The Finite Element Analysis Of Anchorage Zones For Cable-stayed Bridge And Study Of Fatigue Damage

The Anchorage zone of large span cable-stayed bridge withstand strong cable force whichis one of the key parts of the design. For Anchoring zone of the cable-stayed bridge,especially in cable girder junction, due to the effect of huge centralized force in cableanchorage, making this region have more complex forces. We should do local analysis tounderstand the structure of the actual working conditions and working status. Under the effectof alternating stress, materials and structures is prone to damage. For the safety of the wholebridge, it is significant to search for the position where may have fatigue damage ofAnchorage Zones and research fatigue life and safety factor of fatigue damage.Using ANSYS, which is the large general software, the finite element model of theAnchorage Zones has been established and analyzed. Combined with the software, which isANSYS/FE-SAFE, the fatigue reliability is also studied. Finally, through the analysis offatigue life and nephogram of fatigue safety factor, the position where may have fatiguedamage can be determined, which provides a theoretical basis for structural improvementsand security monitoring of cable-stayed bridge. Content of the study are as follows:(1) The finite element model of the cable-stayed bridge on the Anchorage Zones whichuse shell elements theory has been established in finite element analysis software ANSYS.Under the most adverse load combinations role, do analysis and calculate of stress distributionon the Anchorage area. By looking at the stress cloud, we can see, welded area of stiffenedplate and bearing plate have the maximum stress, and sharp corners is more prominent.(2) Anchorage Zones stiffener corners is structural stress concentrated region. Its VonMiss stress value is283MPa. The improvement of stiffened plate reduces stress concentrationand provides a reference for structural improvements of Anchorage Zones. Meanwhile, thisarticle also studied the deformation of the contact of the anchor plate and the bearing plate.Under different loads, the deformation curve of the anchor plate is given which provides areference in order to prevent the destruction of anchor plate in prestressing process.(3) Anchorage zone are safe and it have less fatigue damage under the action of thestandard fatigue vehicle and M7model vehicle. The most likely injured location are weldseams of stiffened plate of diaphragm and N7under the action of model vehicle at full loadand overload20%,50%. In case of overload of50%and100%, the fatigue life of the the stiffened plate on the diaphragm and N7plate weld less than2million times, which is proneto fatigue failure.(4) In the case of50%overload model vehicle,100%overload model vehicles with differentlevels of wind load as fatigue load amplitude, fatigue damage position are different. Furtherstudy the wind load on the anchorage zone: Under the action of100%overload model vehiclewith six to seven wind loads, fatigue life change is not very obvious, when the wind speed ismore than seven, the rate of decrease fatigue life is large, that is to say, it will have fatiguedamage when the wind speed over seven.