既有桥墩扩大截面加固混凝土开裂原因分析  

Analysis on Cracking Causes of Concrete Reinforcement by Expansion Section of Existing Bridge Piers

作　　者：马晓可 林丽军 张志国 Ma Xiaoke;Lin Lijun;Zhang Zhiguo(School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;China Construction Transportation Construction Group Co.Ltd.,Beijing 100071,China)

机构地区：[1]石家庄铁道大学土木工程学院,河北石家庄050043 [2]中建交通建设集团有限公司,北京100071

出　　处：《石家庄铁道大学学报（自然科学版）》2022年第3期50-57,共8页Journal of Shijiazhuang Tiedao University(Natural Science Edition)

基　　金：中建股份科技课题(CSCEC-2020-Z-22)。

摘　　要：针对大莱龙铁路海港路中桥桥墩加固混凝土开裂问题,结合裂缝分布特征,对可能引起开裂的因素进行分析。采用有限元分析方法对加固混凝土水化热温度与应力进行了模拟计算。结果表明,加固混凝土表面拉应力分布以及超限情况与实际裂缝分布较为吻合,验证了开裂的必然性,其中水化热温差以及加固混凝土复杂的截面形状、不同的厚度变化应该是造成开裂的主要原因。另外,新旧混凝土收缩差异和环境温度变化也会起到综合影响,加固混凝土终凝前列车过桥产生的动力效应对已有裂缝延展具有促进作用,也是不利的影响因素。研究为采取针对性的措施,避免开裂事故的发生具有一定的参考意义。Aiming at the cracking problem of bridge pier reinforced concrete in Haigang Road of Dalailong Railway,combined with the distribution characteristics of cracks,the factors that may cause cracking were analyzed.The finite element analysis method was used to simulate the hydration heat temperature and stress of reinforced concrete.The results show that the distribution of tensile stress on the surface of reinforced concrete and the overrun situation are consistent with the actual crack distribution,which verifies the inescapability of cracking.The temperature difference of hydration heat,the complex cross-section shape of reinforced concrete and the change of different thickness should be the main reasons for cracking.In addition,the shrinkage difference between old and new concrete and the change of ambient temperature also have a comprehensive impact.The dynamic effect of the train passing through the bridge before the final setting of the reinforced concrete has a promoting effect on the extension of the existing cracks,which is also an adverse factor.This study has certain reference significance for taking targeted measures to avoid cracking accidents.

关 键 词：桥墩 加固混凝土 裂缝 有限元分析 水化热 

分 类 号：U44[建筑科学—桥梁与隧道工程]