Reinforced concrete structural walls with staggered opening configurations under reversed cyclic loading

Results of an experimental study on the behavior of reinforced concrete structural walls with staggered door openings under reversed cyclic loadings are presented. The program was part of a larger project involving a detailed study of a few selected Chilean buildings that experienced the earthquake of March 3, 1985, and was inspired by the remarkably good performance of the wall-dominated reinforced concrete buildings in that region. The following two characteristics were found typical of Chilean buildings: (i) a generous use of structural walls in all buildings, and (ii) a staggered door opening configuration.;To study the effect of staggered openings on wall behavior, four scaled reinforced concrete wall specimens were constructed and tested under this program. The lightly reinforced specimens, which were constructed on about one-fifth scale, were five stories high and barbell shaped in cross-section. Reinforcement ratios were in the range of light to moderate. While specimen W-1 had no openings, specimens W-2, W-3, and W-4 had a horizontal stagger between door openings of approximately 30, 15 and 10 percent of the total wall length, respectively. Wall specimens were tested in a vertical position under a constant axial stress. Reversed cyclic loads were applied at the top.;In general, all the test specimens exhibited ductile behavior. Energy was mainly dissipated through flexural action. There was significant flexural yielding and the development of an intersecting pattern of flexural-shear cracks at drift ratios of 1.0 percent, but no sign of impending failure. At an average ratio of 1.5 percent, the three specimens with door openings failed by shear-compression in the compressed portion of the wall outside the opening in the first story level.;In the analytical part of this study the force-displacement response envelope curve for the wall specimens was predicted using three techniques, namely, (i) basic principles of mechanics, (ii) equivalent column analogy, and (iii) finite element method. Predicted response was generally good and within acceptable limits.;Results of dynamic analysis of the 23-story Almendral Building subjected to three different ground motion histories are presented. The equivalent column analogy was used to model the structural walls of the building. An almost elastic response to the earthquake motion, which was recorded in the close vicinity of the building, compared favorably with the reported light damage to the building during the earthquake.