Open Access

ARTICLE

Bending Stiffness of Concrete-Filled Steel Tube and Its Influence on Concrete Placement Timing of Composite Beam-String Structure

by Zhenyu Zhang¹, Quan Jin¹, Haitao Zhang¹, Zhao Liu¹, Yuyang Wu², Longfei Zhang², Renzhang Yan^2,*

1 CCCC Third Highway Engineering Co., Ltd., Beijing, 101300, China
2 School of Civil Engineering, Chongqing Jiaotong University, Chongqing, 400074, China

* Corresponding Author: Renzhang Yan. Email:

Structural Durability & Health Monitoring 2025, 19(1), 167-191. https://doi.org/10.32604/sdhm.2024.053190

Received 26 April 2024; Accepted 25 June 2024; Issue published 15 November 2024

Abstract

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.

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Keywords

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