Seismic performance assessment and probabilistic repair cost analysis of precast concrete cladding systems for multistory buildings

Analytical and experimental tests have shown that the seismic response of multistory moment-frame structures with precast concrete cladding in moderate to severe earthquakes is significantly influenced by the cladding system. The purpose of the research discussed in this dissertation is to study the effect that the cladding system has on the structural response of multistory buildings, to develop analytical equations to estimate the seismic demands in the cladding connections, to calculate the probability of failure of typical cladding connections, and to determine the postearthquake repair costs and repair times of typical cladding systems.;The nine-story LA SAC steel moment-frame building is selected as the study building, and a two-dimensional, nonlinear model is developed of the bare-frame structure in OpenSees. The steel moment-resisting frame of the bare-frame structure is modeled using nonlinear force beam-column line elements capable of representing distributed plasticity along their length. The frame connections are reduced-beam section (RBS) moment connections, and their modeled cyclic moment-rotation behavior is based on experimental test results of the connection. Analytical models of three different precast cladding designs are applied to the bare-frame structure to study their effect on the building's seismic response. The three cladding designs represent common systems used in regular multistory buildings in modern construction.;The effects of the cladding on the seismic response of the bare-frame structure are studied by performing modal analyses, nonlinear static pushover analyses, and nonlinear dynamic timehistory analyses of the analytical models. The inclusion of cladding decreases the fundamental period of the building by only 4%; however, the effects of the cladding on the maximum interstory drifts, floor accelerations, and plastic hinge rotations are significant. Time-history analyses of each model are performed using 140 ground motions. The ground motions in each bin are scaled by a common factor (cloud method with constant scaling) to ensure nonlinear response was captured. The time-history results are plotted in log-log space, and a linear trend line is fitted to the data to represent the mean maximum response values. The time-history results reveal that the addition of cladding reduces the mean maximum interstory drift ratios in the bareframe model by up to 22%, 28%, and 33% for the 50%-, 10%-, and 2%-in-50 year probability of exceedance levels, respectively. The reductions in interstory drift are the largest for cladding type C3 and smallest for cladding type C1. The mean residual interstory drifts are small for all levels of intensity and were not significantly affected by the cladding. The mean maximum floor accelerations are not significantly affected by cladding types C1 and C2: the mean values of maximum floor accelerations in the bare frame structure are reduced by only 8% for these two cladding types.;The time-history analysis results show that significant deformations develop in the column cover connections in moderate earthquakes. The deformations exceed the life-safety, and in some cases, the collapse prevention performance criteria. Thus, the failure probabilities of the column cover connections subject to multiple hazard levels are investigated using structural reliability theory. The analytical equations for estimating the deformations in the column cover connectors are used to construct the limit-state function describing the structural reliability of the connectors. The random variables consist of the maximum interstory drift, the gap width in the slotted connections, and the failure shear deformation in the connectors. The deterministic parameters in the limit-state functions are the panel dimensions and the story height. The correlation coefficients are calculated for the maximum interstory drifts between different stories.;To gain additional insight on the seismic performance of multistory buildings with cladding, post-earthquake repair cost analyses are performed on the analytical models using the performance-based earthquake engineering (PBEE) methodology developed by the Pacific Engineering Earthquake Research (PEER) Center.Based on the repair cost analyses, it is apparent that cladding type C2 is the most cost-effective cladding design. Because the cladding panels have window punch-outs, the window panes are protected from damage due to interstory drift. In addition, cladding type C2 does not use the highly damageable column cover connections that are expensive to repair. (Abstract shortened by UMI.)...