Seismic risk assessment of precast concrete frame structures with cladding panels

Precast frame structures are widely used in Europe for single-story buildings devoted to industrial production in areas exposed to seismic hazard. Proper design and detailing of these structural systems can guarantee a seismic behavior characterized by large flexibility and significant displacement capacity. However, recent earthquakes showed that a strong interaction may occur between the structural frame and the cladding panels due to inadequate decoupling of their typical connection systems. Recently, the design of precast structures including their cladding panels has been framed within the European research project SAFECLADDING. Innovative solutions have been conceived and investigated, including isostatic systems able to effectively decouple the seismic response of frames and panels. The seismic risk assessment of precast concrete frame industrial structures with cladding panels are currently investigated within the framework of the research project RINTC (implicit seismic risk of code-conforming structures) funded jointly by the Italian Civil Protection Department and ReLUIS (Italian network of university laboratories). In this paper, seismic risk assessment is performed for frame-panel structural assemblies with different isostatic panel connection systems, including pendulum, cantilever, and rocking systems. The case of cantilever panel system is studied with two models, with and without the contribution of friction sliding force under multiaxial loading. The proposed approach is applied to a typical precast structure considering three different sites in Italy. The probabilistic structural response is assessed based on the results of static nonlinear analysis and multi-stripe dynamic nonlinear analyses under ten hazard levels characterized by mean return period ranging from 10 up to 100000 years. The influence of the panel connection system on the seismic performance of the overall system is investigated based on demand over capacity curves and reliability analysis carried out at both ultimate and damage limit states.