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Biaxial Bending Of Cold-Formed Steel Storage Rack Uprights – Part I: Parametric Studies And Response, Nima Talebian, Benoit P. Gilbert, Cao Hung Pham, Romain Chariere, Hassan Karampour

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper first introduces an advanced finite element model to determine the biaxial bending capacity of cold-formed steel storage rack upright sections. The model is found to accurately predict published experimental results with an average predicted to experimental capacity ratio of 1.02. Second, the validated model is used to run parametric studies and analyse the biaxial response of slender, semi-compact and compact unperforated storage rack upright cross-sections. Analyses are run for local and distortional buckling failure modes only. Ten and four different cross-sectional shapes are analysed for local and distortional buckling, respectively, and nine biaxial bending configurations are considered per …

Sidelap And Structural Fastener Tests For Steel Deck Diaphragms, Y. Shi, S. Torabian, Benjamin W. Schafer, W. S. Easterling, M. R. Eatherton

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Steel deck diaphragm systems, which are commonly used for roof construction in steel-framed buildings, consist of many parts such as corrugated steel deck sheets, sidelap fasteners between adjacent sheets, structural fasteners from the sheets to the supporting beams or joists, chord elements, and collectors. Load-deformation behavior of a steel deck diaphragm system is typically dominated by sidelap and structural fastener limit states. To understand and accurately model the behavior of steel deck diaphragm systems, it is therefore necessary to characterize the behavior of the individual fasteners. The effect of local geometry and detailing at these fasteners such as how the …

The 2017 Aisi Cold-Formed Steel Design Manual, Joshua Buckholt, Helen Chen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The 2017 edition of AISI D100, the Cold-Formed Steel Design Manual (Manual) has been published. Updates to the Manual include: alignment with AISI S100-16, the North-American Specification for the Design of Cold-Formed Steel Structural Members (NA Specification); several new and varied design examples; additional discussions related to the design of cold-formed steel structures and components; and expanded bibliographies of relevant resources. The database of examples illustrating the Direct Strength Method (DSM) and new provisions in the NA Specification has been expanded. Also published with the Manual are the North-American Specification and its Commentary.

Distortional Buckling Of Cold-Formed Steel Flanges Under Stress Gradient, Robert S. Glauz

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The strength of cold-formed steel beams with stiffened flanges may be controlled by distortional buckling. Buckling stress prediction methods have been developed for flanges under uniform compression. However, channel sections are commonly used where bending occurs about the minor axis with flanges under stress gradient, such that the edges are in compression and the flanges may experience distortional buckling. Current design specifications do not explicitly address this failure mode, which could lead to unsafe designs. This paper presents and verifies an analytical approach for distortional buckling stress prediction for flanges under stress gradient. The approach is consistent with the design …

Tensile Strength And Serviceability Of Cold-Formed Steel Clip Angles, Wenying Zhang, Zhishan Yan, Mahsa Mahdavian, Mohamad Yousof, Cheng Yu

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper reports the recent research findings of cold-formed steel clip angles in tension. The relevant experimental program and the proposed design methods are presented. The test program involved two phases of testing: Phase I of program focused on the pull-over strength of screw connections on the anchored leg of the clip angles, and Phase II of program concentrated on the tensile strength of the anchored leg of the clip angles within the service deflection limit. Design methods for predicting the pull-over strength as well as tensile strength within the serviceability deformation limit are proposed based on the test results …

Strength Of Cold-Formed Steel Clip Angle In Combined Bending And Shear Loading, Cheng Yu, Zhishan Yan, Wenying Zhang

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Thin-walled cold-formed steel (CFS) clip angles have been commonly used for connecting CFS framing members or attaching CFS members to the major building structure. The implementation of clip angles involves consideration of ultimate strength for combined bending moments and shear forces. Therefore, a test program of CFS clip angle was recently conducted to investigate the behavior and strength of cold-formed steel clip angle subjected to combined bending moments and shear forces at different boundary conditions. The research included connection tests on clip angle. The testing method was adopted from the AISI S914 Test Standard for Joist Connectors Attached to Clod-Formed …

Critical Design Criteria For Standard, Truncated, And Parallel Chords Cold-Formed Steel Trusses, Maelle Van Thienen, Johannes Dimyadi, James B. P. Lim, G. Charles Clifton

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The design of cold-formed steel trusses can be a very complicated and long repetitive process involving up to 28 load combinations added to serviceability checks depending on the design standards being used. This process is particularly tedious if a near optimal solution is required. Additionally, the risk of introducing human errors is usually quite high as it is a process often done by hand. FRAMECAD Structure is a niche software solution born from the desire to provide a complete solution for constructing with cold-formed steel by a company selling roll-forming machines. FRAMECAD Structure specialises on automating the calculations and design …

Cold-Formed Ferritic Stainless Steel Tubular Sections Under End-One-Flange Loading Condition, Hai-Ting Li, Benjamin Young

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper presents experimental and numerical investigations of cold-formed ferritic stainless steel tubular sections under End-One-Flange (EOF) loading condition. A series of web crippling tests was conducted on cold-formed square and rectangular hollow sections of ferritic stainless steel grade EN 1.4003. The web crippling test results were used for the verification of the finite element (FE) model. Upon verification, a parametric study was performed thereafter. The codified web crippling design provisions in American, Australian/New Zealand and European standards for stainless steel structures were assessed. Improved web crippling design rules are proposed for cold-formed ferritic stainless steel tubular sections under EOF …

Optimum Slot Weld Width For Cold-Formed Steel, Emilee A. Martin, Fredrick R. Rutz

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Slot welds can be used for connections in cold-formed steel (CFS) structures. However, structural engineers will find AISI S100, “North American Specification for the Design of Cold-Formed Steel Structural Members” (AISI 2016) - which can be used for guidance in calculating structural capacity of many welds types - silent on this specific application.

Research at the University of Colorado Denver has been directed toward determination of the strength of slot welds in sheet steel. A comprehensive series of tests were performed to determine structural capacity and ductility of various slot weld widths using a metal inert gas (MIG) welding process. …

Using Generalized Beam Theory To Assess The Behavior Of Curved Thin-Walled Members, Nuno Peres, Rodrigo Goncalves, Dinar Camotim

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

In this work, the first-order behavior of naturally curved thin-walled bars with circular axis, without pre-twist, is assessed with the help of the Generalized Beam Theory (GBT) formulation previously developed by the authors. With respect to the previous work, which dealt with simple cross-sections, the present paper presents a method to obtain the deformation modes for arbitrary flat-walled cross-sections. Despite the complexity involved in this generalization, the standard GBT kinematic assumptions are kept, since they are essential to (i) subdivide the modes in a meaningful way and (ii) reduce the number of DOFs necessary to obtain accurate solutions. It is …

Proposal To Improve The Dsm Design Of Cold-Formed Steel Angle Columns: Need, Background, Quality Assessment And Illustration, Pedro Borges Dinis, Dinar Camotim

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper presents a proposal for the codification of an efficient design approach, based on the Direct Strength Method (DSM), for cold-formed steel equal-leg angle columns with short-to-intermediate lengths, i.e., those buckling in flexural-torsional modes. Initially, the available experimental failure load data, comprising fixed-ended and pin-ended (“cylindrical hinges”) columns with several geometries (cross-section dimensions and lengths) and tested by various researchers, are collected and used to show that the currently codified DSM design provisions are not able to handle adequately short-to- intermediate angle columns and that a specific DSM-based design approach is needed to estimate the failure loads of such …

Comparison Of Experimental And Numerical Results For Flexural Capacity Of Light-Gage Steel Roof Deck, Christopher H. Raebel, Dawid Gwodzdz

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The objective of this paper is to present a comparison between experimental results to each of two numerical analyses of cold formed steel roof deck in flexure. Prior numerical studies using the Direct Strength Method (DSM) and the Equivalent Width Method (EWM) have shown discrepancies between results obtained by the two methods. The goal of this research initiative was to compare results from each of the two numerical analysis methods to experimental results in an effort to determine which numerical method is most appropriate for analyzing steel deck in flexure.

Twenty-four physical tests were conducted using four different deck gages …

The Design And Development Of Lightweight Composite Panels For Rigid Wall Structures, Jeremy J. Artman, Cheng Yu

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The paper presents a research effort aimed at developing a stronger, lighter, and more economic shelter for both military and civilian use. Reported herein are the research results on developing solid wall panels using cold-formed steel corrugated sheathing and members, as well as polyurethane spray foam for insulation. This research includes calculating uniform load density, determining the overall strength of the panel, and investigating the flexural strength of the roof panels. Research incorporated different connection methods, with varied stud spacing, to determine the safest design for the new mobile facilities. Previous research has shown that cold-formed steel corrugated sheathing performs …

Experimental Study On Uplift Capacity Of Purlins Considering Restraints From Standing Seam Roof Systems, Wei Luan, Yuanqi Li

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A total of 32 specimens of single-span purlin roof assemblies considering uplift wind load were tested to investigate the structural behavior of cold-formed steel purlins with one flange fastened to standing seam roofs. Failure modes and failure loads of purlins with different parameters were obtained. Full finite element models, incorporate purlins, clips and standing seam roof panels, were developed, and the analysis results were consistent to a high degree with the test results. Using the same element type and material model, the rotational restraint of test roof systems and corresponding influence factors were investigated by finite element models. Finally, using …

A Finite Element Study Of Corrugated Steel Deck Subjected To Concentrated Loads, Vitaliy V. Degtyarev

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

An extensive parametric study was initiated to get a better understanding of steel deck behavior under concentrated loads and to develop design recommendations for a wide range of deck profiles. This paper presents first results from the study related to 1.5-in. deep roof decks of types B and F. The study was performed on non-linear finite element models of deck validated against available test data. Deck gage, span length, span condition, concentrated load locations along and across the deck span were varied in the study. The observed deck behavior under concentrated loads, as well as the effects of the studied …

Web Bearing Capacity Of Cold-Formed Ferritic Stainless Steel Unlipped Channels With Web Perforations Under The End-Two-Flange (Etf) Loading, Amir M. Yousefi, James B. P. Lim, G. Charles Clifton

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Laboratory and numerical evaluations on the web bearing capacity of unlipped cold-formed ferritic stainless steel channels are described in this paper. The channels considered have circular perforations in the web and are loaded under the end-two-flange (ETF) load case. A total of 387 results comprising 27 laboratory and 360 numerical results are presented. A nonlinear quasi-static finite element (FE) model was developed for the numerical investigation. An extensive parametric study is described to determine web bearing capacity reduction factors for different sizes of circular web perforations and cross-section dimensions; the circular web perforations are either centred or offset to the …

Web Crippling Behavior Of Cold-Formed Ferritic Stainless Steel Unlipped Channels Under Interior-One-Flange And End-One-Flange Loadings, Amir M. Yousefi, James B. P. Lim, G. Charles Clifton

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The web crippling strength of cold-formed ferritic stainless steel unlipped channels subject to interior-one-flange and end-one-flange loading is considered in this paper. A total of 144 results are presented, comprising 36 laboratory and 108 numerical results. These results cover the cases of both flanges restrained and unrestrained to the load and reaction plates. Unlike other work in the literature, the numerical analysis in this paper uses nonlinear quasi-static finite element analysis with an implicit integration scheme, which has advantages over static and quasi-static with an explicit integration scheme analyses, particularly for post buckling predictions of unlipped channels subject to web …

Experimental And Analytical Studies Of Cold-Formed Steel Sections With Edge-Stiffened Circular Holes Subjected To Web Crippling, Asraf Uzzaman, James B. P. Lim, David Nash, Amir M. Yousefi, Benjamin Young

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Cold-formed steel sections are often used as wall studs or floor joists and such sections often include web holes for ease of installation of services. The holes are normally punched or bored and are unstiffened; when the holes are near to points of concentrated load, web crippling can be the critical design consideration. Recently, a new generation of cold-formed steel channel sections with edge-stiffened circular holes has been developed. The web holes are stiffened through a continuous edge stiffener/lip around the perimeter of the hole. In this paper, a combination of experimental investigations and non-linear finite element analyses are used …

Parametric Studies And Design Recommendations Of Cold-Formed Steel Sections With Edge-Stiffened Circular Holes Subjected To Web Crippling, Asraf Uzzaman, James B. P. Lim, David Nash, Amir M. Yousefi, Benjamin Young

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A parametric study of cold-formed steel sections with edge-stiffened circular holes subjected to web crippling under one-flange loading condition was undertaken using finite element analysis. The effect of different hole sizes, edge-stiffener length and distances of the web holes to the near edge of the bearing plate on the web crippling strengths of channel sections were investigated. The web crippling strengths are influenced by various geometry parameters: the ratio of the hole depth to the flat portion of the web, a/h, the location of the hole as defined by the distance of the hole from the edge of the …

A Preliminary Study On Stainless Steel Hollow Flange Beams Featuring Lateral-Distortional Buckling, Shuang Niu, Zhidong Zhang, Feng Fan

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

To explore the potential of using stainless steel structurally, extensive research has been carried out to study the structural behavior of stainless steel member as associated with the nonlinear stress-strain relationship. Hollow flange sections feature improved structural efficiency and a unique issue of web distortion. Steel hollow flange sections have been studied and commercially distributed (e.g. the very first HFB section and lately LSB section). As a proactive study, this paper investigates stainless steel hollow flange beams of double-symmetric section with numerical modeling and parametric analysis. The validity of the idealized FE model was verified with existing study on steel …

On The Effect Of Web Stiffening Of Cold-Formed Steel Thin-Walled Lipped Sigma Sections In Compression Members, Rashideddin Cheraghi, Hamidreza Mohammadzadeh

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Cold-formed steel cross sections are high strength thin-walled profiles which are highly prone to local and distortional instabilities. Stiffening techniques are utilized in the industry as a solution to enhance local and distortional buckling strengths. The sigma section is that channel section which its web pushed inward for the stiffening reason. In this research, the effect of side sway of the web (dx) on the buckling behavior of lipped sigma sections is investigated. The results demonstrate that stiffening inclined components of the web in lipped sigma sections for dx up to 0.5512”(14 mm) act as a stiffener and change the …

Bracing Design For Torsional Bucking Of Cold-Formed Steel Wall Stud Columns, C. D. Moen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A method is presented for calculating the required brace stiffness and strength to limit torsional buckling deformation in cold-formed steel wall stud columns. The bracing (bridging) design method utilizes recent insight from classical stability solutions that define twist of singly and doubly-symmetric columns with an initial twist imperfection as a function of column compressive load. A wall stud design example is provided.

Behavior Of Beam To Column Cold-Formed Section Connections Subjected To Bending Moments, Maged T. Hanna, Mohamed M. El-Saadawy, Ghada M. El-Mahdy, Ehab H. A. H. Aly

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Cold formed sections are often used in the construction of mid-rise buildings due to their high strength weight ratios, and fast erection. In these buildings, the connections between joists and studs are mainly simple connections. However, application of these sections can be extended to moderate span frames where connections between members are subjected to bending moments. Strength and stability of such frames depends to large extent on the behaviour of the connections between their members. Over the last twenty years, several researchers undertake tests on cold formed section connections subjected to bending moments. Major of them classify the connections as …

Investigation On Shear Capacity For Screw Connections Of Cold-Formed Steel Framed Shear Walls With Steel Sheathing, Ruoqiang Feng, Ying Ma

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Experimental and numerical investigations were carried out to learn the shear capacities for screw connections of cold-formed steel framed shear walls with steel sheets for the base layer combined with gypsum wallboards for the face layer. The design methods of test specimens, the loading equipment and the data processing method were introduced. According the phenomenon of tests for multiple self-drilled screw connections, the loading-deformation curves, shear capacity and failure modes were testified. The influence of end distance of screw, edge distance of screw, diameter of screw, spacing of screw, thickness of steel sheets, thickness of gypsum wallboards, thickness of studs …

Cold-Formed Steel Bolted Moment-Resisting Connections With Friction-Slip Mechanism For Seismic Areas, Marzie Shahini, Alireza Bagheri Sabbagh

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper presents investigation on cold-formed steel (CFS) beam-to-column moment-resisting (MR) bolted connections with high energy dissipation capacity suitable for seismic areas. Bolting friction-slip mechanism of the introduced CFS MR connection is developed as its main seismic energy dissipation fuse aiming to postpone or eliminate local buckling and yielding in the CFS MR connections. Finite Element (FE) modelling techniques are employed to effectively simulate the connections with an activated friction-slip mechanism. Hysteretic energy dissipation response of the connections with circular bolting (CB) arrangement designed to slip at 0.5Mp are presented. Based on the obtained FE results, full-scale physical tests on …

Planning The Future Of North American Cold-Formed Steel Design Standards, Benjamin W. Schafer, Jay Larson, Helen Chen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Growth in cold-formed steel structures has long been tied to developing and advancing the engineering standards that govern their use in construction. The American Iron and Steel Institute (AISI) has taken a leadership role in this activity in North America since 1946. Conventional standards providing closed-formed solutions to member capacity, such as the recently completed suite of AISI Standards in 2015 and 2016. These standards have reached an impressive level of maturity given the complexity of designing entire (building) structural systems out of steel that is rarely greater than 2mm thick. However, the demands on the structural engineer designing cold-formed …

The Impact Of Bearing Conditions On The Behavior Of Cold-Formed Steel Stud Assemblies, Abbas Joorabchian, Zhanjie Li, Kara D. Peterman

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The objective of this study is to explore the structural response of cold-formed steel stud assemblies (i.e., stud and track) with partial bearing conditions. It is hypothesized that studs bearing under partial bearing conditions (i.e., not fully bearing on a concrete slab) may result in reduced axial capacities. Currently, the behavior of these systems on concrete slabs due to member instabilities is not well-understood, and cold-formed steel design specifications provide no guidance. This study provides an integral experimental and numerical investigation of the stability response of the studs under partial bearing conditions in order to quantify the reduction of their …

Behavior Of Cold-Formed Steel Metal Industrial Buildings, Adrianna M. Early, M. Ebrahim Mohammadi, Richard L. Wood, Kara D. Peterman

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper presents research focused on understanding the observed behavior of cold-formed steel (CFS) metal buildings during Hurricane Harvey, which made landfall Friday, August 25, 2017 between Port Aransas and Port O’Connor, Texas. Through the Geotechnical Extreme Event Reconnaissance (GEER) association (funded by the National Science Foundation) a team of structural engineers and researchers performed rapid and detailed assessments of structural damage caused by the hurricane. The National Science Foundation gathered photographs, damage assessments sheets, and three-dimensional laser point cloud data of severely damaged cold-formed steel industrial buildings. The Port Aransas County Airport experienced severe damage to several cold-formed steel …

Sustainability Of Modular Lightweight Steel Building From Design To Construction, Ornella Iuorio, Loredana Napolano, Luigi Fiorino, Raffaele Landolfo

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The increasing concerns over population growth, depletion of natural resources and global warming as well as catastrophic natural events is leading the international scientific community to envisage sustainability as a crucial goal. The built environment plays a key role on the triple bottom line of the sustainable development -- Planet, People, Profit -- because of several environmental, social and economic impacts produced by the construction sector. The acknowledged need to promote a sustainable building market is an international high-priority issue as underlined by the 2030 Agenda for Sustainable Development. Indeed one of its strategic objectives highlights to make cities and …

Experimental Study Of Apex Connection Stiffness And Strength Of Cold-Formed Steel Double Channel Portal Frames, J. Peng, J. Bendit, H. B. Blum

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Cold-formed steel portal frames are an increasingly popular structure in the housing and industrial sectors, and are commonly used for garages, sheds, and shelters. Longer span cold-formed steel portal frames are relatively new to the market, and as a result limited design guidance and recommendations exist, including the strength and stiffness of the connections. The apex connection stiffness affects the distribution of internal actions and deflections of a portal frame, and therefore, it is necessary to quantify the apex stiffness for use in design models to accurately determine the frame behavior. An experimental program was carried out on a series …