Effective Width Research Articles

Optimization of Process Parameters and Microstructure of CoCrFeNiTiAl High-Performance High-Entropy Alloy Coating

CoCrFeNiTiAl high-entropy alloy coatings have been prepared by laser cladding technology based on response surface methodology (RSM). The results show that the effects of laser power, cladding speed, and pulse width on the dilution rate and microhardness of the high-entropy alloy coatings are investigated. Among the single-factor results, the laser power has the most significant effect on the properties of high-entropy alloy coatings, followed by the cladding speed, while the pulse width has no significant effect. In the interaction term analysis, the interaction term of laser power and pulse width has a remarkable effect on both output responses, whereas the interaction term of pulse width and cladding speed only has a considerable effect on microhardness, while the interaction term of laser power and cladding speed has an insignificant effect on both output responses. The optimum parameters for the preparation of high-performance high-entropy alloy coatings are found at laser power P = 676.73 W, cladding speed V = 5 mm/s, and pulse width P0 = 9 ms. The microstructures of the high-entropy alloy coating prepared with optimal process parameters have been characterized, which show that the metallurgical bonding between the cladding layer and the substrate is strong and without obvious defects such as porosity and cracks.

Study on PCD tool wear in pulsed laser assisted turning Al-50wt % Si alloy

Al-50wt % Si alloy is widely used in aerospace, automotive, electronic packaging and other fields due to its excellent material properties. However, the presence of reinforced particle phase differing in hardness from the alloy matrix phase leads to significant tool wear during turning with PCD tools. Therefore, this paper proposes a pulsed laser assisted turning (PLAT) method combining pulsed laser with conventional turning, which has unique advantages in reducing PCD tool wear. The effects of laser power, pulse width and frequency on tool wear during PLAT were studied by comparative experiments. And the potential mechanism of PLAT to reduce tool wear was revealed by finite element simulation. The results shown that PLAT effectively reduces PCD tool wear compared with conventional turning (CT). The increase of laser pulse width will aggravate tool wear. While, the increase of laser pulse frequency will reduce tool wear. Temperature is the main factor affecting the wear form. The tool mainly experiences abrasive wear at low temperature. However, the predominant type of tool wear shifts to adhesion as the increasing temperature. At the same time, EDS analysis shows that the rise in temperature results in an elevation of the O element content within the wear region, which proves that temperature is also the decisive factor affecting oxidative wear. This study provides valuable insights into actual machining involving Al-50wt % Si alloys and gives strategies for reducing PCD tool wear using PLAT.

Monitoring northern Greenland proglacial river discharge from space

Large volumes of meltwater produced on the northern Greenland Ice Sheet (GrIS) are directly routed into proglacial rivers, forming continuous supraglacial-proglacial catchments. Thereby, estimating proglacial river discharge is crucial for better understanding of northern Greenland hydrology and mass balance. We propose a method for estimating proglacial river discharge solely from space by combining Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2), ArcticDEM, and Harmonized Landsat and Sentinel-2 (HLS) data. Firstly, we use the modified normalized difference water index to extract proglacial river water masks from 30 m HLS imagery time series and calculate river effective width (We). Secondly, we derive near-dry riverbed cross-sectional curves from ICESat-2 ATL06 data. Thirdly, we intersect proglacial river water masks with riverbed cross-sectional curves to calculate the mean depth, wetted perimeter, cross-sectional area, and hydraulic radius, and combine ArcticDEM to estimate the channel bed slope. Finally, with these hydraulic geometry estimates, we calculate proglacial discharge and analyze its uncertainty via error propagation. We apply this method to estimate the proglacial discharge (Qs) of the Denmark catchment (area ∼ 3254 km2) in northern Greenland during the 2020–2021 melt seasons and compare Qs with the surface meltwater runoff (Qm) simulated by two regional climate models (RCMs, including MARv3.12 and RACMO2.3p2), and validate the accuracy and spatial transferability of the method with in-situ proglacial discharge (Qin-situ) of the Watson River in southwestern Greenland. The results show that: (1) the satellite-estimated We and Qs exhibit significant seasonal variations, with the average We of 579 ± 371 m for 2020, 505 ± 394 m for 2021, and a maximum of 2040 m, and Qs has the average value of 207.6 ± 134.1 m3/s for 2020, 210.4 ± 243.2 m3/s for 2021, and a maximum of 1509.4 ± 190.3 m3/s; (2) the satellite-estimated Qs is positively correlated with the RCM-simulated Qm (R2 = 0.82 and 0.69 for MAR and RACMO, respectively), indicating that RCMs can reflect the overall seasonal variations of proglacial discharge reasonably well; (3) the RCM-simulated Qm is considerably higher than our satellite-estimated Qs, with the bias, RMSE, and RRMSE for MAR (RACMO) being 116.6 ± 5.9 m3/s (130.3 ± 5.9 m3/s), 174.7 ± 6.7 m3/s (208.9 ± 6.1 m3/s), and 83 ± 4 % (100 ± 4 %), respectively, and (4) our satellite-based method can be successfully applied to the Watson River in southwestern Greenland and the resultant Qs matches well with Qin-situ (RRMSE = 27 %). In conclusion, multi-temporal and multi-source satellite observations facilitate the estimation of proglacial river discharge and provide an approach to directly estimate GrIS ice surface meltwater runoff.

Comparative analysis of capacitorless DRAM performance according to stacked junctionless gate-all-around structures

The characteristic comparison of the capacitor-less DRAMs in the structural form variation is investigated. Based on the simulation results of the three basic structures, such as circular, square, and rectangular nanosheets, the gate length (Lg), channel thickness (Tsi), and width of the nanosheet (Wsi) are considered as the main factors in design and the characteristic variations are verified according to the junctionless (JL) gate-all-around (GAA) geometry factors. The channel thickness is a major factor that has a major influence on the sensing margin and the retention time, which are important characteristics of DRAM. The thinner the thickness, the more deteriorated the sensing margin is confirmed. Retention time is due to the influence of the electric field distribution of the JL GAA structure, resulting in differences in structure. Finally, the rectangular type nanosheet is implemented in the stacked structure. As the number of stacks increases, the effective channel width increases compared to the layout footprint. In addition, by stacking vertically, the area where holes can be stored increases. Therefore, the sensing margin tends to increase as the number of stacks increases. However, the difference in diffusion due to the difference in the initially stored hole density, the retention time deteriorates as the number of stacks increases

Research of laser width variability in line laser infrared thermal wave inspection of CFRP laminates and defect reconstruction method for mobile detection

The line laser scanning infrared thermography method is a rapid and comprehensive approach for defect detection. This study investigates the impact of line laser width on detecting Carbon fiber reinforced polymers (CFRP) defects, revealing that narrower line lasers are more effective for shallow subsurface defects, while wider line lasers provide greater stability for deeper subsurface defects. To address issues like target loss, misdetection, and leakage in moving detection, a quasi-static reconstruction method based on Discrete Fourier Transform and Principal Component Analysis (DFT-PCA) is proposed. This method tracks and localizes moving defects, converting the image sequence into a quasi-static format and applying frequency domain denoising to achieve clear defect boundaries and reduced background noise. The study further explores the optimal line laser width by analyzing the relationship between the defect diameter-to-depth ratio and the signal-to-noise ratio of the reconstructed images. The findings indicate that for defects with a diameter-to-depth ratio greater than 6, a line laser with a width smaller than 4 mm offers better detection results, whereas for a diameter-to-depth ratio smaller than 6, a line laser with a width larger than 4 mm is more effective. These conclusions confirm previous research on the varying effects of line laser width on detection performance.

Experimental study and finite element analysis of concrete columns with square GFRP tube confined cross stirrups under axial compression

This article investigates the axial compression performance of glass fiber reinforced plastic (GFRP) tube restrained transverse ring reinforced concrete composite columns. Six composite columns were designed for axial compression experiments and subjected to multi condition ABAQUS finite element simulations. Analyzed the effects of constraint width, circumferential spacing, GFRP tube thickness, and concrete strength on the bearing capacity of composite materials, mainly studying the effect of hoop section form on the mechanical properties of composite columns. The results show that the spacing between the stirrups and the width of the constraint on the bearing capacity show a trend of increasing first and then decreasing, with the optimal constraint width being 40–60 mm; Increasing the thickness of GFRP tubes can effectively improve the bearing capacity, but the gain effect weakens with the increase of concrete strength.

Experimental and numerical studies on enhanced flow boiling in tube with superwetting micro-finned surfaces

Due to the high latent heat from evaporation, flow boiling has been applied in a variety of industrial applications. However, the occurrence of “annular bubble” will dramatically increase the thermal resistance near the wall, causing decreases both in heat transfer coefficient (HTC) and critical heat flux (CHF). To tackle this issue, we propose the micro-finned surfaces with strong capillary force to enhance the heat transfer coefficient and critical heat flux for flow boiling. With deionized water as the coolant, we investigate the effects of fin width, fin height, fin pitch, coolant flow rate and heat flux on flow boiling through experiment and numerical simulation. The results show that the wider the fin width, the lower the fin height, and the smaller the fin pitch, the higher the convective heat transfer coefficient. In addition, the higher the coolant flow rate leads to higher heat transfer coefficient and lower flow boiling instability. When the heat flux increases, the convective heat transfer coefficient and flow instability increase. Among them, the microchannel with fin width of 20 μm, fin height 40 μm, and fin pitch 40 μm obtains the maximum convective heat transfer coefficient, 59.3 % higher than that of the smooth microchannel.

Lubrication Characteristics of a Warhead-Type Irregular Symmetric Texture on the Stator Rubber Surfaces of Screw Pumps

A theoretical model for the micro-texture on the inner wall of the stator rubber in screw pumps was developed. The finite element analysis method was employed. The pressure and streamline distributions for warhead-type, concentric circle-type, and multilayer rectangular-type textured surfaces were calculated. The effects of textured morphology, groove depth, groove width, and other parameters on the lubrication field were systematically investigated and analyzed. A nanosecond laser was employed to process the textured rubber surface of the stator in the screw pump. Subsequently, a micro-texture friction performance test was conducted on the rubber surface of the stator in actual complex well fluids from shale oil wells. Given the results of the simulation analysis and experimental tests, the lubrication characteristics of textured rubber surfaces with varying texture morphologies, rotational speeds, and mating loads were revealed. Furthermore, it indicated that the irregular symmetric warhead-type micro-texture exhibited excellent dynamic pressure lubrication performance compared with concentric circle-type and multilayer rectangular-type textures. The irregular symmetry enhanced the dynamic pressure lubrication effect, enhanced the additional net load-bearing capacity of the oil film surface, and reduced friction. As the groove depth increased, the volume and number of vortices within the groove also increased. The fluid kinetic energy was transformed into vortex energy, leading to a reduction in wall stress on the surface of the oil film, thereby affecting its bearing capacity. Initially, the maximum pressure on the wall surface of the oil film increased and then decreased. The optimal dynamic pressure lubrication effect was achieved with a warhead-type texture size of 3 mm, a groove width of 0.2 mm, and a groove depth of 0.1 mm. Well-designed texture morphology and depth parameters significantly enhanced the oil film-bearing capacity of the stator rubber surface, improving the dynamic pressure lubrication effect, and consequently extending the service life of the stator–rotor interface in the screw pump.

Friction drag reduction of Taylor–Couette flow over air-filled microgrooves

Reducing drag under high turbulence is a critical but challenging issue that has engendered great concern. This study utilizes hydrophilic tips in superhydrophobic (SHP) grooves to enhance the stability of plastron, which results in a considerable drag reduction ( $DR$ ) up to 62 %, at Reynolds number ( $Re$ ) reaching $2.79 \times 10^{4}$ . The effect of the spacing width $w$ of the microgrooves on both $DR$ and flow structures is investigated. Experimental results demonstrate that $DR$ increases as either microgroove spacing $w$ or $Re$ increases. The velocity fields obtained using particle image velocimetry indicate that the air-filled SHP grooves induce a considerable wall slip. This slip significantly weakens the intensity of Taylor rolls, reduces local momentum transport, and consequently lowers drag. This phenomenon becomes more pronounced with increasing $w$ . Furthermore, to quantify the multiscale relationship between global response and geometrical as well as driving parameters, $DR\sim (w, \phi _s, Re)$ , a theoretical model is established based on angular momentum defect theory and magnitude estimate. It is demonstrated that a decrease in the surface solid fraction can reduce wall shear, and an increase in the groove width can weaken turbulence kinetic energy production, rendering enhanced slip and drag reduction. This research has implications for designing and optimizing turbulent-drag-reducing surfaces in various engineering applications, such as transportation and marine engineering.

Trail vs. thicket: Evaluating conservation detection dog performance in varied terrain

AbstractUse of detection dogs has emerged as an effective survey method for rare and cryptic species, outperforming traditional methods. However, there is little information available on how survey conditions may affect survey efforts. This study investigates the detection probability, effective sweep width, and search time of a detection dog working on‐lead in varying vegetation and weather conditions in Florida. We established 4 200‐m long transects in habitats with varying vegetation structure: open field, open canopy forest, closed canopy forest, and trail. American mink (Neogale vison) scat was set along each transect, in locations unknown to the detection dog handler, at distances ranging from 0 to 24 m from the transect. Vegetation and weather conditions were recorded for each survey. Between August 2021 and October 2022, we conducted 28 surveys (112 total transect surveys). Across all transects the detection dog located 66% of hidden scats (n = 384). We calculated an effective sweep width of 49 m (24.5 m on either side of the transect) and detection probability decreased with distance from transect line. Contrary to expectations, vegetation structure and weather conditions did not influence detection probability, but vegetation structure did affect search time, an important variable to consider when designing surveys. Search time increased with increases in understory vegetation obstruction and basal area. Conducting surveys on trails showed promise as an effective search method, having similar detection probability to off‐trail transects and faster search times than the closed canopy forest transect. Trail surveys may be particularly useful for areas that would otherwise be impassable, but their effectiveness may vary based on the target species' behavior. Our study underscores the importance of understanding search metrics in conservation detection dog surveys to design effective and appropriate surveys for anticipated field conditions.

Effect of dynamic resistance reduction in spiral copper-plated multifilament coated conductors

Abstract Theoretically, it has been shown that the dynamic resistances of coated conductors can be reduced by decreasing their effective width through multifilamentation. In the case of copper-plated multifilament coated conductors, coupling currents are expected to worsen the effect of multifilamentation in reducing dynamic resistance. Therefore, the purpose of this study is to experimentally investigate the dynamic resistances of spiral copper-plated multifilament coated conductors, which are expected to reduce the coupling time constant in a manner similar to twisted low-Tc superconducting wires. We measured the dynamic resistance of four different samples—straight monofilament, straight multifilament, spiral monofilament, and spiral multifilament coated conductors—using the four-terminal method. We discuss the dynamic resistivity characteristics of the copper-plated multifilament coated conductors by comparing the magnetic field dependence of the dynamic resistivity, normalized by the critical current of each sample.

An overview of the STEP divertor design and the simple models driving the plasma exhaust scenario

Abstract This paper presents a comprehensive overview of the preliminary divertor design and plasma exhaust scenario for the reactor-class Spherical Tokamak for Energy Production (STEP) project. Due to the smaller size of the machine, with a major radius less than half that of most DEMO concepts, the current design features a double-null divertor geometry, comprising tightly baffled extended outer legs and shorter inner legs approaching an X-divertor. Leveraging a significant database of SOLPS-ITER simulations, the exhaust operational space is mapped out, offering valuable insights into the plasma exhaust dynamics. An approach involving the validation of simple, yet robust models capable of accurately predicting key exhaust parameters is detailed, thereby streamlining the design process. The simple models are used to simulate the entire plasma scenario from the plasma current ramp-up, through the burning phase, to the plasma current ramp-down. Notably, the findings suggest that pronounced detachment, with peak heat loads below engineering limits and electron temperatures below 5 eV, is achievable with a divertor neutral pressure between 10 - 15 Pa during
the burning phase, and pressures below 5 Pa during the ramp-up to maximise the auxiliary current-drive efficiency. Throughout the scenario, an Ar concentration of ~3% in the scrape-off layer (SOL) is required, in combination with a core radiation fraction of 70% driven by intrinsic emission and extrinsic injection of Xe seeded fuelling pellets. However, significant uncertainties remain regarding key parameters such as the SOL heat flux width, Ar screening, and plasma kinetic effects.

Effect of rib width on the thermo-electro-mechanical behavior of solid oxide fuel cells

In this study, a three-dimensional multi-physics coupled model is employed to investigate the effects of the rib width of the cathode-side interconnect on the flow characteristics, electrochemical performance, temperature distribution and stress distribution of solid oxide fuel cells (SOFCs) under cross-flow conditions based on a fixed gas channel-electrode interface area. The results show that as the rib width is reduced, there is a marked improvement in the uniformity of gas distribution and gas flow velocity within the channels, leading to an increase in the output power density of the SOFC stack, a reduction in the temperature gradient of the cell and a reduction in the thermal stress carried by the cell. However, if the ribs are of insufficient width, the pressure drop within the channels will be significantly increased, reducing the static pressure head of the gas and leading to a decrease in the gas flow velocity within the electrodes. This, in turn, will result in an increase in concentration polarization and higher manufacturing costs. The simulation results facilitate a more detailed comprehension of the internal reaction processes of SOFCs, thereby offering valuable guidance for the structural optimization of interconnects.

Local-global buckling interaction in steel I-beams—A European design proposal for the case of fire

This paper presents a comprehensive review of the developments leading to the proposal of European fire design rules for steel beams with thin-walled I-sections. Thin-walled beams are favoured in steel construction due to their structural efficiency, however they are prone to buckle when subjected to in-plane loads, phenomenon which requires a thorough investigation. The focus lies on addressing the interaction between local and global buckling in these members. This study discusses modifications to the Effective Width Method at elevated temperatures, aiming to rectify underestimation of section capacity on certain cross-sections. Additionally, an overview of lateral-torsional buckling resistance is provided, being a new Effective Section Factor proposed to account for its interaction with local buckling. The paper revisits the European fire design proposal, comparing the improvements of the existing Eurocode 3 Part 1–2 (EN1993-1-2:2005) relative to the recent second generation of Part 1–2 of Eurocode 3 (FprEN1993-1-2:2023) through an extensive numerical study. Limitations and future research directions are also discussed, such as dependency on the section classification and broadening the application scope of these rules to higher steel grades.

Anomalous influence of electrode width on the critical current of Nb/Au Josephson junctions

Abstract We study the effect of electrodes width on superconducting current transport in Nb-Au-Nb Josephson bridges. The critical current as well as the normal bridge resistance drop with decreasing electrode width on scales of a few μm, which are orders of magnitude larger than the estimated coherence length of Au strip. We consider several physical reasons of such an anomalous influence of the width W of the superconducting electrode on the critical current Ic (AIWIc) and provide model fits for the resistive and superconducting properties of the bridges. {The smooth dependence of the Nb-Au-Nb bridge parameters on the electrode width can be used to optimize the design of superconducting devices for specific applications.

Dielectric Hybrid Optimization Model Based on Crack Damage in Semi-Rigid Base Course

To accurately predict the relative permittivity of cement-stabilized base materials, a study on the dielectric mixing model for cracked base materials was conducted. Based on the electromagnetic mixing theory of multiphase composites, a comprehensive dielectric mixing model of cement-stabilized base materials was derived. The volume ratios and relative permittivity values of the specimen constituents in different cracking states of the cement-stabilized base were determined using industrial CT and a Percometer relative permittivity meter, with comprehensive consideration given to the effects of different initial porosities and crack widths on the dielectric properties. Based on the volumetric and dielectric properties of the base material specimens in both intact and cracked states, as well as the error analysis between the predicted and measured values of the relative permittivity constant, the u-optimal solution of the dielectric mixing model for cement-stabilized base material was determined to be 1. Consequently, an optimization dielectric mixing model for semi-rigid base course materials in a cracked state was developed. The optimization model proposed is suitable for predicting the dielectric properties of cement-stabilized base material with crack widths generally greater than 3 mm during the service life of semi-rigid base course in engineering practice.

Aeroelastic analysis of non-conventional and slender suspension bridges

The aim of this study was to investigate the dynamic effects of wind actions on bridge cross sections, with a goal to propose design charts for non-conventional and slender bridge decks. An eigenvalue analysis was conducted first and the results were validated experimentally. Subsequently, aeroelastic analysis of the bridge deck section was performed. This analysis encompassed the analytical method adhering to the Eurocode and computational fluid dynamics simulations. Both methodologies indicated that the bridge was susceptible to vortex-induced vibrations. To mitigate these vibrations, wind noses provide better stability than the currently used guide vanes. The effect of changing deck width was also studied. Wider and more streamlined sections displayed better aeroelastic performance. The study also revealed that the Eurocode overestimates the derivatives of aerodynamic moment coefficient by 53% to 93%. Consequently, optimized charts are proposed to enhance the accuracy of torsional divergence and flutter speed calculations, facilitating the safe and efficient design of such bridges.

Seasonal distribution of cetaceans in the European Atlantic and Mediterranean waters

As apex predators, cetaceans play an essential ecological role in marine ecosystems. Fluctuations in the abundance of these top predators linked to human activities can have detrimental consequences for the entire ecosystem. Cetaceans face numerous anthropogenic threats that can have both short and long-term effects. To ensure their conservation, it is necessary to identify changes in seasonal distributions at small and large scales. We aimed to model the seasonal distribution of the most abundant cetacean species in the European Atlantic waters and the Mediterranean Sea by assembling datasets collected over 16 years of surveys using a standardised line-transect protocol. Data were homogenised, detection functions fitted and effective strip widths estimated. We extracted environmental variables integrated over the water column, which we transformed using a principal component analysis (PCA). The dimensions of the PCA were then integrated as explanatory variables in a generalised additive model, taking seasonal and spatial effects into account to predict the seasonal cetacean distribution. We were able to highlight changes in the spatial distribution and/or density of cetaceans throughout the year at a large scale, considering environmental extrapolation areas to predict where environmental variables were sampled during the surveys. For minke (Balaenoptera acutorostrata) and fin (B. physalus) whales, densities varied over the seasons but not the distribution, suggesting a seasonal migration outside the survey areas. For common dolphins (Delphinus delphis), bottlenose dolphins (Tursiops truncatus) and harbour porpoises (Phocoena phocoena), densities varied little but distributions did over the seasons. Finally, pilot whales (Globicephala spp), Risso’s (Grampus griseus) and striped (Stenella coeruleoalba) dolphins showed little seasonal variation in their distribution. Using monthly dynamic environmental variables at depth and PCA dimensions in habitat models, we produced maps of the seasonal distribution of cetaceans in the Mediterranean Sea and the European Atlantic waters to help fill gaps in our knowledge of cetacean distribution.

Measurement of Steam-Generator-Tube Vibration Damping Caused by Anti-Vibration-Bar Supports

Abstract In 2013, Atomic Energy of Canada Limited (now Canadian Nuclear Laboratories) experimentally measured the damping of a straight tube with a variety of tube supports to examine low-frequency damping. These tests were motivated by the discovery of severe tube damage caused by in-plane fluidelastic instability (FEI) in the U-bend regions of new replacement recirculating steam generators (SG). The measurements were intended to assess the applicability of existing design guidelines for estimating the support-related damping of a tube. In the tests, the damping ratios of a single steam generator tube were measured using both log-decrement and power-based methods. Noncontacting excitation and position-sensing techniques were employed to improve accuracy. Initial baseline tests explored configurations with no support and drilled-hole supports of different hole sizes, and these results were compared with previously published work. Subsequent tests were performed to measure damping of tube vibration parallel to flat-bar supports. Most of the tests were performed with the tube fully submerged in still water. The tests examined the effects of fluid (water or air), natural frequency, gap width, preload, and vibration normal to the bars. This paper describes the test apparatus, methods, and analysis techniques. A summary of the results is presented. The initial baseline results showed that the damping ratios measured without any supports and with a drilled-hole support were consistent with previously published data. However, the subsequent measurements showed that, contrary to a published design guideline, the anti-vibration bars resulted in no significant additional viscous or squeeze-film damping when the vibration was parallel to the bars. On the other hand, the results did show that anti-vibration bars could introduce significant in-plane Coulomb-type damping if there was sufficient tube-to-support preload or impacting.

Research on axial compression behavior of cold-formed steel built-up T-shaped columns

A series of axial compression tests were conducted on cold-formed steel (CFS) built-up T-shaped columns consisting of three identical single-limb sections connected by longitudinally arranged high-strength bolts and filler plates at the webs. At first, the buckling behavior, failure mode, ultimate bearing capacity, and load response curves of columns are analyzed. Subsequently, finite element models of tested columns were then developed and validated to provide a base for conducting parametric studies of built-up T-shaped columns with different slenderness ratio, web height to plate thickness ratio and bolt spacing. Finally, the design methods in the Chinese code GB50018–2002 and AISI S100–16 specifications for predicting the resistance of the built-up T-shaped columns were evaluated by using both the test and numerical results. The study shows that the current design procedure in AISI S100–16 are unstable in predicting the resistance of the built-up T-shaped columns within a certain range of overall slenderness ratio, while the provisions in the Chinese code GB50018–2002 are overly conservative. Hence, a reliable design procedure is proposed based on the the Effective Width Method (EWM) in the Chinese code GB50018–2002 equations obtained from the paper. The strength predictions of the proposed design procedure match well with those of experimental studies in the literature and the experimental and numerical studies of this paper.