Study On The Mechanical Properties Of Inclined Concrete-Filled Steel Tubular Stub Columns

Mechanical properties of inclined concrete-filled steel tubular (CFST) stub columns subjected to longitudinal loading were investigated in this paper, including theoretical and experimental studies. Based on the systematic analysis of parameters and calculating comparison of different design codes, practical computational methods for longitudinal loading bearing capacity of inclined CFST stub columns were suggested.Experimental studies were performed on sixteen inclined CFST stub columns under longitudinal loading to analyze the influence of sectional type and inclined angle on mechanical properties and failure modes of inclined circular and rectangular CFST columns.Based on the actual material attributes, nonlinear finite element software ABAQUS was adopted to establish the analytic models of inclined CFST stub columns, which was used to calculate the whole process of load-deformation of the inclined stub columns subjected to longitudinal loading, and the calculated results showed good agreements with the experimental results.Finally, the theoretical model of finite element expansion analysis could be determined on the basis of above work.Then, according to the theoretical material attributes, finite element expansion analysis was carried out, the main parameters of which included inclined angle, steel strength, concrete strength and sectional steel ratio, to study the influence of these parameters on bearing capacity and the interaction between steel tube and concrete of columns.Calculations were made on bearing capacity of straight CFST stub columns with different codes, including ACI (2005, American), AISC (2005, American), AIJ(2008, Japan), BS5400(2005, England), CECS159:2004 (2004, China), DL/T5085-1999(1999, China),and DBJ13-51-2003(2003,China), to make sure the most fit bearing capacity equations of CFST stub columns in the range of test data through comparison between the calculated results and tests ones.The calculating equations on compression bearing capacity of inclined CFST stub columns subjected to longitudinal loading with circular and rectangular sections were suggested, respectively. Then the calculated results of finite element models and the tests were analyzed to prove applicability of the new equations.The consequence indicates that the equations can supply practical engineering and specifications with reliable references.