Seismic performance evaluation of a ductile R/C structure with masonry infills

Abstract

The seismic performance of a ductile four-storey R/C structure with masonry infills was analyzed through nonlinear static and dynamic analyses and the effects of infills on the structural response were investigated. On the basis of results obtained from experimental tests carried out at the JRC Elsa Laboratory, numerical models were developed in order to properly simulate the seismic response of the R/C structure. A simplified approach based on nonlinear static analyses was applied for the seismic performance assessment of the R/C structure, comparing deformation capacity and demand. The expected contribution of masonry infills in terms of both strength and stiffness was evident when comparing the response of the different structural configurations under nonlinear static analyses. The increase of stiffness provided by the masonry infills led to anticipate, in terms of drift, the attainment of the different Limit States in the infilled structure compared to the bare counterpart. The presence of uniformly distributed infills considerably changed the distribution of damage throughout the structure. The maximum drift demand on the bare structure was registered at the second storey. On the contrary, the drift demand on the uniformly infilled structure concentrated at the first storey without excessive demands at the upper storeys. The influence of uniformly distributed infills on the seismic response of the investigated structure was beneficial according to the simplified assessment procedure. The effects of masonry openings on the structural response were investigated and different types of infills were considered in the numerical analyses. The presence of openings and the mechanical properties of the infills significantly affected the seismic response of the structure. The sudden drop of strength due to the failure of the infills led to damage concentration at the first storey in case of strong infills for severe seismic input motions.