摘要：预应力混凝土连续箱形梁桥由于具有结构轻盈、抗弯、抗扭性能优良等众多优点，在桥梁建设中得到了广泛的应用。但这些桥梁在修建过程中和运营过程中，有时会发现梁体不同部位出现横向、纵向和斜向等裂缝。裂缝一旦出现，轻则影响结构的耐久性，重则直接影响结构的承载能力，甚至危及结构的安全。对此，应予以重视，弄清裂缝产生的原因，采取措施预防裂缝发生。本文作者对连续梁箱梁桥裂缝成因进行了分析总结，归纳研究出裂缝大致种类及形成因素，并针对性地提出了预防和控制裂缝的措施，以供参考。

关键词：预应力连续梁裂缝分析防治措施

Abstract: Due to its multiple advantages of light structure, bend resistance, torsion resistance, and so on, the prestressed concrete continuous box girder bridge has been widely used in bridge construction. However, in the construction and operation process, transverse crack, longitudinal crack and diagonal crack has occurred in the bridge sporadically. Crack once appearing, the light will affect the durability of the structure, and the serious will directly affect the bearing capacity, and even the safety of the structure, to which should be paid attention, finding out the causes and taking measures to prevent the cracks. In this paper, the author makes an analysis on the causes of the cracks in continuous box girder bridge, concludes the categories and causes of the cracks, and proposes the prevention and control measures, for reference.

Key words: prestress; continuous girder; crack analysis; prevention and control measure

一、顶底板纵向裂缝

纵向裂缝是主要的裂缝类型。裂缝是由于顶板横桥向拉应力过大造成的。在恒载、活载和温度荷载的作用下，都会产生横桥向拉应力。

1.沿后张法预应力孔道的裂缝

这种裂缝一般都出现在顶底板布置预应力束最薄处及预应力管道距混凝土表面最近的预应力束处。当混凝土板受力弯曲时，就易产生纵向裂缝。

防治措施：合理地布置预应力束，严格按设计安设锚头，减少施工误差。要使预应力管道尽量靠近腹板，有足够的混凝土层，管道间的距离不能过小，至少应保持18~20cm。从统计来看，板厚小于波纹管直径3倍时常会出现劈裂缝。在混凝土板内上下层钢筋之间设置足够的抗拉锚筋，可避免经向崩裂，抗拉锚筋虽不属结构钢筋但决不可忽视。下载本文