重庆朝天门长江大桥高强度螺栓群栓试验研究

针对重庆朝天门长江大桥拼装式节点板层多、板束厚度大、外形尺寸变化大及单个节点高强度螺栓数量多等特点,结合重庆地区气侯条件、该桥设计采用的抗滑移摩擦面技术参数和目前国内高强度螺栓连接副的性能,选取具有代表性的不同板厚组成的板束,通过压力传感器及静态应变系统进行了群栓模拟试验。通过群栓试验,了解了高强度螺栓预拉力随时间变化的损失情况,螺栓施拧先后顺序对栓群预拉力的影响,用终拧扭矩值的50%作为厚板的初拧扭矩时板束密贴情况,确定了高强度螺栓终拧扭矩检查时机,验证了该工程高强度螺栓施拧工艺的可操作性。该试验研究为今后类似工程的施工提供了宝贵的数据和经验。

Experiment and Study of High-strength Cluster Bolts for Yangtze River Bridge at Chaotianmen, Chongqing

Chongqing Chaotianmen Yangtze River Bridge is characterized by many assembled node layers,great thickness of plate bundle,great change in outer detention and many high strength bolts in each separate node,etc.Combining with the climatic conditions of Chongqing,the technical parameters of skid resistant rubbing surface used in the design of the bridge,and the performance of the connections of high strength stud bolts in domestic at present,choosing a representative plate bundle,which is made up of different thickness of plates,the simulation tests for bolt group is carried through the pressure transducer and static strain system.Through the test,it is realized that the loss situation for the pre-tension of the high strength bolt changes with time,the effect on the pre-tension of bolts group by the tightening sequence of bolts,50 % of the twisting torque value as the closing contact situation of thick plate group at the initial twisting torque,the time to check the final twisting torque of high strength bolts is ensured,and the operability of the technology for twisting the high strength bolt is verified.The experimental research provides valuable data and experiences for other similar projects.