Key Techniques of Asymmetric Steel-Concrete Hybrid Girder Bridge
This paper discusses the design and construction issues of the multi-span asymmetric steel-concrete hybrid girder bridge.The construction of Longxiang Bridge,a four-span asymmetric steel-concrete hybrid girder bridge,was numerically simulated with link elements,to analyze the effects of the installation sequences of key segments and steel box girder length on the alignment and internal forces of completed bridge,as well as the influences of 9 key parameters on the precamber of the superstructure and longitudinal deformations at the closure gaps.It is shown that the closure sequences have minor influence on the alignment and internal forces of the completed bridge,and the two central spans were closed one by one during construction.The absolute values of pier-top negative moments and the midspan deflections of main spans are linearly decreased as the length of the steel box girder and the side span to main span ratio k1 increase,and the finally selected values of k1and steel box girder length in the main spans were 0.371 and 75 m,respectively.The self-weight of steel box girders and the elastic modulus of main girder concrete govern the precamber of the superstructure,when the former and the latter were changed by 6%and 10%,respectively,the corresponding variations of precambers were 15 mm and 13 mm.Ambient temperature is a critical influential factor of the longitudinal deformation of closure gap,with a variation of 10 ℃,the longitudinal deformation at the closure gap showed a change of 12 mm.The self-weight of steel box girders and the elastic modulus of main girder concrete should be strictly controlled,to ensure the closure be conducted at the design temperatures.
steel-concrete hybrid girder bridgeasymmetric systemclosure sequencesteel box girder lengthprecamberlongitudinal deformation of closure gapparametric analysisfinite element method