混凝土桥梁应变的区间型预警阈值设定  

Interval strain threshold setting method for early warning of concrete bridge

作　　者：马中军[1,2] 谈志诚[2] 张铟[2] 

机构地区：[1]武汉理工大学,湖北武汉430070 [2]南阳理工学院,河南南阳473004

出　　处：《西安建筑科技大学学报（自然科学版）》2013年第4期526-532,共7页Journal of Xi'an University of Architecture & Technology(Natural Science Edition)

基　　金：国家自然科学基金(50978151);河南省科技攻关项目(122102210165)

摘　　要：在桥梁健康监测系统的预警模块中,如何设定合理的应变监测阈值还有待做进一步的研究.考虑混凝土自身的离散性,提出了一种针对混凝土桥梁的区间型应变阈值的设定方法.由于实际中一般难以获取大量的弹性模量数据样本,需要专门考虑对弹性模量代表值的小样本分析问题.为此,首先引入t分布来对弹性模量的均值进行区间估计,以置信区间作为弹性模量的取值.然后分别以区间的两个端点值作为弹性模量的取值,对结构进行有限元分析,可得到各测点处应变的边界值,即可得到应变预警的区间型阈值.数值模拟算例验证了方法的有效性.基于区间型的应变阈值,可实现多级预警,确保桥梁安全.How to set proper strain threshold in the early warning module of bridge health monitoring system still remains a subject to be studied. Considering the discreteness of concrete, a novel interval strain threshold setting method for con crete bridges has been proposed in this paper. In practice, it is very difficult to obtain large amounts of elastic modulus da- ta sample, so the small sample analysis of elastic modulus representative value is necessary. For this purpose, t distribu tion is introduced to carry out interval estimation for the mean value of elastic modulus firstly. A confidence interval can be obtained and used as the representative value of elastic modulus. By employing the end values of this interval, strain of each measurement point can be calculated by the finite element method respectively and used as boundary values. Suhse quently, the interval strain threshold for the early warning can be obtained. Numerical simulation example shows that reasonable interval threshold can be obtained by the method proposed in this paper. Based on the interval strain threshold, multiple level early warning can be actualized and then the safety of bridge can be ensured well.

关 键 词：混凝土 应变 区间 阈值 T分布 

分 类 号：TU997[建筑科学—市政工程]