The Shear Analysis Of Single Box Chamber Corrugated Steel Web Cable-stayed Bridge

Single box multi-room composite box girder with corrugated steel web as a new combination of bridge structure,there just have been less studies on it at home and abroad, and some questions still need to be further studied. For example, whether corrugated steel webs assume the full shear of composite box girder, concrete roof and floor only act the effect of anti-bending? Whether the shared shear ratio of the per piece steel web in multi-chamber single box composite box girder is the same? How is the anti-torsion effect of the concrete diaphragm on the composite box girder? In this paper, the Chaoyang ditch bridge which is a single box multi-room corrugated steel webs partially cable-stayed bridge as an engineering example is used to research the above questions, the main research contents and the completion of this work are described as follow:1. To establish a finite element fine calculation model of the Chaoyang ditch Bridge, and demonstrate the "similarity of plane hypo-thesis" through simulation analysis.2. Carrying out the structure analysis of Chaoyang ditch bridge, prestressing force, the tension forces in the cable, full-span distributed live load and offset load, quantitatively analysing of the bearing shear ratio of each corrugated steel web and the bearing shear ratio of the corrugated steel webs on the shear bearing section under each working condition. There is a conclusion that the corrugated steel webs bear the most shear of composite box girder, each bears their own web shear approximately equal proportions under the condition of symmetrical load. Among them, corrugated steel webs bear the largest shear under the conditions of structural weight; as a result of the prestressing tendon inside and outside, corrugated steel webs bearing shear ratio of Chaoyang ditch bridge under the condition of prestressing force is lower than under the condition of structural weight; as a result of the tension forces in the cable, corrugated steel webs bearing shear ratio is relatively low under this condition; under the conditions of prestressing tendon, the tension forces in the cable and full-span distributed live load, corrugated steel webs bear 85% of the shear; under the offset load, each wed bears the shear no longer equal, the bearing shear rate of the weds nearing the offset load position is higher, the bearing shear rate of the steel weds away from the offset load position is relatively lower.3. In order to study the impact of concrete diaphragm on the multi-room single box corrugated steel web torsion, this paper changes the number of diaphragm and the thickness of concrete diaphragm, quantitatively analyses the influence degree of concrete diaphragm on the composite box girder, and there comes a conclusion, with the increasing thickness of concrete diaphragm, box girder torsion angle section grows smaller, but the change of box girder torsion angle section and thickness of concrete diaphragm are not in linear relationship; as the increasing number of concrete, box girder torsion angle section grows smaller, but the change is not obvious; once the number of concrete has increased to a particular value, box girder torsion angle section although has been somewhat lower, but the change is getting smaller and smaller.