合江

视频脚本——古斯塔夫林德撒尔奖

泸州市合江县位于长江上游，是一座欠发达城市。为促进发展，修建泸州至重庆高速公路，在合江县跨越长江。

Hejiang is located in the upper reaches of the Yangtze River, and is a developing county. In order to promote its development, the Luzhou-Chongqing Expressway was built to cross the Yangtze River at Hejiang.

合江长江一桥全长841m，双向4车道，桥宽28m，设计时速120Km/h，于2017年10月通车，工程造价4000万美元。

The First Hejiang Yangtze River Bridge is 841m long, 4 lanes in two directions, 28m wide and design speed at 120Km/h. It was opened to traffic in October 2017 with cost about 40 million US dollars.

根据通航要求，主跨不能小于500m，工程师对混凝土斜拉桥、钢桁梁悬索桥、钢箱拱、钢管混凝土桁式拱桥进行了比较。

According to navigation requirements, the main span should not be less than 500 m. Engineers compared possible bridge types, they are：concrete cable-stayed bridge, steel truss suspension bridge, steel box arch bridge, and Concrete Filled Steel Tube (CFST) truss arch bridge.

最终业主选择了材料最省、造价最低、工期最短的钢管混凝土桁式拱桥方案。

Finally, the owner chose CFST arch bridge with the least material consumption, the lowest cost and the shortest construction period.

主桥跨度530m，矢高120m。主拱采用钢管混凝土主管为矩形布置的桁式拱肋，拱肋宽4m；拱脚桁高16m、拱顶桁高8m。腹管采用“N”字形布置的空管结构。主梁采用钢格子梁与钢混组合桥面板的组合结构，通过吊索与主拱连接。

The span of this bridge is 530m and main arch reaches a height of 120m. The arch is a truss rib with rectangular arrangement of CFST structure. The width of rib is 4m, the height of arch foot truss is 16m, and the height of arch top is 8m. The empty web tube is arranged by "N" shape. The main girder is composed of steel grid beam and steel-concrete composite deck, connecting arch with suspension cable.

充分利用钢管结构具备自架设能力的特点，结合建设条件，采用缆索吊装、斜拉扣挂法完成主拱钢管安装。

Making full use of the self-erecting capability of steel tube structure, combined with construction conditions, cable hoisting and cable-stayed buckling method were adopted to complete the installation of main arch steel tube.

合江长江一桥拱肋节段长45m，高16m，重量超过200t，起吊高度140m，扣挂最大悬臂265m，安装风险高，施工控制难。

The arch rib installation segment is 45m long & 16m high. Its lifting weight is more than 200t, lifting height is 140m and the maximum buckle cantilever is 265m, which has high installation risk and difficult construction control.

传统的制造、运输安装节段无法自成体系，需要临时构件辅助形成结构，导致安装重量更重，工期长、精度难以保证、施工风险大、无法满足530m钢管混凝土桁式拱桥的快速成拱需要。

Traditional manufacturing, transportation and installation segments need temporary components to assist in the formation of structure. As a result, installation weight is heavier, construction period is longer, accuracy is more difficult to guarantee, and construction risk is higher, which can not meet rapid arch-forming needs of 530m CFST truss arch bridge.

工程师研发了制造、运输、安装一体化节段单元，即主拱节段单元与主拱节段单元之间的横撑自成独立的结构体系，制造、运输和安装不需要临时构件，空中安装仅需完成主管对接接头的就位匹配和焊接，生产厂内全部完成了节段高精度制造。较传统单元重量减轻30%，高空接头焊接量减少33%，实现每天安装1个节段，提高安装速度2-3倍，降低了风险和费用。

Engineers have developed a manufacturing, transportation and installation integrated segment unit, that is, main arch segment unit and cross brace form an independent structural system. No temporary components are needed for manufacturing, transportation and installation. Only in-place matching and welding of main tube needs to be completed at high altitude. All segments in production plant have been manufactured with high precision. Compared with traditional unit, weight is reduced by 30% and welding quantity of high altitude joint is reduced by 33%. One segment was installed in one day only. The installation speed is increased by 2-3 times and the risk and cost are reduced.

合江长江一桥主拱管内混凝土泵送距离450m，高差120m，单根主管如何一次性完成800m³C60混凝土泵送，并保证密实度，是该桥成拱的又一技术难题。

The pumping distance of concrete in main arch tube of the bridge is 450m and height difference is 120m. It was necessary for a single tube to be successfully completed 800 m3 C60 concrete pumping once for all and ensure the compactness, which is another technical problem in arching of the bridge.

在两岸各布置两台泵压大于20MPa的双泵高性能泵机，并备用一台可随时启用，保证了混凝土灌注的压力和泵送的连续性。

Two high-performance pumps with pressure greater than 20 MPa are arranged on both sides, and a spare pump can be used at any time to ensure the pressure and the continuity of concrete pumping.

同时，工程师们提出了半拱高、中、低三个泵入点、两岸对称布置的接力泵送工艺，将泵送难度降低60%。并在拱顶设置真空设备，实现钢管内真空度达到负压0.8MPa。减少主拱主管内混凝土空气集聚形成的脱空气囊，将混凝土含气量降低了30%。

Meanwhile, engineers have proposed pumping technology with high, middle and low three pumping points at half arch, and symmetrical arrangement at both sides, which reduces the difficulty of pumping by 60%. Vacuum equipment is installed on the vault to achieve a negative pressure of 0.8 MPa. By reducing the degassing bag of concrete in main arch main tube, the air content of concrete is reduced by 30%.

工程师研发了具有扩展度大于600mm、坍落度大于220mm、12小时坍落度损失小于30mm的大流动度泵送自密实混凝土；同时开发了内养护机制、通过膨胀剂，实现自密实混凝土的补偿收缩，补偿收缩量为万分之五。

Engineers have developed self-compacting pumping concrete with expansibility greater than 600 mm, slump greater than 220 mm, and slump loss less than 30 mm in 12 hours. Meanwhile