Key Technology Research On Steel-concrete Combined Sections Of Prestressed Concrete-steel Truss Mixed Continuous Rigid Frame Bridge

Prestressed Concrete-steel truss mixed continuous rigid frame bridge, of which the main feature is mid span section of the main girder using plate-truss composite steel truss and the rest consists of prestressed concrete(PC) box girder, is an innovative form of hybrid girder bridge.This hybrid girder structure is not only with the advantage of existing hybrid girder bridge,but also with less the difficulty of construction in the moutain,which is suitable for construction of long-span bridge in the mountains.Steel-concrete composite segment of the hybrid girder is the transition section of the two materials composed by steel and concrete,of the which the stiffness existing mutation that easily cause local stress concentration,and is the weak segment of the overall force, and is the key part to the success or failure of hybrid girder design,so it is necessary to study the consititution design and the transfer Mechanism of it.This paper designed the steel-concrete composite segment of Prestressed Concrete-steel truss mixed continuous rigid frame bridge, and use finite element analysis software ANSYS to establish finite element mode of steel-concrete combined sections and to research its mechanical properties and transfer mechanism,and took the comparatively analysis of stress states of the section under different parameters which revealed the change law of its mechanical properties with the structure parameters. The main contents of this paper are as follows:1.Describing the development and current research of hybrid girder bridge and steel-concrete combined sections at home and abroad, and summarizing the different structural forms and characteristics of the combined sections,and summarizeing the connecting member of the combined sections at the same time,and analysising the construction features,the force characteristics,etc,of different connection forms.2.Using finite element software Midas Civil establish whole bridge model of Prestressed Concrete-steel truss mixed continuous rigid frame bridge, getting internal force of the steel-concrete combined sections under the most unfavorable load combination action.3.Designing the steel-concrete combined sections of Prestressed Concrete-steel trussmixed continuous rigid frame bridge, using Ansys software to establish local model segment of the steel-concrete combined sections,and to analysis stress distribution of each component about the steel-concrete combined sections, and to study its transfer mechanism.4. Carrying out further optimization of parameters of its steel-concrete combined sections. Analysis effect of the different thickness of bearing plate and different welded connections nail stiffness to the steel-concrete combined sections,which revealed the change law between the mechanical properties of it with the different parameter.