Comparative Seismic Response of a Hospital Building Equipped with Lead Rubber and Friction Pendulum Bearings Comparative Seismic Response of a Hospital Building Equipped with Lead Rubber and Friction Pendulum Bearings

Abstract

Hospitals in active seismic regions must maintain structural safety and operational continuity after strong earthquakes. This study compares the seismic response of the Anutapura Medical Center hospital building in Palu using three support configurations: a conventional fixed base, lead rubber bearings (LRBs), and friction pendulum bearings (FPBs). A three-dimensional structural model was developed in ETABS using the as-built geometry, material properties, gravity loads, and seismic parameters prescribed by Indonesian standards. The isolated models incorporated nonlinear bearing properties obtained from the isolator design and numerical characterization. Fundamental period, lateral displacement, interstory drift ratio, horizontal seismic force, and base shear were used as comparative indicators. The fixed-base fundamental period of 1.528 s increased to 2.869 s with LRB and 2.588 s with FPB. At the base level, LRB reduced the base shear by 60.51% in the X direction and 60.89% in the Y direction, whereas FPB achieved reductions of 55.25% and 55.97%, respectively. FPB produced the smaller roof displacement, with reductions of 17.98% in X and 22.50% in Y relative to the fixed-base model; the corresponding LRB reductions were 14.44% and 17.18%. The results indicate a clear performance trade-off: LRB is preferable when reducing seismic force demand is the governing objective, while FPB provides better displacement control. These findings support performance-based selection of isolation systems for essential facilities in high-seismicity areas.