Retrofitting Options for Un-Reinforced Brick Wall Subjected to Impact Load

Abstract

In this research we investigate the possibility of enhancing the way brick walls can be retrofitted in an economical manner and become more resistant to blast impact. Retrofitting a method usually done on constructed walls; however, the same strengthening procedures can also be applied to a new construction project. In this research we investigate three methods of reinforcing brick walls against blast impact. First, reinforcing the brick layer using carbon fiber strips only without epoxy, with the fiber being placed on the bare bricks before it is plastered with mortar finishing, second, reinforcing the brick wall by placing CFRP onto the bare bricks and fixing with epoxy prior to finishing or being plastered over with mortar, and third, retrofitting the outer surface of a finished, or plastered, brick wall with CFRP and fixed with epoxy as is commonly done. The impact test was conducted using a drop weight released at a fixed height to simulate blast energy of an explosion. The effects of the test on all the samples were observed to identify failure patterns. Flexural testing was also conducted to observe how the samples perform under normal flexural loading. It was discovered that the second option, i.e. placing the CFRP on the bare bricks and fixing with epoxy before it is finished or plastered over with mortar, performs the best. This is due to the CFRP being firmly fixed before mortar finishing, causing the CFRP to be held steadily in place during the impact, thus, helping the wall to resist the impact load. With the third option, the CFRP was able to resist the impact but, as has been observed in other studies, the CFRP delaminates from the wall. The first option does not work very well since the mortar is unable to perform as well as the epoxy in holding the fiber to the wall to resist the impact force. Thus, for plastered brick walls, it is better suited for it to be reinforced by FRP under the finished mortar rather than on it, thus reducing the problem of delaminated FRP from the wall surface.