A method for estimating probability of effective prestress in concrete structures based on sequential theory
To establish a method for evaluating the distribution characteristics of prestress in concrete structures and calculating the evaluating characteristic value based on measured data,the concept of prestress ratio was introduced to represent the probability distribution of prestress in three levels,including single-bar level,component level and structure level.Through the combination of theoretical analysis and numerical simulation,the probability distribution of prestress ratio of each level was studied,and a Gaussian mixture model classification simplified analysis theory considering the prestress system layout features and the influence of design variances was established.Additionally,by introducing the sequential estimation theory and setting the maximum estimation error of the guarantee rate feature parameter at 95％as the constraint condition,a sampling stopping criterion combined with the bootstrap method,EM algorithm,and pivot method was established.A sequential sampling estimation and evaluating characteristic value calculation method for prestress ratios of the structure,single-bar,and component levels was proposed.The effectiveness of this method was verified by a numerical example of a prestressed concrete frame structure without bond.The research shows that compared to traditional sampling methods using fixed sample sizes,sequential sampling methods can effectively quantify estimation accuracy,reduce the estimated sample size and reduce detection costs.The maximum estimation error of the evaluating characteristic value of components decreases gradually with the increase of the number of prestressing bars,and the estimation accuracy can be higher than 95％.
国家科技期刊平台
NSTL
万方数据
