Experimental and analytical investigation of seismic behavior of centercore-retrofitted masonry walls

Abstract

There are a significant number of historic masonry buildings and monuments in seismic areas all over the world that need to be retrofitted. Conventional methods of seismic rehabilitation conflict with the appearance of the masonry element and cannot be employed in the case of monumental buildings where the façade and finishing are decorative or where the exposed masonry defines the character of the structure. Centercore strengthening method has been developed in recent decades and is used in various projects of seismic rehabilitation. However, due to the lack of sufficient experimental and numerical investigation, there is no analytical model to predict the behavior of masonry components retrofitted using this technique. In this research, the material properties of conventional brick masonry used for the construction of Iranian historic buildings and monuments were obtained through base material tests. Afterward, two masonry walls were tested under reversed cyclic in-plane loading. The results showed that centercore method improved the cyclic in-plane behavior of the specimens including ultimate lateral strength and energy dissipation. Moreover, based on flexure theory an analytical model is proposed for prediction of ultimate lateral capacity of masonry walls and piers strengthened by centercore technique, associated with rocking and toe-crushing mechanisms. In addition, regarding dowel action of reinforcing bars and using “Beams on elastic foundation analogy”, a simple formula is proposed to predict the dowel action capacity of centercore rebar and hence, the diagonal crack strength of the retrofitted wall. Comparing the values calculated by the proposed models with available experimental data, showed that the proposed models accurately predicted the ultimate lateral capacity of the specimens.