Assessment of international standard provisions on stiffness of reinforced concrete moment frame and shear wall buildings

The accuracy of the lateral stiffness provisions of international standards is examined for concrete buildings. The stiffness provisions of American, Japanese, Canadian, New Zealand, and European standards are evaluated. Standard stiffness estimates are compared with the experimentally derived lateral stiffnesses of a four-story, full-scale, reinforced concrete building tested under multi-directional seismic motions on the Japanese E-Defense shaking table. The structure was designed to Japanese seismic design requirements and met most U.S. design requirements for regions of high seismicity. The building had moment frames resisting lateral loads in one direction and shear walls in the other. Building stiffness was found to degrade substantially with increasing lateral drifts and relate to prior deformation history. In general, standard stiffness values were higher than those of the building. Standard provisions produced more accurate stiffness estimates for frame members than for walls. All standard provisions produced substantially larger stiffness estimates than experimental values for shear walls. Study results therefore indicate that improvements in the stiffness provisions of all investigated standards for concrete buildings may be warranted.