A Study On Overall Stability And Deflection Of Castellated Beams With Hexagonal Openings

Because of its high strength, light weight, perfect seismic performance, easy to assemble, high degree of industrialization, high recovery rate and it’s environmentally friendly, steel structure application in our country have got a rapid development in recent years. Compared with traditional solid-web beam, because of it’s advatages such as rational section forms, light-weight, nice and economic, castellated beam has a good prospection for it’s development.Current<Code for design of steel structures (GB50017-2003)> didn’t made any design rules about castellated beam member.<Code for design of steel structures (draft)> only made deflection calculation rules about castellated beam member which has a span-height ration between 18～40, but any castellated beam member which has a span-height ration out of range will no longer applicable with this code. Parameters affect castellated beams’ mechanical properties changing with different production methods, but<Code for design of steel structures(draft)> was not treated differently. In some extent, these problems severely restricted castellated beams’ widely use and development in China.At first, this paper introduced the characteristics and production methods of castellated beams, as well as its research and application status.Then, analyze its flexural-torsional buckling with ANSYS and energy principle.In addition, this paper has done a lot of research about deflection of castellated beams. Using ANSYS to analyze castellated beams’ deflection. Meanwhile, using the classical theory of mechanics of materials to consider the beam bending and shear deformation, simplified truss theory was used to consider the additional deflection, theoretical formulas of deflection and overall stability are conducted. Compared FEM and theoretical solution, a set of simplified design method of castellated beams about deflection is put forward for the desigh.On the basis of the theoretical formula deduced before and FEM, analyzed the main factors influencing the castellated beams’ deflection and overall stability. Theoretical formulas of deflection and overall stability are conducted and a set of design method of castellated beams is put forward for the desigh and practical applications relevant reference of castellated beams.