The Theoretical Analysis And Research Of Design Method On Ultimate Tensile Strength Of Gusset Plate Connections To Slotted Tubes

Hollow structural Sections (HSS) are commonly used as members in space trusses and lattice shells or as bracing members in steel-framed buildings. The tubes are frequently slotted onto gusset plate to simplify fabrication and avoid profiling. These joints are known as gusset plate connections to slotted tubes which can be strengthened by welded hollow sphere or cambered plate. As yet, some design proposals abroad are only valid to gusset plate connections to slotted tubes which aren't strengthened. In China, the study of gusset plate connections to slotted tubes is initiatory, for which there isn't design proposal in Code for Design of steel structures.Based on the experimental study around the world, analysis of nonlinear finite element for ultimate tensile strength of gusset plate connections to slotted tubes with ANSYS program are carried out in this dissertation. Effects of configuration, material properties and geometrical parameters were considered in the numerical study. In the study of gusset plate connections to slotted tubes which aren't strengthened, the influence of nondimensional parameterαon failure mode and ultimate tensile strength is mainly considered. In the study of gusset plate connections to slotted tubes which are strengthened by welded hollow sphere, the influence of nondimensional parametersβandγon failure mode and ultimate tensile strength is mainly considered. In the study of gusset plate connections to slotted tubes which are strengthened by cambered plate, the influence of dimensional parametersθand nondimensional parametersδon failure mode and ultimate tensile strength is mainly considered.Because only a part of the tube cross-section is connected to the plate, these gusset plate connections to slotted tubes which are under tension loading can be susceptible to failure in the net area of the HSS due to shear lag. As far as the gusset plate connections to slotted tubes which aren't strengthened are concernde, shear lag is serious andαis decisive of failure mode. When the joints strengthened by welded hollow sphere, shear lag is obviously weaker since the welded hollow sphere can transfer a part of tension load and geometrical parameters of the welded hollow sphere are the primary factor of ultimate tensile strength. When the joints strengthened by cambered plate ,with the increasing of cambered plate's length, there is an obvious improvement on the performance under tension loading on condition thatθ≥65. In the basis of the results of finite element analysis, design proposal for the ultimate tensile strength of gusset plate connections to slotted tubes is recommended, in which the influence to coefficient for shear lag net section fracture calculation of the factors such as f u f y,α,β,γ,δandθis defined. It is significant to establish design formula of gusset plate connections to slotted tubes and perfect design formula of steel tension member and it also can give some advices to practice engineering.