Experimental evaluation of a sacrificial system for masonry infill walls

The Seismic Infill Wall Isolator Subframe (SIWIS) system is developed for use in building moment frame systems with masonry infill walls in order to prevent damage to columns or infill walls due to infill-frame interaction during potentially damaging earthquakes. Because of the conventional tight-fit construction within structure frames, infill walls generally participate in resisting wind and seismically induced loads. Although beneficial during wind loads and minor earthquakes, the interaction of infill wall and frame during strong events can damage the wall or the frame if the infill wall is not designed as shear walls. The SIWIS system can be designed as a "sacrificial fuse" to allow infill wall-frame interaction under wind loading and minor-to-moderate earthquakes for reduced building drift, but to disengage their interaction under severe damaging events. An experimental testing program was carried out to test the concept of the SIWIS system. The experimental program included a series of component tests on three different designs for fuse element materials including concrete disk, steel disk, and lumber disk. These tests were followed by a series of in-plane static pushover tests on a scaled two-bay three-story steel frame equipped with SIWIS fuse elements. This paper discusses the experimental program and presents the results of the tests. Copyright ASCE 2006.