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先张法折线预应力施工优化方案研究

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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.
Optimization Scheme for the Zigzag Prestressing Construction with Pretension Method
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.

pretension methodprestresspedestalstorqueschemesoptimizationconstruction

刘殿生、魏明光、杨东辉

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上海建工建材科技集团股份有限公司,上海 200131

上海市政预制技术开发有限公司,上海 200092

大连理工大学,辽宁 大连 116024

先张法 预应力 台座 力矩 方案 优化 施工技术

2024

施工技术(中英文)
亚太建设科技信息研究院 中国建筑设计研究院 中国建筑工程总公司 中国土木工程学会

施工技术(中英文)

影响因子:1.244
ISSN:2097-0897
年,卷(期):2024.53(12)