Fatigue Performance Analysis Of New EMR Concrete Expansion Joint

As an important accessory component of bridge,the working state of bridge expansion device has an important impact on driving comfort and bridge structure itself.The components of expansion joint are small in size and complex in structure.Under repeated loads,the components are in complex alternating stress state,and the stress variation amplitude is large.In common diseases of expansion joint devices,concrete failure in anchorage zone caused by fatigue can also be seen.Therefore,fatigue problems in bridge expansion joint devices are more prominent.The fatigue problems of expansion joint devices are studied.Questions have important application value.The expansion joint studied is a new type of EMR concrete expansion joint.Resin concrete is used in the anchorage zone of the steel beam and the beam body of the expansion joint device.After the resin concrete is solidified,it has the advantages of high strength,good affinity,impact resistance and better tensile performance than concrete.The new expansion joint device has the advantages of rapid construction,short interruption time,and quick replacement of expansion joint device.The stress-strain relationship can be obtained by compression test of resin concrete material,and the appropriate S-N curve of expansion joint material is selected to pave the way for fatigue analysis of the following structure.It's said that establishes a local finite element model of expansion joint and applies wheel load to obtain the stress history of key points of materials in the structure.At the same time,according to the analysis of the results of lateral stress of the structure,it is concluded that under the action of single wheel load,the extension range of lateral influence does not exceed half of the lateral action distance of wheel load;that is to say,wheels of vehicles in adjacent lanes keep the lateral safe distance when driving.The loading zones do not overlap with each other.Referring to the codes and documents of other countries,it's said that takes the average daily traffic volume of a bridge as an example,and establishes a simplified vehicle fatigue load spectrum through the equivalent calculation of axle load and wheelbase.Based on the Palmgren-Miner linear cumulative damage rule and the finite element stress history and vehicle fatigue load spectrum,the daily average fatigue damage values of the key points of the new EMR concrete expansion joints are calculated,and then the fatigue life of the expansion joints is estimated.The results show that the fatigue performance of the new expansion joint device is good,and the pavement asphalt near the concrete in the anchorage zone is the first one that may cause fatigue damage.The theory validates the excellent fatigue performance of the new EMR concrete expansion joint device.Resin concrete can effectively diffuse vehicle loads to a wider area,thus effectively avoiding the phenomenon of fatigue damage caused by excessive local stress.