Performance of Steel Fiber-Reinforced Concrete Beams Under Shock Tube Induced Blast Loading

Abstract

This thesis focuses on the dynamic and static behavior of steel fiber-reinforced concrete (SRFC) beams. As part of this study a total of eighteen (18) beams are tested, including fourteen (14) SFRC beams, and a companion set of four (4) beams built without fibers. Seven (7) of the beams are tested under quasi-static (slowly applied) loading with the remaining eleven (11) beams tested under simulated blast loading using the University of Ottawa shock-tube. The variables considered in this study include: concrete type (SFRC vs. conventional concrete), fiber content, fiber type, as well as the effect of transverse reinforcement. The criteria used to evaluate the blast performance of the beams includes: overall blast capacity, maximum and residual mid-span displacement, secondary fragmentation and damage control. Static results confirm the beneficial effect of fibers on improving the shear and flexural capacity of beams. Dynamic results show that use of steel fibers at a sufficient content can increase shear capacity and effectively replace transverse reinforcement in beams tested under blast loads. The results also show that increasing fiber content can improve the blast response of the beams by reducing maximum and residual mid-span displacement, improving damage tolerance and minimizing secondary blast fragments. However, at high fiber contents, problems with workability of the concrete mix can occur, resulting in a reduction of improvements when compared to SFRC specimens with lower fiber content. The analytical research program aimed at predicting the response of the test beams using dynamic inelastic single-degree-of-freedom (SDOF) analysis. Overall the analytical results demonstrate that SDOF analysis can be used to predict the blast response of beams built with SFRC.