Testing Of Connectors For Cold-Formed Steel Construction - Challenges, Recent Innovation, And Future Direction,
2012
Missouri University of Science and Technology
Testing Of Connectors For Cold-Formed Steel Construction - Challenges, Recent Innovation, And Future Direction, Timothy M. Stauffer, Hien Kim Nguyen
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
As cold-formed steel construction continues to evolve, manufacturers are making advances in prefabricated connectors for use in a variety of applications. Often, establishing available strengths for connectors requires testing. This paper will examine some of the challenges associated with testing of these products. Available standards and criteria will be discussed, and an overview of potential difficulties with their use will be presented. Test programs conducted by one manufacturer during recent product development will be presented to illustrate some of the challenges and highlight innovations made to address them. Finally, based on experience gained through extensive testing and product development, recommendations …
Self-Shape Optimisation Of Cold-Formed Steel Columns,
2012
Missouri University of Science and Technology
Self-Shape Optimisation Of Cold-Formed Steel Columns, Benoit P. Gilbert, Timothee J-M Savoyat, Lip H. The
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This paper presents the optimisation of cold-formed steel open columns using the recently developed self-shape optimisation method that aims to discover new profile shapes. The strength of the cold-formed steel sections is calculated using the Direct Strength Method, and the rules developed in the present work to automatically determine the local and distortional elastic buckling stresses from the Finite Strip and constrained Finite Strip Methods are discussed. The rules are verified against conventional and optimum sections yielded in this research, and found to accurately predict the elastic buckling stresses. The principles behind the self-shape optimisation method are summarised herein and …
Innovative Cross-Section Shapes For Built-Up Cfs Columns. Experimental Investigation,
2012
Missouri University of Science and Technology
Innovative Cross-Section Shapes For Built-Up Cfs Columns. Experimental Investigation, Iveta Georgieva, Luc Schueremans, Lincy Pyl, Lucie Vandewalle
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Innovative cross-section shapes for built-up columns from cold-formed steel (CFS) profiles are evaluated experimentally. The goal is to obtain highly stable members with reduced sensitivity to bucking effects and initial imperfections, and therefore, higher strength-to-weight ratios. The columns have been designed following the principles of the direct strength method [1], with the ambition to exclude (or reduce) various buckling effects from the column response to compressive loads. Cross-section proportions and bolt spacing have been adapted, in order to interfere with the distortion of individual profiles and the overall buckling of the columns. Experiments show that, through proper design and insight …
Compressive Strength Tests And Design Of Cold-Formed Plain And Dimpled Steel Columns,
2012
Missouri University of Science and Technology
Compressive Strength Tests And Design Of Cold-Formed Plain And Dimpled Steel Columns, V. B. Nquyen, C. J. Wang, D. J. Mynors, M. A. English, M. A. Castellucci
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This paper presents the experiments and design formulae of cold-formed plain and dimpled steel columns. A series of compression tests on plain and dimpled channel columns were conducted over a range of different geometries and the strength of the columns were investigated. The change in strength of the dimpled columns resulting from the cold working associated with the dimpling process was considered. The results showed that the buckling and ultimate strengths of dimpled steel columns were up to 33% and 26% greater than plain steel columns, respectively. The test results were evaluated by comparing buckling and ultimate loads of plain …
Steel Deck Institute Standards For Composite Steel Floor Deck-Slabs,
2012
Missouri University of Science and Technology
Steel Deck Institute Standards For Composite Steel Floor Deck-Slabs, Thomas Sputo
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
As an ANSI accredited standards developer, the Steel Deck Institute (SDI) has developed an updated and expanded version of its “Standard for Composite Steel Floor Deck-Slabs”, ANSI/SDI C-2011 and a new standard, “Test Standard for Composite Steel Deck-Slabs”, ANSI/SDI T-CD-2011. These two standards reflect the current state-of-the-art for the design and testing of composite steel deck-slabs where the steel deck provides the tensile reinforcement for the slab. Substantial changes in the ANSI/SDI-C-2011 Standard include increased information regarding the use of fibers for concrete crack control purposes and concrete serviceability, consideration of moving and concentrated loads, and use of updated shear …
Aisi Standards Update,
2012
Missouri University of Science and Technology
Aisi Standards Update, Helen Chen, Roger Brockenbrough, Richard Haws
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Since the publication of the 2007 editions, changes and additions have been made to AISI design and construction standards. Accordingly, new editions of the standards, or supplements to existing standards, will be published to formalize these changes. This paper provides an overview of the major changes and additions to those standards.
Direct Strength Method Of Design For Shear Of Cold-Formed Channels Based On A Shear Signature Curve,
2012
Missouri University of Science and Technology
Direct Strength Method Of Design For Shear Of Cold-Formed Channels Based On A Shear Signature Curve, Gregory J. Hancock, Cao Hung Pham
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Thin-walled sections in compression and/or bending may undergo one of the three modes of local, distortional or overall (Euler) buckling, or combinations of these. The Semi-Analytical Finite Strip Method (SAFSM) developed by YK Cheung has been widely used in computer software (THIN-WALL, CUFSM) to develop the signature curve of the buckling stress versus buckling half wavelength for a thin-walled section under compression or bending to allow identification of these modes. The minimum points on the signature curve are now used in the Direct Strength Method (DSM) of design of cold-formed sections in the American Specification and Australian/New Zealand Standard for …
Shear Strength Of Hollow Flange Channel Beams With Stiffened Web Openings,
2012
Missouri University of Science and Technology
Shear Strength Of Hollow Flange Channel Beams With Stiffened Web Openings, P. Keerthan, M. Mahendran
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This LiteSteel beam (LSB) is a new cold-formed steel hollow flange channel section produced using a patented manufacturing process involving simultaneous cold-forming and dual electric resistance welding. The LSBs are commonly used as floor joists and bearers with web openings in buildings. Their shear strengths are considerably reduced when web openings are included for the purpose of locating building services. Shear tests of LSBs with web openings have shown that there is up to 60% reduction in the shear capacity. Hence there is a need to improve the shear capacity of LSBs with web openings. A cost effective way to …
The Effects Of Web Holes On Web Crippling Strength Of Cold-Formed Steel Channels Under End-Two-Flange Loading Condition,
2012
Missouri University of Science and Technology
The Effects Of Web Holes On Web Crippling Strength Of Cold-Formed Steel Channels Under End-Two-Flange Loading Condition, Asraf Uzzaman, James B. P. Lim, David Nash, Jim Rhodes, Ben 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; such sections often include web holes for ease of installation of the services. Web crippling at points of concentrated, or localised, load or reaction in thin-walled beams is well known to be a significant problem, particularly in the case of beams with slender webs, and is of high importance in the field of cold-formed steel members, as such members are generally not stiffened against this type of loading. In this paper, a combination of experimental tests and non-linear elastoplastic finite element analyses are used to investigate the effect …
Push Tests On Innovative Shear Connector For Composite Beam With Cold-Formed Steel Section,
2012
Missouri University of Science and Technology
Push Tests On Innovative Shear Connector For Composite Beam With Cold-Formed Steel Section, S. O. Bamaga, M. M. Tahir, C. S. Tan
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
In this study, experimental tests were conducted to investigate the ductility and strength capacity of new shear connector. Push test specimens were prepared and tested according to EN1994-1-1 standard. The push test specimen consists of two cold-formed steel lipped channel sections oriented back-to-back to form an I-section beam, transverse metal deck and normal concrete slabs grade C25/30. Angle brackets were obtained from the same section of the beam and fastened to the web of steel beam to provide the shear connection. Two shear connectors were tested namely; “SC1” and “SC2” shear connectors. Both shear connectors showed a ductile behavior and …
Direct Strength Design Of Metal Building Wall And Roof Systems - Through-Fastened Simple Span Girts And Purlins With Laterally Unbraced Compression Flanges,
2012
Missouri University of Science and Technology
Direct Strength Design Of Metal Building Wall And Roof Systems - Through-Fastened Simple Span Girts And Purlins With Laterally Unbraced Compression Flanges, Tian Gao, Cristopher D. Moen
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
A Direct Strength Method (DSM) prediction approach is introduced and validated for metal building wall and roof systems constructed with steel panels through-fastened with screws to girts or purlins. The focus is capacity prediction for simple spans under wind uplift or suction, however the DSM framework is generally formulated to accommodate gravity loads, continuous spans, standing seam roofs, and insulated roof and wall systems in the future. System flexural capacity is calculated with the usual DSM approach – global buckling, local global buckling interaction, and distortional buckling strengths are determined with a finite strip eigen-buckling analysis including a rotational spring …
An Explicit, Dynamic Finite Element Model For The Local Failure Of Cold-Formed Trapezoidal Sheeting,
2012
Missouri University of Science and Technology
An Explicit, Dynamic Finite Element Model For The Local Failure Of Cold-Formed Trapezoidal Sheeting, Hèrm Hofmeyer
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
Trapezoidal sheeting, made of cold-formed, thin-walled steel, is widely used for the construction of cladding and roofs. At an interior support, the sheeting is subject to bending moments and a concentrated load, which leads to possible failure followed by two post-failure modes: the yield-arc and yield-eye modes. Until recently, it was not fully understood why a specific post-failure mode occurs and it was suggested that mode-jumping of the compressed sheeting flange may influence the mode occurring. This paper presents new research, in which both the compressed flange in isolation and the sheeting are modeled by using an explicit, dynamic finite …
Design Of Perforated Industrial Storage Rack Columns For Distortional Buckling,
2012
Missouri University of Science and Technology
Design Of Perforated Industrial Storage Rack Columns For Distortional Buckling, Teoman Peköz, Güven Kıymaz, Miquel Casafont, Maria Magdalena Pastor, Jordi Bonada
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The results of an on-going research program to develop a design procedure for perforated industrial storage rack columns are presented. The design procedure includes the effects of distortional buckling. The types of columns studied include those commonly used in Europe and some that are used in the US. The design procedure is being developed based on finite element studies verified by physical testing. The design procedure involves the use of the current US rack column design approach with an extension to distortional buckling with Finite Strip Method (FSM) solutions and Direct Strength Method (DSM) approaches. The approach originally developed for …
Advanced Design Optimization Of Cold-Formed Steel Portal Frame Buildings,
2012
Missouri University of Science and Technology
Advanced Design Optimization Of Cold-Formed Steel Portal Frame Buildings, Duoc T. Phan, James B. P. Lim, Tiku T. Tanyimboh, Wei Sha
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
The design optimization of cold-formed steel portal frame buildings is considered in this paper. The objective function is based on the cost of the members for the main frame and secondary members (i.e., purlins, girts, and cladding for walls and roofs) per unit area on the plan of the building. A realcoded niching genetic algorithm is used to minimize the cost of the frame and secondary members that are designed on the basis of ultimate limit state. It is shown that the proposed algorithm shows effective and robust capacity in generating the optimal solution, owing to the population’s diversity being …
Using Generalized Beam Theory (Gbt) To Assess The Buckling Behavior Of Cold-Formed Steel Structural Systems,
2012
Missouri University of Science and Technology
Using Generalized Beam Theory (Gbt) To Assess The Buckling Behavior Of Cold-Formed Steel Structural Systems, Cilmar Basaglia, Dinar Camotim
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This paper deals with the application of beam finite element models based on Generalized Beam Theory (GBT) to analyze the buckling behavior of three cold-formed steel structural systems, namely (i) beams belonging to storage rack systems, (ii) portal frames built from rectangular hollow section (RHS) profiles and (iii) roof-supporting trusses, exhibiting different support conditions and subjected to various loadings. In particular, taking advantage of the GBT unique and structurally clarifying modal features, it is possible to assess how different geometries and/or bracing arrangements affect (improve) the local, distortional and/or global buckling behavior of the above structural systems. The accuracy of …
Investigation Of Behavior Of Cold-Formed Steel Sheeting Systems In Fire Using Finite Element Modeling,
2012
Missouri University of Science and Technology
Investigation Of Behavior Of Cold-Formed Steel Sheeting Systems In Fire Using Finite Element Modeling, W. Lu, P. Mäkeläinen, J. Outinen, Z. Ma
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
A 3D Finite Element (FE) model of steel sheeting, which includes the screw connector and support plate, is created to investigate the behavior of both steel sheeting and connections at elevated temperatures. The created model considers the material nonlinearity, large deformation and contact behavior. The material damage model for sheeting steel is defined so that the FE model is analyzed through the elastic and plastic ranges up to failure. The FE model is used to predict the ultimate resistance and deformation. The current FE model captures the main behavior of steel roof systems well up to around 20 minutes according …
Active Shear Planes In Block Shear Failure Of Bolted Connections,
2012
Missouri University of Science and Technology
Active Shear Planes In Block Shear Failure Of Bolted Connections, Drew D. A. Clements, Lip H. Teh
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
In the AISI Specification for the Design of Cold-formed Steel Structural Members 2007, there are two types of shear planes used to determine the resistance of a bolted connection to block shear failure. When the block shear failure occurs by shear yielding and tensile rupture, the shear failure plane is taken to be the gross shear plane. Conversely, when the block shear failure is deemed to occur by simultaneous shear and tensile ruptures, the shear failure plane is assumed to be the net shear plane. Such an approach is not logical since the shear failure planes should be unique irrespective …
In-Plane Shear Lag Of Bolted Connections,
2012
Missouri University of Science and Technology
In-Plane Shear Lag Of Bolted Connections, Lip H. Teh, Benoit P. Gilbert
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This paper points out that the shear lag factors embedded in the design equations specified in the North American, European and Australasian cold-formed steel structures codes for determining the net section tension capacity of bolted connections in flat steel sheets either yield “anomalous” results or become irrelevant when they exceed unity. The anomaly is demonstrated through laboratory tests and is explained using simple calculus. A proper mathematical expression for the in-plane shear lag factor, which does not suffer from the anomaly of the code equations and never implies shear lag factors greater than unity for any configuration, is presented and …
Prediction Of Joint Temperatures In Shot-Nailed Cold-Formed Steel Sheeting With Finite Element Modelling,
2012
Missouri University of Science and Technology
Prediction Of Joint Temperatures In Shot-Nailed Cold-Formed Steel Sheeting With Finite Element Modelling, Z. Ma, W. Lu, P. Mäkeläinen, J. Outinen
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This paper investigates the 3D temperature fields of the shot-nailed steel roof sheeting joints in fire using commercial Finite Element (FE) software ABAQUS when the connected members and connections are protected by either intumescent paint or rockwool panels. Numerical models and parameters used in the models are briefly introduced. When expanded in fire, both thickness and thermal conductivity are varied with increased temperatures. The simplified representation of intumescent paint is described. Parametric analyses are performed in order to investigate the sensitivity of the parameters of thermal contacts. When the joints are protected with rockwool panels, the approximate cavity radiation method …
Modal Identification Of Cold-Formed Steel Members In Shell Finite Element Models,
2012
Missouri University of Science and Technology
Modal Identification Of Cold-Formed Steel Members In Shell Finite Element Models, Z. Li, S. Ádány, B. W. Schafer
CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)
This paper illustrates new capabilities for modal identification of shell Finite Element Method (FEM) models of thin-walled cold-formed steel members. The separation of general deformations into fundamental buckling deformation classes: local, distortional, global, shear, and transverse extension, originated with the constrained Finite Strip Method (cFSM) and is extended here to shell element based FEM analysis. The cFSM base vectors for general end boundary conditions, previously developed by the authors, provide a series of general base functions capable of separating displacements into classes. FEM displacements are identified by minimizing error between the actual FEM displacements and those predicted by the cFSM …
