竖向预应力精轧螺纹钢筋锚具接触刚度识别及其张拉力测试原理

摘要

基于预应力混凝土箱梁桥腹板竖向预应力精轧螺纹钢筋锚固螺母与锚垫板通过接触传递预应力,其法向接触刚度、锚固螺母段抗弯刚度与张拉力存在正比增加关系,建立竖向预应力筋外露段双参数变化的动力学模型,获得锚固螺母与锚垫板法向接触刚度与张拉力的关系式,室内模型试验和多座桥梁现场试验表明其法向接触刚度与张拉力关系具有稳定性.在此基础上提出现场标定法向接触刚度与张拉力关系的方法和现场测试竖向预应力精轧螺纹钢筋张拉力技术路线,并形成测试标准,可彻底解决竖向预应力精轧螺纹钢筋张拉力失效的问题.%Considering that the anchoring force is transferred through the contact between the prestressed anchor and prestressed anchor plate,and the normal contact stiffness and bending stiffness of nuts are in proportion to the anchoring force,a new dynamic model with two parameters is proposed for the exposed section of vertical finishing prestressed reinforced bars,and the relationship between the normal contact stiffness and the anchoring force is established.The test results of indoor model tests and field tests show that there is a stable linear relationship between the normal contact stiffness and the anchoring force.In additional,the standard method to obtain the relationship curve and the site operation to test the anchoring force on site are provided,which means the problem of tension failure of vertical finishing prestressed reinforced bars can be solved completely.