| The development and application of high performance steel has greatly facilitated the construction industry.It also allows the inspiration of structural engineered to be fulfilled.Wuyang steel plants developed the first type of high performance steel,namely GJ steel in our country,and it has now mastered the technologies for manufacturing and quality control.However,the load capacity of GJ steel members has not been fully investigated.Research studies on structural members fabricated by Q345 GJ and Q460 steel showed that the members could develop higher global buckling resistances than the values calculated from GB50017-2003 and Eurocode 3.With the financial support provided by the National Natural Science Foundation of China(No.51578089),the author's research group conducted experimental tests and numerical simulations on the global buckling behavior of welded Q460 GJ steel box column subject to axial compression.The following conclusions were obtained.(1)Residual stresses in welded box columns were measured by using sectioning method.Test results showed that the maximum value of residual compressive stresses was lower than that in traditional steel columns.(2)Eight welded Q460 GJ steel columns were tested under axial compression.Test results suggested that the global buckling resistances of the columns were higher than those calculated in accordance with GB50017-2003 and Eurocode 3,but lower than the values determined from ANSI/AISC360-10.(3)It was concluded in the experimental tests that the difference between test and calculated values was associated with the normalized slenderness and width-thickness ratio of steel columns.(4)The effects of initial bending and residual stresses were studied through numerical modellings.It was found that the initial deflections had a significant influence on the load capacity against global buckling.(5)Parametric studies were conducted to identify the factors dominating the global buckling resistance.Based on experimental and numerical results,design recommendations were provided for the global buckling design of welded Q460 GJ steel box columns under axial compression.Novelties:(1)This study represents the first attempt to determine the global buckling behavior of Q460 GJ steel columns.It also provided a good understanding of the differences between experimental and calculated load capacities and recommended a relatively accurate design method for this type of columns.(2)The distribution mode of residual stresses on welded box sections were measured for the first time,and comparisons were made with conventional Q460 steel box columns to highlight the differences.(3)This study represents the first attempt to research the influence of initial imperfection on global buckling resistance of Q460 steel box columns. |
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