摘要
沪通长江大桥主航道桥为(142+462+1 092+462+142)m钢桁梁斜拉桥,桥塔墩基础采用沉井基础,其中28号墩钢沉井顶平面尺寸为86.9m×58.7m,高44m。28号墩钢沉井在船坞内制造完后整体浮运至桥址处,浮运总重达14 500t。为合理地配置浮运拖轮,确保浮运顺利,采用理论方法、数值模拟方法和物模试验方法对钢沉井浮运阻力进行计算。经过对比分析,经首尾形状修正的《海上拖航指南》方法计算结果与数值模拟和物模试验结果相近似,适用28号墩钢沉井浮运阻力计算。通过计算,在钢沉井吃水8m、风速6级、对水速度2.5m/s时,钢沉井纵向拖航的总阻力为2 167kN;采用"7+1"8艘(1艘备用)拖轮的配置模式进行拖航作业,有效输出拖力(3 060kN)>拖航最大总阻力(2 326.74kN),满足钢沉井浮运要求。
The main navigational channel bridge of Hutong Changjiang River Bridge is a steel truss girder cable-stayed bridge with span arrangement of（142＋462＋1 092＋462＋142）m.The foundations of the pylon piers adopt caisson foundations,among which the top plan dimension of steel caisson of pier No.28 is 86.9 mby 58.7 m,and 44 m high.The steel caisson for the pier No.28 was fabricated in a dock and then transported to the bridge site by floating,with a total floating weight of up to 14 500 t.To rationally allocate the floating tugboats and assure smooth floating,the theoretical method,numerical simulation method and physical model testing method were used to calculate the floating resistance of the steel caissons.Based on the comparative analysis,by modifying the head and end shapes of the boats,the results gained by using the method presented in the Guidelines for Towage At Sea is approximate to those gained respectively by numerical simulation and physical model testing,which is proved applicable to the floating resistance calculation for the steel caisson of pier No.28.It is proposed by calculation that the steel caissons have a draft of 8m,when the wind speed is at Grade 6,and the tugboat′s speed through water is 2.5m/s,the total resistance for a steel caisson is 2 167 kN under the condition of longitudinal towing.The arrangement of the tugboats adopts the＂7＋1＂mode,namely one used as a backup tugboat,the efficient output towing force is 3 060 kN,and the maximum resistance of the towing is 2326.74 kN,satisfying the floating requirements of the steel caisson.
出处
《世界桥梁》
北大核心
2015年第6期79-82,共4页
World Bridges
基金
中国铁路总公司科技研究开发计划项目(2013G001-A-2)
关键词
斜拉桥
钢沉井
浮运阻力
水流力
理论方法
数值模拟
物模试验
拖轮
cable-stayed bridge
steel caisson
floating resistance
water flowing force
theoretical method
numerical simulation
physical model testing
tugboat
