连续刚构箱梁悬臂浇筑节段混凝土裂缝成因及控制研究  

Research on the Causes and Control of Concrete Cracks in CantileverCasting Segment of Continuous Rigid Frame Box Girders

作　　者：戴利平 Dai Liping(Yuhang Traffic Construction Group Co.,Ltd.,Hangzhou 311100,China)

机构地区：[1]宇航交通建设集团有限公司,杭州市311100

出　　处：《北方交通》2023年第7期24-29,共6页Northern Communications

摘　　要：以某跨河特大桥连续刚构混凝土箱梁悬臂浇筑第24、第25节段为依托,通过建立有限元模型,模拟不同养护方式、不同环境温度、不同环境风速下混凝土主拉应力的变化趋势。研究结果表明:在其他条件相同时,采用复合养护方式的混凝土箱梁主拉应力明显减小;外界环境温度与混凝土浇筑温度的温差越小,混凝土温度梯度越小、主拉应力越小,混凝土的开裂较少;随着环境风速的增大,混凝土内外部温度差变化明显,箱梁主拉应力增大明显,混凝土开裂面积明显增加。通过模拟实验与工程验证,对于连续刚构箱梁混凝土浇筑,建议采用复合式养护方式,同时采取降低前后节段浇筑的时间间隔、薄膜覆盖减少混凝土内外部温度差、增加防风围挡等措施,可以有效减少裂缝。Based on the cantilever pouring of the 24th and 25th segment of a continuous rigid frame concrete box girder of a river-crossing super large bridge,the variation trend of the main tensile stress of concrete under different curing methods,environmental temperature,and environmental wind speed is simulated by establishing the finite element model.The research results show that:under the same other conditions,the main tensile stress of concrete box girders treated with composite curing method significantly decreases;the smaller the temperature difference between the external environmental temperature and the pouring temperature of concrete,the smaller the temperature gradient of concrete,the smaller the main tensile stress,and the less the concrete crack;with the increase of environmental wind speed,the temperature difference inside and outside the concrete changes significantly,the main tensile stress of the box girder increases significantly,and the concrete crack area increases significantly.Through the simulation experiments and engineering verification,it is recommended to adopt a composite curing method for the pouring of continuous rigid frame box girder concrete.At the same time,measures such as reducing the time interval between the pouring of the front and rear segment,adopting the film coverage to reduce the temperature difference between the inside and outside of the concrete,and adding wind barriers are adopted,so as to effectively reduce cracks.

关 键 词：连续刚构 箱梁 悬臂浇筑 混凝土 裂缝控制 

分 类 号：U455.7[建筑科学—桥梁与隧道工程]