埃及中央商务区项目大跨钢连廊施工方案研究与实施

Research and Implementation of Construction Plan for Long-Span Steel Corridor in Egyptian CBD Project

近年来,大跨高空连体钢结构被广泛应用在各类复杂的大型公共建筑中,例如北京央视新总部大楼、重庆来福士广场、新加坡滨海湾金沙酒店等,其施工复杂,难度大。埃及新行政首都中央商务区中区酒店项目设计采用了高空大跨度钢结构连廊的形式,连廊平面呈圆弧形,共2层,一层高9.0 m,二层高6.5 m,外弧最大跨度为43 m,宽为24 m,钢结构总质量约600 t。根据钢结构连廊特点,结合国内外大跨度高空连体钢结构施工方法经分析提出了两种施工吊装方案:方案1采取“分片吊装、高空连接”的方式,在地面分片安装完成后,按照合理的顺序分片吊装,并在空中完成整体连接;方案2采取“高空悬臂散装”方式,同时从两端支座位置开始逐根吊装钢桁架构件,并于跨中位置对接合龙,形成空间桁架。综合考虑工期要求、成本要求、质量要求、安全性要求以及属地工人能力等因素,确定采用方案1“分片吊装、高空连接”的施工方法。通过施工过程数值模拟法对方案1进行计算分析,结果表明,钢结构安装过程中主体桁架竖向位移和构件应力比均很小,吊装顺序合理,侧向支撑有效,可以满足施工过程中钢构件稳定性和施工精度控制的要求,方案可行。同时,为了确保施工过程中的安全和质量,采取了多项关键控制措施,如采用大型履带吊保证吊装过程安全、设置临时支撑保证施工过程中构件稳定、设置可调节式拉杆控制构件水平度、严格控制每天作业时间以避免温差影响安装精度等。

In recent years,long-span high-altitude conjoined steel structures have been widely used in various complex large-scale public buildings,such as the new headquarters building of CCTV in Beijing,Raffles City in Chongqing,and the Marina Bay Sands Hotel in Singapore,of which the construction methods are very complex and difficult.For the design of the hotel in the Central Business District(CBD)project in the new administrative capital of Egypt,the form of a high-altitude long-span steel structure corridor was also adopted.The steel structure corridor plane is arc type,a total of 2 layers,the height of the first layer is 9.0 m,the height of the second layer is 6.5 m,the maximum span of the outer arc is 43.0 m,the width is 24.0 m.The total weight of the steel structure corridor is about 600 t.According to the characteristic of steel structure corridor,and combined with domestic and foreign long-span high-altitude conjoined steel structures construction methods,two construction hoisting schemes were proposed according to the characteristics of the steel structure corridor.Scheme 1 adopts the method of“segmented hoisting and high-altitude connection”.After installation completed on the ground,the fragments are hoisted in a reasonable order and the overall connection is completed in the air.Scheme 2 adopts the method of“high-altitude cantilever bulk installation”.The steel truss members are hoisted one by one at the end support position,and are butted together at the mid-span position to form a space truss.Comprehensively considering factors such as construction period requirements,cost requirements,quality requirements,safety requirements,and the ability of local workers,the construction method of Scheme 1 was proposed.The construction process simulation method was used to calculate and analyze Scheme 1.The results show that the vertical displacement of the main truss and the component stress ratio are small during the installation of the steel structure,the hoisting sequence is reasonable,and the lateral support is effective,which can meet the requirements of steel component stability and construction precision control during the construction process.The feasibility of the scheme has been verified.At the same time,in order to ensure the safety and quality of the construction process,a number of key control measures have been adopted.Super crawler crane was used to ensure the safety of the hoisting process;temporary supports were set to ensure the stability of components during the construction process;and adjustable tie rods were set to control the levelness of components;it set strict control the daily work time to avoid temperature differences from affecting the installation accuracy,etc.