Behavior of bare and masonry infilled R/C frames under cyclic loading: experiments and analysis

摘要

In this study an analytical investigation and experimental verification of the influence of infill panels on the seismic behavior of reinforced concrete frames is presented. The project includes three 1/3-scale, single-story, single-bay reinforced concrete frame specimens subjected to lateral cyclic loading; one infilled frame specimen with clay brick solid masonry and two bare frame specimens one with transverse steel in the form of common stirrups and one with continuous rectangular spirals of the same spacing. Special elements are employed for the modeling of the examined specimens. Beam and columns were modeled using elements with distributed plasticity. For the contribution of the behavior of the infill to the response of the frame the equivalent diagonal strut model is used. Two different types of elements were employed for this purpose. The first element is an inelastic truss element with bilinear brittle response. The second one is an inelastic element with response that can include degrading branch. The actual properties of the infill and henceforth the characteristics needed for the diagonal strut model were determined using the experimental results. Comparisons of the experimental results with the analytical predictions are presented and commented. The use of the element with degrading branch for the equivalent strut model yielded the most satisfactory results.