埃塞俄比亚奥莫河大跨度钢桁架桥提载加固研究  

Study of Methods to Improve Load Bearing Capacity of Long-Span Steel Truss Bridge Crossing Omo River in Ethiopia

作　　者：刘迪 李睿[1] 王宗琴 吴艳珍 LIU Di;LI Rui;WANG Zong-qin;WU Yan-zhen(Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming 650504,China;CGCOC Road and Bridge Construction Co.,Ltd.,Kunming 650228,China)

机构地区：[1]昆明理工大学建筑工程学院,云南昆明650504 [2]中地海外路桥建设有限公司,云南昆明650228

出　　处：《世界桥梁》2019年第1期87-91,共5页World Bridges

摘　　要：为满足现有交通量及荷载等级的要求,需对埃塞俄比亚奥莫河上的下承式简支钢桁架桥进行提载加固。大桥全长128m,共16个节间,节间长度为8m,主桁高9m,每个主桁由2个桁架片组成,主桁中心距为9.35m。分别对体外预应力法和增设斜拉索法2种加固方案进行计算分析。计算结果显示:2种加固方案均能满足提载要求。采用体外预应力法加固后,桥梁挠度和下弦杆拉应力有较大改善,且施工简单,成本较低;采用增设斜拉索法加固后,桥梁挠度值和应力值有较大改善,全桥承载力提高比例比体外预应力法高,但对承台、地基承载力和锚固端地质条件要求较高。综合比选,确定采用体外预应力法为现阶段加固方案,增设斜拉索法为远期加固方案。To meet the demands of current transportation volume and load grade,the simply-supported through steel truss girder bridge crossing the Omo River in Ethiopia must be strengthened to improve its load bearing capacity.The bridge is 128 m in full length,consisting of 16 panels each 8 m long.The main truss is 9 m high,and each main truss is formed of two pieces of trusses,the distance between the centers of the two trusses is 9.35 m.The two strengthening schemes were calculated,including the method of using external prestressing and the method of adding stay cables.The results of the calculation show that both schemes can meet the demands of improving the load bearing capacity of the bridge.After being strengthened by adding external prestressing,the deflection of the bridge and the tensile stresses in the lower chord are greatly rectified,the construction is simple and the cost is low.But after strengthened by adding stay cables,the deflection of the bridge and the stresses are greatly rectified,the rate of load bearing capacity improvement is higher than strengthened by adding external prestressing,but with critical demands for the ground condition of the pile cap,ground bearing capacity and the geological condition of the anchoring locations.By comprehensive comparison and selection,the external prestressing method is chosen as the strengthening scheme at present,and for further strengthening in the future,the scheme of adding stay cables will be considered.

关 键 词：钢桁架桥 下承式 提载 加固 体外预应力 增设斜拉索 

分 类 号：U448.211[建筑科学—桥梁与隧道工程] U445.72[交通运输工程—道路与铁道工程]