The reliability analysis of earth slopes is considered. For slope safety assessment, the first-order reliability method is employed for estimating the probability of failure or reliability index. Since the failure of any slip surfaces implies failure of the slope, the slope is considered as a series system. The system aspect of the slope in the reliability analysis is dealt with by defining a limit state of the system as a function of the minimum of the ratio of the shear strength to the mobilized shear strength for each of all potential slip surfaces. Such a ratio for a given slip surface is evaluated using the extended generalized method of slices. The reliability analysis procedure described is applied to example slopes to illustrate the impact of the probability distribution type, and the spatial variability of the soil properties on the probability of failure of the slopes.

This study investigates probabilistic characteristics of the peak ductility demand of inelastic single-degree-of-freedom systems. The hysteretic behavior of structural systems is represented by the Bouc-Wen model, which takes various hysteretic curves with degradation and pinching behavior into account, and a prediction equation of the peak ductility demand is developed. The application of the developed equation in reliability analysis of structures subject to earthquake loading is illustrated. The results indicate that the effects due to degradation and pinching behavior on the peak ductility demand as well as the reliability of structures can be significant, especially for stiff structures.

Eight or nine tropical cyclones (TC) per year make landfall over mainland China and cause large typhoon wind speeds and economic loss. This study estimates the return period value of the annual maximum typhoon wind speed, vT, for a set of grid points in the coastal region of mainland China. vT can be used to characterize the typhoon’s wind hazard and to assign the wind load in design codes. The estimation uses a typhoon wind hazard model consisting of the TC track and wind field models. For the estimation, the development of track model for a circular subregion centered at each of the grid points is carried out by using the best-track dataset from China Meteorological Administration, and a well-accepted wind field model for simulating the TC is adopted. The spatial trends of the parameters controlling the track model are investigated, and the time histories of the wind speeds estimated by using the adopted wind field model are compared with those observed from two historical typhoon events. The es...

The minimum expected life-cycle cost decision rule leads to an optimal design for a risk-neutral decision maker, but fails to incorporate the magnitude of uncertainty in the life-cycle cost and is incapable of coping with risk attitudes. The maximum expected utility decision rule results in a utility function dependent optimal decision that may not be accepted by a decision maker with a different utility function. This study develops a framework for selecting efficient or optimal seismic designs by considering the decision maker’s risk attitude, societal tolerable risk level, and societal life quality criterion. Analysis results suggest that use of the developed framework can identify different sets of optimal designs for different risk attitudes. The results also show that the societal life quality criterion, for the considered examples, could only lead to a lower bound on the seismic design level for risk-seeking decision makers, whereas a reasonable tolerable risk level could provide a lower bound on t...