Reliability Factors Analysis Of Extradosed Cable-stayed Bridge

Extradosed cable-stayed bridges with its aesthetic appearances, low costs and high adaptabilities have developed rapidly in the past two decades. Based on the structural reliability theory and combining engineering practice, this paper is focused on the evaluation of reliability for extradosed cable-stayed bridges under service limit state and ultimate limit states, analyzing the random variable design parameter's impact of the extradosed cable-stayed bridge, find the most impact design parameters. As follows are the mainly contents in this thesis:1. Stayed at the extradosed cable-stayed bridge research results in home and abroad, analyze and summarize the shortcomings of certainly analysis, based on the current development situation of reliability theory, leads to this paper:considering the randomness of the design parameters. Analysis the impact of the various parameters of the extradosed cable-stayed bridge, calculate the reliability of the background and assessment of the reliability of bridge, and then study the various random variables on the reliability of extradosed cable-stayed bridge, provide the engineering design reference.2. Based on existing reliability analysis theory, to clear the limit state of structure and the reliability metrics, analysis of the existing scope of application of the method of reliability. Limit for the performance function dosed bridge can not be calculated explicitly express the reliability problems, to introduce the response surface method model complex bridge ultimate performance function, provide the structure of random static analysis and reliability evaluation of theoretical basis and method of support.3. Based on the theory of finite element analysis, combining engineering practice, using the bridge structural analysis software, establish the finite element model of the extradosed cable-stayed bridge, compared the static load test check the model. Consider the nonlinear effects of extradosed cable-stayed bridge, analysis linear and nonlinear calculation under the live load to definite the analysis mode. Providing the model relying for stochastic static analysis and Reliability Analysis.4. Considering the material properties,geometry,external loads and other parameters of the stochastic,applicating the Response Surface Method, combining engineering practice, by Midas and Matlab,analysis the random static of the extradosed cable-stayed bridge,resrarch the impact of the various random factor's variation. 5.Based on the theory of reliability, by the response surface method and the R-F method, with the maximum vertical deflection of the bridge as the limit state from Design Specifications Of Highway Cable-Stayed Brigde,calculating the reliability of deflection of the normal background state, and assess the reliability. On this basis, calculate the impact of material properties, geometry design parameters of random variables, analysis the sensitivity of the reliability of each parameter to identify the main factors, provide the basis for the rational design.