Abstract
In this paper, an evaluation method is proposed for determination of planar shear deformation of a shear wall, considering the three-dimensionality, which is a part of an underground box-type structure such as screen chamber and pump chamber of important outdoor civil engineering structures in nuclear power plants. In underground box-type structures, as a result of large-scale ground motion side walls that are perpendicular to the direction of ground motion is pushed by the ground, hence soil pressure acting on the side wall centre is reduced by the deformation (deflection) occurred due to the decrease in the rigidity. On the other hand, acting soil pressure on the side wall end and the shear force acting on the shear wall surface is increased, resulting in in-plane shear fracture of the shear wall, which can lead to cases where critical breakage of the entire structural system occurs. In this case, a method for calculating the limit value of deformation angle (limit deformation angle) is proposed by applying the index of structural member's deformation angle to the damage index of the shear wall of an underground box-type structure, and the validity of this method is verified by utilising it in a seismic evaluation.
