沪通长江大桥Q500qE钢的适用性研究

摘要

To meet the construction requirements of Hutong Yangtze River Bridge,the highway-railway cable-stayed bridge with the longest span in the world,the tension,low temperature toughness and antibreaking of QS00qE steel,the processing technology of cutting,welding and heat correcting of distortion,as well as structural safety reserve,fatigue resistance and the stability reduction factor of compression bar were studied from three aspects,including the basic properties of base metal,the manufacturing performance and design parameters.Results show that QS00qE steel has good plasticity and high yield strength.QS00qE steel plate with the thickness of 16 mm and 32 mm has good anti-breaking capacity from 11 to-50 ℃ ambient temperature.The low-temperature fracture resistance of 44 mm and 60 mm thick QS00qE steel plate decreases when the temperature is below-40 ℃.QS00qE steel has good performance of flame cuttingand welding process.Both the apparent and internal quality of butt weld,penetration fillet weld,angle fillet weld and T-shape fillet weld can meet quality requirements.The welding orthopedic temperature of Q500qE steel should not exceed 750 ℃,and the security reserve is equivalent to common steel when the yield strength ratio is less than 0.86.The fatigue design of Q500qE steel structure can use the design index of fatigue resistance in existing codes.The stability reduction factor of QS00qE steel compression bar is recommended based on the research ideas of relevant specifications of various countries and finite element calculation results.%为满足世界上跨度最大的公铁两用斜拉桥——沪通长江大桥的建造要求,从母材基本性能、工厂制造性能和设计参数3个方面研究Q500qE钢的拉伸、低温韧性和防断性能,切割、焊接和热矫形加工性能,以及结构安全储备、疲劳抗力和压杆稳定折减系数.结果表明:Q500qE钢在具有高屈服强度的同时还具有良好的塑性;16和32 mm厚的Q500qE钢板在11～-50℃的环境温度下具有良好的防断能力,44和60 mm厚的Q500qE钢板在低于-40℃时低温防断性能有所降低;Q500qE钢的焰切和焊接工艺性良好,对接焊缝、熔透角焊缝、坡口角焊缝和T形角焊缝的表观和内部质量均能达到质量要求;Q500qE钢的焊接矫形温度不应超过750℃,而且在屈强比不大于0.86时具有与普通钢材相当的安全储备;Q500qE钢结构的疲劳设计可采用现有规范中的疲劳抗力设计指标.基于各国相关规范的研究思路和有限元计算结果给出了Q500qE钢压杆稳定折减系数的推荐值.