Civil and Environmental Engineering Commons^™

Incorporation Of Elastic Local Buckling In A Plain Channel Section Beam Subjected To Double-Curvature Bending: An Effective-Width Approach, Edwin Lim, Barry J. Goodno, James I. Craig

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

When electrical cabinets are subjected to lateral loads, such as earthquakes, the beams of the cabinet frame typically experience double-curvature bending deformation. These beams are usually constructed from cold-formed plain channel sections so they are vulnerable to elastic local buckling near their ends, where high stresses from applied loads are more likely to develop. To capture local buckling behavior, structural engineers typically use high-fidelity finite element models, but this approach can be complex and computationally expensive. A Timoshenko beam element model is simpler and less computationally costly but it is not capable of capturing local buckling behavior. In this paper, …

Tests Of Cold-Formed Ferritic Stainless Steel Beams, Lianghao Li, Ben Young

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

Ferritic stainless steel is characterized by its low or even no nickel content, which provides a good alternative to a more commonly used austenitic stainless steel (with 8.0-10.0% nickel content) in structural application. The low nickel content attributes to low initial material cost and more stable price for ferritic stainless steel. A series of four-point bending tests was conducted on both square and rectangular hollow sections to investigate the flexural performance of cold-formed ferritic stainless steel hollow sections. The experimental results obtained from this test program and the available data in the literature on cold-formed ferritic stainless steel beams were …

Lateral-Torsional Buckling Of General Cold-Formed Steel Beams, Robert S. Glauz

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

The design of unbraced cold-formed steel beams must consider lateral-torsional buckling due to the low torsional stiffness associated with open cross-sections. The American Iron and Steel Institute incorporated design equations for the critical elastic lateral-torsional buckling stress in the North American Specification for the Design of Cold-Formed Steel Members. These equations are based on elastic theory for singly-symmetric and doubly-symmetric sections. However, the equation for point-symmetric sections is only a rough approximation. Furthermore, there are no provisions for lateral-torsional buckling of non-symmetric sections, or sections oriented to non-principal axes. This paper investigates and develops a general formulation of the lateral-torsional …

Unconstrained Cross-Sectional Shape Optimisation Of Cold-Formed Steel Beams And Beam-Columns, Bin Wang, Benoit P. Gilbert, Guillaume L. Bosco, Hong Guan, Lip H. Teh

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

This paper is focused on optimising the cross-sectional shapes of simply-supported, singly-symmetric and open-section cold-formed steel (CFS) beams and beam-columns without manufacturing or assembly constraints. A previously developed Genetic Algorithm (GA) is used in this study. Fully restrained and unrestrained beams against lateral deflection and twist, as well as unrestrained beam-columns are optimised, of which the nominal member capacities are determined by the Direct Strength Method (DSM). The optimised cross-sectional shapes are presented and the evolution of the unrestrained cross-sectional shapes for various combinations of axial load and bending moment is analysed and discussed.

Identifying Shear Buckling Coefficients For Channels With Rectangular Web Stiffeners Using The Generalised Cfsm, Morgan A. Rendall, Gregory J. Hancock, Kim J. R. Rasmussen

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

The Direct Strength Method (DSM) of design for cold-formed sections was recently extended in the North American Specification for Cold-Formed Steel Structural Members (NAS S100:2012) to include members in shear. The method has largely been developed on the basis of work done on lipped channel sections. To utilise the method requires the critical shear buckling load of the section, which may be determined from a minimum point on the signature curve for the section in pure shear. However when longitudinal web stiffeners are added to the channel a minimum may not exist, or may occur at half-wavelengths where the critical …

A Direct Strength Method (Dsm) Of Design For Channel Sections In Shear With Square And Circular Web Holes, Song Hong Pham, Cao Hung Pham, Gregory J. Hancock

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

The Direct Strength Method (DSM) design rules for cold-formed steel members in shear have been incorporated recently into the North American Specification (AISI S100-12) and are being implemented in the Australian standard (AS/NZS 4600:2005). The method, which was calibrated for unperforated members only, requires two inputs including the buckling load Vcr and the shear yielding load Vy. For members with square web cut-outs, Vcr can be computed by either the Spline Finite Strip Method (SFSM) or the tabulated values based on the shear buckling coefficients kv as studied by CH Pham or the Finite Element Method (FEM). However, Vy has …

New Sdi Diaphragm Design Manual, Larry Luttrell, John Mattingly, Walter Schultz, Thomas Sputo

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

The Steel Deck Institute (SDI) has released the new and long awaited 4th Edition of the Diaphragm Design Manual (DDM04). This new edition complies with the requirements of the ANSI/AISI S310-13 North American Standard for the Design of Profiled Steel Diaphragm Panels. At 408 pages, the 4th Edition is larger than its predecessor and will be an invaluable resource to structural designers because of the background information, design examples, and extensive load tables.

The First Edition of the DDM, published in 1981, was authored by Dr. Larry Luttrell, P.E., the Technical Advisor to the SDI. The diaphragm design method developed …

Recent Developments In The Australian/New Zealand Standard As/Nzs 4600 For Cold-Formed Steel Structures, Gregory J. Hancock

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

The Australian/New Zealand Standard AS/NZS 4600 is currently under revision based in part on the latest edition of the North American Specification AISI S100:2012 and partly based on the latest research in Australia and New Zealand. The Direct Strength Method (DSM) of design has undergone substantial research since the 2005 edition of AS/NZS 4600 and this research is now incorporated in the revised edition. The new areas in the DSM include shear, combined bending and shear, combined bending and compression, sections with holes and inelastic reserve capacity. Further, the prequalified sections now include most sections with longitudinal web and flange …

Progress In The Development Of Asce 41 For Cold-Formed Steel, Deniz Ayhan, Robert L. Madsen, Benjamin W. Schafer

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

The objective of this paper is to document progress on new cold-formed steel provisions for the forthcoming edition of ASCE 41, Seismic Evaluation and Retrofit of Existing Buildings. The current edition of ASCE 41 (2013) is weak with respect to the application of cold-formed steel and provides only limited information on cold-formed steel framed buildings, shear walls, members, and connections. The emphasis in this paper is on cold-formed steel framed shear walls, and the development of modeling parameters that characterize the backbone shear-deformation response, and acceptance criteria that provide allowable demand-to-capacity ratios (m-factors) for the shear walls based on a …

Aisi Standards Developed And Updated In 2015 And 2016, Helen Chen, Roger Brockenbrough, Richard Haws

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

During 2015 and 2016, AISI developed framing standards were consolidated and updated, the North American Specification was updated and reorganized in format, and two new test standards were published. This paper provides an overview of the reorganized standards and major changes, and a brief introduction to the newly developed test standards.

Advancing Bim For Cold-Formed Steel Structures, Adam Johnson, Roni Ramirez, Cheng Yu

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

This paper presents a research project aimed at advancing BIM for cold-formed steel (CFS) structures. The creation of the CFS family for Autodesk Revit is a handy solution for the lack of CFS members and information inside the Autodesk Revit libraries. Revit is one of the industry’s standard software for producing building information models. To overcome the disadvantages of not having CFS members in Revit, this research project focused on two phases to reach completion. Phase one consisted of developing a BIM library of industrial standard CFS members such as studs, tracks, and channels. Parameters were added to the members …

The Design And Development Of New Cold Roll Formed Products By Finite Element Modeling And Optimisation, V. B. Nguyen, P. K. C. Wood, M. A. English, M. A. Castellucci

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

The design and development of new cold roll formed products can incur significant cost and the product may not be optimised for either performance or manufacture. This paper describes a new method to develop an optimum structural design of profile by cold roll forming using a combined approach of finite element analysis and optimisation techniques. To illustrate the concept, the design and development of a new channel beam and a new drain grating subjected to bending are presented. The two case studies, demonstrate how a roll formed profile may be optimised to improved structural performance through use of stiffeners and/or …

Buckling Strength Of Cold-Formed Circular Steel Column Subjected To Axial Load, Ayana Ito, Nobutaka Shimizu, Keiichi Sato, Yoshimichi Kawai

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

In this study, the global buckling behavior of a cold-formed circular steel column was discussed with a focus on the effects of its mechanical properties and initial imperfections on the behavior. As the first step, the stress–strain curves of the column under tensile and compressive loads as well as its residual stresses were investigated. Subsequently, a finite element analysis was conducted to clarify if the analysis properly simulated the stub column behavior. The analysis results obtained using measured compressive stress–strain curves and residual stresses agreed well with experimental results. Finally, another finite element analysis was performed on the long column …

Proposal For Codification Of A Dsm Design Approach For Cold-Formed Steel Short-To Intermediate Angle Columns, 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 for cold-formed steel short-to-intermediate equal-leg angle columns, consisting of a slight modification of a design approach developed by Dinis & Camotim (2015) and based on the Direct Strength Method (DSM). After (i) collecting the available experimental and numerical failure load data, comprising fixed-ended and pin-ended columns with several geometries (cross-section dimensions and length) and reported by various researchers, and (ii) briefly reviewing the mechanical reasoning behind the proposed procedures, the search for new/simpler expressions to provide the DSM design curves is addressed. Their merits are assessed through …

Effect Of Web Perforation On The Behaviour Of Cold-Formed Steel C-Shape Slender Column Subjected To Non-Uniform Cross-Sectional Distribution Of Elevated Temperatures, S. Yang, L. Xu

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

Presented in this paper is a numerical investigation on the effect of web perforations on the behaviour of cold-formed steel C-shape columns subjected to non-uniform cross-sectional distribution of elevated temperature with use of finite element analysis. The length of web perforation investigated varies from 0 mm to 630 mm (25 in.). The non-uniform cross-sectional distributions of elevated temperatures are obtained from finite element thermal analysis of insulated CFS walls subjected to standard fire up to 105 minutes. Sequentially coupled thermal-stress analyses were carried out under a transient state condition. The concentrically loaded cold-formed steel C-shape columns with load ratios of …

Distortional Buckling Experiment On Cold-Formed Steel Lipped Channel Columns With Circle Holes Under Axial Compression, Xingyou Yao, Yanli Guo, Zhen Nie

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

The objective of this paper is to research the distortional buckling mode and load-carrying capacity of cold-formed thin-walled steel columns with circle holes in web. Compression tests were conducted on 26 intermediate length columns with and without holes. The test members included four different kinds of circle holes. Test results show that the distortional buckling occurred for intermediate columns with holes and the strength of columns with holes was less than that of columns without circle hole. The ultimate strength of columns decreased with the increase of the total transverse width of hole in cross-section of members. For each specimen, …

Dsm For Web Crippling Under Two-Flange Conditions, Pedro Natário, Nuno Silvestre, Dinar Camotim

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

This paper summarizes recent investigations on the development of Direct Strength Method (DSM) for the design of cold-formed steel beams under two-flange (TF) loading against web crippling failure. Recently, the authors proposed a new approach to predict the web crippling failure load of cold-formed steel beams under External Two Flange (ETF) and Internal Two Flange (ITF) loadings using DSM. Firstly, existing experimental test data are summarized and then the accuracy of North-American Specification (AISI 2012) and Eurocode 3 (CEN 2006) provisions is briefly assessed. In order to obtain additional information on the web crippling behavior of each test specimen, non-linear …

Experimental Investigation Of Cold-Formed C-Sections With Central Square Holes In Shear, Cao Hung Pham, Andreas Pelosi, Thomas Earls, Gregory J. Hancock

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

The North American Specification S100:2012 Edition has recently included DSM design rules for unperforated channel sections in shear. However, there are no rules presented in this standard for the DSM in shear for sections with holes. Recently, a testing program has been performed at the University of Sydney to determine the ultimate strength of high strength cold-formed C-sections with a thickness of 1.5 mm and central square holes of varying sizes. Three different sizes of the square holes were chosen for testing. For thin sections, the DSM shear curve was found to be applicable for design of sections with square …

Effective Post-Tensioned Splicing System For Prestressed Concrete Piles, Zhongxin Wu

USF Tampa Graduate Theses and Dissertations

Precast prestressed concrete piles are widely used in deep foundation construction. Due to unexpected site soil conditions and difficulties associated with transportation and handling long precast piles, splicing is sometimes necessary at the construction site.

Available splicing methods utilize steel type connections that are more suitable for reinforced concrete construction and result in limited tensile capacity at the splice. This dissertation describes studies associated with the development of a new post-tensioned splicing system using staggered, embedded anchorages. The new system has the potential to provide the same tensile capacity as a one piece prestressed pile.

To develop the post-tensioned splicing …

Simulation Of Value Stream Mapping And Discrete Optimization Of Energy Consumption In Modular Construction, Md Mukul Chowdhury

Theses and Dissertations

With the increased practice of modularization and prefabrication, the construction industry gained the benefits of quality management, improved completion time, reduced site disruption and vehicular traffic, and improved overall safety and security. Whereas industrialized construction methods, such as modular and manufactured buildings, have evolved over decades, core techniques used in prefabrication plants vary only slightly from those employed in traditional site-built construction. With a focus on energy and cost efficient modular construction, this research presents the development of a simulation, measurement and optimization system for energy consumption in the manufacturing process of modular construction. The system is based on Lean …

Understanding The Behavior Of Embankment Dams Under Blast Loading, Courtney L. Busch

Civil Engineering ETDs

This purpose of this study is to investigate the deformation-induced stability of earthen embankment dams to explosive airblast loading. This study specifically investigated the effects of close-in explosive airblast loads on the downstream toe of a homogeneous earthen embankment dam composed of cohesive soils. Small-scale explosive airblast experiments were performed on cohesive soils to obtain an experimental data set with which to compare numerical analyses. Experimental measurements included crater geometry, ground vibration energy, and air overpressure from the blast events. Laboratory tests were conducted on the experiment soils to obtain engineering properties including shear strength and compressibility indices. Finite element …

Pyrolysis Of Wastewater Biosolids Significantly Reduces Estrogenicity, T. C. Hoffman, Daniel Zitomer, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Most wastewater treatment processes are not specifically designed to remove micropollutants. Many micropollutants are hydrophobic so they remain in the biosolids and are discharged to the environment through land-application of biosolids. Micropollutants encompass a broad range of organic chemicals, including estrogenic compounds (natural and synthetic) that reside in the environment, a.k.a. environmental estrogens. Public concern over land application of biosolids stemming from the occurrence of micropollutants hampers the value of biosolids which are important to wastewater treatment plants as a valuable by-product. This research evaluated pyrolysis, the partial decomposition of organic material in an oxygen-deprived system under high temperatures, as …

Effect Of Rainfall Timing And Tillage On The Transport Of Steroidhormones In Runoff From Manure Amended Row Crop Fields, Sagor Biswas, William L. Kranz, Charles A. Shapiro, Daniel D. Snow, Shannon L. Bartelt-Hunt, Mitiku Mamo, David D. Tarkalson, Tian C. Zhang, David P. Shelton, Simon J. Van Donk, Terry L. Mader

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Runoff generated from livestock manure amended row crop fields is one of the major pathways of hormone transport to the aquatic environment. The study determined the effects of manure handling, tillage methods, and rainfall timing on the occurrence and transport of steroid hormones in runoff from the row crop field. Stockpiled and composted manure from hormone treated and untreated animals were applied to test plots and subjected to two rainfall simulation events 30 days apart. During the two rainfall simulation events, detection of any steroid hormone or metabolites was identified in 8–86% of runoff samples from any tillage and manure …

Anisotropic Contrast Optical Microscope, D. Peev, T. Hofmann, N. Kananizadeh, S. Beeram, E. Rodriguez, S. Wimer, K.B. Rodenhausen, C.M. Herzinger, T. Kasputis, E. Pfaunmiller, A. Nguyen, Rafal Korlacki, A. Pannier, Y. Li, E. Schubert, D. Hage, M. Schubert

Department of Civil and Environmental Engineering: Faculty Publications

An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. …

Pepper Mild Mottle Virus As A Surrogate For Enteric Viruses: Implications For Assessing Water Quality, Erin Michelle Symonds

USF Tampa Graduate Theses and Dissertations

Less than 10% of the world’s domestic wastewater is disinfected prior to discharge into surface waters; therefore, human exposure to diverse wastewater-related pathogens results in millions of cases of illness each year. Among the enteric pathogens, viruses represent an important group of emerging pathogens and are frequently the cause of food- and water-borne outbreaks of illness. Although the World Health Organization and many government agencies mandate the use of bacterial indicators to identify poor microbial water quality, it is well known that these indicators poorly correlate with fecal pollution contamination events and risk of disease. The field of public health-related …

Formation Of Trihalomethanes (Thms) As Disinfection By-Products (Dbps) When Treated Municipal Wastewater Is Disinfected With Sodium Hypochlorite, Helene Kassouf

USF Tampa Graduate Theses and Dissertations

Disinfection is an essential process in the treatment of municipal wastewater before the treated wastewater can be discharged to the environment. Hillsborough County's Northwest Regional Water Reclamation Facility (NWRWRF) in Tampa, Florida, currently uses ultraviolet (UV) light for disinfection. However, this method has proven expensive to implement and maintain, and may not be effective if the light transmission is poor. For these reasons, Hillsborough County is considering switching from UV light to sodium hypochlorite for disinfection. However, hypochlorite (chlorine) disinfection has disadvantages as well, such as the production of disinfection by-products (DBPs) such as trihalomethanes (THM) and haloacetic acids (HAAs), …

Cracking Potential And Temperature Sensitivity Of Metakaolin Concrete, Andrew Robert Williams

USF Tampa Graduate Theses and Dissertations

Metakaolin is a pozzolanic material with the potential to reduce permeability and chloride ingress; however, quantification of the effects of metakaolin use on the cracking sensitivity of concrete mixtures is needed to ensure that these improvements in performance are not compromised. This study was conducted to investigate the early age cracking potential due to restraint stresses from incorporating metakaolin in concrete. Calorimetry testing showed that metakaolin was more sensitive to temperature than mixtures with only Portland cement. Results showed more shrinkage, less stress relaxation, and higher restraint stress from the inclusion of metakaolin, potentially increasing cracking sensitivity of mixtures.

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The Effect Of The Antecedent Dry Conditions On Nitrogen Removal For A Modified Bioretention System, Mackenzie Peterson

USF Tampa Graduate Theses and Dissertations

Eutrophication is defined as the ‘over enrichment’ of a water body from nutrients, resulting in uncontrolled growth of primary producers, leading to periods of oxygen depletion from decomposition of the algal organic matter. According to the 2010 Water Infrastructure Needs and Investment (a U.S. Congressional Report), 40% of U.S. water bodies are contaminated with pollutants, including nutrients. Non-point sources of nutrient pollution are a major cause of this reduction in water quality. One way to decrease eutrophication is to manage nutrients found in stormwater runoff, before they reach a receiving water body.

Bioretention cells containing an internal water storage zone …

Usu Awwa Tour | Civil And Environmental Engineering, Usu College Of Engineering

College of Engineering News

The newly formed student chapter of the American Water Works Association (AWWA) recently went on tours of two water facilities. In early October, ten students attend a tour of the Utah Water Research Laboratory here at USU. The students enjoyed seeing applied research that is conducted at the lab. This week, the chapter also visited the Franklin Idaho Drinking Water Treatment Plant. This exposure to the industry has been a remarkable professional and academic experience for the Chapter.

Behavior Of Double-Sided Concrete Corbels Reinforced With Glass-Fiber Reinforced Polymer Bars, Ayman Farid Abu Obaida

Theses

Steel reinforced concrete members with small shear span-to-effective depth ratios (a/d), such as corbels; have many classical applications, mostly in tall building, precast structures, factory buildings, bridges, and foundations. Despite extended research works on the performance of such members, little information is available on the performance of these members when reinforced totally with internal fiber reinforced polymer (FRP) bars. The use of FRP bars in reinforcing concrete members would eliminate corrosion problems thus increasing the service life of the structure. This thesis aims at investigating the shear strength of double-sided concrete corbels reinforced with glass-fiber reinforced polymer (GFRP) bars. The …