Engineering Commons^™

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 …

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 …

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 …

Wei-Wen Yu International Specialty Conference On Cold-Formed Steel Structures 2018: Recent Research And Developments In Cold-Formed Steel Design And Construction, Wei-Wen Yu Center For Cold-Formed Steel Structures

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

No abstract provided.

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 …

Computational Modeling Of Joist-To-Ledger Connections In Cold-Formed Steel Diaphragms, Hernan Castaneda, M. Eng, Kara D. Peterson

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

Cold-formed steel framed buildings can involve a range of options for framing systems, including balloon framing, platform framing, and ledger framing. Transfer of lateral forces from the diaphragms to the wall system (and ultimately to the ground) depends on the interactions within the wall-diaphragm connection, which is dependent on choice of framing system. In ledger framing, floor joists are hung from top of wall studs via a rim track (ledger) and clip angle connection. Recent experimental efforts at Johns Hopkins University studied the wall-diaphragm connection with the goal of quantifying its contribution to overall diaphragm response. Results from these experiments …

Effect Of Connection Details On The Cyclic Behavior Of Nestable Screw Sidelaps, S. Torabian, H. Folk, Benjamin W. Schafer

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

The connection strength and stiffness sensitivity of screwed sidelaps in nestable steel decks to screw installation details has been experimentally explored via cyclic testing. The cyclic behavior of sidelaps has been recently incorporated in the high fidelity modeling and seismic evaluation of the steel deck diaphragm in rigid wall - flexible diaphragm buildings, where “unzipping” a sidelap (loss of a significant number of sidelap connections along a deck edge) could significantly reduce the seismic performance of the whole diaphragm. A total of 24 monotonic and cyclic sidelap tests have been performed in the Thin-Walled Structures Laboratory at Johns Hopkins University. …

Shake Table Testing For Seismic Response Evaluation Of Cold-Formed Steel-Framed Nonstructural Architectural Components, Luigi Fiorino, Bianca Bucciero, Tatiana Pali, Ornella Iuorio, Raffaele Landolfo

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

The seismic response evaluation of cold-formed steel-framed nonstructural architectural components was investigated in an experimental campaign carried out within of the research study agreement between Knauf Gips KG and the Department of Structures for Engineering and Architecture of the University of Naples “Federico II”. The main objective of this research was to investigate the seismic performance of drywall nonstructural systems, i.e. cold-formed steel-framed indoor partition walls, outdoor façade walls and suspended ceilings. The present paper deals with the dynamic shake table tests. The tests were carried out on two different typologies of prototypes (Type 1 and Type 2) for a …

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 …

New Web Crippling Design Rules For Cold-Formed Steel Beams, L. Sundararajah, M. Mahendran, P. Keerthan

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

Lipped channel beams (LCBs) and SupaCee sections are commonly used as floor joists and bearers in the construction industry. SupaCee section is one of the cold-formed steel members, which is increasingly used in the building construction sector. It is characterized by unique ribbed web and curved lip elements, and is claimed to be more economical with extra strength than the traditional channel sections. These thin-walled LCBs and SupaCee sections are subjected to specific local and global failures, one of them being web crippling. Several experimental and numerical studies have been conducted in the past to study the web crippling behaviour …

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 …

Cyclic Performance And Behavior Characterization Of Steel Deck Sidelap And Framing Connections, S. Torabian, D. Fratamico

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

A wide variety of steel deck sidelaps and framing connections have been experimentally studied to characterize the cyclic performance required in seismic evaluation of steel deck diaphragms. This study intends to provide cyclic test results of common steel deck connections including screw nestable and top arc seam sidelaps; and powder actuated fasteners, arc spot weld, and arc seam weld framing connections. A total of 24 sidelap and 36 framing connection tests have been performed in the Thin-Walled Structures Laboratory at Johns Hopkins University by NBM Technologies. The connection test results have been used to parameterize a nonlinear hysteretic spring element …

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 …

Bearing Strength Of Untightened Double-Shear Bolted Connections In Cold-Formed Steel Construction, Refat Bhuiyan, Lip H. Teh

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

This paper presents the experimental investigation of cold-formed steel double-shear bolted connections where both the bolt head and the nut are not in contact with the outer sheets. The inner sheet of each specimen is not constrained from out-of-plane distortion or bulging downstream of the bolt, and fails in bearing. Based on a series of tests involving specimens having bolt diameters ranging from 12 to 16 mm and sheet thicknesses ranging from 1.5 to 3.0 mm, it has been found that the absence of out-of-plane constraint in untightened bolted connections leads to much lower bearing capacities than predicted by 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.

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 …

Transverse Shear Stiffness Of Bolted Cold-Formed Steel Storage Rack Upright Frames With Channel Bracing Members, Nima Talebian, Benoit P. Gilbert, Hassan Karampour

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

Accurately evaluating the transverse shear stiffness of cold-formed steel storage rack upright frames is crucial to calculate the frame elastic buckling load, perform earthquake design and serviceability checks. This is especially essential for high-bay racks, which are subjected to large second-order effects, and racks supporting the building enclosure, which are exposed to transverse wind loads. The shear behaviour of these frames is poorly understood and experimental testing is usually required to measure their stiffness. Previous studies have shown that Finite Element Analyses (FEA), solely using beam elements, fail to reproduce experimental test results and may overestimate the transverse shear stiffness …

Biaxial Bending Of Cold-Formed Steel Storage Rack Uprights – Part Ii: Design Methods, Nima Talebian, Benoit P. Gilbert, Cao Hung Pham, Hassan Karampour

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

This paper uses the results from the parametric studies reported in the companion paper to verify the accuracy of different forms of published direct strength method (DSM) equations. They consist of the classical DSM equations and considering the inelastic reserve capacity into these equations, with and without an extended range of the cross-sectional slenderness. The verifications are made for local and distortional buckling modes. Results show that for all investigated buckling modes, the DSM results in better predictions when the inelastic reserve capacity is considered. The appropriate form of the DSM to predict the biaxial capacity of unperforated cold-formed steel …

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 …

Finite-Element Analysis Of The Eaves Joint Of Cold-Formed Steel Portal Frames Having Single Channel-Sections, Pouya Pouladi, John Ronaldson, George Charles Clifton, Jason Maxwell Ingham, Andrzej M. Wrzesien, Paul Milewski, James B. P. Lim

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

A finite element model is described for the eaves joint of a cold-formed steel portal frame that comprises a single channel section for the column and rafters eaves connections. The members are connected to the brackets through both screws and bolts. Such a joint detail is commonly used in practice in New Zealand and Australia, where the function of the screws is to prevent slip of the joint during frame erection since the bolt holes are detailed for nominal clearance. The results of the finite element model are compared against two experimental test results. In both, the critical mode of …

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 …

Shear Resistance Mechanisms On Steel Sheet Shear Walls With Burring Holes And Cross-Rails, Yoshimichi Kawai, Kazunori Fujihashi, Shigeaki Tohnai, Atsushi Sato, Tetsuro Ono

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

Steel sheet shear walls with burring holes are employed in low and mid-rise buildings in seismically active regions. A configuration with burrs on the inside enables the thinner wall and omitting the machining of equipment holes. The effects of cross-rails which are generally designed to strengthen the bearing capacities of the studs, on 2.73~4.53m height shear walls were clarified by finite element analysis and experiments. Post-buckling behavior depends on tension fields restrained by the cross-rails. The formulas of the allowable strengths and the indexes of ultimate strengths were developed using the mechanisms.

Influence Of Fire On The Shear Capacity Of Cold-Formed Steel Framed Shear Walls, M. S. Hoehler, B. Andres

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

This paper presents experimental investigations of the performance of common lateral force-resisting systems used in cold-formed steel construction under sequential thermal (fire) and mechanical (earthquake) loading. Wall specimens with gypsum-sheet steel composite sheathing, Oriented Strand Board (OSB) sheathing, or steel strap bracing were tested. The results demonstrate that the lateral capacity of wall systems can be reduced by exposure to fire. Additionally, fire performance of wall systems can be affected by pre-damage to the fire-resistive components that provide fire protection to these walls. The results are useful for fire compartmentation design when significant lateral deformation of a building is anticipated …

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 …

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 …

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 …