Probabilistic seismic evaluation of reinforced concrete structural components and systems.

摘要

An accurate evaluation of the structural performance under seismic loading, one of the critical issues of the performance-based earthquake engineering, requires a probabilistic approach due to uncertainties in structural properties and the ground motion (referred to as basic uncertainties). In spite of a large number of previous studies on probabilistic evaluation of structures, efforts on identifying relative significance of different sources of uncertainties and structural components with respect to the performance of the structural system are scarce.; The objective of this study is to identify and rank significant sources of basic uncertainties and structural components with respect to the seismic demand (referred to as the Engineering Demand Parameters, EDP) of reinforced concrete structural systems. The methodology for accomplishing this objective consists of three phases. The objective of the first phase is to understand the propagation of basic uncertainties to structural system with respect to its EDPs. The first-order second-moment (FOSM) method and the tornado diagram analysis are used to estimate EDP uncertainties induced by basic uncertainties where EDP uncertainty is used to identify and rank significant sources of basic uncertainties.; The objective of the second phase is to propagate basic uncertainties to structural components with respect to their capacities. For this purpose, the stochastic fiber element model is developed, such that spatial variability of basic uncertainties is accounted for in the conventional fiber element model using Monte Carlo simulation. This model is applied to typical structural components of a given structural system to develop probabilistic section models such as the moment-curvature relationships at critical sections of the structural component.; The objective of the third phase is to propagate uncertainty in the capacities of structural components to the structural system, a collection of structural components, with respect to its EDPs. A plastic hinge model, whose behavior is dictated by probabilistic section models, is used to develop a computational model of the structural system. Using the FOSM method, EDP uncertainties induced by structural components are estimated to identify and rank significant components. Several case studies demonstrate the effectiveness and robustness of the developed procedure of propagating uncertainties.