Research On Main Beam Deflections With Stay Cable Damage Of Wuhu Yangtze River Bridge

Cables are the important parts of stay cable bridge structures. Many accidentsshow that the cable damage often causes the bridge mechanical characters change,which especially changes the cable tension of the stay cable and the deflections ofmain beam, even threatens the bridge’s safety. Due to the complexity of cable systemand the imperfection study on damaged cable, there is not a formed research methodfor cable about damage identification, and safety evaluation of damaged cable. Themain channel of the Wuhu Yangtze River Bridge is Cable-Stayed Bridge with LowPylon, which is chosen as the research background to analyze the sensitivity of thegirder deflection to the damaged cable and then discusses the feasibility of cabledamage based on the method of deflection measurement. The main research contentsinclude the followings:Firstly, utilizing the ANSYS software to establish the three-dimensional finiteelement model of the bridge, and then comparing the model with the measured dataof bridge load test in order to improve the accuracy of calculation model. Secondly,the cable damage is simulated through reducing the cable area by10%,30%,50%.Analyzing the deflection change rules and characteristics induced by the differentdegree of single cable damage or double cables damage, when no train drives acrossthe bridge. Finally, comparing deflection change rules and characteristics under theaction of different marshalling train loads, train load and cable damage.Through comparative analysis of cable damage, the author found that the changeof girder node deflection corresponding to the end of the damaged cable is the mostobviously, Corresponding deflection of damaged cables increase faster than shortercables and close to the ones of longer cables. And train loads will significantlyenlarge the changes of the beam deflection of damaged cable zone. At the same time,the author also found that the deflection of damaged cable anchored nodes increaseslinearly with cable damage rate. Thus, the case for damaged cable, through the corresponding node deflection of the damaged cable (extreme value point), andnearby the deflection tendency, not only can we identify the damage location, but alsodistinguish the extent of the damage.