摘要
某大型公铁两用长江大桥的钢桁梁经过20多年的超负荷运营,公路桥面系出现了桥面板破损、钢横联工字形钢横梁腹板开裂等病害。经检测,大桥桁架整体受力良好,仅对上层公路桥面系进行加固改造。预先搭设铁路防护平台,保证了改造期间公路桥下方的铁路正常运行,同时为公路桥面系横联及正桥托架改造提供施工平台。公路桥面系采用与原结构受力体系相似的正交异性钢桥面板,在保证公路桥面通行活载提高到公路-Ⅰ级后,上层公路桥面系活载与恒载之和较改造前小,为后期下层铁路提速、提载预留了足够富余量。为适应公路活载提高的需要,对主桁外侧托架、内侧横联进行了加肢、更换杆件等局部加固补强设计。
After more than two-decade operation,the road deck of a long-span rail-cum-road Changjiang River bridge has displayed the deteriorations like deck slab damage and steel cross beam cracking.The inspection showed that the integral load bearing capacity of the steel truss is in good condition,the job needed to do was to strengthen the upper road deck.A railway protection platform was erected beforehand to ensure the normal operation of the railway under the road deck during the renovation period,as well to act as a construction platform for the renovation of the lateral bracings and main bridge brackets of the upper road deck.After the scheme comparison,the orthotropic steel bridge deck that has the similar load bearing system of the original structure was chosen as the new road deck,to ensure that the live load of the upper road deck can be improved to the level of highway gradeⅠ,the total amount of the live and dead loads of the upper road deck is smaller than that before renovation,so as to provide enough margin for the speed acceleration and improvement of the load bearing capacity of the lower railways.To meet the demands of the enhancement of the road live loads,the external brackets and inner lateral bracings of the main truss were locally strengthened by adding struts and replacing some members.
作者
吴晓亮
刘华
WU Xiao-liang;LIU Hua(China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan 430050,China;China Railway Major Bridge(Nanjing)Bridge&Tunnel Diagnosis&Remedial Co.,Ltd.,Nanjing 210015,China)
出处
《世界桥梁》
北大核心
2018年第2期84-88,共5页
World Bridges
关键词
公路铁路两用桥
公路桥面系
改造设计
防护平台
正交异性钢桥面板
钢横梁
托架
rail-cum-road bridge
road deck
renovation design
protection platform
orthotropic steel deck plate
steel cross beam
bracket
