Sliding bed joint for seismic response control of ashlar stone masonry structures

Abstract

An isolation technique using sliding bed joint for seismic response control of ashlar stone masonry buildings was developed and investigated in this paper. Eight triplet specimens were tested under cyclic loads to identify suitable interface material for the sliding bed joint. Further, four stone masonry wall specimens were tested to investigate the frictional performance of the sliding bed joint. The sliding friction coefficient of stainless steel plate-stainless steel plate interface was about 0.17 and found to be insensitive to sliding displacement and the level of compressive stress. The proposed interface was found suitable for the sliding bed joint application. Stable frictional performance of sliding bed joint in practical engineering buildings could be achieved by leveling the interface of each group of the discrete distribute steel plates (two pairs of steel plates equidistantly adhesive on one stone block). A two-degrees-of-freedom mathematical model was adopted to investigate the isolation performance of stone structure's sliding bed joint. No sliding displacement was observed in the isolated stone structures in the case of frequent level earthquake. On the other hand, the average absolute acceleration response in the case of design and rare level earthquakes was significantly reduced compared to fixed base structures. The maximum average sliding displacement of isolated stone structures considered was about 71 mm which is within the half-length of the steel plate. Simple expressions were proposed to predict the average absolute acceleration spectrum of isolated stone structures. The experimental and analytical results provided reference for the application of the sliding bed joint in the stone masonry buildings.