Abstract: The bridges in cold area has been affected by circulation change of plus and minus temperature all the year. The character of physic and mechanic of materials composing the structure can be affected in some degree. Then objectively estimate about the actually character of bridge and the capacity of loading and using to get the actual data of all kinds of designed parameter of bridge. It can also offer the scientific evidence of later mending and reinforcing. On the base of researching degree of damage of component the text suggested to use the theory of fuzzy evaluating to set up the three levels comprehensive estimating system from components to subordinate system and whole loading capacity of bridge. The method not only considered the important components of bridge but also subordinate ones. It simplified the comprehensive estimating work through levels of fuzzy evaluating and made it scientific, simple and useful.

Key words: the bridges, capacity of loading, degree of damage of component, fuzzy theory, comprehensive estimating

摘要： 公路桥梁常年在正温—负温环境循环变化影响下，其各构件组成材料的物理、力学性质均受到不同程度的影响。这时对该地区的旧桥实际性态和承载能力做出客观的评定，即可以获得对应于各种桥梁设计参数的现实值，也可以为后续的维修、加固提供科学的依据。本文在充分分析了寒区桥梁承载能力影响因素的基础上，给出了其组成构件损伤度的评定方法，并提出了利用系统模糊理论建立从构件到分部结构再到旧桥整体承载能力的三级综合评判体系。该评定方法不仅考虑寒区旧桥结构的重要构件，并兼顾次要构件，简化了错综复杂的旧桥评估工作，科学、简捷而又实用。

关键词: 公路桥梁, 承载能力, 构件损伤度, 系统模糊理论, 评定方法