日本钢桥高强度螺栓病害处治与新型螺栓研究

Remedial Measures for High-Strength Bolts Deterioration and Research on Novel-Type Bolts for Steel Bridges in Japan

高强度螺栓连接是日本钢结构桥梁常用的连接形式,对日本钢桥用高强度螺栓病害处治措施及新型螺栓研发应用进行介绍。结合日本2座钢结构桥梁工程实例,对高强度螺栓断裂、掉落和索夹螺栓轴力减小等病害原因进行分析,为确保桥梁安全运营,对全部螺栓进行了补拧与更换。针对螺栓生锈、腐蚀,开发了新型防腐涂层材料SZ工法,该工法选择锌作为高强度螺栓表面的牺牲防腐保护膜,试验及应用结果表明防腐效果较好。延迟断裂是高强度螺栓常见病害,研发了耐延迟断裂优质钢及螺栓,改善耐氢脆化特性,并在此基础上研发了超高强度高可靠性(FS)螺栓,室外暴露试验证明,FS螺栓具有优越的耐延迟破坏性能。针对钢桥面板连接接头处凹凸不平现象,开发了高强度沉头螺栓,并在实际工程中应用。

In Japan,the steelworks in bridges are conventionally connected by using high-strength bolts.The Japanese experiences in remedying high-strength bolts deterioration as well as research and development of novel-type bolts are introduced.Based on the engineering practices of two steel bridges,the causes of various deteriorations of high-strength bolts,such as breaking,stripping and axial force loss,were analyzed.To ensure the safe operation of the two bridges,bolts have been either tightened or replaced.To address the bolt corrosion issue,the SZ method that uses an innovative anti-corrosion coating is proposed.In this method,zinc is employed to form a sacrifice anti-corrosion protective membrane on the surface of high-strength bolts.Tests and implementation on real bridges proved the efficiency of the method.To deal with the delayed fracture of high-strength bolts,which is a common deterioration found in high-strength bolts,the high-quality steel that has better hydrogen embrittlement resistance is developed,on the basis of which,the super high-strength and high-reliability(FS)bolts are produced.The outdoor exposure testing proved that the FS bolts have superior delayed fracture resistance.It is often hard to make evenly-flat joints between deck plates,to deal with the issue,the high-strength countersunk bolts are researched,which has already been used in real bridges.