| At present,rubber bearings are widely used in bridge engineering.However,there are some problems of bearing failure,such as void,fracture,loss of telescopic capacity,corrosion failure to slip,etc because of bearing aging,corrosion,wear and other problems,so the bridge can’t wok normally and bearing needed to be replaced.In the process of bearing replacement of jacking bridge.On the one hand,the process of replacing the bearing in the jacking bridge will inevitably cause damage to the bridge structure,which will affect the service life of the bridge.On the other hand,the jacking bridge needs to interrupt the traffic,thus causing a certain degree of traffic inconvenience,and the jacking cost is obviously too expensive relative to the cost of the bearing.Therefore,the development of "life-cycle(durable)" bearing,so it can reach the same life like the bridge structure(100 years),and that has become the focus of the current bearing development direction.What’s more,the reliability analysis which is newly developed called Full Life Pot Steel Ball Bearing is studied.Therefore,from the function of mechanical properties,durability,positioning of weak nodes under seismic action,the thickness of anchor bolts and different ways of loading caused by the weak force changes location on the differences and application to different Anti-seismic of bridge structure in the form,the study carried out the methods of test,numerical simulation method and theoretical analysis on five key issues.The main conclusions of essay are as follows.(1)The basic mechanical properties of the bearing are examined by the vertical bearing capacity comparison test and torsion test.The test results show that the Full Life Pot Steel Ball Bearing has higher stiffness and better rotational performance than pot-type spherical Steel Bearing,which meets the requirements of "Spherical Bearings for Bridges"(GB/T 17955-2009).(2)The durability of the bearing is examined by the fatigue test of the bearing and the wear test of the modified polytetrafluoroethylene sliding plate.The bearing durability test results show that the bearing has no obvious Fatigue damage in the process of500000 times fatigue loading.The maximum friction coefficient is 0.023 and the final friction coefficient is stable at 0.01 in the 100 km abrasion test and the maintain positive correlation.The test results show that Full Life Pot Steel Ball Bearing has good durability.(3)Through the analysis of finite element model building by ANSYS,it is concluded that when the horizontal load is 15% of the vertical design bearing capacity,the deformation caused by monotonic and cyclic loading can be recovered.And the stress distribution state of the bearing is that the stress concentration phenomenon occurs at the bolt hole of the lower seat plate when the bearing is loaded,so that the weak node position of the bearing is positioned at the joint of the bearing bolt,the bottom steel plate and the bearing pad stone.(4)The finite element analysis software ABAQUS was used to simulate the weak node locations of the bearings and analyze the anti-seismic performance of eight Full Life Pot Steel Ball Bearing weak nodes with Reinforced Protective Layer thickness of20mm-90 mm under monotonic and cyclic loading.According to the comprehensive evaluation from four aspects of horizontal bearing capacity,anti-seismic,ductility and stiffness.In order to ensure that the bearing can have a higher level of horizontal bearing capacity limit,better ductility and greater stiffness,the thickness of anchor bolts should not be less than 50mm;In order to ensure that the bearing can also have a good energy consumption performance,the thickness of the anchor bolts should not be greater than80 mm.By comparing the difference of the horizontal ultimate bearing capacity between monotonic loading and cyclic loading,it is concluded that the effect of cyclic loading on the reduction of the horizontal ultimate bearing capacity should be considered in the seismic design of full life pot type ball steel bearing.(5)Full Life Pot Steel Ball Bearing is reduced to an elastomeric connection For building the whole bridge finite element model in Midas Civil software,creating 3-25 m prefabricated small Box Girder,3-35 m prefabricated small Box Girder,4-30 m T-beam and 4-40 m T-beam Girders.In addition,Response Spectrum Analysis Method is used to compare and study the seismic performance of Full Life Pot Steel Ball Bearing by changing site types Ⅰ to Ⅳ and the intensity of seismic defenses:In accordance with the analysis of numerical value of horizontal ultimate bearing capacity,The bearing in two types of bridges can meet the requirements of seismic fortification intensity of 9 degree in Class I venue and Class II venue;The bearing of small box girder can meet the requirements of seismic fortification intensity of 9 degree and The bearing of T-beam can meet the requirements of 8 degree seismic fortification intensity in Class Ⅲ venue;bearing in small box girder bridge can meet the requirement of 9 degree seismic fortification intensity when its span is 25 m in Class IV venue,and it can meet the requirement of 8 degree seismic fortification intensity when its span is 35 m,and T-beam can meet the requirements of 8 degree seismic fortification intensity when its span is 30 m and it can meet the requirements of 7 degree seismic fortification intensity when its span is 40 m.The seismic analysis results of Midas are shown that in accordance with the form of bridge structure and span bearing arrangement selection,the seismic performance of The bearing of small box girder is better than of T-beam bridge as well as the larger the span,the worse the seismic performance.Therefore,only from the perspective of seismic bearing arrangement,support model of small box girder bridge can be lower than that of T bridge in the selection. |
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