TY  - EJOU
AU  - Zhang, Zhenyu 
AU  - Jin, Quan 
AU  - Zhang, Haitao 
AU  - Liu, Zhao 
AU  - Wu, Yuyang 
AU  - Zhang, Longfei 
AU  - Yan, Renzhang 

TI  - Bending Stiffness of Concrete-Filled Steel Tube and Its Influence on Concrete Placement Timing of Composite Beam-String Structure
T2  - Structural Durability \& Health Monitoring

PY  - 2025
VL  - 19
IS  - 1
SN  - 1930-2991

AB  - When the upper chord beam of the beam-string structure (BSS) is made of concrete-filled steel tube (CFST), its overall stiffness will change greatly with the construction of concrete placement, which will have an impact on the design of the tensioning plans and selection of control measures for the BSS. In order to accurately obtain the bending stiffness of CFST beam and clarify its impact on the mechanical properties of composite BSS during construction, the influence of some factors such as height-width ratio, wall thickness of steel tube, elasticity modulus of concrete, and friction coefficient on the bending stiffness are analyzed parametrically by the numerical simulation technology based on an actual project. The calculation formula of the equivalent bending stiffness of CFST is also established through mathematical statistical simulation. Then, the equivalent bending stiffness is introduced into the construction and use stages of the composite BSS, respectively, and the mechanical properties such as prestress-tensioning control value, structural deformation, and internal force of key members are comparatively analyzed when adopting two different construction plans. Moreover, the optimal construction plan of concrete placement first and then prestress-tensioning is proposed.
KW  - Beam-string structure (BSS); concrete-filled steel tube (CFST); bending stiffness; timing of concrete placement; prestress-tensioning

DO  - 10.32604/sdhm.2024.053190