Global Seismic Reliability Analysis Of Frame-core Tube Structure Based On Stochastic Response Surface Method

There are a large number of uncertainties in material properties, geometry dimensions, load variation of engineering structures. In addition, the earthquake also has strong randomness in occurrence time, occurrence space and intensity, and the probabilistic seismic performance evaluation based on reliability theory has become a research hotspot in recent years. In this dissertation, in consideration of factors such as stability, accuracy and computation efficiency, optimization analysis is carried out on the stochastic response surface method. Based on that, a seismic reliability analysis method based on stochastic response surface is developed by using the structural global limit states. Then global seismic reliability of frame-core tube structure is studied systematically. Specific studies are as follows:Reliability analysis based on stochastic response surface method. In this paper, the stability of collocation method based on linearly independent principle is studied. Afterwards, two common reliability analysis methods of response surface function are compared for their accuracy. In consideration of the factors above and computation efficiency, the optimal order of response surface function is selected. What is more, compared to some other reliability analysis methods such as first order reliability method, second reliability method and the response surface methods, the stochastic response surface method has higher accuracy and efficiency.The global reliability analysis based on the global limit state equations. The global limit state equations include the limit state of bearing capacity made up by base shear force and seismic action, the limit state of deformation capacity made up by the threshold of the interlayer displacement angle and the maximum interlayer displacement angle response, the limit state of stability capacity made up by the threshold of the degradation rate of instantaneous equivalent stiffness-weight ratio and the degradation rate response of instantaneous equivalent stiffness-weight ratio, which provide the structure with multi-angle global seismic reliability evaluation. Then the structure seismic vulnerability function is deduced based on structural seismic reliability analysis, and seismic vulnerability analysis method is given.The global seismic reliability analysis of frame-core tube structure and reliability indices evaluation. A typical frame-core tube model is built in Open Sees. Based on the three limit state equations established in second part, the global seismic reliability of the frame-core tube structure is analyzed by using the stochastic response surface method with the combination of Matlab and Open Sees. Then the failure probability of different degree of damage under earthquake of different intensity can be obtained as well as the aseismic reliability index. Furthermore, a new frame-core tube model with a strengthening layer is built, after the comparison of aseismic reliability between the regular frame-core tube structure and the one with strengthening layer, the seismic reliability indices based on different limit states are judged of. The load-carrying capacity reliability is insensitive to the increasement of reliability accused by the strengthened story, so it just can be taken as a reference index. While the deformability reliability and the stability reliability are consistent and both have good accuracy in evaluating the reliability.