Prediction of the earthquake response of a three-storey infilled RC structure

Over the last years, the seismic behaviour of infilled reinforced concrete (RC) structures has been the focus of innumerable experimental and numerical studies. A big effort is being made by the scientific community to increase the knowledge regarding the seismic performance of these types of structures and to improve the numerical modelling capabilities to predict their expected behaviour accurately. In 2015, a blind prediction contest was organized by the Faculty of Civil Engineering, University of Osijek, with the main goal of inviting the technical and scientific community to predict the nonlinear seismic behaviour of a 1:2.5 scaled 3D building structure. A three-storey infilled RC structure was subjected to a sequence of ten incremental earthquakes in a shake table test. The blind numerical simulations were carried out by different international teams invited by the organizational committee. The teams knew only the specimen geometry, reinforcement detailing, material properties, and ground motions recorded during the testing. In this context and, in the light of the authors' success in the contest, the present paper mainly aims at presenting several issues regarding the numerical modelling strategies adopted (and related difficulties) which proved to yield good results while also providing some insight regarding key problems in numerical simulations of infilled RC structures under seismic actions. The main numerical results obtained by all of the participating teams will be presented and compared with the experimental ones. Discussion concerning the reasons behind the mismatching of some results will be presented. Finally, a parametric study was carried out with the aim of assessing the influence of some modelling issues and parameters on the structural global response, in particular when affected by some variations.