Research On Key Technology For Assembling And Lifting Construction Of Steel Box Basket Arch Rib Bridge With Big Rise-Span Ratio

With the development of arch bridge structure,the bridge type is more and more novel,big rise-span ratio and basket arch structure are applied to arch bridge design,which not only puts forward higher requirements for designers,but also generally increases the construction difficulty,and puts forward new requirements for construction technology.This paper relies on the project of Yulin River Bridge,its arch construction technical scheme from the initial cable hoisting method,to the in-situ bracket assembling method,and finally adopts the low-position assembling lifting method.Lasted more than a year before and after,in view of this situation,this paper adopts theoretical analysis method and the finite element numerical analysis method,the royal canal bridge main span large rise-span ratio basket steel box arch rib construction technical scheme is proposed for research,and key technologies for final assembly to promote construction of in-depth study,the results of the study can provide with seems to provide the reference to the design and construction of bridge structure.The main research contents and conclusions of this paper are as follows:1 The application and development of steel box arch bridge at home and abroad,as well as the main construction methods of steel box arch bridge are summarized by consulting literature;At the same time,analyzes and summarizes the construction characteristics and difficulties of big rise-span ratio basket steel box arch rib.2 According to the structural form and characteristics of the large arch rib of the main bridge of the Yulin River Bridge,the finite element software SAP2000 was used to study the characteristics of various construction techniques of the large arch rib;The key construction stages of the two construction schemes plans to be adopted are selected for comparative analysis.In addition,the four aspects of construction difficulty,construction safety,construction quality and construction progress of the two construction schemes are summarized,analyzed and researched.The results show that: for the construction of the big rise-span ratio basket steel box arch rib of the main bridge of Yulin River Bridge,the overall lifting construction scheme after the low-level assembly is the best.According to the structural form and characteristics of the large arch rib of the main bridge of the Yulin River Bridge,the finite element software SAP2000 was used to study the characteristics of various construction techniques of the large arch rib;The key construction stages of the two construction schemes plans to be adopted are selected for comparative analysis.In addition,the four aspects of construction difficulty,construction safety,construction quality and construction progress of the two construction schemes are summarized,analyzed and researched.The results show that: for the construction of the big rise-span ratio basket steel box arch rib of the main bridge of Yulin River Bridge,the overall lifting construction scheme after the low-level assembly is the best.3 The strength,stiffness and stability of each temporary structure component in the construction of the low arch rib assembly,as well as the stress and stability of the arch rib in each key construction stage of the low arch rib assembly are studied.The structure of trestle is optimized and corresponding construction suggestions are put forward.The results show that the strength,stiffness and stability of each component of the optimized trestle and bracket meet the requirements of the code in the process of the low assembling.The stability of each key stage of low level assembly construction under two working conditions of dead weight and dead weight plus wind load meets the construction requirements,and the structural dead weight is the main controlling factor of stability in the key construction stage.4 The stability and safety of the lifting bracket in the whole lifting construction stage were analyzed and studied.The results show that reasonable initial tension of the wind cable will improve the overall stability of the lifting bracket,and the strength of each component,the strength of the steel strand wind cable and the overall structural stability of the lifting bracket under three typical construction load conditions meet the requirements of the code.5 The sensitivity analysis of the key design parameters involved in the lifting construction process is carried out,and the influence rules of the key design parameters on the stress and deformation of the lifting section arch rib structure are obtained.The results show that the biggest influence on the stress and deformation of arch rib structure is the lifting point position parameter.