Papers by Author: Xiao Lin Yu

Abstract: The response surface method (RSM) developed in recent years is an effective way to solve the structural reliability problems with implicit performance function. In order to improve the computational efficiency and make RSM suitable well to large and complex engineering structures, the reliability analysis method based on uniform design method (UDM) and support vector machine (SVM) was proposed. UDM is adopted to select training data and SVM is used as response surface. Structural reliability index is calculated in combination with the traditional reliability analysis methods (such as, the first-order reliability method (FORM), the second-order reliability method (SORM) or Monte Carlo simulation method (MCSM)). Numerical examples show that sampled with the UDM can greatly reduce the number of samples required for training by SVM model, and a very good approximation of the limit state surface can be obtained to get the failure probability. The reliability analysis of the under serviceability limit-state of a typical self-anchored suspension bridge——Sanchaji Bridge was carried out with the improved response surface method.

Abstract: Since the performance functions of large complex structures can not be expressed explicitly in the process of reliability analysis, support vector machines (SVM) with good ability of generalization are used as the response surface function based on the small training samples. The uniform design method was adopted in selecting the training data. The least support vector machines (LS-SVM) were used to find the support vectors. The limit state function was expressed by the LS-SVM regression. Reliability analysis was then performed by the usual reliability method (e.g., the first-order reliability method, the second-order reliability method or Monte Carlo) on the response surface. The results of calculations of numerical examples and a typical cable-stayed bridge show that LS-SVM using the uniform design method can well approximate the real response of complex structures which has a good efficiency and accuracy and can be applied in complex structures.

Abstract: In this paper, first order reliability method (FORM) is generalized to the seismic reliability analysis of long-span bridges and the first excursion probability of a single tower cable-stayed bridge is studied. The seismic motivation is firstly dispersed as a series of random variables. Then the cross velocities on the dispersed time points can be obtained by solving the motivation of the design checking points with FORM. The upper bound of first excursion probability is also obtained by integrating the cross velocities at different time. The results show that the seismic reliability analysis method based on the FORM is feasible and effective to solve the first excursion probability problem. The single tower cable-stayed bridge studied in this paper has a higher reliability under strong seismic.