Research On The Mechanical Behavior And Design Method Of High-strength Bolted Joints Of Steel Frame Column

As the most important component of steel frame, column plays a vital role to theoverall carrying capacity, mechanical proterties, resistance to deformation of steelframe. Limited by factory production conditions and transportation conditions, acomplete column is spliced together by many short columns in the field, steel framecolumn splicing joint is a key joint of structure. In the Technical Specification forSteel Structure of Tall Buildings (Draft), the design formulas of steel frame beamsplicing are quoted from the Architectural Institute of Japan. Recommendation forDesign of Connections in Steel Structures2006, and the design formulas of steelframe column splicing aren’t. However, the design formulas of steel frame columnsplicing are similar to the steel frame beam’s in Japanese specification.This thesis traces to the source of the design formulas of steel frame columnsplicing in Japanese specification and compares the design formula between Japanesespecification and Chinese specification. Then, based on the Japanese design formulas,this thesis combines with our existing design methods, proposes improved designformulas of high-strength bolted friction-type joints of steel frame column.This thesis designs a high-strength bolted joint of steel frame column based on aexample in the Architectural Institute of Japan. Recommendation for Design ofConnections in Steel Structures2006, by using formulas in Japanese specification,JGJ99-98and this thesis, compares design results and mechanical properties of joints,then, compares the three joints with completed steel column without hith-strengthbolted joint. Then, this thesis makes designing of high-strength bolted joints whichhave different sectional dismensions and steel material, then makes finite elementmodes by ANSYS, it is showed that joints designed by using formulas in Japanesespecification are greatly affected by internal forces of joints, and that differentposition and loads of joints cause different results. Intensity of joints designed byusing formulas in JGJ99-98based on intensity of net section of steel column throughsubtracting areas of bolt holes, which will weak components partly. ANSYS analysisshows that joints designed by using formulas in JGJ99-98slippage occurres beforesteel reaches yield strength, however, the destruction of specimens with jointsdesigned by using formulas in this thesis are located at the bottom of the components,and intensity of joints is larger than components’, the load-displacement curves of specimens are similar to the completed steel columns’, which means joints don’tweaken intensity of components. Formulas in thesis are only related to sectionaldimensions instead of position and loads of joints, which is quiet convenient fordesigning. This thesis makes formulas in Japanese specification more simply.According to JGJ99-98, this thesis designs joints through allocating the internalforces of flanges and webs by using full section instead of net section, consideringbending moment transfer coefficient of webs, which means formulas in this thesis aremore reasonable and reliable.