The main bridge of Qilu Huanghe River Bridge in Jinan is a network tied arch bridge that consists of three continuous arch spans of 420 m,flanged by an expansion unit of two spans of 280 and 90 m on each side,with the deck width reaching 60.7 m.The stiffening girder is composed of steel boxes that were erected by using a combined static and dynamic method,and ahead of the construction of the arches,accomplishing the erection of steel box girders in limited space and the placement of extra wide steel box girders.The incremental launching of the steel box girders was performed using the intelligent crawler launching equipment and tank wheels,to enhance the controllability,security and efficiency of the incremental launching process.The stiffening girder in the two spans of 280 m was cast in situ on full scaffolding.Each arch spanning 420 m was divided into three sections to facilitate construction,the end 60 m-long sections were installed on the full scaffolding,the 300 m-long intermediate section was assembled on the previously-installed steel box girders and lifted integrally to connect with the side sections to achieve the closure of the arch via matching and cutting operation.In accordance with the finite element analysis and taking the internal forces of hangers as control,the hangers with lower stress level at the midspan were tensioned first,and the tensioning was proceeded towards the arch springs.During the hanger tensioning,extension rods were used to reduce the tensioning work and improve the tensioning efficiency and security.
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