摘要
为研究界面粗糙度、新混凝土减缩剂掺量、玄武岩纤维掺量等因素对新老混凝土收缩性能的影响,制作新老混凝土组合试件,采用变形测定仪观测试件收缩情况。依托某市政预应力混凝土箱梁桥项目建立桥梁上部结构有限元模型,分析加固后结构应力情况。研究认为:(1)随着新老混凝土界面粗糙度增大,结构整体收缩率下降,但幅度有限;(2)随着减缩剂掺量增大,试件收缩率减小,减缩剂掺量从0提升至4%,收缩率下降27.13%;(3)随着玄武岩纤维掺量增大,试件收缩率减小,纤维掺量从0提升至6kg/m^(3),收缩率下降46.59%。根据有限元模拟结果,采用界面粗糙度2.5~3.0mm、减缩剂掺量2%、玄武岩纤维掺量6kg/m^(3)的加固方案,最大收缩应力和剪切应力均可满足新老结构的粘结与抗拉要求。
In order to study the influence of factors such as interface roughness,content of shrinkage reducing agent in new concrete,and content of basalt fiber on the shrinkage performance of new and old concrete,composite specimens of new and old concrete are made,and the shrinkage of the specimens is observed by using the deformation tester.Based on the municipal prestressed concrete box girder bridge project,the finite element model of the upper structure of the bridge is established,and the stress situation of the reinforced structure is analyzed.The research shows that:(1)As the roughness of the interface between new and old concrete increases,the overall shrinkage rate of the structure decreases,but the magnitude is limited.(2)As the content of the shrinkage reducing agent increases,the shrinkage rate of the specimen decreases.When the content of the shrinkage reducing agent increases from 0 to 4%,the shrinkage rate decreases by 27.13%.(3)As the content of basalt fiber increases,the shrinkage rate of the specimen decreases.When the fiber content increases from 0 to 6kg/m^(3),the shrinkage rate decreases by 46.59%.According to the finite element simulation results,the reinforcement scheme with interface roughness of 2.5~3.0mm,content of shrinkage reducing agent of 2%,and basalt fiber content of 6kg/m^(3)is adopted,so as to meet the bonding and tensile requirements of both new and old structures in terms of maximum shrinkage stress and shear stress.
作者
上官渤麒
Shangguan Boqi(Shanxi Jiaotou High-tech Expressway Management Co.,Ltd.,Jincheng 048300,China)
出处
《北方交通》
2025年第8期15-18,23,共5页
Northern Communications
关键词
桥梁
加固
新老混凝土
收缩
受力分析
Bridge
Reinforcement
New and old concrete
Shrinkage
Force analysis
