Blast Resistance of Un-Reinforced Masonry Walls Retrofitted with Fiber Reinforced Polymers


The increased amount of terrorist activities directed against U.S. facilities led to an evaluation of the survivability of masonry structures to blast Ioadings. Un-reinforced masonry (URM) walls have a low resistance against out-of-plane blast loading due to their low flexural capacity and their brittle mode of failure. Therefore, failures of URM walls were identified as one of the major causes of material damage and loss of human life due to blast loads. This led to an urgent need in developing effective retrofitting techniques in lieu of more elaborate conventional approaches to upgrade masonry members to resist blast loads. One alternative method is the use of Fiber Reinforced Polymer (FRP) composites on the surfaces of the walls to resist high flexural stresses. However, this is a new approach to blast resistant design and there is little available test data to use as a basis for the design of wall upgrades. Two series of walls, reflecting eight un-grouted URM walls with different slenderness ratios and different strengthening schemes using FRP composite materials were tested in this study by varying blast charge weights and standoff distances. FRP composites in the form of rods and laminates were used as strengthening materials. The walls were supported from the top and bottom without side wall-to-frame connections and subjected to blast waves at their mid-height. The tests caused a well- distributed range of damage levels; from no damage to complete failure. The shear capacity controlled the blast behavior of the strengthened walls. Furthermore, the analytical analysis showed that a single degree of freedom (SDOF) approach could be used to predict the behavior of masonry walls strengthened with FRP. The wall behavior could subsequently be related to threat and damage levels defined by the Department of Defense (DOD) Standards.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Fiber Reinforced Polymer (FRP) Composites; Un-Reinforced Masonry (URM); Blast Charge Weights; Blast Loads; Flexural Capacity; Out-Of-Plane Blast; Retrofitting Techniques; Single Degree of Freedom (SDOF); Standoff Distances; Terrorist Activities

Document Type

Article - Journal

Document Version


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© 2004 the Masonry Society, All rights reserved.

Publication Date

01 Jan 2004