摘要
采用有限元方法对60m简支预应力混凝土箱梁的收缩应变、徐变应变与混凝土龄期之间的关系,收缩徐变效应对简支箱梁的竖向变形的影响,以及收缩徐变效应引起的预应力损失对简支箱梁的竖向变形的影响进行了研究。研究结果表明,在浇筑结束至龄期100d范围内,收缩徐变应变随龄期增长呈现出线性快速增长态势;龄期超过100d后,应变增大速度逐渐减缓;在混凝土浇筑结束至龄期25d时间范围内,徐变变形随龄期增长呈线性快速增长趋势;随混凝土龄期进一步增长,徐变变形增速减缓;在混凝土浇筑结束至龄期140d范围内,收缩徐变效应导致的预应力损失引起主梁最大下挠2.3mm,龄期达1000d时的主梁下挠最大值为4.0mm。
The finite element method was used to study the relationship between shrinkage strain,creep strain,and the age of a 60m simply supported prestressed concrete box girder.Additionally,the effects of shrinkage and creep on the vertical deformation of the box girder,as well as the impact of prestress loss caused by shrinkage and creep on its vertical deformation,were also examined.The research findings indicate that within a period of 100 days from the end of pouring until the specified age,both shrinkage and creep strains exhibit a linear and rapid growth trend with the increase of the age.However,after surpassing the 100-day mark,the rate of strain increase gradually slows down.In the time span ranging from the end of concrete pouring to an age of 25 days,the creep deformation demonstrates linear and rapid growth with increasing age.As the age of the concrete continues to progress,the rate of creep deformation growth decelerates.Furthermore,during the period of 140 days following the completion of concrete pouring,the prestress loss resulting from shrinkage and creep effects induces a maximum deflection of the main beam at 2.3mm.Subsequently,when the age reaches 1000 days,the main beam exhibits a maximum deflection of 4.0mm.
作者
孙贯拓
赵呈涛
Sun Guantuo;Zhao Chengtao
出处
《城市建筑》
2024年第12期210-212,共3页
Urbanism and Architecture
基金
浙江省自然科学基金项目(LY24E080010)
宁波市交通科技项目(202104)。
关键词
桥梁工程
预应力混凝土
预制箱梁
收缩效应
徐变效应
bridge engineering
prestressed concrete
precast box girder
shrinkage effect
creep effect
