Research on The Slip-Resistant Joints of Bridge with Corrosion Resistance Surfaces

本研究研究了具有耐腐蚀表面的防滑接头在持续荷载（1年）和短时间静荷载作用下的性能。主要是将热浸镀锌表面与金属锌表面一起进行测试，也使用未处理的表面作为对照。试验变量为镀锌层的厚度、螺栓等级、螺栓的镀锌程度和扭矩后的运行时间。研究得出的主要结论如下：(1)未处理和镀锌表面在加载后1 ~ 7天内，持续荷载作用下剪切蠕变位移（约为设计节点刚度的一半）达到恒定值。对于热镀锌表面，前2周（初蠕变）与时间的对数成正比，然后以等速增加（二次蠕变），最后在1年后达到恒定值。(2)在对数尺度上，螺栓张力随时间的流逝成比例地减小。一个月后，与初始螺栓张力相比，未处理表面螺栓张力损失为9%，热镀锌表面螺栓张力损失为11-16%，镀锌表面螺栓张力损失为19%。(3)摩擦系数（发生滑移的载荷与螺栓实际张力的比值）在未处理表面保持恒定值，但在热镀锌和金属化锌表面有增加的趋势。

This research studied the behavior of slip-resistant joints with corrosion resistance surfaces under a sustained load (1 year) and a short-duration static load. Mainly, hot-dip galvanized surfaces were tested together with zincmetallized ones, and as a comparison non-treatment ones were used too. The test variables were thickness of the galvanized coating, bolt grade, galvanizing of bolt and elapsed time after torquing.The main conclusions derived from this study can be summarized as follows:(1) The shear creep displacement under sustained load (about half the design joint stiffness) came to a constant value within 1-7 days after loading for the non-treatment and the zinc-metallized surfaces. For hot-dip galvanized surfaces, it was in proportion with the logarithmic value of elapsed time for the first 2 weeks (primary creep) and then increased at a constant speed (secondary creep) and finally reached a constant value after a year.(2) The bolt tension decreased in proportion to elapsed time on a log scale. After a month,the loss in bolt tension was 9% for the non-treatment surfaces,11-16% for the hot-dip galvanized ones and 19% for the zinc-metallized ones as compared to the initial bolt tension.(3) The coefficient of friction (the rate of the load at which slip occurred compared to the real bolt tension) kept a constant value for the non-treatment surfaces but had a tendency to increase in the case of hot-dip galvanized ones and zinc-metallized ones.