Experimental and numerical studies on the seismic behavior of spherical reticulated shells with sliding isolation bearings

Spherical reticulated shells are spatial structures widely used for important public buildings with concerns of seismic behaviors. To assess the feasibility of friction pendulum bearings (FPBs) for seismic response control in reticulated shell structures, a 1/10 scale single-layer spherical reticulated shell model with small-scale FPBs was designed and fabricated. A shaking table was used to generate triaxial dynamic and seismic inputs for the test structures with and without isolators, and their natural vibration characteristics and seismic responses were measured. Based on the experimental results, significant increase of the fundamental natural period of the test structure was achieved using the sliding isolation system. The damping ratio also improved for the sliding isolated structure. Moreover, seismic response of the isolated test structure was significantly lower than that of the test model with fixed roof bearings. Following the experimental study, an OpenSees-based numerical simulation was conducted to capture the seismic behavior of the isolated test structure. The numerical and experimental responses agreed well. The modeling method was extended to full-sized reticulated shell structures using FPB systems. The effects of the FPB parameters (radius of curvature and friction coefficient) on the seismic behavior of the structures were numerically analyzed, indicating that the friction coefficient is the most critical parameter governing the structural responses. The seismic fragility of FPB-isolated full-sized reticulated shell structures considering various friction properties was investigated to provide beneficial design recommendations for the engineering practices of such isolated structures.