Strengthening of unreinforced masonry structures with glass fiber reinforced polymers to mitigate the effects of blast.

摘要

The subject of this dissertation is to evaluate the performance of unreinforced masonry walls (URM) retrofitted with glass fiber reinforced polymer (GFRP) and to integrate blast prediction tools, dynamic modeling tools and small scale beam dynamic and static tests to develop full scale design guidelines for GFRP use to enhance the performance of URM walls to blast pressures. In December of 2001, a full-scale internal blast test was conducted on a URM structure retrofitted with four different levels of reinforcement at Kirtland Air Force Base, New Mexico. The four walls were externally retrofitted with two levels of GFRP composites and with internal reinforcement of shotcrete on two of the four walls, yielding four unique reinforcement conditions. When subject to a detonation of 2 lbs. TNT equivalent charge within the structure, the GFRP reinforced URM walls performed remarkably well in the blast testing. Three of the four walls remained attached to the structure with significant permanent deformation. The least reinforced wall ejected masonry fragments yet left fabric attached to the test structure.; Static and dynamic tests were conducted on similarly reinforced wall panels in order to compare the modes of failure between scaled wall panel testing and full-scale tests. The results of the scaled tests revealed a consistent failure mechanism of shear in the concrete masonry unit web. Results of these scaled tests and observations of the full-scale blast test proved that the membrane effect of the GFRP controlled the behavior of the walls and contained fragmentation in three of the four test walls. Therefore an analytical model was developed to account for the primary membrane action of the GFRP layers.