Abstract: The web cracks of box girder usually appear in the 0 block of continuous rigid frame bridge． According to location， direction and distribution of the web crack at L/4 section of box girder of a bridge in Chongqing，this paper analyzes the causes of the appearance of crack and the development of crack on the basis of on－site construction work． It is indicated that the pouring time difference between the former segment and the latter segment is the main cause for crack formation and development．

Key words: web plate crack, cause, analysis

摘要： 连续刚构桥梁箱梁腹板裂缝大多出现在0号块的腹板上，在跨中出现腹板裂缝的较少。根据重庆某大桥箱 梁L/4截面处出现的裂缝位置、走向及分布，结合现场施工情况分析了裂缝形成和发展的原因，认为前后现浇节段 的浇注时间相差过大是裂缝发生的主要原因之一。

关键词: 腹板裂缝, 成因, 分析