Application of Steel and FRP Reinforcement Combination in Moment Resisting Frames: Prospects and Challenges

Abstract

The demand for seismic resilient communities is the main driving force behind efforts of research engineers to develop novel reinforced concrete (RC) structures with superior seismic performance. Post-earthquake damage observations raise concerns about the behavior of conventional steel bars in seismic resisting structural systems which are susceptible to large residual deformations after surviving seismic events. Therefore, for the last two decades, considerable efforts have been made to find alternative reinforcement materials such as fiber reinforced polymers (FRP) and to develop various concepts for the adoption of these materials to enhance the seismic resiliency of RC structures. One of these concepts is the combination of both steel and FRP bars in seismic resisting structures. Herein, this paper discusses the seismic performance of steel-FRP reinforced concrete moment resisting frames (SFRC-MRFs) with the aim to determine the prospects and existing challenges of this new system. This paper starts with brief discussion about lateral performance of SFRC beam-column joints and then investigates the cyclic behavior of SFRC-MRFs. Afterward, the feasibility of using FRP bars with predefined surface texture details to avoid undesirable failure modes in SFRC-MRFs under severe earthquakes is discussed. Finally, existing research gaps and challenges are determined to facilitate the future adoption of the SFRC-MRFs.