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Steel-FRP Reinforced Concrete Moment-Resisting Frames under Lateral Loads: Numerical Investigation

Research Authors
Mohamed F. M. Fahmy and Haitham A. Ibrahim
Research Member
Research Department
Research Year
2020
Research Journal
Journal of Composites for Construction
Research Publisher
ASCE
Research Vol
24(6)
Research Rank
1
Research_Pages
04020005-1-To-13
Research Website
https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29CC.1943-5614.0001078
Research Abstract

This paper suggests using a combination of steel and fiber-reinforced polymer (FRP) reinforcements to introduce sustainable reinforced concrete moment-resisting frames (RC-MRFs) characterized by damage-controlled seismic performance, cost-effectiveness, and postearthquake recoverability. The aim of this study is twofold. First, according to a predefined seismic performance of RC-MRFs, this study introduces the optimum replacement ratio of the longitudinal FRP reinforcement of FRP RC-MRFs with steel bars. Second, this study investigates the application of FRP-steel reinforcement details to alleviate damage in the plastic-hinge zones of the beams. A detailed three-dimensional finite-element model (3D-FEM) of an RC-MRF is developed and validated against the experimental results of a large-scale, two-bay, two and half story MRF entirely reinforced with FRP rebars and stirrups. Results indicate that compared with FRP RC-MRFs, for a replacement ratio of FRP reinforcement ≤42%, the serviceability state of the proposed steel–FRP RC-MRFs is characterized by a controlled deformability, and the ultimate state is characterized by an acceptable residual lateral strength ensuring safe exit of the structure from its functionality. Furthermore, when steel reinforcements are only provided at the ends of the beams, the frame lateral deformability is based on the development of two sequential plastic hinges at each end of the beams, leading to higher deformability and lower damage levels.