Study On Walking Jacking Method Technic Of 6×80m Steel Girder Of The Binhe Yellow River Bridge In Yinchuan

Yinchuan Binhe Yellow River Bridge is located between Yinchuan Central Urban Area and Binhe District,which is the main river passage across the two districts.The superstructure of approach bridge in west bank adopts continuous composite box girder with constant cross section,whose span arrangrment is 6 × 80 = 480 m.It is located on a flat curve with a radius of 3285 m and sets a 0.5% of the longitudinal slope in longitudinal direction.The beam is composed of steel groove beam and precast concrete slab,in which the steel groove beam is constructed by one-way multi-points walking synchronous jacking method and the precast concrete slab is set up after jacking the steel beam.Then the wet joint will be poured to connect slabs.In this paper,according to the structural characteristics of the water approach bridge in west bank of Yinchuan Binhe Yellow River Bridge,the steel beam walking jacking construction method is systematically designed combined with the hydrology,geology and walking jacking equipment.This paper mainly focuses on the research of overall construction scheme comparison,the jacking construction step,process analysis of walking jacking method and the design and optimization of main temporary auxiliary structure etc.The main finished work is included in the following:(1)Based on the overall scheme analysis between scaffold assembly method and jacking method,the one-way walking jacking scheme is determined as the construction method of steel beam from economy,technology advancement and construction period.(2)A beam element model is set up by using MIDAS CIVIL finite element software and then a calculation simulation analysis is carried out for the whole construction process of jacking a 2m steel beam.So the key construction steps can be determined based on the above results.The three dimensional plate element model is calculated according to the key construction steps.Then the more exact value of the structural stress and deformation of the steel beam and guide beam in each calculation condition can be obtained from this processs.At the same time,the top slab,bottom slab,web slab and longitudinal and transverse stiffeners of the main girder are examined to ensure the safetyof the structure.(3)According to the simulation results of the whole process of walking jacking construction,the design and optimization of guide beam,jacking platform,abutment scaffold and guide beam dismounting scaffold were carried out.(4)Meanwhile,the steel beam jacking deformation is monitored and the actual construction measured data is analysed during above process to smooth the construction,but also verify the design accuracy.