ABSTRACT This study aims to evaluate the diaphragm force of steel dual frames, composed of a special moment frame (SMF) and a braced frame, with sliding slab and a suitable diaphragm force reduction factor for designing horizontal energy dissipation devices, connected between the precast sliding slab and the frame. The new system allows slab sliding at the design‐based earthquake (DBE) level to reduce floor acceleration and enhance the seismic performance. Full‐scale shaking table tests and detailed nonlinear modeling were conducted on a steel three‐story recentering braced frame (RCBF) to accurately simulate the nonlinear behavior of the sliding slab system, including horizontal sandwiched buckling‐restrained braces (H‐SBRBs) for energy dissipation and interface friction between the sliding slab and the frame. This modeling scheme was adopted to three‐story, seven‐story, and eleven‐story dual frame models to evaluate the diaphragm force in sliding slab. The Method 2, specified in ASCE 7–22 (2022), can capture a floor inertial force distribution and is served as a basis for developing a design approach for the dual frame with sliding slab by calibrating a new force reduction factor, R f . With a proposed R f value of 1.5, the slab sliding can be activated with all H‐SBRB yielding at DBE level while maintaining uniform slab displacement along the building height, reducing floor acceleration by up to 28% and frame drift by up to 9% compared to the frames with conventional slab. The results confirm the sliding‐slab effectiveness in suppressing higher‐mode effects and provide a practical design force reduction factor for estimating the diaphragm force in the steel dual frame with sliding slabs.
Córdova et al. (Tue,) studied this question.