Fastener Spacing Research Articles

Lateral loading performance of end narrow panel reinforced light wood frame shear walls

PurposeThe sheathing panels of traditional light wood frame shear walls mainly use oriented strand board (OSB) panels, and the damage of the traditional walls is mainly caused by the tear failure at the bottom corner of the OSB panel. In order to improve the lateral performance of the traditional light wood frame shear wall, a new type of end narrow panels reinforced light wood frame shear wall is proposed.Design/methodology/approachThe monotonic loading tests and finite element analysis of nine groups of walls, with different types of end narrow panel, types of fasteners used on the end narrow panels and the end narrow panels edge fastener spacing, are carried out. The effects of different characters on lateral performance of light wood frame shear walls are reported and discussed.FindingsThe failure modes of the wall reinforced by parallel strand bamboo narrow panels with 150 mm edge nails spacing are similar to the traditional wall. Conversely, the failure modes of other groups of walls reinforced by end narrow panels are the tears of the bottom narrow panel or the bottom beam. The end narrow panel reinforced light wood frame shear wall can make full use of the material property of sheathing panels. Compared with the lateral performance of traditional walls, the new-type end narrow panels reinforced walls have better lateral performance.Originality/valueA new type of end narrow panels reinforced light wood frame shear wall is proposed, which can enhance the lateral performance of the traditional light wood frame shear wall. The new-type walls have advantages of convenient operation, manufacture cost saving and important value of engineering application.

Study on the effect of the fastener support structure on rail corrugation in metros based on the friction-induce vibration

Rail corrugation is very serious in Cologne egg fastener track; effective control measures are still lacking. The cause of the corrugation wear on a curved metro track is analyzed based on the friction-induced vibration theory. A finite element model is established to study the frequency domain and time domain features of the friction-induced oscillation of this system. The influences of the fastener spacing and the fastener support length on the corrugation wear are investigated to develop countermeasures. The simulation results show that the friction-induced vibration of the wheel-track system is the wavelength-fixed mechanism of the corrugation wear of rail of the curved Cologne egg fastener track. There are two reasons why the low rail corrugation wear is more serious. The contact resultant force between the low rail and the wheel is obviously bigger than that between the wheel and the high rail, resulting in a higher wear rate of the low rail. The contact force fluctuation of the low rail caused by the friction-induced vibration is more severe, resulting in a higher corrugation wear evolution speed on the low rail. The friction-induced oscillation cannot be eliminated only by adjusting the fastener support length and spacing. However, the long-wavelength corrugation wear instead of the more harmful short-wavelength corrugation wear can be produced by adjusting the fastener support length and the fastener spacing to alleviate the influence of corrugation wear on the vehicle-track system.

Evaluation of parameters influencing the load-deformation behaviour of connections with laterally loaded dowel-type fasteners

ABSTRACT Connections made with laterally loaded dowel-type fasteners are important details in timber structures. According to Eurocode 5, their load-carrying capacity can be calculated with the so-called European Yield Model (EYM) and simplified rules for the determination of slip-moduli are given. The slip modulus is given as a mean value for the serviceability limit state and a simple reduction of slip modulus in the ultimate limit state is given in addition. Despite these simple regulations, it is well known that connections with dowel-type fasteners show a considerable non-linear load-deformation behaviour with different degrees of ductility. This ductility can enable the load redistribution in complex and statically undetermined structures and allow to achieve higher capacities compared to linear elastic design. In the paper, the deformation behaviour of connections with laterally loaded dowels dowel-type fasteners is studied based on more than 750 test results of bolted connections. The parameters influencing the slip-modulus, ductility ratio, and ultimate deformation are evaluated. It is focused on the effects of these parameters and the resulting variability in deformation behaviour. Recommendations are given on how different levels of ductility and deformation capacity can be achieved in dependency of the spacing of fasteners and other geometrical parameters.

Cyclic numerical analyses on wood-based in-plane retrofit solutions for existing timber floors

Timber-based strengthening interventions on existing wooden floors showed great potential to improve the diaphragm response in seismic rehabilitation. This is particularly important in masonry buildings in earthquake prone areas, to achieve a global box behaviour. A numerical model able to describe the non-linear cyclic behaviour of unreinforced and reinforced floors is illustrated in the present paper. Since in strengthening interventions on timber floors made by the application of timber-based panels, the fasteners proved to be the main source of non-linearity, a proper connector element is developed as an assembly of non-linear springs. Each one describes a particular aspect of the fastener behaviour in order to consider stiffness and strength degradation during the cyclic response. The model was validated by means of experimental data, acquired in a previous test campaign or available in literature. It can be used to analyse and optimize other in-plane strengthening configurations of timber floors, changing parameters as geometry, fastener spacing, sheathing orientation, opening location. This detailed numerical model can be useful also to calibrate the simpler macro models generally used for the floors in the non-linear evaluation of seismic global behaviour of buildings. A few parametric analyses and an example of a life-size floor are also presented as case studies.

Continuous assessment of longitudinal temperature force on ballasted track using rail vibration frequency

In this study, the possibility of using the rail vibration frequency to assess the longitudinal temperature force on the rail of ballasted track was investigated experimentally. An empirical formula was subsequently derived to link the frequency index to multiple factors, including the longitudinal temperature force, under-rail stiffness, and fastener spacing. Further tests were conducted to analyse the applicability and accuracy of the frequency index in continuous longitudinal force measurements under different line conditions (i.e. in the non-expansion zone and expansion zone). A technique for using the frequency index to assess the longitudinal temperature force was finally developed. The main results are as follows. (1) The first-order pinned–pinned modal frequency and peak frequency of the mid-span response are very close, and they both change linearly with the longitudinal temperature force on the rail. The rate of change in the vertical direction is larger than that in the horizontal direction. (2) Even if influenced by multiple factors, the peak frequency of the rail mid-span response is suitable for continuous longitudinal temperature force assessment under appropriate measures, and longitudinal temperature force detection could be realized with proper preparation. (3) Using the mid-span response frequency to detect the temperature force of rail located in the expansion zone causes deviation of the results, and under-rail materials whose stiffnesses are insensitive to temperature help reduce this deviation.

Numerical investigation on the composite action of cold-formed steel built-up battened columns

Cold-formed steel (CFS) built-up sections are widely used to achieve adequate load-bearing capacity when individual shapes are not able to resist the design loads. In the existing codes, there are few guidelines for designing and fabricating these members. This paper evaluates the influence of fastener patterns and spacing as well as reinforcing plates on the global and local buckling behavior of the CFS battened columns comprising two individual lipped channels. A large set of experimental results, available in the literature, were considered for the calibration of the developed numerical models. The effectiveness of the composite action between all profiles is crucial to fully exploit the capabilities of the built-up sections. To evaluate the performance of the investigated battened columns as well as the influence of spacing and configuration of the connecting plates, a large numerical investigation was undertaken. The results showed improved axial load-bearing capacity for the CFS battened columns when the number of fasteners rows was increased. Considering the spacing of the battened plates and their configuration, detailed analysis was conducted on the predominant buckling modes. The numerical results were also compared with analytical predictions based on Eurocode and the North American Specification (NAS). The results of this paper recommend that three rows of fasteners per battened plate are the optimal scenario for achieving composite action within the CFS built-up sections.

A Computational Study on Buckling Behavior of Cold-Formed Steel Built-Up Columns Using Compound Spline Finite Strip Method

This paper presents a computational methodology to compute the critical buckling stress of built-up cold-formed steel columns joined with discrete fasteners. The fasteners are modeled as three-dimensional beam elements, and their effect is integrated into the spline finite strip framework, evolving the compound strip methodology. Although this technique has been presented in the literature, this paper presents yet another robust framework for the buckling load evaluation of compound cold-formed steel columns with arbitrarily located fasteners. The proposed framework is applied to study the effect of fasteners on the formation of local, distortional, and global buckling modes of built-up section and a comparison is drawn with the buckling behavior of a single section. In this study, the proposed formulations are also used to get insights into the stability behavior of single-span and multi-span compound cold-formed steel columns in the presence of (i) fasteners with varied spacings with respect to span and (ii) the presence of the additional restraining system such as wall panels. For different buckling modes, a significant increment in buckling stress for a built-up section from a single section is observed when the fastener spacing is kept less than the critical buckling half-wavelength of the respective buckling modes. The study on the effect of wall panels shows that in comparison to unsheathed wall studs, the sheathed wall studs that produce additional constraints lead to the elimination of the global buckling deformations. The proposed formulations are simple, yet rigorous and have been validated using finite element-based numerical results.

Axial capacity of back-to-back built-up cold-formed stainless steel unlipped channels-Numerical investigation and parametric study

In cold-formed steel structures, such as trusses, wall frames and portal frames, the use of back-to-back built-up cold-formed stainless steel unlipped channels as compression members are becoming popular. The advantages of using stainless steel as structural members are corrosion resistance and durability, compared with carbon steel. Current guidance by the American Iron and Steel Institute (AISI) and the Australian and New Zealand (AS/NZS) standards for built-up carbon steel sections describes a modified slenderness approach, to consider the spacing of the intermediate fasteners. The AISI and AS/NZS do not include the design of stainless-steel built-up channels and very few experimental tests or finite element (FE) analyses have been reported in the literature for such back-to-back cold-formed stainless steel unlipped channel section columns. This paper presents a numerical investigation on the behavior of back-to-back built-up cold-formed stainless steel unlipped channel section columns. Three different grades of stainless steel i.e., duplex EN1.4462, ferritic EN1.4003 and austenitic EN1.4404, were considered. The effects of screw spacing on the axial strength of such built-up unlipped channels were investigated. As expected, most of the short and intermediate columns failed by either local-global or local-distortional buckling interactions, whereas the long columns failed by global buckling. All three grades of stainless-steel stub columns failed by local buckling. A comprehensive parametric study was then carried out covering a wide range of slenderness and different cross-sectional geometries to assess the performance of the current design guidelines of carbon steel built-up sections in accordance with the AISI and AS/NZS. In total, 647 FE models were analyzed. From the results of the parametric study, it was found that the AISI and AS/NZS are conservative by around 14 to 20% for all three grades of stainless steel built-up unlipped channel section columns failed through global buckling. However, the AISI and AS/NZS carbon steel design rules can be un-conservative by around 8 to 13%, when they are used to calculate the axial capacity of those stainless steel built-up unlipped channels which are failed in local buckling.

Parameter Influences on Rail Corrugation of Metro Tangential Track

Rail corrugation can reduce riding comfort by vibration and noise, and even cause running accident. In this paper, the vehicle–track coupled dynamic model was developed for a metro’s tangential track considering the wear in rail materials. The influences of different track structure parameters and vehicle speed on the generation and development of rail corrugation of the tangential track were analyzed using the developed model by the control variable method. The results show that for different parameters, the friction power in wheel–rail contact patch fluctuates with time, but the overall fluctuation range is relatively uniform. Meantime, an analysis of one-third octave curves of the friction power reveals that the characteristic frequencies of friction power are mainly concentrated in the middle and low frequency bands. At the dominant characteristic frequency, the longitudinal stiffness and damping of fasteners, and lateral and vertical damping of fasteners have less influence on rail corrugation, while the lateral and vertical stiffnesses of fasteners, spacing of fasteners, wheel–rail friction coefficient and vehicle speed have greater effect on rail corrugation. The changes in vertical stiffness and spacing of fasteners will cause the characteristic frequency of friction power to be offset, resulting in a shift from 80[Formula: see text]Hz to 100[Formula: see text]Hz, which will further lead to rail corrugation of the corresponding wavelength. Thus, it can be concluded that the vertical stiffness and spacing of fasteners have an important impact on the generation and development of rail corrugation at the specific frequency. Besides, the variations of the other variables bring little change to the characteristic frequencies of friction power as well as on rail corrugation. The mechanism of parameters unveiled here provides some guides for the parameter optimization problem on restraining the generation or development of rail corrugation on the tangential track.

Moment-rotation response of cold-formed steel joist-to-ledger connections with variable-finishes in ledger-framed construction

Ledger framing is the dominant framing system in North American cold-formed steel (CFS) construction. In this system, the floor, which is typically sheathed with oriented strand board, is framed into the top of the wall via a rim track (ledger) and clip angle connection. The diaphragm is essentially hung from the walls. Recently completed experimental work involving full-scale shake table tests on a ledger-framed CFS building exhibited the presence of alternate load paths that contributed to the lateral force resisting system. Within the goal of quantifying this contribution to the overall diaphragm response, experimental tests on joist-to-ledger connection have demonstrated to have a complex behavior involving limit states such as ledger flange buckling, stud web crippling, and fastener pull-out. Current design practices do not account for these limit states. To improve design recommendations and understanding of load transfer mechanisms, a robust finite element model for a joist-to-ledger connection in ABAQUS, validated via existing experimental tests, is presented herein. Experimental testing on the pull-out capacity of screw-fastened connections was conducted for implementation into the finite element environment. Results were then implemented directly in ABAQUS as connection behavior. Generally, the modeling approach accurately captures connection capacity and behavior. In addition, influence of other floor sheathing materials, fiber cement board and steel deck, on the moment-rotation stiffness and strength of this connection is explored. In steel deck sheathing, effects of deck thickness and fastener spacing are explored. This work enables predictions for both design and system-scale characterization.

Examination of Ductility and Seismic Diaphragm Design Force-Reduction Factors for Steel Deck and Composite Diaphragms

This paper analyzes the ductility and overstrength of steel deck diaphragms and composite concrete on steel deck diaphragms and computes associated diaphragm design force-reduction factors, Rs. First, a database of past tests on steel deck and composite diaphragms was created, and more than 750 specimens were compiled into the database. A subset of 95 cantilever diaphragm specimens with postpeak inelastic behavior was identified for which specimen ductility and overstrength were calculated. The effects of variables such as fastener type, fastener spacing, and deck thickness on diaphragm ductility are explored. A method is then developed for converting cantilever diaphragm specimen ductility to diaphragm system-level ductility. Finally, diaphragm design force-reduction factors, Rs, are calculated consistent with an accepted methodology to be Rs=2.09, Rs=1.13, and Rs=2.36 for bare deck diaphragms with mechanical fasteners, bare deck diaphragms with welds to the supports, and concrete on steel deck diaphragms, respectively, for cyclically loaded specimens and assuming a long period structure.

Compressive Strength of Axially Loaded Built-up Sigma Cold Compressive Strength of Axially Loaded Built-up Sigma Cold Formed Sections Columns Formed Sections Columns

The use of cold formed steel sections in building constructions has lately seen rapid growth due to their light weight and easier erection. Generally, lipped channel sections are used more frequently .Sigma sections while requiring more effort in fabrication, they exhibit high strength to weight ratios compared with the lipped channel sections. This work presents experimental as well as numerical study of the strength of pinned-pinned axially loaded columns utilizing sigma sections. The column section consists of two back to back sigma cold formed sections. The two sections are connected through their webs with connecting fasteners. Eight specimens with variable plate element width to thickness ratio, and having different member slenderness ratios were tested. Residual stresses and geometrical imperfections were recorded. Moreover, the specimens were simulated by a nonlinear finite element model using four node isoparametric shell element that accounts for both geometric and material non-linearities. The measured geometric imperfections and residual stresses were included in the numerical model. The parameters studied include the properties of the cross-section such as the flange, web, and lip dimensions as well as the spacing of the web fasteners. Furthermore, several column heights are considered to study the different modes of failure. Finally, the results are compared with the ultimate strength predicted by the American AISI, the Eurocode-3 and DSM specifications. Results reflect that sectional (local/distortional) buckling governs the failure mode of short columns. Moreover, the AISI, the Eurocode-3 and DSM can reasonably predict the ultimate load capacity of such sections.

A SIMPLIFIED ANALYTICAL PROCEDURE FOR SEISMIC ANALYSIS OF TIMBER LIGHT-FRAME SHEAR WALLS

The seismic performance of timber light-frame shear walls is investigated in this paper with a focus on energy dissipation and ductility ensured by sheathing-to-framing connections. An original parametric finite element model has been developed in order to perform sensitivity analyses. The model considers the design variables affecting the racking load-carrying capacity of the wall. These variables include aspect ratio (height-to-width ratio), fastener spacing, number of vertical studs and framing elements cross-section size. A failure criterion has been defined based on the observation of both the global behaviour of the wall and local behaviour of fasteners in order to identify the ultimate displacement of the wall. The equivalent viscous damping has been numerically assessed by estimating the damping factor which is in use in the capacity spectrum method. Finally, an in-depth analysis of the results obtained from the sensitivity analyses led to the development of a simplified analytical procedure which is able to predict the capacity curve of a timber light-frame shear wall.

Axial strengthening of RC columns by steel encasement with direct fastening connections

Reinforced concrete (RC) columns are crucial structural members that sustain vertical loads. Their strength may deteriorate due to fire, corrosion of the reinforcements or design errors. In response, a new strengthening method that uses a steel encasement to increase the axial capacity and ductility of RC columns is proposed in this paper. This method is quick and convenient because direct fastening is used to assemble the system. Four columns including one control column and three strengthened columns have been tested to examine the reliability and effectiveness of the proposed method. Although direct fastening plays a crucial role in the structural performance of the proposed method, current design guidelines have not incorporated this new connection technique. Hence, extensive connection tests have been conducted to evaluate the key factors (e.g. fastener type, fastener spacing, protuberance, etc.) that affect the strength of the connections. New design equations are subsequently proposed based on the test results for shear connections that use direct fastening.

Shear strengthening of hybrid externally-bonded mechanically-fastened concrete beams using short CFRP strips: Experiments and theoretical evaluation

Hybrid externally bonded (EB) mechanically-fastened (MF) technique for carbon-fiber-reinforced-polymers (CFRP) strips offers a high potential in shear strengthening to preclude debonding phenomenon and effectively utilize the maximum use of CFRP. This study investigated the failure envelope of reinforced concrete (RC) beams, designed deficient in shear, strengthened with hybrid EB/MF technique and reduced-size CFRP strips. The investigated parameters included strip length, number, spacing, and diameter of fasteners. The beams were subjected to three-point loaded testing with a shear span-to-depth ratio of 2.5. The strengthening had an axial rigidity of 1.8 GPa. The hybrid EB/MF technique for the reduced-size CFRP strips (up to 44% length reduction) inhibited crack propagation and could preclude the debonding phenomenon provided that adequate spacings of fasteners used. The results showed that the hybrid EB/MF specimens with reduced-size CFRP strips could achieve up to 65% shear load gain over the unstrengthened specimen. Also, a theoretical evaluation was conducted using other specimens from past studies to estimate the contribution of CFRP strips with and without steel stirrups. In addition, the ultimate shear loads were predicted, as per North-America’s guidelines, and compared with the experimental results. Finally, a set of recommendations was drawn based on the results of this study and the available literature.

Behavior of shear connectors joined by direct fastening

Direct fastening is an effective method to quickly and easily connect two steel components. However, the behaviors of this kind of connection have been rarely studied and there is no direct reference to them in current design specifications. Therefore, it is now timely to investigate the properties and behavior of this type of connection. In this paper, 11 coupons were tested at room temperature and 24 coupons were tested at high temperatures and after fire, to examine the deterioration of the mechanical properties of the steel. Moreover, 24 samples that were connected by direct fastening were tested at high temperatures and post fire conditions to study the deterioration in the shear strength of the fastener at different temperatures. Furthermore, 100 samples that were connected by direct fastening were tested in an ambient temperature to examine the effect of the number of fasteners, fastener spacing, fastener arrangement, knurled fasteners and protuberance. Based on the tested results, a modified expression for the yield strength of this kind of connection was proposed. Besides that, the bearing resistance versus displacement (BRVD) of the connections was numerically modeled and plotted into a simple curve based on the three key parameters of yield strength, effectiveness stiffness and ultimate displacement.

Experimental and numerical investigations on the axial capacity of cold-formed steel built-up box sections

Built-up box sections are becoming increasingly popular for column members in cold-formed steel (CFS) construction; uses of such sections include CFS trusses, space frames, and portal frames. In this article, the built-up box sections are formed through two identical lipped channels connected at their flanges with self-drilling screws. In such an arrangement, independent buckling of the individual channels is prevented by the screws. This paper presents an experimental investigation on axial capacity of built-up CFS box sections. Tests were conducted for different values of slenderness from short to slender columns. In total, the results from 16 experimental tests are reported. Of these, 8 tests were conducted on built-up CFS box sections and the remaining 8 tests were conducted on single channel sections. Load-axial shortening relationship, and failure modes are discussed for built-up columns. Nonlinear finite element (FE) models were developed for built-up CFS box sections and single channels. FE models considered material nonlinearities, initial imperfections and modeling of intermediate fasteners. FE results showed good agreement against the test results. A parametric study was conducted which comprises 148 models to investigate the effect of fastener spacing on axial capacity of built-up CFS box sections. Both FE and test results were compared against the design strengths calculated in accordance with the American Iron and Steel Institute (AISI) and Australian and New Zealand Standards (AS/NZS). From the comparison, it was observed that the AISI & AS/NZS are conservative by around 17% while determining the axial capacity of such built-up CFS box columns.

Bracing effect of sheathing in point-symmetric cold-formed steel flexural members

This paper presents an experimental investigation on sheathed cold-formed steel wall panels subjected to out-of-plane loading. The objective is to determine the two-sided gypsum sheathing effect on the design and behavior of the point-symmetric CFS studs. The design parameters such as global slenderness of the CFS stud, sheathing thickness and distance between the fasteners are varied, totaling twenty full-scale experiments that were tested under four-point bending. In general, the experimental results indicate that the gypsum sheathing board with a thickness of 15 mm and a fastener spacing of 150 mm hindered the occurrence of the biaxial bending of the point-symmetric CFS stud and led the CFS stud to reach its yield moment. To quantify the bracing effect of sheathing, the design predictions were carried out as per the current AISI report. The design results indicated that the design strength of a majority of the point-symmetric CFS studs can be drastically increased by the sheathing's bracing effect. However, few design results are unconservative compared to the experimental results which was confirmed by the reliability analysis as per AISI. Further investigation reveals that the current AISI design procedure requires significant modification with respect to the loading conditions and geometry of the CFS stud. In addition, the present study also discovered certain procedures to make the current sheathing braced design methods conservative and robust.

Sheathing Bracing Requirements for Cold-formed Steel Wall Panels: Experimental Investigation

This paper presents an experimental investigation to arrive at minimum sheathing requirements to inhibit the lateral torsional buckling (LTB) of the hat-shaped cold-formed steel (CFS) member subjected to out-of-plane loading. This study also describes the need for explicit minimum sheathing requirement provisions for different geometries of CFS structural members which are currently absent in the present design specifications. The design parameters for wall panels such as slenderness of the CFS member, the thickness of the sheathing board, the spacing between the fasteners that connect the sheathing and CFS member are considered in the experimental tests. A total of 30 full-scale tests (24 sheathed panels and 6 unsheathed tests) were carried out to study the behaviour of unsheathed CFS stud, sheathed panel and to determine their corresponding ultimate moment capacities. While all the unsheathed inverted hat-shaped CFS studs failed in LTB, the CFS stud with the gypsum sheathing effect did not undergo lateral torsional buckling and the sheathing effect led to reach its corresponding yield moment which is significantly higher than the lateral torsional buckling moment of the unsheathed CFS stud. It was also observed that until the failure of CFS stud, the gypsum sheathing did not experience damage (no bearing or pull-through failure). Based on the experimental investigation, it is shown that the gypsum sheathing board of thickness (tb) 12.5 mm with intermediate fastener spacing (df) 300 mm is sufficient to inhibit the LTB of the inverted hat shaped CFS studs. In addition, the analytical investigations were also performed to check the strength of the sheathing bracing. The analytical investigation results showed a good agreement with the experimental results in terms of sheathing failure mode and bracing requirement. Hence, the explicit minimum sheathing requirements to inhibit the LTB of the different geometry of CFS studs are suggested conservatively by considering the practicality of the wall construction.

Finite element modelling of back-to-back built-up cold-formed stainless-steel lipped channels under axial compression

In cold-formed steel structures, such as trusses, wall frames and portal frames, the use of back-to-back built-up cold-formed stainless-steel lipped channels as compression members are becoming increasingly popular. The advantages of using stainless-steel as structural members are corrosion resistance and durability, compared with carbon steel. The AISI/ASCE Standard, SEI/ASCE-8-02 and AS/NZS do not include the design of stainless-steel built-up channels and very few experimental tests or finite element analyses have been reported in the literature for such back-to back cold-formed stainless-steel channels. Current guidance by the American Iron and Steel Institute (AISI) and the Australian and New Zealand (AS/NZS) standards for built-up carbon steel sections only describe a modified slenderness approach, to consider the spacing of the intermediate fasteners. Thus, this paper presents a numerical investigation on the behavior of back-to-back cold-formed stainless-steel built-up lipped channels. Three different grades of stainless steel i.e., duplex EN1.4462, ferritic EN1.4003 and austenitic EN1.4404 have been considered. Effect of screw spacing on the axial strength of such built-up channels was investigated. As expected, most of the short and intermediate columns failed by either local-global or local-distortional buckling interactions, whereas the long columns, failed by global buckling. All three grades of stainless-steel stub columns failed by local buckling. A comprehensive parametric study was then carried out covering a wide range of slenderness and different cross-sectional geometries to assess the performance of the current design guidelines by AISI and AS/NZS. In total, 647 finite element models were analyzed. From the results of the parametric study, it was found that the AISI & AS/NZS are conservative by around 10 to 20% for cold-formed stainless-steel built-up lipped channels failed through overall buckling, irrespective of the stainless-steel grades. However, the AISI and AS/NZS can be un-conservative by around 6% for all three grades of stainless-steel built-up channels, which failed by local buckling.