Dynamic Tests on a Five-Storey Structural Steel–Reinforced Concrete Hybrid Building

Hybrid structures, combining reinforced concrete walls and structural steel frames, have become increasingly common in mid-to-high-rise buildings. The stiffness and toughness of reinforced concrete, combined with the high strength-to-weight ratio and rapid construction of steel components, represent the advantages of this design solution. Nevertheless, limited experimental data exist regarding the overall response of hybrid structures to earthquake demands. Additionally, few large-scale dynamic tests have been conducted on buildings with horizontal irregularities arising from uneven stiffness distributions. This study, conducted through a joint research program between the National Center for Research on Earthquake Engineering (NCREE) and New Zealand’s Centre for Earthquake Resilience QuakeCoRE, presents the results of 42 simulated earthquake tests on a five-storey structural steel–reinforced concrete hybrid building with horizontal irregularities. Two building configurations (braced and unbraced) were tested to investigate the effect of limiting drift on the seismic response of structural and non-structural elements. Both building configurations exhibited a stable structural response up to roof-drift ratios of approximately 3%. Building torsion generated drift demands in the more flexible façade up to 4 times larger than in the stiffer façade. Drift demands were sensitive to the building configuration used and the shape of the displacement spectrum of the simulated ground motions. Regarding non-structural elements, damage on partition walls was observed but remained easily repairable for storey-drift ratios up to 1%. The response of ‘acceleration-sensitive’ non-structural elements was not clearly sensitive to the building configuration used.