Three “small devices” at the Nanjiang Precast Yard of the 16th Project Department of CCCC First Harbor Engineering Co., Ltd. No.1 Company, through effective combination, achieved the construction effect of a girder-lifting machine, creating high benefits for the project department.

　　The Nanjiang Precast Yard of the No.1 Company's 16th Project Department undertakes the precasting and shipment of components such as box girders and fence panels. The conventional box girder shipment scheme relies on a girder-lifting machine. However, since the box girders precast at this yard are all large-span box girders, with a maximum length of 55 meters and a weight of up to 434 tons, common girder-lifting machines on the market cannot handle this task. Custom-building a new set of girder-lifting machines to meet the work requirements would cost more than 20 million yuan, which is not only too costly but also involves long periods of work at height and a relatively high risk factor.

　　Based on a full analysis and study of the on-site construction conditions, and from the perspectives of cost savings and construction safety, the project department proposed the construction method of “one dragging two jacks, four-point synchronous lifting, and transverse and longitudinal movement for shipping large-span box girders.” By rationally combining three “small devices”—jacks, transverse (longitudinal) moving vehicles, and winches—the key steps of lifting, transverse movement, and longitudinal movement were successfully achieved, thereby enabling the smooth and successful shipment of box girders.

　　This method is simple and flexible to operate. The entire process takes only 0.5 hours, almost the same as the time required by a girder-lifting machine to lift and transport box girders. Moreover, there is no work at height. More importantly, the total investment for the entire shipment system is only 3 million yuan, effectively saving cost input.