混凝土现浇箱梁超长单端张拉法预应力损失分析  

Analysis on prestress loss of ultra-long single-end tension prestressed concrete cast-in-situ box girder

作　　者：彭闵敏 王洪杰 刁宇 宋发达 Peng Minmin;Wang Hongjie;Diao Yu;Song Fada(Power China Sinohydro Bureau 7 Co.,Ltd.,Chengdu 610000,China)

机构地区：[1]水利水电第七工程局有限公司,四川成都610000

出　　处：《山西建筑》2022年第16期162-166,共5页Shanxi Architecture

摘　　要：为了研究在施工过程中预应力张拉方法和张拉次序对现浇预应力混凝土箱梁受力的影响,以成都市火车北站扩能改造配套市政工程主线桥预应力混凝土箱梁超长预应力张拉项目为例,采取有限元计算分析,研究不同张拉方式和张拉次序下有效预应力的变化。分析结果表明:当预应力筋长度小于30 m时,单端张拉和双端张拉两种施工方式导致的预应力损失差别不大,有效预应力基本保持一致。当预应力筋长度达到80 m,单端张拉的预应力损失大于双端张拉,单端张拉锚固端的有效应力约为采用双端张拉时有效应力的0.85,且预应力钢束平弯转角越大,预应力丧失也就越多。同时张拉次序不同时,预应力损失也随之改变,需要进行设计计算来明确影响量以保证足够的安全储备。In order to study the influence of prestressed tension mode and tension order on the stress of the bridge during the construction of prestressed cast-in-situ concrete box girder,taking a municipal road prestressed concrete box girder bridge as the analysis object,the finite element calculation and analysis is carried out by using the numerical simulation method to study the change of effective prestress when the tension mode and tension order are different.The analysis results show that when the length of prestressed reinforcement is less than 30 m,the difference of prestress loss caused by single end tension and double end tension is not obvious,and the effective prestress is basically the same.When the length reaches 80 m and the prestress tension mode is changed from double end tension to single end tension,the prestress loss at the fixed end is much greater than that at the tension end.The effective stress at the fixed end of single end tension is about 0.85 of the effective stress at the fixed end when double end tension is adopted,and the greater the horizontal bending angle of prestressed steel tendon,the more prestress loss.At the same time,when the tension order is different,the prestress loss also changes.It is necessary to determine the specific impact through detailed calculation and analysis to ensure sufficient safety reserve.

关 键 词：单端张拉 箱梁 有效预应力 预应力损失 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]