FRP rehabilitation of blast and impact damaged reinforced concrete

Blast resistant design has gained interest in the civil engineering community, as the threat of terrorist attack or accidental explosion becomes more prevalent. Research on the effects of blast on structural components is limited however, experiments using impact machines have provided additional insight into their behaviour under extreme loads. Fibre reinforced polymers (FRP) have gained acceptance as a viable alternative to conventional methods of structural strengthening, and recent research suggests they may be applicable to post-blast rehabilitation.This study found that the rapid application and short duration of loading applied by an impact machine may be suitable to simulate the response of RC elements to explosive events. However, in order to reproduce the damage more accurately, a means of distributing the load across the full length of the specimen is required. The CFRP repair used in this project improved the strength of damaged columns and re-established their original design strength. The SDOF calculations provided a reasonable prediction of the impulsively loaded specimens, while AUTODYN provided a general prediction of maximum and residual mid-span deflections.The aim of the present work was to determine if blast damage to reinforced concrete (RC) could be accurately represented by the damage caused by an impact machine and to study the effectiveness of FRP repair techniques on blast damaged RC elements. The experimental program included blast and impact test phases involving eight scaled RC specimens each. The applied loads, strains, accelerations, velocities and deflections were monitored during testing and the residual damage was documented. Five sets of the damaged RC specimens were then selected for further experimentation. Each set consisted of two specimens, one unrepaired and one that was repaired using Carbon FRP (CFRP) sheets. The final strength of all specimens was estimated through quasi-static axial loading. The blast and impact tests were modeled using a single-degree-of-freedom (SDOF) approach, as well as the explicit analysis software, AUTODYN.