empirically reducing the bending stiffness. A very interesting approach for estimating the bending stiffness of concrete sections and the bending moment of cracked sections as a function of the curvature is provided by the moment-curvature relationship derived from the beam theory. This model has been implemented in many structural software codes that can calculate and use the nonlinear moment-curvature response for a given reinforced concrete section. The proposed approach has been applied in the case of a deep excavation supported by diaphragm wall, where a nonlinear mutli-stage simulation process has been implemented. Comparative analyses disregarding the cracking onset have been carried out as well and interesting conclusions were drawn relating the effect of cracking and reduction in the bending stiffness to the response of the diaphragm wall, the bending moment distribution along the wall and the displacement field in the surrounding soil and adjacent buildings. © The authors and ICE Publishing: All rights reserved, 2015.