Numerical analysis of square concrete‐filled double‐skin tubular columns with outer stainless‐steel tube

With the advancement in the concrete technology, the application of precast concrete elements in the buildings and road infrastructures is increasing very rapidly. One of such applications is the use of precast hollow concrete elements in the bridge construction. As the conventional steel reinforcement is highly susceptible to corrosion, the use of non‐corrosive reinforcement in precast hollow concrete piers and piles of bridges could be a good option for the durability of bridge structures., In this regard, hollow concrete columns reinforced with fiber‐reinforced polymer (FRP) have been considered as a potential solution to overcome the structural deterioration due to corrosion. In the past, limited studies have been carried out on hollow concrete columns reinforced with FRP, consequently, the behavior of such columns is not fully understood. Therefore, to comprehensively evaluate the behavior of hollow concrete columns for various design parameters, a finite element model (FEM) was developed in this study using the commercial tool “Abaqus”. The model was developed and verified based on the experimental results of studies conducted by two independent research groups on circular concrete columns. The proposed model well predicted the peak loads with an error less than 10% and the failure modes of the tested columns. The verified constitutive relation and establishing method were further employed to conduct parametric evaluations to observe the influence of different parameters, such as inner‐to‐outer diameter ratio, longitudinal reinforcement ratio, lateral reinforcement ratio, and concrete strength, on the behavior of hollow concrete columns. Parametric analyses show that reduced inner‐to‐outer diameter ratio and larger longitudinal or lateral reinforcement may lead to higher peak load and confined concrete strength. Finally, based on the experimental and FEM evaluations, the strength prediction equations were developed for the analysis and design of hollow concrete columns reinforced with GFRP bars.

Section: Meshing and Selection Of Element Typementioning

confidence: 99%

Numerical evaluation of axial compressive behavior of hollow concrete columns reinforced with GFRP bars and spirals

Tahir

Karam

Hassam

et al. 2023

“…Concrete‐filled steel tubular (CFST) columns are widely utilized in various modern building structures, especially in high‐rise buildings, owing to their excellent structural performance, which includes large energy‐absorption capacity, high ductility and stiffness 1–4 . As a member of the CFST column family, recently, an innovative composite column referred to as concrete‐filled double‐skin steel tubular (CFDST) columns with concrete infilled between the two centric tubes has captured the interests of researchers 5–9 .…”

Section: Introductionmentioning

confidence: 99%

“…performance, which includes large energy-absorption capacity, high ductility and stiffness. [1][2][3][4] As a member of the CFST column family, recently, an innovative composite column referred to as concrete-filled double-skin steel tubular (CFDST) columns with concrete infilled between the two centric tubes has captured the interests of researchers. [5][6][7][8][9] The flexural stiffness and fire resistance of CFDST columns are higher compared to CFST columns.…”

mentioning

confidence: 99%

Performance analysis and design of circular high‐strength concrete‐filled double‐skin aluminum tubular short columns under axial loading

Yan

Ahmed

Hassanein

et al. 2023

This study investigates the performance and design of high‐strength circular concrete‐filled double‐skin aluminum tubular (CFDAT) columns under axial loading. A new fiber element (FBE) model incorporating a new lateral confinement model is developed that considers the confinement effects and material nonlinearities. A new strength degradation factor is proposed for determining the postpeak behavior of the confined concrete in CFDAT circular columns. Existing experimental results are used to validate the accuracy of the predicted ultimate strength and axial load‐strain () curves of CFDAT columns under axial loading. A comparison of the predictions of the ultimate strength and curves of CFDAT columns using the proposed lateral confinement model is made against the prediction using the three‐dimensional finite element modeling and the existing lateral pressure model of CFDAT columns proposed by other researchers. The performance of the CFDAT columns under axial loading is investigated using a detailed parametric study. The accuracy of existing empirical formulas given in various design standards for conventional concrete‐filled steel tubular columns as well as given by another researcher in predicting the ultimate strength of CFDAT columns is examined. Finally, a simple design formula is proposed and validated against the experimental and numerical results obtained from this study. It is found that the proposed FBE model and the simplified model developed in this study can accurately predict the performance of CFDAT columns under axial loading.

“…However, both the studies 14–18 and engineering practices on the axial compression mechanical behavior of the ordinary SCFST columns have shown that the smaller the tube wall width‐to‐thickness ratio was, the higher the bearing capacity and ductility were. However, it is still unknown‐‐whether increasing the tube wall thickness or setting longitudinal stiffeners could directly constrain core concrete and effectively improve the bearing capacity and ductility.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical studies on mechanical behavior of stiffened concrete‐filled square steel tube columns subjected to axial compression

Sun¹,

Xu²,

Zuo³

2022

In this study, nine square concrete‐filled steel tubular (SCFST) columns considering longitudinal stiffeners as parameters were produced to investigate the axial compression mechanical properties of SCFST columns in the condition of constant steel consumption. This included one specimen without stiffeners, three specimens stiffened with one stiffener on each tube wall, two specimens stiffened with two stiffeners on each tube wall, two specimens stiffened with three stiffeners on each tube wall and one specimen stiffened with four stiffeners on each tube wall. Simultaneously, numerical simulations were performed under identical conditions using ABAQUS software. The results showed that the longitudinal stiffeners can act as an out‐of‐plane restriction support to delay the development of local buckling of the steel tube, which indirectly improved the constraint effect of steel tube on core concrete. First, both the number of local buckling and the ultimate displacement of the specimens grew correspondingly when the number of stiffeners increased. As the sub‐wall width‐to‐thickness ratio was increased, the steel tube became prone to local buckling. Second, the installation of stiffeners decreased the confinement effect of steel tube on the core concrete, in which the sub‐wall width‐to‐thickness ratio and the stiffener width‐to‐thickness ratio had a great influence on the ultimate bearing capacity of the specimens. Further, the experimental outcomes indicated that the bearing capacity of stiffened specimens was less than that of the unstiffened specimen. The bearing capacity of the specimens stiffened with three and four stiffeners was higher than that of the specimens stiffened with one and two stiffeners. Third, the stiffener width‐to‐thickness ratio had a considerable impact on the ductility of the specimens. The ductility of specimens stiffened with one and two stiffeners was greater than that of the specimens stiffened with three and four stiffeners. Finally, the finite element simulations were consistent with the experimental process. The confinement factor of stiffened specimens became enlarged when either the number of stiffeners in the same thickness condition increased or the thickness of steel tube wall under condition of the same number of stiffeners grew.