Seismic resistance of multi-storey reinforced concrete wall-frame structures at destructive earthquakes

Abstract

This article shows results of a numerical study of the behavior of multi-storey reinforced concrete wall-frame structure under loads of special combination, considering seismic impact that corresponds to destructive earthquake. The purpose of the study is to identify conditions that increase energy absorption capacity of wall-frame structure under the effect of destructive earthquakes as well as methods for assessing the energy absorption capacity of wall-frame structure at the design stage. Numerical studies were carried on 9-storey frame building, designed for construction in the area with an estimated seismicity of 7 points. Loads of special combination were applied until the complete exhaustion of the bearing capacity of the structure. The calculations were made using the LIRA software package. Performed studies made it possible to identify and assess bearing capacity margin of buildings designed to meet the requirements of valid antiseismic construction regulations if earthquake intensity exceeds the design calculated value. As a result of a numerical study of the work of a 9-storey frame reinforced concrete building of a frame scheme corresponding to the third version of the system, the building withstood the load exceeding the estimated norm by 30%. The value of the coefficient showing the deformation properties during operation of the system at loads exceeding the calculated values before failure, amounted to K = 3.1. The results obtained give the designer the opportunity to create conditions for the appearance of plastic joints in as many cross sections of frame elements as possible. This in turn leads to an increase in the energy intensity of the skeleton, capable of absorbing the excess energy of a destructive earthquake. We have developed the recommendations for determining bearing capacity margin of buildings at design stage if earthquake intensity exceeds calculated value.