Study On Overall Stability Of Welded Q460GJ Steel Axial Compressed H-shaped Members

As a kind of high performance material which is suitable for large span space steel structures and super high-rise steel structures,GJ steel has been used in many important construction projects.Compared with common low alloy high strength structural steel,GJ steel has a good application prospect.However,for the GJ steel,the research work is relatively scarce,and the design parameters are not included in the relevant specifications,which hinder the application and promotion of GJ steel.So for GJ steel,especially for high strength GJ series steel,there are still a lot of basic research work to do.Based on the prophase preparation for the research work of Q460 GJ steel,in this paper,the experimental study on the overall stability of Q460 GJ steel welded H section axial compression members,the finite element analysis of global stability of axial compression members,and Study on the column curves of Q460 GJ steel welded H section members are carried out.The experimental research mainly includes the long column axial compression test,which is mainly based on the previous material test and residual stress test.The material properties test has 12 mm,25mm and 42 mm these three specifications of the plate thickness.According to the different thickness of flange and web,the component measured by the residual stress test is divided into 2 categories and 8 kinds of cross section.The components of the axial compression test are divided into 14 components according to the sectional specification and length.The sectional specification is consistent with the residual stress test.The experimental study of long column around weak axis is carried out.The finite element analysis of the integral stability of axial compression members,establishes a finite element analysis model,which takes the initial geometric imperfections and residual stresses into account.Meanwhile,the process of establishing finite element model is introduced in detail.At the same time,the finite element analysis results are compared with the test results,which verifies the accuracy and reliability of the model.Meanwhile,the finite element analysis and experimental values are compared with the theoretical values.In the study of the column curve,the integral stability coefficient of 208 components with different radius of gyration,different section sizes and lengths are calculated,through the comparison with China,the United States and Europe,three countries and regions of the steel structure design code.The selection of the type of the Q460 GJ steel welded thin H shaped member and the thick H shape column curve is suggested,and presents a design method for the application of Q460 GJ shaped steel welded H members in Engineering.The innovations of this paper are as follows:(1)Through the research of this topic,it will benefit the performance advantages of Q460 GJ steel on the component level.The performance advantages are reflected by the corresponding design parameters and serve the major domestic engineering projects.(2)By introducing the distribution patterns of residual stress obtained by our team and taking account of the factors of geometric initial imperfections,the overall stability of welded Q460 GJ steel axial compressed H-shaped members can be accurately analyzed.(3)A reasonable test scheme is designed to obtain more reasonable ultimate bearing capacity limit of Q460 GJ steel axial compression members.By means of parametric analysis,a large number of column curves are obtained,and a more rational proposal for curve selection could be given by comparing the column curves with the codes of other countries.At the same time,the performance database of GJ steel axial compression members is enriched,and In order to obtain the uncertainty of calculation model for welded Q460 GJ steel axial compressed H-shaped members based on the theory of structural reliability,the foundation of the calculation model is given.