Nonlinear Performance Evaluation of Reinforced Concrete Steel Frames: A Review

Reinforced Concrete Column–Steel Beam (RCS) frames represent a hybrid structural system that combines the compressive strength and stiffness of reinforced concrete columns with the ductility and flexural efficiency of steel beams. Owing to these complementary material properties, RCS frames have attracted considerable significant research interest as an alternative to conventional reinforced concrete and steel frame systems, particularly in seismic regions. This paper presents a comprehensive review of the nonlinear performance of RCS frames, with emphasis on global structural behavior, beam–column connection performance, and performance evaluation methodologies. The review synthesizes findings from experimental investigations, analytical studies, and numerical simulations reported in the literature. Key performance parameters examined include strength, lateral stiffness, ductility, and energy dissipation capacity under gravity and seismic loading. Particular attention is given to the role of beam–column connections, as their rigidity and detailing are shown to significantly influence stiffness degradation, failure mechanisms, and overall seismic resilience of RCS frames. Commonly adopted evaluation approaches, including linear static, nonlinear static (pushover), and nonlinear dynamic (time-history) analyses, are critically discussed, highlighting the limitations of linear methods and the reliability of nonlinear procedures for performance-based design. The review assesses factors influencing RCS performance, such as material properties, construction practices, and environmental exposure, and examines the potential for adapting RCS systems within the Nigerian construction industry. The findings indicate that RCS frames generally exhibit superior ductility and energy dissipation compared to traditional reinforced concrete frames, while offering improved stiffness and fire resistance relative to steel frames. However, limited region-specific research and absence of dedicated design provisions remain key challenges. The paper concludes by identifying critical research gaps and emphasizing the need for localized experimental studies and code development to support the safe and effective adoption of RCS systems.