Seismic response of new and repaired steel-concrete composite structures using bi-axial shaking table tests designed with similitude law

This paper presents the analysis of the seismic response and repair efficacy of half-scale, two-storey 3D steel-concrete composite building specimens, based on original dynamic shake table tests subjected to biaxial horizontal ground motion. The Specimens featured Dissipative Replaceable Beam Splices (DRBeS) and Dissipative Replaceable Bracing Connections (DRBrC) in their main directions. The study explores the influence of mass eccentricity on the three-dimensional lateral-torsional coupling mechanism. The dynamic characteristics of the specimens were determined before and after seismic testing through sine sweep tests, while ground motion intensity levels corresponded to the three limit states prescribed by Eurocode 8. After replacing the damaged components, the specimens were retested to demonstrate the resilience of the repaired buildings to endure subsequent strong earthquakes. The shaking table tests of the half-scale structures were designed according to similitude law. The integration of experimental test data and numerical analyses allows for the generalization of efficient energy dissipation by the implemented Dissipative Replaceable Components (DRCs). The research results show the capacity of DRCs to protect non-dissipative elements and to preserve the overall structural integrity, and the ease of DRC replacement. • Seismic response of new and repaired half-scale steel-concrete structures tested. • Shaking table tests designed with similitude law for accurate scaling and modeling. • Global models validated full-scale building performance under seismic conditions. • Design instructions developed from validated experimental and numerical results.