Level Of Ductility Research Articles

Spatial distribution of damage potential of the 2023 Pazarcik Turkey earthquake using inelastic-response spectra of recorded and simulated ground motions

On 6 February 2023, a devastating earthquake of magnitude 7.7 struck the southeastern part of Turkey, followed by multiple aftershocks. The sequence of earthquakes caused extensive damage in Southern Turkey and Northern Syria. This study evaluates the destructive potential of ground shaking resulting from the Pazarcik mainshock by developing spatial distribution of inelastic demand spectra across the region by using the recorded ground motions. These spectra provide an additional step toward more realistic estimates of the damage potential of ground shaking than the traditional elastic response spectra. Given the recorded ground motions, we also developed simulated ground-motion time series at numerous un-instrumented sites. We used these recorded and simulated motions to estimate ductility demands across the affected area. Constant-ductility spectra were derived using recording stations within 100 km of the fault rupture. The results indicated that in the near-fault area, and for structural periods of 0.5 and 1.0 s, the yield strength demand at a ductility level of 3 exceeded the levels specified in the local seismic design code for a 475-year return period. Our findings demonstrate that with more refinement and efficiency of the ground-motion simulation approach, the development of near-real-time spatial distribution of ductility demand is a promising approach for rapid seismic damage assessment of earthquakes.

Performance of concrete beams strengthened with FRP rods: A review

Ductility is a critical property in structural engineering, ensuring that beams can undergo significant deformation before failure, thereby giving plenty of notice before disastrous collapse. This study investigates the ductility properties of constructions that have been reinforced using FRP rods, which are increasingly popular due to their corrosion resistance, superior strength with low mass, and durability. Traditional steel reinforcement has well-documented ductility properties, but FRP bars, due to their brittle nature, pose challenges in achieving the desired ductility levels in structural applications. This research evaluates various factors influencing FRP-reinforced beams' ductility, including the type of FRP material, the hybridization of FRP with other reinforcing materials, and the effect of utilizing fibres in the mixtures to enhance the mechanical characterstics of concrete. Studies have indicated that the ductility of beams can be enhanced using hybrid rebar systems, which integrate steel and fibre reinforced polymer. However, complex and expensive production methods limit their practical application. Using steel bars with FRP bars can significantly incresese seriviceability requiremts such as crack width and deflection, but they also lower corrosion resistance, especially in aggressive environments. The beams' overall ductile behavior is primarily determined by the concrete's characteristics. Fibres greatly increase the mechanical characteristics, toughness, and ductility of the concrete mix, strengthening the bond between bars and the concrete and improving the overall performance of the beam.

Dry sliding wear characteristics of hybrid aluminum alloy with nano-fly ash and nano-yttrium oxide

Aluminum alloys feature impressive levels of strength, ductility, castability, wear resistance, and corrosion resistance, making them highly advantageous for the aviation and automotive industries. This study investigates the dry wear performance of hybrid nanocomposites (HNCs) produced using Al6061 as the matrix, with nano-fly ash (FA) and nano-yttrium oxide (Y2O3) as reinforcing agents, utilizing the stir-casting method. The weight percentage (wt-%) of FA was fixed at 4 wt-%, while the Y2O3 varied from 1 wt-% to 3 wt-%. The specimens were prepared following ASTM-G99 standards and tested using a pin-on-disc apparatus with an E31 steel disc under four different loads: 10 N, 20 N, 30 N, and 40 N. It has been observed that wear rate has been increased with the increase in the applied load. The maximum wear rate has been recorded for the base Al6061 alloy as 5.63 × 10−4 mm3/N-m at 40 N load due to its lower wear resistance and less hardness value. The addition of reinforcement particles in the base alloy results in the grain refinement and improvement in the load-bearing capacity. It has been found that at 40 N load, the Al-6061 alloy reinforced with (4 wt-% FA + 3 wt-% Y2O3) is 56.83% superior in terms of wear resistance (2.43 × 10−4 mm3/N-m) as compared to Al6061 base alloy. The hybrid nano-composite containing 4 wt-% FA + 3 wt-% Y2O3 showed the highest value of microhardness as 123.2 HV, which is 136% higher than that of base alloy due to the higher load-bearing characteristics of the reinforcement particles. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) have been employed to analyze both unworn and worn surfaces, revealing uniform dispersion of reinforcement particles, the formation of an oxide layer, micro-pitting, wear debris, and material delamination. Grain refinement has been examined using the line intercept method (ASTM E1382-97), and X-ray diffraction (XRD) confirmed the elemental composition of the nano-reinforcements.

Understanding and phenomenological modeling of the pinching effect of the load–deflection curve of reinforced concrete beams subjected to bending

The reliable prediction of the seismic response of reinforced concrete (RC) structures hinges on accurate modeling of the cyclic behavior of their constituent elements. The load–deflection curve in RC beams exhibits a pinched hysteresis pattern corresponding to energy dissipations. This pinching effect, often observed under seismic loading conditions, reflects a reduction in stiffness and energy dissipation capacity at certain loading stages. Despite its significance, the detailed mechanisms underlying this phenomenon remain underexplored in existing literature. This paper aims to address this gap by presenting simplified models that directly represents the pinching effect at the crack scale. The model is grounded in a comprehensive analysis of shear stress interactions and crack closure dynamics, hypothesized as primary contributors to the pinching phenomenon. Our approach involves a meticulous examination of the hysteresis loops’ area and shape, facilitating the estimation of an equivalent viscous damping ratio to represent energy dissipation in seismic simulations, irrespective of changes in the structure’s damage or ductility levels. The paper unfolds in three key sections: The first section underscores the significance of a nuanced understanding of the pinching effect in seismic analysis. The second section presents an extensive literature review, consolidating crucial insights into the nature of the pinching phenomenon. The third section details the development and application of the proposed mesoscopic model, highlighting the impact of various geometrical and material parameters on the pinching effect.

Experimental assessment of FRP repairing in concrete cylinders exposed high temperatures

This study presents an experimental evaluation of fiber-reinforced polymer (FRP) strengthening in concrete specimens damaged by exposure to high temperatures. For this purpose, sixty cylindrical concrete specimens were produced. Specimens exposed to temperatures of 200 °C, 400 °C, and 600 °C were strengthened using carbon and glass FRP fabrics in two or three layers. Compression tests were conducted to assess the strength of the specimens. The impact of temperature, fabric type, and the number of fabric layers on the concrete's strength was thoroughly investigated. Digital microscopy was employed to explore the formation of cracks due to temperature changes, followed by Scanning Electron Microscopy (SEM) analyses to examine the microscopic structural changes in the concrete samples. The study highlights the importance of considering changes in both strength and behavior models together when evaluating the strengthening contributions provided by FRP. The results indicate that FRP applications on fire-damaged concrete structures can provide effective strengthening up to 400 °C but may be insufficient at temperatures of 600 °C and above. Although an effective increase in strength was achieved at 600 °C, low levels of ductility were observed, which is undesirable for an engineering structure. Therefore, it has been determined that FRP-strengthening applications may not be effective in reinforced concrete (RC) structural elements exposed to temperatures of 600°C and higher.

Effect of Microstructure on Oxidation and Micro-mechanical Behavior of Arc Consolidated Mo-Ti-Si-(B) Alloys

AbstractThe present study deals with the development and characterization of Mo-35Ti-10Si and Mo-35Ti-10Si-2B (wt.%) alloy for ultra-high temperature applications beyond the temperature limit of existing super alloys. The microstructural characterization using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), electron back scattered diffraction (EBSD), x-ray diffraction (XRD) revealed that the Mo-35Ti-10Si-2B alloy was consisted of three phases, namely, (Mo, Ti)ss, (Mo, Ti)5SiB2 and (Ti, Mo)5Si3; whereas, Mo-35Ti-10Si alloy was found to be consisting of (Mo, Ti)ss, and (Mo,Ti)3Si phases. Since quantification of boron is difficult by EDS, Particle Induced Gamma-ray Emission (PIGE), a nuclear reaction analysis technique was used for chemical composition analysis of boron. The oxidation behavior of the Mo-35Ti-10Si-2B alloy in the temperature regime of 825-1250 °C was studied in detail and compared with boron-free Mo-35Ti-10Si alloy. Mo-35Ti-10Si-2B alloy exhibited superior oxidation behavior at intermediate temperatures of 825 °C, and excellent oxidation resistance at higher temperatures between 1000 and 1250 °C due to the formation of the protective borosilica and double oxide layers (TiO2 and duplex borosilica-TiO2), respectively. High-temperature oxidation mechanisms were discussed using detailed microstructural cross section analysis of the oxidized alloy samples. The micro-mechanical behavior of constitutive phases of the Mo-35Ti-10Si-2B alloy were studied by microhardness, nano-indentation and micropillar compression testing. The micropillar compression of (Mo, Ti)ss phase showed fairly ductile behavior with the evidence of activation of dislocation in the form of slip lines revealed through the post-deformation fractography. Deformation studies of (Mo, Ti)5SiB2 and (Ti, Mo)5Si3 phases were also carried out which showed large strain bursts indicating possibility of activation of dislocation activities even at room temperatures imparting low level of ductility.

Skirt piles in foundation: a structural rehabilitation solution for fixed offshore platforms

An analysis and structural design of strength and ductility level earthquake is presented in this paper. Numerical results show that structural failure under seismic loads is sensitive to the degree of deterioration of structural steel. The structural elements do not present any excess stress, that is, all stress ratios are less than unity. The maximum stress ratio is 0.942, in the superstructure of element 1586-1571, which corresponds to a main deck beam elevation (+) 15,850 m.

Evaluation of Seismic Demand on Nonstructural Elements Based on Shake-Table Testing of Full-Scale 2-Story Steel Moment Frame

ABSTRACT A shake table test using a full-scale 2-story steel moment frame was conducted to investigate the peak floor acceleration (PFA) and the peak component acceleration (PCA), which directly affect the seismic demand on nonstructural elements. The main focus of this study was to evaluate the effects of structural and component nonlinearity on the nonstructural seismic demand. The PFA reduction suggested by ASCE 7-22 to account for structural nonlinearity was shown to be larger than the experimental results for low-to-moderate ductility levels. The analysis on the resonant PCA showed the importance of structural nonlinearity on the elastic C AR (=PCA/PFA). The high resonant PCA around the fundamental period of the elastic test frame (7 times PFA) was effectively decreased as the test frame experienced a moderate level of ductility; PCA was lowered by 36% and 25% on the 2nd and roof floors, respectively. The effect of component yielding on the PCA was evaluated based on the test results of steel racks mounted on flexible and rigid access floors. The PCA reduction depending on the component ductility level was less than the relevant provisions of ASCE 7-22, and the reason was discussed from the perspective of the pinched hysteretic behavior of the tested specimens.

Push-out test of eco-friendly steel-concrete–steel composite sections enhanced by polypropylene fibers: An experimental study and statistical analysis

Steel-concrete-steel (SCS) structural element solutions are rising due to their advantages over conventional reinforced concrete in terms of cost and strength. The impact of SCS sections with various core materials on the structural performance of composites has not yet been fully explored experimentally, and in this work, both slag and polypropylene fibers were incorporated in producing eco-friendly steel-concrete-steel composite sections. This study examined the ductility, ultimate strength, failure modes, and energy absorption capacities of steel-concrete-steel filled with eco-friendly concrete, enhanced by polypropylene fiber (PPF) to understand its impact on modern structural projects. Eco-friendly concrete was produced by the partial replacement of cement with waste material such as ground granulated blast-furnace slag (GGBS) to reduce carbon dioxide emitted as one of the by-products of cement which harms the environment. A constant rate of cement replacement with GGBS was used. Polypropylene fibers were used as a fill material in the structural elements to enhance the performance. Seven specimens of SCS were analyzed for their mechanical properties using push-out monotonic loading. The control specimen was constructed with a conventional concrete core, even as testing specimens had different amounts of polypropylene fiber added to the core. The current investigation indicates that the impact of polypropylene fiber (PPF) material filling concrete on SCS performance is somewhat smaller than that of ordinary concrete (less than 10 percent). Applying PPF to concrete can increase its tensile strength, slow the spread of cracks, and strengthen the material overall. The compressive strengths of the samples were affected by the proportion of PPF, with the strength increasing from 47.6 MPa to 56.43 MPa as the PPF levels increased from 0 to 2 percent. Compared to the control sample, the PPF SCS specimens had an increased energy absorption. On the other hand, in comparison to PPF SCS specimens, the ductility level of the control sample was smaller.

Microstructure, mechanical, and wear properties evaluation of Al-Cu based composite using RHA as reinforcement

ABSTRACT This study utilised a two-step stir-cast technique to fabricate Aluminium-based composites reinforced with 5% wt Copper (Cu) and varying weight percentages (1–4% wt) of Rice husk ash (RHA). Our work investigated the role of RHA reinforcement on the microstructure, mechanical properties, and wear characteristics of AlCuRHA composite. Characterisation of the composites and fracture surfaces was performed utilising SEM. The hardness and tensile properties were evaluated. Wear was conducted on the composites in dry and wet conditions using H2SO4 as the medium. The microstructure revealed the homogeneous distribution of the RHA within the AlCu matrix. The hardness of reinforced AlCu is enhanced from 54.24 Hv to 122.74 Hv with an increment of RHA reinforcement from 0 to 4%. The Ultimate tensile (UTS) and specific strengths were noted to increase with increased RHA content from 1 to 4% wt. The ductility levels were reduced with the increase in RHA content. The RHA-reinforced AlCu composite exhibits mixed ductile and brittle fracture modes. The composites with RHA exhibited greater wear resistance. Compared to the dry condition, the composites exhibited improved wear resistance in the acidic environment. The composite with 4 wt% RHA exhibited the lowest wear rates regardless of the environment.

Experimental Study on Flexural Performance of lap-spliced and mechanical-spliced (clamp type) rebars in RC Beams

Various methods can be employed to splice reinforcement bars, including lap splicing, welding, and mechanical splicing. Lap splicing is the most used method among these techniques. However, this study primarily focuses on evaluating the potential of mechanical splicing to replace the lap splice method. The investigation involved assessing the flexural performance of six RC beams in a series of laboratory experiments. These beams represented a control beam, an RC beam with lap-spliced rebars, and an RC beam with clamp-type mechanical spliced rebars. The laboratory testing results indicated that the RC beam with lap-spliced rebars had the highest load-bearing capacity, resulting in the highest nominal flexural moment (Mn). In contrast, the control beam demonstrated the highest deflection, signifying a greater level of ductility. However, RC beams with mechanical splices (clamp type), while not achieving the highest flexural moment and ductilities, are still competitive, as the experiment revealed that the difference is not significant. Consequently, it can be concluded that mechanical splicing has the potential to compete with or replace lap splicing in RC beams.

A Review on Slit Steel Shear Walls: Development, Implementation, and Performance

Over centuries, natural phenomena have claimed a large number of lives and caused large amounts of damage. However, they were the reason for the development of knowledge and science. In engineering, there is no doubt that earthquakes were the driving force behind many design philosophies and advanced technologies. In this regard, steel plate shear walls (SPSWs) represent one of the technologies employed in both new constructions and existing structures to bolster lateral load resistance. In addition to its high elastic stiffness and strength, SPSWs often experience significant pinching during their hysteretic response unless heavily stiffened. Thus, numerous investigations have been performed recently to enhance the seismic behavior of SPSWs during severe ground shaking. The shear walls of steel plates have been studied in various ways, including stiffened and unstiffened steel plates, low yield strength steel plates, SPSWs perforated with circular holes or vertical slits, steel walls with stiffened and unstiffened openings. A stiffened SPSW panel dissipates significantly more energy than an unstiffened panel, as well as exhibiting a ductile and stable behavior. In view of its high elongation, the SPSW with low yield point has the best damping capacity. It has been demonstrated that steel walls perforated with circular holes have improved energy dissipation, in addition to allowing utilities to pass through their openings. Vertical slits on steel plate shear walls produce an exceptionally full hysteresis loop with improved performances. Slit steel walls (SSWs) can sustain a drift of over 3% while experiencing minimal hysteresis degradation. Additionally, a frame with a SSW can endure up to 6% drift without significant damage, surpassing expected ductility levels of a special moment frame, particularly with efficient slit geometry.

Additive Manufacturing for Rapid Sand Casting: Mechanical and Microstructural Investigation of Aluminum Alloy Automotive Prototypes

The automotive industry is undergoing a rapid evolution to meet today’s challenges; therefore, continuous innovation and product development are needed. Validation tests on prototypes play a crucial role in moving new components into industrial production. There is also a pressing need for faster prototyping processes. In this context, rapid sand casting (RSC), based on additive manufacturing technology, offers a promising solution for a quick production of sand molds. While this technology is already employed in the industry, the need to deepen the general understanding of its impact on the casting properties is still a relevant item. In this study, different geometries of automotive prototypes made of aluminum EN AC 42100-T6 alloy were experimentally analyzed. Microstructural examinations, tensile tests, and fractography and porosity analyses were conducted. The findings demonstrate the considerable potential of RSC, giving, in general, high mechanical properties. A comparative analysis with prototypes produced through traditional sand casting revealed similar results, with RSC exhibiting superior yield strength and stress at brake. However, both technologies revealed a reduced elongation percentage, as expected. Future efforts will focus on standardizing the RSC process to enhance ductility levels.

Numerical investigation on stress concentrations of circular steel X joints

The most important reasons for the usage of steel as a building material are its high strength and ductile behavior, which can be defined as inelastic deformation or displacement capacity under a certain load. Steel frames are required to sustain the horizontal loads during an earthquake. The steel frames are classified as moment-resisting steel frames, concentric steel braced frames, eccentric braced steel frames, and buckling restrained braced frames. These steel frames can be designed with a high ductility level frame, limited ductility level frames, and ductility level mixed frames. In this study, stress concentrations due to the maximum compression force that may occur during an earthquake have been examined by the finite element method at the connection point of the circular cross-sectional braces of the central X-type braced steel frame with a high ductility level. Stress concentrations in the X-type brace were investigated depending on the variation of the cut surface required for the connection plate due to the change in the angle between the braces and the differences in the weld thickness applied in this region. In the models, the angle between the braces is designed as 60°, 75°, and 90° and the weld thicknesses are defined as 3.5 mm, 5 mm, and 7 mm. The results are obtained by applying the same compressive and tensile forces to the braces under the same boundary conditions and compared for these different models. It is obtained that the highest stress values occur along the direction of the tensile force in the tension profile and nearly at a distance of 5 mm after the cut. The maximum stress values decrease when the intersection angle between the braces increases from 60° to 90°.

Influence of Ductility on the Performance of Lunar Habitat Structures Under Recurrent Disturbances

This research examines how ductility affects the durability of lunar surface structures against recurring disturbances like moonquakes, micrometeorite impacts, and thermal cycles over an extended period. The structural performance at various levels of ductility was determined by adjusting material parameters and the thickness of a reference multilayered dome structure. Moonquake and micrometeorite impact-induced lateral displacements were estimated using a reduced-order model under a control-oriented dynamic computational modeling framework. The study considered the degradation of the metallic dome’s strength properties over time due to thermal cycles. Fragility curves were generated by assessing the likelihood of reaching three predefined damage levels as a result of multiple hazards. Additionally, a discounted cash flow analysis was conducted to incorporate a financial aspect into the performance comparison. The findings revealed that structures with sufficient ductility capacity have a lower probability of sustaining severe damage or collapsing within a shorter time frame. Hence, having ductile structures in lunar environments is advantageous as it allows the postponement of maintenance and repair actions, thereby conserving scarce resources for more urgent tasks. Moreover, the financial analysis demonstrated that lunar habitats with higher ductile capacities result in larger net present values, offering a higher return on the initial investment.

Phenomenon of ignition and explosion of high-entropy alloys of systems Ti-Zr-Hf-Ni-Cu, Ti-Zr-Hf-Ni-Cu-Co under quasi-static compression

The phenomenon of ignition and explosive failure of specimens from high-entropy alloys (HEAs) of systems Ti-Zr-Hf-Ni-Cu, Ti-Zr-Hf-Ni-Cu-Co at quasi-static compression tests was found. It physical model is proposed. It is exhibited that the reason for this phenomenon is the release of energy of the oxidation reaction; such reaction is initiated due to the heat released ahead of the shear crack tip at brittle fracture of the specimens under quasi-static compression. It is shown that ignition and failure by explosion are the specific features of brittle fracture for high-entropy alloys containing Ti-Zr-Hf, in general. This phenomenon is realised when certain critical levels of strength and ductility of these alloys are reached. The importance of these critical levels of strength and ductility lies in the fact that they predetermine the maximum permissible level of strength and brittleness for this class of HEAs, above which they lose their structural and functional properties, turning to the energetic alloys capable of explosive release of a significant amount of thermal energy. This specific feature of the high-entropy alloys containing Ti-Zr-Hf outlines the scope of their application and defines the boundary separating structural and functional high-entropy alloys from energetic high-entropy alloys.

Experimental and numerical study of grooved gusset plate damper for cross-braced frames

An innovative grooved gusset plate damper (GGPD) is further developed in this study by conducting cyclic tests and numerical analysis. The proposed damper is installed in X-Concentrically Braced Frames (X-CBFs) for enhancing the seismic performance and energy dissipation of such a system. To investigate the performance characteristics of the system, three 2/3-scale specimens are constructed that are different only in the details of the damper. The damper consists of a gusset plate in which a number of slits are cut around the diagonal braces. The steel between the slits undergoes large plastic deformations under in-plane double curvature, which provides a good level of ductility and energy dissipation. Low cycle fatigue is observed at drift ratios over 1.5% in the first specimen. Thickness of the middle part of the gusset plate is increased in the third specimen as a remedy which turns out to be successful to postpone degradation of stiffness and strength to the drift ratios larger than 3%. Furthermore, a detailed nonlinear 3D finite element model is developed and validated against the results of laboratory tests. The nonlinear finite element model is shown to be successful in predicting failure and fracture due to low cycle fatigue and showing the superiority of the modified specimens in preserving the stable shapes of the hysteresis loops and the cyclic energy dissipation.

Influence of Variation in Tie Reinforcement Diameter on the Ductility of Reinforced Concrete Columns

Reinforced concrete columns are crucial structural elements in ensuring the strength and stability of buildings. Column ductility, which is the ability to absorb energy and undergo deformation before failure, is a primary concern in structural engineering, especially in extreme external loading situations such as earthquakes. This study aims to evaluate the influence of variation in Tie reinforcement diameter on the ductility of reinforced concrete columns using Xtract software. The research method involves creating column structure models with specified dimensions and specifications, followed by the gradual application of axial loads to each model. Three models were created with varying Tie reinforcement diameters, namely 10 mm, 12 mm, and 14 mm. Structural analysis was conducted to examine the structure's response to the applied axial and moment loads, including evaluation of stresses, deformations, and column capacities. The analysis results show differences in ductility levels among the models. The model with a 10 mm Tie reinforcement diameter achieves higher ductility levels at low axial loads but fails to meet the requirements at higher axial loads according to the SNI 1726:2019 standard. However, models with Tie reinforcement diameters of 12 mm and 14 mm also exhibit a similar pattern, with good ductility at low axial loads but failing to meet the requirements at higher axial loads. In conclusion, variations in Tie reinforcement diameter affect the ductility of reinforced concrete columns. To ensure full ductility under various axial load conditions, adjustments to the design or specifications of the reinforced concrete column structure are necessary. This research contributes to understanding the factors influencing the ductility of reinforced concrete columns and can serve as a basis for the development of more effective design methods in the future.

Fracture behavior of double edge notch AlSi10Mg alloy fabricated by laser powder bed fusion

In the present study, the fracture behavior of additively manufactured (AM) metal parts has been investigated. To this aim, double edge notch tension (DENT) specimens have been printed using AlSi10Mg alloy based on the laser powder bed fusion (PBF) technique. Particularly, DENT specimens have been fabricated with three different ligament lengths and three different printing directions for each ligament length. In this study, we used the concept of essential work of fracture to describe the fracture behavior AMed parts. According to a series of tests under static loading conditions, influences of the ligament length and printing direction on the structural integrity of the DENT specimens have been determined. According to the experimental practices, levels of ductility and size of plastic zone in the ligament region have been documented. Here, we utilized digital image correlation technique to measure strain fields on the surface of the examined samples. Moreover, numerical simulations have been conducted to simulate the stress distribution from DENT specimens. In addition, visual inspection of the fracture surfaces has been conducted using a free-angle observation system. The outcome of this study can be used for future designs of PBF printed parts with a better structural performance.

Axial load behavior of CFT columns assembled with rectangular wave-shaped ribs

To solve defects caused by welding, a rib assembled CFT column was developed and the central compression performance, including the ultimate compressive strength, was evaluated through actual experiments. The results indicated that the internal ribs of this CFT column effectively suppressed local buckling, thereby enhancing the concrete confinement effect, and ultimately increasing the ultimate compressive strength. This effect was maximized when the rib specifications met a certain value, and it enabled the CFT column to achieve an equivalent level of axial stiffness and ductility compared to conventional CFT columns. Despite its assembly from multiple segments, the CFT column demonstrated high integrity, proving that the cross-sectional area of the steel tube could be applied according to current codes. The difference in concrete compressive strength due to the concrete confinement effect, which depends on the aspect ratio of the rib, was confirmed to be due to the effective confined area ratio (ke). Therefore, a design model for this CFT column was proposed, and as a part of the preliminary review process, limiting conditions for the aspect ratio of the ribs were also proposed.