Circular Steel Tubular Columns Research Articles

Optimum embedment depths for CFST column-to-foundation connections: Analytical and reliability-based approach

In the present study, the pullout capacity models were developed to derive analytical expressions for the minimum required depths of embedment for conventional and two recently published schemes of connection for circular and square concrete-filled steel tubular (CFST) columns. The models were developed by equating the pullout strength of the tube with the pullout capacity of the reinforced concrete (RC) footing. The pullout capacity of the RC footing was a function of the strength of cement grout, footing concrete, and RC footing reinforcement. The analytical expressions derived for the minimum required depths of embedment were utilized to deduce limit state functions. These limit state functions were then employed for the reliability calculations by means of the Monte Carlo Simulation (MCS) technique. The reliability calculations provide optimum embedment depths for CFST columns for the given reliability level. It was shown for the required reliability index of 3.0, the requirements of nominal embedment depth for the second column-to-foundation connecting scheme for circular and square CFST columns are 37.3% and 45.2% less than their corresponding first schemes of connection. This outcome proves the superiority of the second scheme (as a result of mechanical interlocking) over the first scheme. A few parametric studies were also conducted to obtain results of practical value.

Eccentric compressive performances of circular steel-reinforced concrete-filled stainless steel tubular column

Steel-reinforced concrete filled stainless steel tube (SRCFSST) columns are predicted to offer excellent durability, load bearing capacity, ductility, fire resistance, impact resistance, and seismic performance. Therefore, eccentric compressive tests of 18 circular SRCFSST columns were carried out to investigate the effects of the slenderness ratio, load eccentricity, and embedment of carbon-profiled steel (CPS) on circular SRCFSST columns. The ultimate strength and ultimate deflection of the composite columns were improved significantly after the CPS was embedded. A finite element (FE) model was established and the FE analysis indicated that the CPS was proved to be an effective means of constraining concrete. Based on the FE parametric analysis, it was shown that the stability coefficient decreased with increasing concrete strength, proof strength of stainless steel, and CPS yield strength, but increased with increasing rotation radius-diameter ratio. The greater the concrete strength, the more similar the N∼M interaction curves of the SRCFSST columns and reinforced concrete columns. The higher the CPS yield strength, stainless-steel ratio, slenderness ratio, carbon steel ratio, or proof strength of stainless steel, the more similar the interaction curves of the SRCFSST columns and profiled steel columns. Finally, the simplified model was refined to forecast the carrying capability of a circular SRCFSST specimen under the eccentric compression.

Compressive performance of eccentrically double-cell concrete-filled circular steel tubular columns

This paper presents a series of tests conducted on axial compression of concrete-filled steel tubes with double inner circular steel tubes (DIC-CFST) stub columns. The DIC-CFST stub columns are composed of four elements: an outer circular steel tube, two inner hollow circular steel tubes arranged symmetrically along the diameter of the outer tube, and concrete filling the space between the three steel tubes. A total of 27 specimens with varying eccentricity ratio (e), hollow ratio (ψ), and concrete strength (C) were subjected to the tests. The results indicate that under axial compression, noticeable local buckling failures occur in both the inner and outer steel tubes. Concrete failure manifests as vertical through cracks and circumferential crushing zones. The load-deformation curve of the specimens remains essentially the same as that of a full-section concrete-filled steel tube. A general positive correlation exists between the ultimate bearing capacity and the strength of concrete, and the range of eccentricity ratio and hollow ratio significantly influences the relationship between these two parameters and the ultimate bearing capacity of the specimens. As the concrete strength increases, the initial stiffness exhibits a noticeable increase. Conversely, the initial stiffness experiences a significant reduction with an increase in the hollow ratio. The ductility decreases with increasing concrete strength and eccentricity ratio. Furthermore, in comparison to the AISC 360–10 Specification, Eurocode 4, and Han's method, the calculation formula proposed in this paper for determining the ultimate bearing capacity of DIC-CFST stub columns has exhibited superior accuracy.

Seismic behavior of polypropylene fiber reinforced rubber concrete-filled circular steel tubular columns

In this study, the seismic behavior of polypropylene fiber reinforced rubber concrete-filled circular steel tubular columns subjected to low cyclic loading was investigated. The effects of varying rubber content, slenderness ratio, axial compression ratio, and steel content on specimen damage were analyzed. Digital Image Correlation (DIC) and Acoustic Emission (AE) instruments were utilized to monitor the full-field strain on the surface of the specimens and the generation and development of internal concrete cracks. A fiber modeling method was developed for calculating the compression bending bearing capacity of the columns. The results indicated a uniform failure pattern, primarily located at the column base. Adding rubber powder decreased the bearing capacity of the specimen, yet enhanced their energy dissipation capacity and ductility. Higher axial compression ratio led to early failure in the steel tube, with the slenderness ratio significantly affecting seismic performance. The calculation methods according to GB 50936–2014 (CECS 254–2012) and DL T5085–1999 showed higher accuracy than other codes, with average values of 0.558 and 0.576, and standard deviations of 0.067 and 0.089, respectively. The variation coefficient for the calculation method in GB 50936–2014(CECS 254–2012) was 12.02%, lower than that of DL T5085–1999. The proposed fiber modeling method demonstrated superior calculation accuracy, with an average value of 0.957, a standard deviation of 0.032, and a variation coefficient of 3.29%.

Numerical analysis of circular steel–reinforced concrete-filled steel tubular stub columns

This paper presents a computational model for determining the axial responses of short circular steel–reinforced concrete-filled steel tubular (SRCFST) columns. A novel confinement model is formulated for the concrete core, which is effectively confined by the external circular steel tube and the embedded steel section. The modelling scheme of the confinement is programmed using a mathematical model that utilises fibre-element discretisation of column cross-sections. The numerical predictions are verified by experimental measurements and results obtained from finite-element analysis, demonstrating the accuracy of the modelling technology. In addition, existing concrete confinement models for concrete in circular concrete-filled steel tubular columns are assessed. The new confinement model is shown to be superior in replicating the responses of SRCFST columns. The influences of the design parameters on the column's performance are numerically investigated and ranked in order of importance through a sensitivity analysis. In this study, not only is the validity of current design standards in determining the axial load capacity of SRCFST columns examined but a new design formula is also proposed. The proposed confinement model can be employed in numerical procedures for the inelastic simulation of SRCFST columns; the design formula is suitable for use in practical design.

Study on Eccentric Compression Mechanical Characteristics of Basalt Fiber-Reinforced Recycled Aggregate Concrete-Filled Circular Steel Tubular Column

During this study, eight basalt fiber-reinforced recycled aggregate concrete-filled circular steel-tubular (C-BFRRACFST) column specimens were subjected to eccentric compression tests with different replacement ratios of recycled coarse aggregate (RCA), basalt fiber (BF) contents, length-diameter (L/D), and eccentricity. The whole process of stress as well as failure mode of the specimens were observed, and a load–displacement curve as well as a load–strain curve for the specimens were measured. The impacts of various parameters upon the bearing capacity, peak displacement, and ductility coefficient of the specimens were analyzed. Subsequently, a 3D finite element model of the C-BFRRACFST column was established, and the whole process of stress was simulated. Based on the finite element simulation results, the N/Nu-M/Mu correlation strength curve of the C-BFRRACFST columns was verified. The exploration demonstrated that under eccentric load, the C-BFRRACFST column eventually underwent destruction of the overall instability. The load–axial displacement curve was characterized as three stress stages: elastic, elastic–plastic, declining, as well as declining stages. The strain of the mid-span section for the specimens follows the plane section assumption, and the lateral deflection basically follows the sine waveform curve. The ultimate bearing capacity of the specimens exhibited little change as the replacement ratio of RCA improved, while the ductility progressively reduced. Furthermore, the ultimate bearing capacity of the specimens failed to be obviously changed as the BF content enhanced, while the ductility progressively rose. Increasing the L/D gradually reduced the specimen’s ultimate bearing capacity alongside its ductility. The corrected N/Nu-M/Mu curve agreed well with the findings of finite element simulation.

Mechanical behavior and design applicability of ultra-high-performance concrete-filled circular steel tubular short columns under axial compression

This paper presents the results of axial compression tests conducted on 12 short columns made of ultra-high-performance concrete-filled steel tubes (UHPCFST) with different diameter-to-thickness (D/t) ratios and steel fiber contents. The study aimed to investigate the interaction between infilled concrete and steel tubes as well as the confinement effect on the compressive behavior of UHPCFST short columns. Two types of load–displacement curves were observed in the test, which were related to the D/t ratio of the steel tube. Besides, the results showed that columns with smaller D/t ratios exhibited higher strength enhancement and better post-yield performance due to increased concrete confinement. Furthermore, the presence of steel fibers improved the post-yield ductility of the columns but did not significantly contribute to the strength enhancement. Owing to the longer elastic branch and less lateral dilation of UHPC compared to normal-strength concrete (NSC), the establishment of confining effect to UHPC core is relatively later than the yielding of steel tube, leading to a redistribution between axial stress and hoop stress. The test results were compared with current design codes, including Eurocode 4, Chinese code GB 50936, and American code AISC 360. The results showed that Eurocode 4 and GB 50936 overestimated the axial load-bearing capacity when considering the confinement effect of the steel tube, while the calculations by Eurocode 4 without considering the confinement effect and AISC 360 were closer to the test results. Therefore, the consideration of the confinement effect in design is not recommended and a reduction factor of UHPC is suggested to obtain a reliable prediction of the axial load-bearing capacity of UHPCFST short columns as safe as that of the CFST short columns infilled with NSC.

Compression behavior of the concrete-filled double skin steel tube columns under hydrostatic pressure: Experimental and modeling study

This paper conducted an experimental study focusing on the axial compressive behavior of circular concrete-encased concrete-filled steel tubular (CFDST) columns composed of a circular inner steel tube under active confinement. The investigation aimed to explore the impact of concrete compressive strength grades and diameter-to-thickness ratio of steel tubes in the presence of hydrostatic pressure. The effects of varying outer diameter-to-thickness ratios (44, 45.6, 85.84, and 86) and concrete compressive strength grades (10 and 20 MPa) on the performance of CFDST columns were investigated in this paper. Additionally, the study considered the impact of two inner steel tube diameter-to-thickness ratios (20.5 and 39). The experimental results demonstrated that external pressure can significantly enhance both the load-carrying capacity and ductility of the specimens. The ultimate strength of the columns was improved by a minimum of 34% and a maximum of 92%. Finally, empirical formulas for predicting the axial compression capacity of CFDST under active confinement using gene expression programming were presented. The accuracy of the proposed model was then assessed by the artificial neural network, and the results indicate that both models perform well when compared to the empirical equations that take into account the hydrostatic pressure of wet concrete.

Residual stresses in circular steel tubular columns repaired by laser-cladding additive manufacturing

This paper presents a study that investigates the magnitude and distribution of residual stress (RS) in laser cladding (LC) repaired circular steel tubular columns. The study involves experimental tests and numerical simulation. The familiar blind-hole method is employed in the experimental investigation for two RS measurement tests, while the finite element method is used for numerical thermal-mechanical analysis to obtain the temperature field and RS field. The results indicate the presence of residual tensile stress in the LC sheet and its surrounding area. The RS in the LC sheet area and in the vicinity of the LC sheet-substrate boundary is much greater than that in the substrate area located far away from the LC sheet. Additionally, the RS in the LC sheet along the scanning direction is larger than that perpendicular to the scanning direction. Nevertheless, the RS values in both the LC sheet and substrate are less than their respective yield strength values. The temperature-time cooling curves obtained from the finite element analysis, which simulate the laser cladding process for repairing the circular steel tubular column, are used to develop a theoretical model for predicting the RS in the LC sheet. A simplified RS model is proposed based on the thermal-mechanical theory, utilising the linear-exponential two-stage cooling curve. Comparisons between the experimental results and the theoretical results that are predicted using the proposed simplified RS model show both results to be in good agreement. Therefore, the simplified RS model proposed in this paper is suitable for efficiently and accurately predicting the RS in LC sheet for circular steel tubular columns repaired by LC.

The Axial Compression Behavior of Basalt Fiber-Reinforced Recycled Aggregate Concrete-Filled Circular Steel-Tubular Column

Recycled aggregate concrete (RAC) technology has received a lot of attention as a green environmental protection technology. However, the unsatisfactory mechanical behavior of RAC restricts its application in engineering practice. The structure of basalt fiber-recycled aggregate concrete-filled circular steel tubes (C-BFRACFST) can dually improve the mechanical behavior of RAC. To observe the axial compression behavior of the C-BFRACFST column, seven specimens were designed with recycled aggregate replacement ratio (0%, 50%, 100%), basalt fiber (BF) content (0 kg/m3, 2 kg/m3, 4 kg/m3) and length–diameter (L/D, 5, 8, 11) as variable parameters for axial compression tests. The failure mode, load–displacement/strain curve, axial compression deformation, ultimate bearing capacity, energy dissipation, and ductility of specimens have been analyzed. The derived constitutive relation of core basalt fiber-reinforced recycled aggregate concrete (BFRAC) constrained by the circular steel tube and the 3D finite element model of C-BFRACFST column have been established to simulate the whole process of compression. It is observed that instability or shear failure occurs in specimens under axial compression load. When the recycled aggregate replacement ratio was increased from 50% to 100%, the change in the energy-dissipation capacity of the specimens was not significant but the ultimate bearing capacity and displacement ductility coefficient decreased by 3.45% and 8.91%, respectively. When the BF content was increased from 2 kg/m3 to 4kg/m3, the change in the ultimate bearing capacity of specimens was not significant; the energy-dissipation capacity at the later stage of bearing increased, and the displacement ductility coefficient was noted to increase by 13.34%. When the L/D was increased from 8 to 11, the energy-dissipation capacity of specimens was decreased, and the ultimate bearing capacity and displacement ductility coefficient declined by 1.37% and 43.52%, respectively. The finite element simulation results are in agreement with the test results.

Hysteretic performance of circular high-strength concrete-filled double skin steel tubular columns: Experiment

In marine structures, utilizing high-strength materials in concrete-filled double skin steel tubular (CFDST) members can provide an optimized solution upon the tendency of light self-weight and high performance. The cyclic load in the marine environment usually determines the safety margin for whole offshore structures. Therefore, this paper experimentally investigated the hysteretic performance of circular high-strength concrete-filled double skin steel tubular (HCFDST) columns with out-of-code diameter-to-thickness ratios. The typical failure mode appeared with the infill material crushing, steel fracture and local buckling of outer tubes. Subsequently, the detailed analysis of hysteretic curves, skeleton curves and ductility, energy dissipation, stiffness degradation, and lateral force reduction was conducted to reflect the influences of hollow ratios, axial compression ratios, and infill types, e.g., increasing the hollow ratio from 0.54 to 0.68 and 0.82, respectively reduced the bearing capacity by 6.25% and 11.20%, and the ductility coefficient had an apparent decrease of 19.27% and 26.61%. The out-of-code HCFDST columns with reasonable design could behave with favorable hysteretic performance. A theoretical model considering the tensile strength effect of engineered cementitious composite (ECC) was finally established and verified to predict the moment-resisting capacity of HCFDST columns using ECC. The reported research on HCFDST columns can provide significant references to marine structure applications.

Research on Square and Circular Steel Tubular Columns with Deconstructable Splice Joint Under Cyclic and Axial Testing

Abstract: A steel tubular column is a vertical structural member used in construction to provide essential support. Splice joint is a method of joining two members end to end. When the material being joined cannot be obtained in the desired length, the splice joint is used. For high rise buildings the continuity of columns may break, hence splice connections are provided and columns are installed. Splice joints are deconstructable type joints as the failed parts can be repaired, reassembled or can be even removed when failure occurs. These papers focuses on developing models of square and circular cross sections of steel tubular columns with deconstructable splice joint using a finite element software ANSYS and study their structural behavior. This paper includes a parametric study on the effect of axial loading by varying splice length and thickness, bolt diameter and pattern of square and circular cross sections of steel tubular columns with deconstructable splice joints. Bending moment rotation curves were obtained from cyclic load testing for square and circular cross sections

Behavior of concrete-filled circular steel tubular stub columns exposed to corrosion and freeze–thaw cycles

This work experimentally and numerically studies the behavior of concrete-filled circular steel tubular stub columns experiencing corrosion and freeze–thaw cycles. The considered parameters are the corrosion rate, freeze–thaw cycles, and the number of alternations of the corrosion and freeze–thaw cycles. The failure modes and axial load–displacement curves are measured and discussed. The experimental results show that all the columns exhibit shear failure, and the core concrete suffers severe damage as the corrosion rate increases. The residual bearing capacity and ductility coefficient decrease with an increase in the corrosion rate and freeze–thaw cycles. A finite element (FE) model is also developed using the material thickness and strength reduction analysis method and validated using the experiments in this study. Further, a parametric analysis is conducted to identify the influences of the critical parameters on the load–bearing capacity of the columns. The finite element model results demonstrate that exposure to the alternations of corrosion and freeze–thaw cycles significantly influences the residual bearing capacity of the columns: the higher the number of alternations of corrosion and freeze–thaw cycles, the lower the residual bearing capacity of the columns. Finally, a simplified method is proposed for predicting the ultimate bearing capacity of concrete-filled circular steel tubular stub columns exposed to corrosion and freeze–thaw cycles.

Axial compressive performance of ultra-high strength concrete-filled dual steel tubular short columns with outer stiffened tubes and inner circular tubes

Previous literature shows that studies of ultra-high strength concrete-filled dual steel tubular (UHS-CFDST) short columns under concentric compression are rare, and there is no relevant research on ultra-high strength concrete-filled dual stiffened steel tubular (UHS-CFDSST) short columns. In addition, existing design specifications do not include ultra-high strength concrete (UHSC). Therefore, the axial compressive response and resistance of UHS-CFDSST short columns are investigated herein. First, the behaviour of CFDSST columns with normal-strength concrete (NSC) was replicated by finite element (FE) modelling using ABAQUS software. Additionally, the experimental results of square and circular ultra-high strength concrete-filled steel tubular (UHS-CFST) short columns were collected from the available literature, and finite element (FE) modelling is performed accordingly. The results showed that the applied concrete constitutive model is suitable for UHSC and the modelling strategy for UHS-CFST columns and CFDSST columns with NSC is suitable for UHS-CFDSST short columns. Accordingly, parametric studies were carried out on UHS-CFDSST to investigate the effects of geometrical and material properties of different steel and concrete components on the performance of these columns. It was found that the strength of the sandwiched concrete has the greatest effect on the resistance of the columns compared to the other parameters considered. Finally, the axial resistance of the UHS-CFDSST short columns was compared to the resistances calculated by using the European, British and Chinese codes, and it was found that the Chinese code gives the best results.

New confining stress-based design for rubberised concrete-filled single/double-skin steel tubular short columns

Despite being characterised by a reduction in compressive, tensile and flexural strengths when compared to standard concrete, rubberised concrete (RuC) is being used as a way to conserve natural resources and reduce the amount of tires entering landfills. An excellent solution to limit the RuC's compressive strength drop is to incorporate this type of concrete into steel tubes. However, up-to-date there is a lack of lateral confining pressure formulae for square and circular rubberised concrete-filled steel tubular (RuCFST) columns and rubberised concrete-filled double-skin steel tubular (RuCFDST) columns. Hence, the main aim of this technical note is to provide new design formulae based on lateral confining pressure and calibrated by means of test results available in the literature. These formulae are then used to suggest more accurate design strength models compared to those obtained from European, American and Australian specifications.

Compressive behaviour of corroded thin-walled circular section steel stub columns

The influences of corrosion on the buckling behaviour and bearing capacity of the circular section steel tubular (CST) stub columns subject to axial compression were investigated experimentally and numerically. Seven CST stub columns with chloride corrosion were investigated. After the accelerated chloride corrosion test on CST stub columns, three methods were used to evaluate the corrosion degree of each specimen. A monotonic axial compression test was then carried out. Based on the test results, the influence of corrosion degree on failure mode, bearing capacity and deformation behaviour were analysed. In addition, the surface morphology of the corroded column was obtained by a 3D Scanner and processed by Geomagic Studio software. Then the reconstructed models were imported into finite element (FE) software ABAQUS. This novel method considering the natural morphology of surface corrosion was verified by comparing the FE solutions to the experimental result. Based on the verified FE model, the deterioration of the mechanical behaviour of corroded compression stub columns under the actual rusty surface was also studied. It was found that the rough surface of the corroded specimens cause non-uniform stress distribution and change buckling mode. Parametric analysis, therefore, was conducted to study the influences of the corrosion degree and steel grade on the yield load. Finally, the proposed design formula is able to predict the axial compression strength of the rusty stub column with reasonable accuracy.

Tests of circular geopolymer concrete-filled steel columns under ambient and fire conditions

Sixteen circular geopolymer concrete-filled steel tubular (GCFST) columns made with carbon steel were tested at ambient temperature to obtain the axial load-moment interaction curves and buckling curves. Moreover, six circular composite specimens with stainless steel tubes were tested in fire to study the effects of concrete type and presence of internal reinforcement on the fire resistance. It was observed that the provisions in the Australian standard AS/NZS 2327 for composite columns can satisfactorily predict the ambient temperature strength of GCFST columns. From the fire tests, it was found that the use of geopolymer concrete could significantly improve the fire resistance of composite columns compared with the conventional counterpart made with ordinary Portland cement concrete. The results indicate that it is possible to eliminate the internal steel reinforcement or external fire protection to achieve required fire resistance by using high performance materials in composite columns. A life cycle analysis was further conducted, which showed that the life cycle cost of GCFST columns made with carbon steel was similar to that of the conventional counterparts, but the embodied carbon of the former was approximately 13.6 to 20.8% less than that of the latter.

Behaviour of Concrete-Filled Double Skin Tubular Short Column with Plate Stiffeners Welded Intermittently under Axial Compression

This paper presents the experimental and finite element analyses of the behaviours of stub circular and square concrete-filled double steel tubular (CFDST) columns intermittently welded with plate stiffeners under axial compression. The plate stiffeners are welded to the inner surface of the outer tube through predrilled holes. Twenty specimens consisting of two concrete-filled steel tubular (CFST), two unstiffened CFDST, and sixteen stiffened CFDST were tested under axial compression to determine the failure patterns and obtain the load versus axial shortening curve. The key variables are the distance of weld spacing and the dimension of the plate stiffeners. Based on the experiment results, the authors have identified the possible local buckling locations, including the peak load of the specimens that were significantly affected by the intermittently welded plate stiffeners. The developed finite element model is verified by comparing the current and previous experimental results, and it provides an acceptable mean ratio of 1.01 and a standard deviation of 0.04. The validated FE model is employed in a parametric study to investigate the effects of critical parameters, including the two shapes of the specimens, dimension of the plate stiffeners, and weld spacing, on the load-carrying capacity. The findings of the parametric study can be used to justify the optimum dimensions of plate stiffeners for the best stiffened CFDST performance.

Behavior of eccentrically loaded UHPC filled circular steel tubular short columns

This paper presents experimental results of twelve eccentrically loaded short composite columns made by filling circular steel tubes with ultra-high performance concrete (UHPC) cured under room temperature. Using these test data as benchmarks, finite element models are developed and used to perform parametric studies to determine how the capacities of these columns are affected by load eccentricity and tube diameter-to-thickness ratio. In addition, a relationship between the balanced eccentricity ratio and the confinement coefficient is established. The results of the present study have shown that: (1) failure of these columns is characterized by yielding of the steel tubes, followed immediately by failure of the core concrete; (2) a decrease in diameter-to-thickness ratio increases the peak load and improves the column's post-peak behavior; (3) an increase in the load eccentricity ratio results in a reduction of the load capacity, ductility and stiffness of the column; (4) the compressive strain in the steel tube develops more rapidly due to second-order effect, and the assumption that plane sections remain plane no longer applies when the applied load reaches 80% of the peak load. By comparing the axial force – Bending moment (Nu-Mu) interaction diagrams generated in the present study with existing codes, it is found that the code equations are mostly conservative. A set of trilinear Nu-Mu interaction equations that can produce more accurate results is therefore proposed

Mechanical Performance of Circular Ultrahigh-Performance Concrete–Filled Double Skin High-Strength Steel Tubular Stub Columns under Axial Compression

This paper proposed a new type of stiffened circular ultra-high performance concrete-filled double skin steel tubular (UHPCFDST) column, in which stiffeners were applied to connect both inner and outer steel tubes. It efficiently delayed the local buckling of steel tubes and enhanced the integral of the section. This new type of UHPCFDST can be named multicells ultra-high performance concrete-filled double skin steel tubular (MUHPCFDST) column since the stiffener divided the sandwich space between the two steel tubes into multicells. Both the UHPCFDST and MUHPCFDST stub columns were fabricated and tested under centrally compression loading to investigate the axial mechanical behavior. The parameters considered in this study included specimen size, diameter-to-thickness ratio, the quantity of stiffener, and hollow ratio. Based on the tests, specimens’ column failure mode, axial load-shortening curves, local buckling behavior, compounding strength, strength index, and ductility coefficient were obtained and discussed. Then, the authors proposed a uniaxial stress-strain function of ultra-high performance concrete under compression and established three-dimension finite-element (FE) models with this stress-strain model to simulate the axial behavior of UHPCFDST and MUHPCFDST columns. Compared with the experimental results, the average deviation of the FE analysis in predicting the column bearing capacity and corresponding axial shortening was −3% and −5.5%, respectively. Finally, parametric studies were carried out, and a calculation method was proposed. The parametric analysis results and predictions from different methods (including the proposed method and methods suggested by existing design codes) were compared. The proposed method and calculating methods provided in AIJ-2008, EC4, and AS/NZS 2327 can reasonably predict the ultimate bearing capacity of both circular UHPCFDST and circular MUHPCFDST columns.