Study On Performance Of Flat Welded Bearing Plates

The flat bearing plate is an important part of the flat anchor system.During the construction of the flat anchor,the preload stress from the anchorage is transmitted to the concrete in the anchorage area through the flat bearing plate.The safety of the anchorage zone depends largely on the force transfer performance of the bearing plate.At present,the flat anchor bearing used for horizontal or / and vertical prestressed structure is mainly produced by casting,which has low compressive and tensile strength and is easy to be damaged during construction;in areas with high air moisture content,there will be bubbles inside the molten iron,and the bearing plate produced will have sand holes and other problems,which will reduce the bearing capacity of the structure and affect the safety of the structure.In order to reduce the tension accidents caused by the bearing plate itself and ensure the quality of the project,a flat welding bearing plate with high strength,no pollution and low energy consumption is proposed.The flat welding bearing plate is made of Q235 steel by stamping and welding.In this paper,through the finite element software ANSYS,load transfer test in the anchorage zone,the performance of flat welded bearing plate is studied,the main research contents are as follows.1.Based on the analysis of the research results of flat bearing plate at home and abroad,aiming at the shortcomings of flat cast bearing plate,Q235 steel with good plasticity,high strength and economy is selected to replace HT200 cast iron,and the bearing plate of 5-hole BM type OVM flat anchor is made by more environmentally-friendly stamping and welding method to realize automatic production and reduce costs.This paper analyzes the structure and stress of the cast bearing plate,designs the structure form of the welded bearing plate,so that the pre compression stress can spread evenly to the concrete under the anchor during the tension construction,prevents the stress concentration,and improves the structural stability.2.ANSYS is used to calculate the stress of the flat welding bearing plate,and analyze the stress condition of the bearing plate and the concrete under it.The steps of material selection,modeling,meshing,contact analysis and model loading of bearing plate in ANSYS are described.It can be seen from the calculated stress nephogram of the bearing plate and the concrete under it that the stress of the welding bearing plate and the concrete under it is within the limit of the material,and the stress distribution is relatively uniform without obvious stress concentration area.3.Through the load transfer test,the transfer of pressure from the upper surface of the flat bearing plate through the bearing plate,concrete and spiral reinforcement,the stress distribution of the above components in different stress stages,the generation,development and law of concrete cracks,and the ultimate bearing capacity of the bearing plate or anchorage device are inspected.According to the analysis of the test data,the crack width,failure load and other indicators of the bearing plate meet the requirements of the code.4.The results of ANSYS analysis and load transfer test are compared and analyzed.The data obtained by the two methods prove that the welded bearing plate has good transmission performance and can meet the requirements of bearing capacity.According to the results of the finite element simulation and the test of the force transfer performance of the anchorage zone,by changing the structural form of the bearing plate to optimize the uneven area of the stress distribution,the bearing plate with better performance and more uniform force transfer is designed.The completion of this paper can improve the overall quality of flat anchor system to a certain extent and promote the further development of prestressed technology.