EFFECT OF SMALL OPENINGS ON STRENGTH AND STIFFNESS OF SHEAR WALLS IN-REACTOR BUILDINGS

A total of 26 wall specimens were tested to examine the effect of smal l openings on the strength and stiffness of shear walls in reactor bui ldings. The parameters tested were the shape, number and local arrange ment of the openings, and the reinforcing method around the openings. Reversed cyclic loads were applied to the specimens, and their strengt hs and restoring force characteristics were compared with each other t o understand the effects of these parameters. Based on the test result s, two methods for predicting the shear strength of walls with numerou s small openings are examined. One is a method to calculate directly t he strength along assumed failure lines, and the other method allows e stimation of the strength reduction factors for design, taking account of the effect of openings. Both methods are found to be useful to est imate roughly the strength of such shear walls. It is also shown that the stiffness of such walls could be evaluated using a combined multi- spring model. For the reinforcing methods around openings, a simplifie d reinforcing method is proposed and the effectiveness of the method i s discussed by checking the contribution of the reinforcement to the w all strength.