Use of polymer flexible joint between RC frames and masonry infills for improved seismic performance

ABSTRACT: In the paper, an innovative solution for the problem of damage occurrence to masonry infills in r.c. frame structures during earthquakes is presented and analyzed using experimental testing and numerical calculations. In an attempt to alleviate the problem of premature damage to infills while retaining the structural interaction between infill and frame, an idea of using flexible polyurethanes (polymer PM) between the r.c. frame and masonry infill was proposed. In the experimental research part, the behavior of the polymer of stiffness E ≈ 4 MPa and ultimate strain of up to 150% is studied with monotonic and cyclic shear tests of the joint on a large-scale specimen. Results obtained from analysis confirmed that despite the flexibility of the polymer, the brick-to-concrete joint would be capable of transferring significant loads during in-plane and out-of-plane excitations. The proposed innovative method can be used as a structural element applied to new buildings, as pre-seismic retrofit of existing ones or during rehabilitation works after earthquakes.