Study On Lateral-Torsional Buckling Of Splicing Steel Beams With End Plate Joints At Elevated Temperature Based On ABAQUS

In recent years, the steel structures of more green and eco-friendly has been more popular in China. However, the poor fire resistance and more serious damage after fire cannot be ignored, which restricted the application of steel constructions to some extent. Splicing steel beams were widely used in the portal frame industrial building, large trading market and warehouse building of large span buildings as a common structure form. On the one hand, these buildings are more likely to fire than the civil architecture, and then the lateral-torsional buckling capacity of steel beams were largely reduced as the material performance degradation at the elevated temperature which often control the damage of steel beams. Therefore, it is important to research the splicing steel beams in fire.Firstly, the similar model was been verified by finite element analysis according to test date of other researcher. A splicing and tilted steel beam from engineering was been simplified considering the geometric nonlinearity, material nonlinearity and residual stress, then the lateral-torsional buckling capacity was been obtained at different temperatures within the range of 20—700?. At the same time, the results was also been obtained according to the Chinese code CECS200:2006 and European code EC3:1.2. Results show that the capacity of codes is lower than the finite element with the temperature increasing, and the lateral-torsional buckling capacity of splicing steel beams was increased compared with no joints steel beams which the enhancement is vary with temperature and the most increasing is 9.2% at 500?. The effect of joint bending stiffness on lateral-torsional buckling capacity has been researched which shows that its influence is very small. The capacity improvement of splicing steel beams was also been theoretical analyzed according to the capacity increment of steel beams with U-steel stiffeners.Then the six parameters were researched which has effect on the lateral-torsional buckling capacity of splicing steel beams including the load form, joint location, nonuniform-temperature distribution, section changes, the initial geometry defects and beam span aiming at the capacity increments of splicing steel beans than no joint steel beams. The parametric analysis showed that the temperature gradient, the highest temperature and span are the main factors which are related to the lateral-torsional buckling capacity of splicing steel beams. Finally, the design method of lateral-torsional buckling capacity of splicing steel beams was analyzed according to the results of parametric analysis. The formulas with simple in form and high accuracy were proposed by means of data fitting which is a good foundation for the application in engineering.The main innovative point of this article has three aspects: 1)analysis the overall stable performance of the splicing steel beam with end-plate joints with the finite element ABAQUS; 2)the theory solution of splicing steel beam is been put up according to the energy principle; 3)the improve coefficient formula of splicing steel beam is proposed with the parameter analysis and data fitting.