Hardening & Blast Mitigation

QuakeWrap® Blast Protection: Blast Retrofit of Buildings with Carbon Fiber Reinforced Polymer (CFRP)

QuakeWrap® is an economical Carbon Fiber Reinforced Polymer (CFRP) system for protecting buildings against blast loads. Recent tests have clearly demonstrated the effectiveness of QuakeWrap™ in resisting extreme pressures caused during a blast explosion. To view a video of this test, please watch below. An article was published in the Structures Magazine, Edition April 2009, and can be read here.

Tests were conducted on two identical unreinforced masonry block walls. One of the walls was retrofitted by applying QuakeWrap™ fabric to both sides of the wall; the other wall remained unretrofitted as a control specimen.

Loading was simulated by 200 pounds of equivalent TNT placed at a height of 3 feet and a distance of 30 feet away from the walls. This resulted in a pressure of 200 psi (pounds per square inch) on the walls. For comparison, this is 720 times more load than the 40 psf (pounds per square foot) load that is used for the design of a typical floor system in a building.

The wall deflected 9 inches but remained fully intact even though the block units inside the wall crushed in compression (as expected according to the design of the wall). Because of the construction of the wall that included narrow gaps along the vertical edges, some of the blast wave pressure penetrated inside the room. Nevertheless, that pressure inside the room was only about 4.2 psi. Ear drum damage and lung collapse usually occur at 5 and 10 psi, respectively. Thus, it is clear that the occupants of the room retrofitted with QuakeWrap™ would have survived the blast.

The following articles provide additional information on hardening and force protection of structures that might be of interest to you:

  • Fort Bragg Barracks Receives Pioneering Force Protection Retrofit (for Blast Loading) by Erin Barstow, Public Works Digest, May/June 2009, 28
  • Blast Loading Retrofit of Unreinforced Masonry Walls by Mo Ehsani, and Carlos Pena, Structure Magazine, April 2009, 16-19
  • UA Civil Engineers Blast Proof New UN Headquarter in Beirut by Pete Brown, University of Arizona Website, December 19, 2013