预应力混凝土连续箱梁桥混凝土疲劳应力限值研究

The stress limit value for fatigue of concrete in prestressed concrete continuous box-grider bridge

大量预应力混凝土连续箱梁桥在服役期内发生腹板斜裂缝病害,引发了研究人员对于混凝土疲劳应力问题的探讨.结合中国的预应力混凝土桥涵设计规范与混凝土结构设计规范(GB50010-2002)、英国BS EN1992-1-1混凝土设计细则、欧洲CEB-FIP MC1990规范和美国AASHTO 2004规范关于混凝土疲劳应力验算的规定,对混凝土疲劳应力验算方法进行了比较.并以某预应力混凝土连续箱梁桥为例,对各规范中混凝土疲劳验算的具体过程进行了计算与分析,验证了规范的合理性以及适用性.分析结果表明,中国规范的疲劳应力限值较国外规范偏高.在对构件进行疲劳设计时,推荐采用CEB-FIP规范提供的验算方法.

What the incline cracks had been found on many prestressed concrete continuous box girder bridges in service period has made researcher to considering fatigue assessment of prestressed concrete component. Chinese concrete structure design code （GB50010-2002）, British Standard＇s design of concrete structures （BS EN 1992-1- 1）, CEB-FIP Model Code of Europe and AASHTO LRFD Bridge Design Specifications （Third Edition） have been checked and the thoughts of the fatigue assessment of concrete have been compared in all codes. Taking a prestressed concrete continuous box girder for an example, which the specific process of concrete fatigue assessment is calculated and analyzed in all codes. And the rationality and applicability of the ideas involved in all codes have been verified. Finally, the fatigue stress limit value of our nation is higher than other codes. Therefore, the way mentioned in CEB-FIP code has been suggested when the fatigue of component is designed.