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抗滑节点在持续载荷(1年)和短期静载荷作用下的性能。主要对热镀锌表面和镀锌表面进行了测试，并与未处理的表面进行了对比。试验变量为镀锌层厚度、螺栓等级、螺栓镀锌以及扭转后的时间。本研究的主要结论如下：(1)加载后1-7天，未处理表面和镀锌表面的剪切蠕变位移在加载后1-7天内趋于恒定值。对于热镀锌表面，螺栓张力在最初的2周(一次蠕变)与时间的对数成正比，然后以恒定的速度增加(二次蠕变)，一年后达到恒定值。(2)螺栓张力在对数尺度上与时间成正比下降。一个月后，未处理表面的螺栓张力损失为9%，热镀锌表面为11-16%，镀锌表面为19%。(3)摩擦系数(滑动载荷与螺栓实际张力的比率)在未处理表面保持不变，但在热镀锌表面和镀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.