摘要
目前我国既有先张台座绝大部分用于生产中小跨径的直线预应力预制梁,其设计特点一般是能承受较大顺预应力方向剪力,但无法抵抗很大倾覆力矩。当生产较高折线预应力梁时,由于预应力合力点升高,台座的倾覆和强度破坏风险增大。基于实际工程提出一种折线预应力施工方案,并与目前常见的2种折线预应力施工方案进行对比研究。研究和工程实践表明,所提方案可有效降低折线预应力在台座处的合力中心,进而减小预应力张拉时在台座上产生的倾覆力矩和柱底弯矩,预应力施工的安全性显著提高。采用所提方案生产的预应力梁的实际上拱度和设计值较接近,能满足工程要求。基于所提方案,预制厂将既有台座用于折线预应力梁生产时,台座改造费用可大幅度减少,具有显著经济效益。
Currently,the majority of existing pretensioning pedestals in China are used for the production of straight prestressed precast beams with medium and small spans.They are generally designed to withstand significant shear forces in the direction of prestress but can not resist large overturning moments.When producing higher zigzag prestressed beams,the risk of overturning and strength failure of the pedestal increases due to the raised center of prestress force.This paper proposes a zigzag prestress construction scheme based on actual engineering projects and conducts a comparative study with two common zigzag prestressing construction schemes.Research and engineering practice show that the scheme proposed in this paper can effectively lower the center of combined forces at the pedestal in zigzag prestressing,thereby reducing the overturning moment and the base bending moment generated on the pedestal during prestress tensioning,significantly improving the safety of prestress construction.The actual camber of the prestressed beams produced using the proposed scheme is closer to the design value,meeting engineering requirements.Based on the scheme proposed in this paper,when precast plants use existing pedestals for the production of zigzag prestressed beams,the cost of pedestal modifications can be significantly reduced,offering notable economic benefits.
作者
刘殿生
魏明光
杨东辉
LIU Diansheng;WEI Mingguang;YANG Donghui(Shanghai Construction Building Materials Technology Group Co.,Ltd.,Shanghai200131,China;Shanghai Municipal Engineering Prefabrication Technology Development Co.,Ltd.,Shanghai200092,China;Dalian University of Technology,Dalian,Liaoning116024,China)
出处
《施工技术（中英文）》
CAS
2024年第12期76-80,共5页
Construction Technology
基金
国家自然科学基金面上项目(52078102)。
关键词
先张法
预应力
台座
力矩
方案
优化
施工技术
pretension method
prestress
pedestals
torque
schemes
optimization
construction
