西部横断山区强降温气候条件下桥塔温度效应及抗裂性能优化研究  被引量：2

作　　者：黄旭 朱金 李永乐[1] 张明金[1] HUANG Xu;ZHU Jin;LI Yongle;ZHANG Mingjin(Department of Bridge Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学桥梁工程系,四川成都610031

出　　处：《防灾减灾工程学报》2022年第2期310-319,339,共11页Journal of Disaster Prevention and Mitigation Engineering

基　　金：中央高校基本科研业务费(2682021CX012);国家自然科学基金青年基金(51908472)资助。

摘　　要：在强降温极端气候条件下,桥塔混凝土表面存在开裂风险。为此,以我国西部横断山脉地区某大跨悬索桥为工程背景,开展了强降温气候条件下桥塔温度效应及抗裂性能优化研究。首先,提出了桥址区极端天气的识别与模拟方法,并验证了所提模拟方法的有效性。随后,建立桥塔节段的3D有限元模型,分析了强降温极端天气下混凝土桥塔的温度场以及温度应力分布特征。最后,针对强降温极端天气下混凝土桥塔外表面存在开裂风险的问题,提出了两种桥塔混凝土表面抗裂优化方法,并通过参数分析给出了本例桥塔的最优参数。研究结果表明:在强降温天气下,当不考虑任何抗裂优化措施前,桥塔表面拉应力极值为2.06 MPa,存在较大开裂风险;当采用抗裂优化措施后,提出的两种措施均能有效降低混凝土桥塔表面的拉应力极值。通过参数分析发现,采用有机涂料涂装桥塔表面的优化方法时,白色有机涂料的优化效果最佳;当采用桥塔表面覆盖UHPC的优化方法时,其厚度为0.04 m时优化效果最佳。The concrete bridge pylon may be at risk of surface cracking under strong cooling weather conditions. In view of this,a study on thermal-induced effect and anti-crack performance optimization of bridge pylon under strong cooling weather conditions is carried out,taking a long-span suspension bridge in the Hengduan Mountain Region of Western China as an engineering background. Firstly,an approach is proposed to identify and simulate the strong cooling weather scenario at the location of the prototype bridge through analyzing the in-situ historical meteorological data. Secondly,a 3D finite element(FE)model of the bridge pylon segment is developed. The established FE model enables the investigation into the characteristics of the temperature field and the temperature induced stress of the bridge pylon under various strong cooling weather scenarios. Lastly,two anti-crack measures are proposed to mitigate the risk of surface cracking of the bridge pylon under strong cooling weather conditions. Parametric studies are also conducted to seek the optimum parameters of the two proposed anticrack measures for the prototype bridge pylon. The simulation results show that the surface of the concrete bridge pylon without any anti-crack measures undertakes tensile stress up to 2.06 MPa,indicating there may exist a risk of surface cracking. After employing the two proposed anti-crack measures,the tensile stress at the surface of the bridge pylon reduces significantly. In addition,according to the parametric study on the two anti-crack measures,it is found that the white organic coating of the first anti-crack measure has the best performance,and the UHPC(Ultra-High-Performance Concrete)with a thickness of 0.04 m of the second anti-crack measure is the best.

关 键 词：桥塔 横断山区 强降温气候 温度效应 抗裂性能优化 

分 类 号：U443.22[建筑科学—桥梁与隧道工程]