Seismic Optimization Analysis of Vertical Stiffener Connection to L-CFST Column

Abstract

In this paper, 14 models in two series were designed and numerically analysed based on the results of quasi-static tests of vertical stiffener connections to L-CFST columns. For the fracture problem of the beam flange connecting plate at the end of the vertical stiffener, four optimization methods were proposed and compared in the H300 series: tapered vertical stiffener, flush vertical stiffener with beam flange, reduction beam section and thickened beam flange connecting plate. For the problem of the vertical stiffener fracture along the column flange, the effect of the vertical st iffener sectional area and width-to-thickness ratio were considered and analysed in the H400 series. The skeleton curves, Von Mises stress distribution and fracture index of each model in the two series were compared. The crack propagation on the beam flan ge connecting plate and vertical stiffener can be reduced and even eliminated using a thickened connecting plate and a minor width-to-thickness ratio, respectively. A calculation method for the flexural capacity of the vertical stiffener connection to the L-CFST column was proposed. Good consistency was observed between the theoretical and test results of both yield and ultimate flexural capacity. Finally, a design example of the flexural capacity of the connection is provided to guide the engineering practice.