基于可拓学理论的简支梁桥安全评价模型研究

Safety evaluation model of the simplified-propped beam bridges based on the extenics theory

针对我国简支梁桥基数大、事故多发的特点,以交通工程理论、可拓学理论等为基础,从人、车、桥梁和环境四方面出发,分析影响桥梁安全性的影响因素,并对8个一级指标和28个二级指标进行量化,得出简支梁桥安全评价指标体系;再利用简支梁桥调研数据进行主成分分析来筛选指标,应用粗糙集理论分析各指标权重,建立基于可拓学理论的关联函数,结合简支梁桥安全等级划分,最终构建基于可拓学理论的简支梁桥安全评价模型,并通过工程实例验证模型的实用性。

The present paper intends to devote itself to an analysis of the probabability factors that affects the safety of the bridges from the following 4 aspects:human-being involvement,vehicles,bridge quality itself and the surrounding environment based on the traffic and transportation engineering and extenics theories.On the above basis,we have brought about 8 first-level indexes and28 second-level indexes that may affect the safety of the simply supported beam bridges while taking into account the characteristic feautres of the huge cardinal numbers and the frequent accidents involved with such bridges in China.To proceed with our study,we have first of all made the principal component analysis to work out the cumulative variance contribution rate and the entire load to the principal components of each second-level index and furthermore determinate the second-level indexes,which let us obtain the safety evaluation index system of the simply supported beam bridges.And,later,under the said safety evaluation index system,it has been made possible to discretize the index data of the actually simply supported beam bridge structure by dividing it into 5 levels so as to get rid of the influence of the subjective factors and the data involved by using the rough set theory.All this helps us to facilitate the calculation of the weights in correspondence with the first-level and the second-level indexes so as to formulate the said safety evaluation model.Besides,it would also be easier to identify and determine the classical domain and the joint domain of the bridge safety evaluation indexes based on the extenics theory,so as to establish a correlation model for the bridge to be clarified.In addition,the paper has also given a detailed account of each security level involved with the division of the security level of the bridge,which has been delivered in accordance with the quantitative indexes.Thus,finally,a safety evaluation model of the simply supported beam bridge has been formulated based on the extenics theory.The calculation results of the model can be used to make a comparison with the current standard results,whereas the effectiveness and practicability of the model can be verified by analyzing some engineering examples through comparison.At the same time,we have also proposed a new efficient easy-going method to evaluate the safety condition of the simply supported beam bridges.