Civil and Environmental Engineering Commons^™

Application Of The Direct Strength Method To Steel Deck, Randall Keith Dudenbostel, Thomas Sputo

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

With the reorganization of the AISI S100 Standard, the Direct Strength Method (DSM) takes a position of equal footing with the Equivalent Width Method (EWM) for calculating the strength of cold-formed steel cross sections. The majority of previous DSM studies focused on C and Z profiles, while little study of panel sections, especially steel deck sections, has been performed. A study was undertaken to determine and compare the behavior and usable strength of existing floor and roof deck sections with both DSM and EWM. The Cornell University – Finite Strip Method (CUFSM) software was used for the elastic buckling analysis, …

Finite Element Modeling Of Concrete Shrinkage In Composite Deck Slabs, Vitaliy V. Degtyarev

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

This paper presents finite element models of composite deck slabs subjected to restrained concrete shrinkage. The models created in ANSYS and validated against test data were based on the assumption of the full shear interaction between the deck and the concrete and accounted for concrete creep, cracking, and nonlinear stress-strain relationship. Concrete shrinkage was modeled by temperature changes applied to concrete. The effects of different shrinkage profiles, concrete creep, and deck slab properties on the long-term concrete and deck strains are presented. Future research work is outlined.

A Combined Direct Analysis And Direct Strength Approach To Predict The Flexural Strength Of Z-Purlins With Paired Torsion Braces, Michael W. Seek, Chris Ramseyer, Ian Kaplan

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

A series of 12 Base Tests for Z-section purlins with paired interior torsional braces and one flange attached to a flexible horizontal diaphragm are evaluated with the Direct Strength Method. Rather than use the conventional constrained bending stress approximation, a direct analysis philosophy is adopted where cross section stress distributions are calculated using a displacement compatibility approach. With a flexible diaphragm typical of a standing seam roof system, these stresses can deviate substantially from the constrained bending approximation and can significantly impact predicted local and distortional buckling behavior. The displacement compatibility approach incorporates estimates of load imbalances and second order …

Advanced Modeling Of Cold-Formed Steel Walls Under Fire, J. C. Batista Abreu, N. Punati, K. R. Prasad, B. W. Schafer

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

This paper discusses an advanced finite element model able to simulate the structural response of cold-formed steel walls during standard fire tests. The model includes experimental thermo-mechanical properties of materials, geometric imperfections, and temperature distributions on studs and sheathing boards. The model is capable of reasonably predicting the thermal bowing of walls, and estimating the shape, size and amount of joint openings between gypsum boards over time of fire exposure. Numerical results validated with experimental data indicate that the maximum out-of-plane displacements due to thermal gradients occur near the wall mid-height. Early in the heating process, joint openings develop on …

Characterization Of Cold-Formed Steel Framed Diaphragm Response Under In-Plane Loading And Influence Of Non-Structural Gypsum Panels, Patrick Latreille, Violetta Nikolaidou, Colin A. Rogers, Dimitrios G. Lignos

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

The in-plane response of CFS framed diaphragm structures subjected to seismic excitation is not well understood. At present, the North American AISI S400 Standard does not include a seismic design procedure for CFS framed diaphragms for use in Canada, and offers limited information for their use in the US. In addition, the effect of non-structural components on the lateral strength and stiffness of the diaphragm component has yet to be explored. In an effort to provide insight into the complex nature of the diaphragm structure and the influence of non- structural components an experimental program was initiated in the Jamieson …

Sheathing Overlapping And Attachment Methods For Cold-Formed Steel Shear Walls With Corrugated Steel Sheathing, Mahsa Mahdavian, Wenying Zhang, Cheng Yu

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

Cold-formed steel (CFS) shear walls sheathed with corrugated steel sheathing are a feasible solution to non-combustible high structural performance CFS shear walls in mid-rise buildings. Corrugated steel sheathings have high in-plane strength and stiffness due to the cross sectional shape of the sheet. This paper presents an experimental study on two specific issues: (1) the sheathing overlapping configurations and their impact to the shear wall performance, (2) the attachment method for sheathing to framing. For the overlapping issue, one overlap and two overlaps in the corrugated sheets were experimentally investigated, it was found that the overlap differences did not cause …

Simulating The Seismic Performance Of Cold-Formed Steel Framed Buildings Using Corrugated Sheet Shear Walls, Wenying Zhang, Mahsa Mahdavian, Yuanqi Li, Cheng Yu

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

Cold-formed steel framed shear wall sheathed with corrugated steel sheets is a promising shear wall system for low- and mid-rise constructions at high wind and seismic zones due to its advantages of non-combustibility, high shear strength, and high shear stiffness. A lot of work has been done on this subject. However, all the previous work is focused on the wall panel levels and more research work is needed on the entire building systems. The objective of this paper is to investigate the response of a cold-formed steel framed building with corrugated sheet sheathing subjected to earthquake excitation primarily through nonlinear …

Experimental Tests For The Seismic Response Evaluation Of Cold-Formed Steel Shear Walls Sheathed With Nailed Gypsum Boards, Luigi Fiorino, Vincenzo Macillo, Maria Teresa Terracciano, Tatiana Pali, Bianca Bucciero, Raffaele Landolfo

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

The European project named "Energy Efficient LIghtweight-Sustainable-SAfe- Steel Construction" (Project acronym: ELISSA) is devoted to the development and demonstration of cold-formed steel (CFS) modular systems. In particular, these systems are nano-enhanced prefabricated lightweight steel skeleton/dry wall construction with improved thermal, vibration/seismic and fire performance, resulting from the inherent thermal, damping and fire spread prevention properties. The different building performances are studied and improved by means of experimental and numerical activities organized on three scale levels: micro-scale, meso-scale and macro-scale. In particular, the evaluation of the seismic performance is carried out at the University of Naples by means tests on connections …

Development Of A Method To Generate A Simplified Finite Element Model For An Electrical Switchboard Cabinet, Edwin Lim, Barry J. Goodno, James I. Craig

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

Electrical switchboards are one of the key pieces of equipment used in operations of most critical facilities such as hospitals and emergency services buildings. Unfortunately, past observations have shown that the switchboard cabinet and its contents may be vulnerable to damage or failure during an earthquake. An electrical switchboard cabinet is a complex structure typically constructed using cold-formed steel frame members enclosed by steel panels and containing a variety of switchgear and bus bars. The panels are usually fastened to the steel members by screws, and the steel members are connected together by bolts or screws. The structural behavior of …

Full-Scale Experimental And Numerical Study About Structural Behavior Of Thin-Walled Cold-Formed Steel Building Affected By Ground Settlements Due To Land Subsidence, Jose A. Ortiz-Lozano, Luis A. Hernández-Castillo, Martin Hernández-Marín, Jesús Pacheco-Martínez, Mario E. Zermeño-Deleón, Raúl Salinas-Salinas

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

Land subsidence phenomenon due to ground water withdrawal is a current problem in many places around the world, particularly in the shallows of Mexico. This causes ground differential settlements that affect structures, mainly dwellings and buildings based on reinforced concrete and masonry. Eventually, these structural materials do not exhibit an adequate performance beyond a certain level of angular distortion. This work presents the experimental and numerical results about a study regarding the performance of a full-scale thin-walled cold-formed steel building affected by angular distortions simulating ground differential settlements due to land subsidence. The experimental stage consisted in the design and …

Design Method For Cold-Formed Thin-Walled Steel Beams With Built-Up Box Section, Ying-Lei Li, Yuan-Qi Li

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

Built-up sections has been extensively used in cold-formed thin-walled steel structures. The structural behaviour and moment capacity of built-up box beams, which is consisted of nested C and U-sections, are the major concerns in this paper. A finite element model for built-up box beams was firstly developed and validated by existing test results. The effects of screw configuration and the global buckling behaviour of built-up box beams were investigated by parametric analysis. Then, the simple superposition method and equivalent cross-section method were introduced and adopted to estimate the moment capacity of built-up box beams bending about major or minor axis. …

Design Of Industrial Cold-Formed Steel Rack Upright Frames For Loads In Cross-Aisle Direction, Francesc Roure, Teoman Peköz, M. Rosa Somalo, Jordi Bonada, M. Magdalena Pastor, Miquel Casafont

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

This paper summarizes research on the cross-aisle stiffness and strength of industrial cold-formed steel rack upright frames for loads in cross-aisle direction. Tests were carried out at the Universitat Politècnica de Catalunya, Barcelona, Spain on joints as well as entire upright frames. A possible rather simple analysis procedure is developed and described.

Behavior Of Steel Sheet Sheathed Cold-Formed Steel Walls Subjected To Combined Lateral And Vertical Loads, Pengchun Jia, Wenying Zhang, Mahsa Mahdavian, Nathan Derrick, Cheng Yu

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

This paper presents an experimental investigation of the behavior of cold-formed steel (CFS) framed walls sheathed by steel sheets subjected to both lateral and gravity loads. The research focuses were on the collapse limit of the CFS shear wall using steel sheet sheathing and the shear resistance of CFS bearing walls. The test results showed that the gravity load has limited impact to the CFS shear wall’s behavior and performance. The CFS bearing wall could provide considerable shear resistance and it shall be considered in numerical modeling CFS buildings.

Site Response Analysis Considering Strain Compatible Site Period, Hoss Hayati, Robb E.S. Moss

Civil and Environmental Engineering

In practice it is common to estimate site effects using a single proxy, or single variable such as 30 m shear wave velocity (V_S30) or site period. Many studies have investigated merits of proposed proxies with contradicting recommendations. Yet, most studies indicate the single proxy approach is less than ideal, resulting in large uncertainty. To provide a better understanding of components that drive site response, we performed a parameterized study on 19 shallow soil profiles with V_S ranging from 150 m/s to 400 m/s. We propagated 74 input motions through each soil column using one-dimensional equivalent-linear …

Site Response Analysis Considering Strain Compatible Site Period, Hoss Hayati, Robb E.S. Moss

Civil and Environmental Engineering

In practice it is common to estimate site effects using a single proxy, or single variable such as 30 m shear wave velocity (V_S30) or site period. Many studies have investigated merits of proposed proxies with contradicting recommendations. Yet, most studies indicate the single proxy approach is less than ideal, resulting in large uncertainty. To provide a better understanding of components that drive site response, we performed a parameterized study on 19 shallow soil profiles with V_S ranging from 150 m/s to 400 m/s. We propagated 74 input motions through each soil column using one-dimensional equivalent-linear …

Ocean–Atmosphere Interactions Modulate Irrigation’S Climate Impacts, Nir Y. Krakauer, Michael J. Puma, Benjamin I. Cook, Pierre Gentine, Larisa Nazarenko

Publications and Research

Numerous studies have focused on the local and regional climate effects of irrigated agriculture and other land cover and land use change (LCLUC) phenomena, but there are few studies on the role of ocean– atmosphere interaction in modulating irrigation climate impacts. Here, we compare simulations with and without interactive sea surface temperatures of the equilibrium effect on climate of contemporary (year 2000) irrigation geographic extent and intensity.We find that ocean–atmosphere interaction does impact the magnitude of globalmean and spatially varying climate impacts, greatly increasing their global reach. Local climate effects in the irrigated regions remain broadly similar, while non-local effects, …

Groundwater Restoration Following In-Situ Leach Mining Of Uranium, Omar A. Ruiz Lopez

Civil Engineering ETDs

From 1950 to the early 1980’s New Mexico played an important role in the production of uranium (U) for the nuclear power industry and the nation’s weapon programs. Though the U mining and milling industry in New Mexico is inactive at present, increased interest in nuclear energy as a CO₂ free power source has led to proposals for renewed development of U resources. In particular, U mining projects have been proposed using both underground mining and in situ leach (ISL) mining. When feasible, ISL mining minimizes waste by eliminating; mine waste, mine dewatering, radiation exposure and the recovered U …

Material Properties Of Cold-Rolled Thin-Walled Steel Plates At Elevated Temperatures, Zhen Nie, Yuanqi Li

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

It is highly important to clarify the high temperature mechanical properties in the design of cold-formed steel structures under fire condition due to the unique deterioration feature in material properties under fire environment and associated reduction to the mechanical performance of members. This paper presents the material properties of coupons cut from raw cold-rolled thin-walled steel plates at elevated temperatures. A set of high temperature extensometer with a range of 12.5mm relative to 50mm gauge was employed in the experiments, which could collect more displacement data between the gauge scope before the coupon fail. The coupons were extracted from original …

On The Direct Strength Design Of Cold-Formed Steel Columns Falling In Local-Distortional Interactive Modes, André Dias Martins, Dinar Camotim, Pedro Borges Dinis

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

This paper present and discusses proposals for the codification of efficient design approaches for cold-formed steel columns affected by local-distortional (L-D) interaction. These proposals, based on the Direct Strength Method (DSM), were developed, calibrated and validated on the basis of experimental and numerical (shell finite element) failure load data concerning columns with several cross-section shapes and obtained from investigations carried out by various researchers. Three types of L-D interaction are taken into account, namely “true L-D interaction”, “secondary local bifurcation L-D interaction” and “secondary distortional bifurcation L-D interaction”. Moreover, previously available DSM-based design approaches to handle column L-D interactive failures …

First-Order Generalized Beam Theory For Curved Members With Circular Axis, Nuno Peres, Rodrigo Gonçalves, Dinar Camotim

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

This paper presents a first-order Generalized Beam Theory (GBT) formulation for thin-walled members with circular axis and undergoing complex global-distortional-local deformation. The fundamental equations are derived on the basis of the usual GBT kinematic assumptions (Kirchhoff, Vlasov and wall in-plane inextensibility), leading to a formulation able to retrieve accurate solutions with only a few cross-section deformation modes (cross-section DOFs). It is shown that the classic Winkler and Vlasov theories can be recovered from the derived formulation. A GBT-based finite element is use to analyze numerical examples illustrating the application and potential of the proposed formulation.

Web Crippling Strength Of Cold-Formed Duplex Stainless Steel Lipped-Channel Sections With Web Openings Subjected To Interior-One-Flange Loading, Amir M. Yousefi, James B. P. Lim, Asraf Uzzaman, Ying Lian, G. Charles Clifton, Ben Young

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

Cold-formed stainless steel sections are becoming more widely used in the residential and commercial sectors due to their high corrosion resistance and high strength-to-weight ratio. However, their susceptibility to web crippling at points of concentrated loading is well-known to be an important design issue. In addition, web openings are also become popular, as they improve ease of installation of services. This paper presents the results of an investigation into the effect of web crippling on cold-formed duplex stainless steel lipped channel-sections, having such openings, under the interior-one-flange (IOF) loading condition. 742 non-linear elasto-plastic finite element analyses are undertaken, with web …

A Finite Element Method For Distortional Buckling Analysis Of Thin-Walled Members, Sheng Jin, Xiao Jiana, Rui Chenga, Shidong Niea, Mingyue Chenga

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

This paper presents a method for distortional buckling analysis of thin-walled members without assuming longitudinal shape of buckling modes. In this method, the pure distortional elastic buckling loads and deformation modes are achieved by performing a linear buckling analysis of a specially constrained finite element model of the thin-walled member in ANSYS. The constraints on each cross-section are applied independently and can be divided into two parts. The first part, by which distortional buckling can be distinguished from local buckling, depicts the transvers deformation of a cross-section, while the second part originated from longitudinal displacement patterns of distortional modes is …

Analyses Of Thin-Walled Sections Under Localised Loading For General End Boundary Conditions – Part I: Pre-Buckling, Van Vinh Nguyen, Gregory J. Hancock, Cao Hung Pham

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

The Semi-Analytical Finite Strip Method (SAFSM) for pre-buckling analysis of thin-walled sections under localised loading has been developed for general end boundary conditions. For different boundary conditions at supports and loading point, different displacement functions are required for both flexural and membrane displacements. As the stresses are not uniform along the member due to localised loading, the pre-buckling analysis also requires multiple series terms with orthogonal functions.

This paper briefly summaries the displacement functions used for different boundary conditions. In addition, the theory of the SAFSM for pre-buckling analysis of thin-walled sections under localised loading with general end boundary conditions …

Analyses Of Thin-Walled Sections Under Localised Loading For General End Boundary Conditions – Part Ii: Buckling, Van Vinh Nguyen, Gregory J. Hancock, Cao Hung Pham

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

Thin-walled sections under localised loading may lead to buckling of the sections. This paper briefly introduces the development of the Semi-Analytical Finite Strip Method (SAFSM) for buckling analyses of thin-walled sections under localised loading for general end boundary conditions. This method is benchmarked against the Finite Element Method (FEM).

For different support and loading conditions, different functions are required for flexural and membrane displacements. In Part 1- Pre-buckling described in a companion paper at this conference, the analysis provides the computation of the stresses for use in the buckling analyses in this paper. Numerical examples of buckling analyses of thin-walled …

Measured Geometric Imperfections For Cee, Zee, And Built-Up Cold-Formed Steel Members, X. Zhao, B. W. Schafer

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

Geometric imperfections play an important role in the performance and behavior of cold-formed steel members. The objective of this paper is to present recent results from measurements of cold-formed steel members conducted by a laser scanner. The measurements provide complete and precise three-dimensional point clouds of the specimens and can be processed to determine dimensional variations as well as variations within the plates. Processing of the data can range from simple: e.g., mean lip length, to complex: e.g., modal decomposition magnitudes of the measured imperfections. Three different shapes of cold-formed steel members are selected for study: Cee, Zee, and built-up …

Stability Analysis Of Thin-Walled Members With Curved Cross-Section Parts: Inelastic Behavior, D. Jobbágy, S. Ádány

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

In this paper the buckling behavior of thin-walled members with cross-sections with curved parts is investigated. Due to the curved parts, shell-like buckling is a potential mode of failure. The objective of the research is to understand whether shell-like buckling behavior might be governing in practical cold-formed steel members. For this aim, numerical studies have been carried out, involving linear buckling analysis as well as nonlinear analysis with imperfections, by considering various cross-sections. Based on the results it is concluded that shell-like behavior might be critical in certain cases.

Wei-Wen Yu International Specialty Conference On Cold-Formed Steel Structures 2016: Recent Research And Developments In Cold-Formed Steel Structures, 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.

Numerical Simulations Of Solid And Slotted Cold-Formed Steel Channels With Different Boundary Conditions In Shear, Vitaliy V. Degtyarev, Natalia V. Degtyareva

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

This paper presents results of a numerical study on the shear strength of cold-formed steel channels with solid and slotted webs. The effects of four different boundary conditions—test setup, realistic, and simply supported with free and restrained ends—on the elastic shear buckling load and the ultimate shear strength were considered. The study was performed on finite element models developed in ANSYS and validated against test data. The obtained results showed that the elastic shear buckling loads and the ultimate shear strengths of the slotted channels are more sensitive to the boundary conditions when compared with the solid channels. The simply …

Buckling Behaviour Of Cold-Formed Steel Beams Under Bending And Torsion, Hong-Xia Wan, Mahen Mahendran

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

This research is concerned with the buckling behaviour and design of cold-formed steel beams subject to combined bending and torsional actions. A finite element model considering the effects of initial geometrical imperfections and residual stresses was developed to simulate the combined bending and torsion of cold-formed steel beams. The finite element model was used to conduct analysis on cold-formed lipped channel sections, Z sections and hollow flange channel sections. Elastic buckling analysis was first conducted to study their buckling modes and buckling loads. Nonlinear analysis including the effects of large deformation and material yielding was conducted to obtain their ultimate …

Finite Element Investigations Of The Effect Of Residual Stress In Cold-Formed Sigma Beams, Feiliang Wang, Jian Yang

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

Press braking is a cold forming operation used to fold the angle along the flat sheet between the top punch and bottom die. The residual stress will be induced in this process as a result of plastic deformation. In the welding process, a dynamic thermal cycle is introduced to generate a non-uniformly temperature distribution on the heat affected zone (HAZ), and the residual stress also occurs in the process as a result of uneven cooling along the welding bead. The existence of residual stress can superimpose onto the external loadings to affect the stiffness and load resistance capacity of the …