Study On The Construction Controlling Of Main Span's Mix With The Erection Of Large Span Hybrid Beam Cable-stayed Bridge

The side span and the main span of hybrid beam cable-stayed bridge were respectively built of concrete beams and steal beams,which were connected and switched by way of steel-concrete combined sections near the tower.Given that different materials and erection methods were adopted in the construction of the side span and the main span of hybrid beam cable-stayed bridge,and due to the complexity of mechanical characteristics in the process of construction and and upon completion,the design and construction of the hybrid beam cable-stayed bridge was confronted with problems concerning construction process and controlling,thus requiring technical workers and research workers to research on the mechanical performance and construction controlling of the hybrid beam cable-stayed bridge.Generally,fabricated cantilever construction method is applied to the construction of the main span steel box girder for hybrid beam cable-stayed bridge.However,this thesis focuses on the application of hybrid erection.As a result of the hybrid erection and wide box girder employed in the construction of main beams of long span and main span,the construction controlling of the cable-stayed bridge becomes all the more crucial.Based on the Qilong Bridge project(mian span 260m of hybrid girder cable-stayed bridge with one tower),key issues of construction controlling of the main span hybrid erection bridge are studied in this paper of which the main contents are listed as follows:(1)Finite element model of Qilong Bridge is established,and the mechanical properties of the bridge are analyzed in detail,compares the different construction schemes and analysis them,based on the results of the analysis,put forward the optimization scheme of only one time tensioned cable in place,simplify the construction process effectively,shorten the construction period.(2)Mainspan of Qilong Bridge use mixed erection construction technology,the stress of the structure and the line of the main girder in the process of construction for effective control,puts forward Suggestions for the optimized closure segments construction and temporary braces of tower and,and adopted by the engineering practice,the effect is very good.(3)Concrete box girder temperature field and temperature effect of concrete box girder in single-box with multi-cells were tested and analyzed,based on the results of the analysis,put forward the control measures of box girder hydration heat temperature stress.At the same time,the effect of different conditions on calculating results is analyzed,and the calculation of temperature stresses in the engineering practice is provided with better guidance.