低温下钢-混凝土组合结构疲劳试验和极限承载力

来源期刊：中南大学学报(自然科学版)2004年第6期

论文作者：侯文崎 叶梅新

文章页码：1025 - 1030

关键词：钢-混凝土组合结构;低温;疲劳;极限承载力

Key words：steel-concrete composite structure; low temperature ; fatigue; ultimate capability

摘    要：针对钢-混凝土结合梁在青藏铁路上的应用情况,模拟青藏铁路线的温度环境,用专门研制的低温设备(最低温度能保持在-50℃以下),对由14MnNbq钢构件、直径为22 mm的栓钉(下称φ22栓钉)和强度等级为C50的混凝土组成的钢-混凝土组合件作了低温疲劳试验和极限承载力试验。试验中,考虑了钢板的轧向和环境温度变化等因素对组合件承载力的影响,研究了低温下φ22栓钉的破坏形式,疲劳承载力和极限承载力等问题,并将低温下的试验结果同常温下的试验结果进行了对比。研究结果表明:在同等荷载下,φ22栓钉在-50~0℃的低温环境下疲劳寿命比在室温下的疲劳寿命长,且有温度越低,抗疲劳性能越强的趋势;钢板轧向对栓钉疲劳寿命影响很大,但对栓钉极限承载力没有明显影响;14MnNbq钢材质优良,转变温度低于-50℃。在温度为-50℃时,栓钉焊在14MnNbq钢板上对钢板材质无影响。

Abstract: Aiming at its application in the construction of Qinghai-Tibet Railway (QTR), experiments on the fatigue performance and ultimate capability of steel-concrete composite structures consisting of 14MnNbq steel girders, studs with diameters of 22 mm(i.e.,φ22 studs) and C50 concrete were done in a set of refrigerating apparatus, which was particularly developed to simulate the environmental temperature of QTR and the lowest temperature can be kept at -50℃. Considering the influence of temperature changes and rolled direction of the steel, the destroyed form , fatigue performance and ultimate capability ofφ22 studs under low temperature were well studied through the experiments. And the results got under low temperature were compared with those got under room temperature . The research results show that under the same load level, the fatigue performance of φ22 studs is better under low temperature than that under room temperature, and the lower the temperature is, the better the fatigue performance will be; rolled direction of the steel has great influence on the fatigue life but no evident effect on the ultimate capability of φ22 studs; 14MnNbq has excellent quality, its transition temperature is lower than -50℃, welding studs on 14MnNbq steel girder has no influence on the quality of the girder under -50℃.