Research on the Calculation Method of Skeleton Curve of Variable Cross Sectional Concrete Filled Steel Tubular Laced Columns with Flat Lacing Tube

摘要

Variable cross-sectional Concrete Filled Steel Tubular (CFST) laced column with flat lacing tube is a kind of emerging combination column; it has broad application prospects in high pier bridges and high-rise buildings. The finite element analysis method of CFST laced columns is built with universal program of OpenSEES, and the influence of structural parameters on seismic performance of CFST laced columns is researched. Then the calculation method of skeleton curve of variable cross-sectional CFST laced columns is studied referencing the computing framework of hysteretic model of CFST single tube column and equal sectional laced column, the calculation formula of elastic stiffness, horizontal peak load and its displacement, fall-period stiffness are developed respectively. Engineering examples verifications of Gan haizi bridge's laced column pier are processed with OpenSEES program, and research results indicated that the calculated values are coincident well with numerical results. Finally a rational method to calculate the skeleton curve of variable cross-sectional CFST laced columns with flat lacing tube is provided on the basis of the analytical results.