| Researches on the steel beam-to-column connections always focus on the bearing capacity and deformation performance,but it is a complicated process.A simplified method called component approach was widely used to analysis the mechanical behaviors of beam-to-column connections.The equivalent T-stub is the elementary component according to component approach.Therefore,researches on T-stub connections are necessary to get a better understanding on the mechanical behaviors of the beam-tocolumn connections.It was found that most of the relevant researches were only for the low-carbon steel T-stub through the literature review,while there is still lack of systematic experimental and numerical analysis on the stainless steel T-stub.The stainless steel has better corrosion resistance,high temperature resistance and plastic deformation performance compared with the low-carbon steel.China is the largest producer of stainless steel,and the level about the application of stainless steel in the construction engineering is also much higher than the world average level.For this reason,this thesis carries out a series of experimental studies and finite element analysis on welded stainless steel T-stubs to provide insight into the influence of different variables on the mechanical properties of these joints and an effect reference for engineering design.This thesis mainly carries on the static tensile test on the welded stainless steel Tstub connections,at the same time the relevant low-carbon steel T-stubs with the similar material properties are also tested to observe the differences on the tensile behaviors between the two kinds of T-stubs directly.All the material properties of the plates and bolts used to fabricate the T-stubs were tested in order to ensure the reliability of the finite element analysis.Finally,a comprehensive parametric analysis is performed on the welded stainless steel T-stub based on the results of the tensile tests and related material test,and the following conclusions are obtained:(1)The main variables affecting the mechanical properties of welded stainless steel T-stub include flange width,bolts gauge,weld throat thickness and the bolt diameter.The increase of the flange width,weld throat thickness and bolt diameter improves the initial stiffness and resistance.But the increase of bolts gauge the will reduce these properties.(2)In the case of a certain bolt hole spacing,the influence of the flange plate length on the mechanical properties is negligible.The ratio of n/m influences the mechanical properties of T-stub in some way,while there is not a uniform law of the effect for the different T-stubs.(3)The bolt pretension only influences the elastic stage of welded stainless steel Tstub,which means the increase of the bolt pretension only improves the initial stiffness and plastic resistance of T-stub and has no influence on the ultimate resistance through(4)T-stub with backing plates has higher initial stiffness,plastic and ultimate resistance than the one without.And the backing plates can reduce the bending deformation of the flange plate effectively and the ductility of the joints.(5)When the constituent materials have similar mechanical properties and the size of specimen is the same,the most significant difference between the stainless steel and low-carbon steel T-stub is the ductility,and the former is much better.While the other mechanical properties are similar.This thesis contains the following innovations:(1)The comparison of the mechanical properties of low-carbon steel and stainless steel T-stubs was made by the tests.(2)A comprehensive experimental study and parameter analysis on the welded stainless steel T-stub were carried out and obtained the main influence variables of the mechanical properties.(3)The bolt pretension and the backing plates were taken into consideration to investigate the influence on the performance of the welded stainless steel T-stub. |
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