Experimental study on performance of repaired and strengthened unreinforced masonry walls using polypropylene bands

This paper is aimed at proposing a strengthening method for improving the seismic performance of unreinforced masonry (URM) brick walls. What is noteworthy regarding the proposed technique is the low price and easy application of polypropylene (PP) bands, which are widely used in the packaging industry. Three half-scale specimens were tested under cyclic lateral loading simultaneously with imposing a constant vertical load. First, the URM wall was tested up to a certain drift in which a reduction in lateral capacity was recorded. According to the crack pattern observed on the wall surface, a repair strategy was taken to upgrade the damaged wall in the shortest possible time and with the minimum manpower. In doing so, the horizontal PP bands were employed to wrap the wall. The repair technique has stopped the spread of the cracks and prevented the reduction in lateral capacity. Besides, the third specimen, which is identical to the URM wall but it is strengthened by PP bands, was tested and developed a superior performance in terms of changing the failure mode and also increasing the maximum strength, the strength at maximum displacement and maximum displacement by 88%, 38% and 185%, respectively, compared to URM wall.