Flexural behavior of composite continuous girders with concrete-filled steel tubular truss chords

To study the flexural behavior and the calculation method of composite continuous girders with concrete-filled steel tubular(CFST)truss chords,model tests and theoretical analysis were carried out. The strain distribution,deformation property,failure mode,flexural bearing capacity of both the positive and negative bending moment area of composite continuous girders with CFST truss chords were studied. The calculation method for the flexural bearing capacity for both the positive and negative bending moment area was also discussed. The brace and the joint in the positive and negative bending moment area of composite continuous girders with CFST truss chords has higher strength and stiffness,and it can make sure that the failure of the joint is not prior to that of the whole section. The strain changes linearly along the depth direction of the cross section,and it meets the plane-section assumption. The flexural bearing capacity failure mode of the positive and negative bending moment area are that the full cross section of the chord and the rebar used in the concrete bridge deck slab yield,respectively. The contributions of the web members to the flexural bearing capacity in the positive and negative bending moment area of composite continuous girders with CFST truss chords are 12.5% and 8.6%,respectively. The calculation method considering the contributions of the web members to the flexural bearing capacity for composite continuous girders with CFST truss chords is put forward. The deviation between the result acquired by the calculation method for the flexural bearing capacity above and that acquired by the test and finite element analysis is less than 8.1%. © 2024 Editorial Board of Jilin University. All rights reserved.