Seismic Evaluation of the Out-of-Plane Response of Masonry Walls and their Retrofitting Techniques

Historical masonry structures were affected occasionally by the various seismic forces and most of them might be destroyed due to un-reinforcing and lack of ductility. As an important case of these destruction of memorial structures can point out to the collapse of Bam Citadel which was the largest adobe structure in the world. Therefore the retrofitting of these structures is the essential problem and consequently various retrofittingmethods were employed for this purpose. The substantial attention which must be considered in the retrofitting of these structures is the prevention of altering the view of structure and no requirement for any changing of foundation. Therefore the selection of suitable retrofitting technique is a challenge in historical building. In this regard, among the various retrofitting techniques, proper reinforcing of the masonry walls was attractedattentions in last decades. The advantages of this method can be summarized in easy implementation, no need for roof and foundation amending and reduction of the strengthening cost and time. For execution of stainless steel bar in the wall, some holes are drilled in vertical, horizontal and/or diagonal direction depends on the reinforcing technique. Then the bars are placed in holes and they should be bonded to masonry materials using the injection of Epoxy resins. In this paper, four feasible patterns of reinforcing including only vertical, only horizontal, vertical-horizontal and diagonal pattern are considered. The results of analysis in FE models of masonry walls using ABAQUS represent that the horizontal pattern has minimum effect in seismic performance; the vertical pattern improves the integrity of wall, the complex pattern poses results similar to vertical pattern and then diagonal bars pose best seismic performance.

Keywords:

Masonry Walls , Retrofitting , Out-of-Plane Response