Experimental and numerical study of strengthened single storey brick building under torsional moment

The torsional capacity of unreinforced masonry brick buildings is generally inadequate to provide a stable seismic behavior. The torsional strength is believed to be the most important parameter in earthquake resistance of masonry buildings and the shear stresses induced in the bed joints of such building's walls is an important key for design purposes. Brick buildings strengthened with wire-mesh reinforced concrete overlay are used extensively for building rehabilitation in Iran. Their quick and simple applications as well as good appearance are the main reasons for the widespread use of such strengthening technique. However, little attention has been paid to torsional strengthening in terms of both experimental and numerical approach. This paper reports the response and behavior of two single-story brick masonry buildings having a rigid two-way RC floor diaphragm. Both specimens were tested under monotonic torsional moment. Numerical work was carried out using non-linear finite element modeling. Good agreement in terms of torque-twist behavior, and crack patterns was achieved. The unique failure modes of the specimens were modeled correctly as well. The results demonstrate the effectiveness of reinforced concrete overlay in enhancing the torsional response of strengthened building. Having evaluated the verification of modeling, an unreinforced brick building with wall-to-wall vulnerable connections was modeled so that the effect of these connections on torsional performance of brick building could be studied. Then this building was strengthened with reinforced concrete overlay and the effect of strengthening on torsional performance of brick buildings with vulnerable connections was predicted numerically.