Analysis on interstory drift of high-rise residential quasi-megastructure

Abstract

Based on the superior lateral resistant performance of mega-X layout pattern, the concept of quasi-megastructure was put forward to introduce quasi-mega mechanism in residential buildings, using normal members only, avoiding large architecture space occupation of mega members. Unlike the megastructures that are dominated by their primary structures, the quasi-megastructures mainly realize a synergistic mechanism between the frame structure and quasi-mega braces. In order to investigate its deformation mechanism and reduce the lateral stiffness irregularity, a simplified method for evaluating interstory drift of high-rise quasi-megastructure was proposed, based on three fundamental assumptions. Thus, the interstory drift formula for any specific layout scheme of quasi-megastructure can be deduced. The formula was validated by different layout schemes. By this method, the interstory drift proportion of quasi-megastructure was investigated, showing that the interstory drift of a target story mainly consists of drift due to rigid body rotation, pure shearing drift, and shear-lag added drift. And the vertical stiffness irregularity of the original scheme was due to great changes of shear-lag added drift in different neighboring stories. Thereafter, stiffened schemes were proposed, which effectively eliminate the interstory stiffness irregularity by complementing a quasi-mega cantilever wall of full height. Compared with mega frame structure, the original scheme has a similar overall deformation mechanism, while the properly stiffened quasi-megastructure scheme behaves quite close to mega braced frame structure, both in deformation mechanism and in structural efficiency.