Multi-hazard damage mitigation for low-rise wood-framed structures using a CarbonFlex composite

This study focused on investigating the ability of a polymeric-enhanced high-tenacity fabric composite called CarbonFlex to mitigate damages from multi-natural hazards, which are earthquakes and tornadoes, in wood-framed structures. Typically, wood-framed shear wall is a seismic protection system used in low-rise wood structures. It is well-known that the main energy dissipation of the system is its fasteners (nails) which are not enough to dissipate energy leading to decreasing of structure's integrity. Moreover, wood shear walls could not sustain their stiffness after experiencing moderate wall drift which made them susceptible to strong aftershocks. Therefore, CarbonFlex shear wall system was proposed to be used in the wood-framed structures. Seven full-size CarbonFlex shear walls and a CarbonFlex wrapped structures were tested. The results were compared to those of conventional wood-framed shear walls and a wood structure. The comparisons indicated that CarbonFlex specimens could sustain their strength and fully recover their initial stiffness although they experienced four percent story drift while the stiffness of the conventional structure dramatically degraded. This indicated that CarbonFlex shear wall systems provided a better seismic protection to wood-framed structures. To evaluate capability of CarbonFlex to resist impact damages from wind-borne debris in tornadoes, several debris impact tests of CarbonFlex and a carbon fiber reinforced storm shelter's wall panels were conducted. The results showed that three CarbonFlex wall panels passed the test at the highest debris impact speed and the other two passed the test at the second highest speed while the carbon fiber panel failed both impact speeds.