Using outrigger systems from steel plates in tall reinforced concrete buildings

Abstract

As the population grows and available land becomes more limited, high-rise buildings have become a popular and sustainable solution to maintain agricultural areas. The evolution of tall building design has been marked by the rise of innovative structural lateral resisting systems. Among these, the core-outrigger system has emerged as a highly efficient solution for mitigating drift and core overturning moments in tall buildings. Studies have suggested various types of outrigger infills, including steel bracing, reinforced concrete, buckling-restrained bracing, and more.. Very few studies have proposed using steel plates as an outrigger infill. This research offers a new outrigger system, the Steel Plate-infilled Reinforced Concrete Frame (SP-RCF), to enhance high-rise building performance by taking advantage of the state-of-the-art properties of thin steel plates and integrating them into reinforced concrete boundary frames. To ensure the new system’s effectiveness, a theoretical foundation was established by analytically determining the optimal number and placement of outriggers and providing practical graphs to be used in the initial design stage for any outrigger type. This was followed by nonlinear simulations in ABAQUS, where a full-scale SP-RCF’s behavior in terms of stiffness, strength and ductility was assessed against the most common outriggers, namely Reinforced Concrete Wall-infilled Reinforced Concrete Frame (RCW-RCF) and Steel Truss-infilled Reinforced Concrete Frame (ST-RCF). Finally, the three outriggers were integrated into a full-scale high-rise case study using ETABS software to simulate and compare their impact on global building behavior under severe seismic loading through static nonlinear analysis. The outcomes of this study demonstrated that the SP-RCF system, compared to conventional outriggers, achieved notable structural enhancements of up to 75% in strength, 18% in post-yield stiffness, 43% overstrength capacity, and 29% in the response modification factor. The findings are evidence of the advantages the proposed system in this study will add if implemented.