嘉绍大桥主航道桥为（70＋200＋5×428＋200＋70） m 的六塔独柱四索面钢箱梁斜拉桥，主梁采用分幅形式，单幅主梁为全宽22．2 m（含风嘴）的封闭式流线型钢箱梁，钢箱梁节段的吊装采用各塔独立同步起吊，每个塔由4台桥面吊机对称施工，一次起吊4片钢箱梁。钢箱梁吊装水域为钱塘江强涌潮水域，为保证吊装同步，船舶定位尤为关键。考虑风向和潮汐影响，通过二次试航试验选定双舵双机的艏上层建筑船舶，乘潮而上在指定水域抛锚定位，定位辅助栈桥缆绳、锚链等措施，在钱塘江平潮期50 min 时间内完成一次吊装，平稳完成374节钢箱梁定位吊装。%The main navigational channel bridge of Jiashao Bridge is a six-pylon steel box gird-er cable-stayed bridge with span arrangement of (70 + 200 + 5 × 428 + 200 + 70) m and with four ca-ble planes .The pylons are single-columned pylons .The main girders are separated into the left and right decks of streamline closed steel box girders ,each with a full width of 22 .2 m (including the guide vanes) .The erection of a steel box girder sections starts from the pylons ,that is to take the girder sections on each side of a pylon and the pylon itself as a unit ,the sections in each unit were independently hoisted and erected but the operation of all the units proceeding in parallel . Four deck cranes were employed to erect the girder sections in each unit and four steel box girder blocks were lifted and erected by one operation .Due to that the steel box girder hoisting and erec-tion was carried out in the strong tidal area of the Qiantangjiang River ,the positioning of the bar-ges is very critical for ensuring the parallel hoisting and erection .By considering the wind direction and the influence of the tides ,the barges with double steers and double engines were selected by the secondary voyage trial ,shipping against the tides ,and anchored and positioned in the designat-ed water area .The ropes of the assistant trestles and anchoring chains were also positioned .Dur-ing the 50 min period of slack water of the Qiantangjiang River ,one hoisting and erection operation was carried out and completed ,and the 374 steel box girder sections were positioned and erected smoothly by this way .
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