Static And Dynamic Analysis Of Prestessed Concrete Composite Continuous Box-Girder Briege With Corrugated Steel Webs

As a new kind of composite bridge, prestressed concrete(PC) composite box-girder bridge with corrugated steel webs appeared in early 1980s. It has a great deal of advantages such as light self-weight, high effective prestressing system, short construction period, beautiful shape, etc. As a unique bridge structure, each part of the box-girder has specific mechanical behavior。It has gained extensive research and application in France and Japan. Now it is getting more rapid development prospects and great application in tapered section of large-span bridges with more complicated structure, in China.At present, many studies on the PC composite box-girder bridge with corrugated steel webs are mainly concentrated on shear buckling mode of the web, characteristics of bending and torsion, bearing capacity of normal section, etc. Scale model tests and finite element analysis are also more focused on mechanical properties of corrugated plate girder or such beam composite structure, there are very few researches on static and dynamic analysis of long-span continuous box girder in this kind of structure. In thesis, the mechanical properties of space and the structural parameters on dynamic analysis are studied by finite element method based on the PC composite box-girder bridge with corrugated steel webs under construction.The research shows that the self-weight of PC composite continuous box-girder bridge with corrugated steel webs is about 20%lighter than general PC continuous box-girder bridge, its deflection and stress can meet the norm requirements on limit State. Because of bending stiffness between box-girder with corrugated steel webs and box-girder with Concrete web is the mutation, roof stress of box-girder with corrugated steel webs is relatively large. Steel web shear stress distribution is more uniform, it reflects the corrugated steel web excellent shear capacity.Comparison of the dynamic performance between PC composite continuous box-girder with corrugated steel webs and other general PC continuous box-girder,it show that torsional vibration frequency of the former is lower than torsional vibration frequency of the latter. Increasing diaphragms can improve the natural frequencies of torsional vibration, but the frequencies of raising are more limited. It is worth noting that natural torsional vibration occurring mainly in high vibration mode, and natural torsional vibration of PC continuous composite box-girder bridge with corrugated steel webs is still much higher than the main frequency of that, it indicating the structure has relatively high capacity of torsional stiffness. This thesis provides references for further research and engineering practice.