A SIMPLE METHOD FOR THE DEFLECTION ANALYSIS OF TALL WALL-FRAME BUILDING STRUCTURES UNDER HORIZONTAL LOAD

摘要

New closed-form formulae are developed for the static deflection of symmetric multi-storey buildings braced by moment-resisting (and/or braced) frames, (coupled) shear walls and cores. The behaviour is characterized by shear, local bending and global bending, and corresponding stiffnesses. The analysis is based on that of a single moment-resisting framework. A closed-form solution is presented for the lateral deflection. The procedure is then extended to a system of frameworks, (coupled) shear walls and cores by creating an equivalent column which represents the whole structure. Another closed-form solution is presented, this time for the deflection of the whole building. The deflection is defined by three distinctive parts: the bending deflection of the building, the shear part of the deflection and interaction between the bending and shear modes. It is shown that the interaction between the bending and shear modes is always beneficial as it reduces the deflection of the structure. According to a comprehensive accuracy analysis of 270 multi-storey building structures with both reinforced concrete and steel bracing units and covering wide ranges of stiffness, the proposed closed-form solution for the top deflection is simple and reliable: the average error of the formula was 4%. A worked example demonstrates the ease of use of the method.