Research On Flange Connection Structure Applied To Fabricated Cylindrical Pier

The application of fabricated technology in bridges can reduce the interference of construction on the surrounding environment,improve the quality of the project,and save construction costs.Its environmental protection and high efficiency are especially suitable for some offshore engineering,rescue and disaster relief engineering and municipal engineering.The application of fabricated technology in the upper structure of the bridge is very mature,but the application of the lower structure of the bridge is still very few.The key technical difficulty lies in the connection of the joints.At present,there are six main connection methods for prefabricated bridge piers at home and abroad:grouting sleeve connection,grouting metal bellows connection,socket connection,posttensioned prestressed reinforcement connection,wet joint connection and flange connection.Relying on the project: Bridge No.4 in Yaoma Village,Xining City,Qinghai Province,which uses prefabricated technology for its substructure,and the piers are cylindrical.The pier column and the pile foundation longitudinally stressed steel bars are not in the same position.In order to solve the problem of force transmission in the dislocation connection of steel bars,this paper proposes to use flanges to connect fabricated cylindrical piers.Then conduct the research on the flange structure design and the mechanical performance of the flange-connected assembled cylindrical pier through theoretical analysis,finite element analysis and experimental analysis methods.Including the following contents:(1)Based on the diameter specifications of piers and pile foundations commonly used in highway bridge construction,the two types of flanges are designed and parameterized with reference to relevant theoretical design methods.The height of the flange is determined by the length of the anchorage of the steel bar.The specifications are selected according to the specifications,and the thickness of the gasket is consistent with the thickness of the flange plate.Then take the pier diameter of 1200 mm and the pile foundation diameter of 1400 mm as an example to establish the flange model.Discuss the applicability of the theoretical design method by analyzing the bearing capacity,stress distribution and deformation of the two types of flanges,as well as the comparison between the calculated value and the theoretical value;(2)Relying on the project engineering,a scaled test was carried out on the flangeconnected fabricated cylindrical pier.The outer dimensions of the specimen structure are determined by a similar length ratio of about 1:2,and the two types of flanges are designed and dimensioned according to the aforementioned theoretical design methods.There are three groups of test models,each with 2 test pieces,which are cast-in-place cylindrical piers,flange type I and type II connected fabricated cylindrical piers;(3)The test structure is studied from the displacement-load curve,pier column steel strain-load curve,pile foundation steel strain-load curve,stiffener strain-load curve,steel pipe strain-load curve and failure mode.By analyzing and comparing the mechanical properties of cast-in-place cylindrical piers and two types of flange-connected fabricated cylindrical piers,the reliability and safety of flange-connected fabricated cylindrical piers are discussed.