桥梁人行道锚固系统加固试验研究  

Testing and research analysis of strengthening sidewalk anchoring system on railway concrete bridge

作　　者：王春芬[1] 陈兴冲[2] 商跃进[3] 丁明波[2] 

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]兰州交通大学土木工程学院,甘肃兰州730070 [3]兰州交通大学机电工程学院,甘肃兰州730070

出　　处：《兰州交通大学学报》2004年第1期15-18,共4页Journal of Lanzhou Jiaotong University

摘　　要：U型螺栓是铁路混凝土桥梁人行道托架系统的唯一锚固装置.在使用过程中,一些螺栓出现了断裂现象,导致步行板坠落桥下.现场振动测试表明,过桥列车对人行道系统的振动存在放大效应.对螺栓的断口进行微观形貌分析后,发现螺栓具有明显的疲劳断裂特征.结合试验分析,在对U型螺栓进行了疲劳强度评估的基础上,提出了改进螺栓设计的意见,并设计了在挡碴墙上锚固钢板条进行锚固系统加固的方案,以降低螺栓疲劳应力幅、延长使用寿命.试验室足尺模型疲劳试验对加固效果进行了验证.The Ubolt is the only holdingdown part for the pedestrian steel truss system anchored along with concrete railway bridge beam. The diameter of the Ubolt is designed according to static stress method. The damage of the Ubolt causes walk slabs on the steel truss falling off the bridges and this threatens the security of the workers walking on the slab and the people passing under the bridge. The vibrating test is executed on those bridges. The results show that it is the train moving on the bridge rapidly that amplifies the vibration of the pedestrian steel truss system and causes the bolts under fatigue load. All of the fracture planes of the bolts collected under those bridges are of fatigue characteristic through scanning electron microscope. The fatigue strength and life of the Ubolts in service are evaluated and some improving methods are also proposed for the future design of Ubolts in this paper. A repair method for the pedestrian anchor system is proposed to ensure the people walking on the slab, which is after welding a steel bar with the truss.The bar is anchored on the slag notch with other two bolts. This will reduce the stressrange of fatigue of the Ubolts and its service life will be prolonged. The fullscale fatigue experiment of the anchor system after reinforcing construction is executed in the lab. The strengthening method employing steel bar to strengthen the pedestrian anchoring system will make it more reliable and satisfy the need of railway maintenance.

关 键 词：桥梁工程 人行道锚固系统 加固试验 振动测试 U型螺栓 疲劳强度评估 

分 类 号：U445.72[建筑科学—桥梁与隧道工程]