Engineering Commons^™

Design Of Cold-Formed Steel Stiffened Elements With Multiple Longitudinal Intermediate Stiffeners, Benjamin W. Schafer, Teoman Pekoz

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

Current specification procedures for calculating the bending strength of members with multiple longitudinal intermediate stiffeners in the compression flange have been found to be inadequate. A new procedure for calculating the effective width of stiffened elements with multiple intermediate stiffeners is presented. The new method introduces the calculation of a buckling coefficient for overall buckling of the entire stiffened element as a unit, and local buckling of the subelement plates between stiffeners. The expression for calculating overall buckling is derived and verified via comparison to numerical methods. The minimum buckling coefficient from the two modes (local and overall) is used …

The Effects Of Perforation Length On The Behaviour Of Perforated Elements In Compression, J. Rhodes, M. Macdonald

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

The compressional behaviour of stub columns having perforations in the form of slots of different length is examined on the basis of testing. Plain channels of a specified geometry are considered, and the geometry examined follows that of a test programme previously carried out to examine the effects of perforation location on stub column strength. Two different perforation layouts, and two material thicknesses are considered and systematic variation in the slot length is carried out for each layout and thickness. It is found that the stub column compression capacity reduces as the perforation length increases. The test results are compared …

Additional Design Considerations For Bolted Connections, Roger A. Laboube, Wei-Wen Yu

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

A multi-year study was conducted at the University of Missouri-Rolla which focused on such topics as deformation characteristics of bearing type connections; strength of bearing and tensile type failure modes of flat sheet connections; tensile strength of staggered bolt patterns in flat sheet connections; and tensile strength of bolted connections for angle and channel sections. The intent of this research was to verify the present design approach for bolted connections and to expand the design methodology to include additional limit states, in particular the effect of deformation of the bolt hole and the influence of shear lag in angle and …

Shear Behavior Of Self Drilling Screws Used In Low Ductility Steel, Randy L. Daudet, Roger A. Laboube

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

The results of 264 shear tests conducted on self drilling screws are presented. The tests conducted include single screws in single shear, two screws in single shear, and single screws in double shear. The performance and behavior of self drilling screws in low ductility steel are compared to the performance and behavior of screws in normal ductility steel. Results are compared to the 1986 AISI specification with 1989 addenda, and the recently approved AISI specification for self drilling screws which will be included in the next edition of the AISI code. Also, new equations are presented for the tilting/bearing limit …

Cold-Formed Steel Design By Spreadsheet Program, Scott A. Burns

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

This paper demonstrates how to use advanced features of a spreadsheet program to design cold-formed steel members efficiently. The example presented in the paper concerns a hat section in flexure which is to be designed for maximum bending strength with a restriction on the total amount of steel that can be used. The nature of the formulas and data entered into the spreadsheet program are presented.

Cold-Formed Steel Sections Experimental Data Base, Dan Dubina, Mircea Georgescu, Dorina Goina, Viorel Ungureanu

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

Thin-walled cold-formed member critical load in the coupling point of overall/local buckling modes is defined, together with critical load erosion factor (ψ). A calibration method for (ψ) using an experimental database called DATACOST is presented.

Evaluation And Modelling Of The Material Properties For Analysis Of Cold-Formed Steel Sections, Nabil Abdel-Rahman, K. S. Sivakumaran

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

The results of two series of experimental investigations to evaluate the mechanical properties and the residual stresses of cold-formed steel (CFS) sections are reported in this paper. These investigations were performed on channel-shaped CFS sections manufactured using cold-roll forming technique. Tensile coupon tests were used to evaluate the mechanical properties at different positions of the channel sections. Electrical resistance strain gauges with an "Electrical Discharge Machining" cutting technique were used to establish the magnitudes and the distributions of residual stresses within the channel sections. Based on the experimental results, appropriate analysis models for the stress-strain relationship, the variation of the …

Geometric Imperfections And Residual Stresses For Use In The Analytical Modeling Of Cold-Formed Steel Members, Benjamin W. Schafer, Teoman Pekoz

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

Geometric imperfections and residual stresses influence the behavior and ultimate strength of cold-formed steel members. Advanced analytical models (i.e. nonlinear finite element models) must reflect this by including appropriate geometric imperfections and residual stresses. To date, little has been done to summarize the existing literature on these topics. As a result, no consensus exists for what magnitudes or distributions should be used when including geometric imperfections and residual stresses in the analysis, In this paper existing literature is reviewed and a new series of measurements carried out with the goal of providing basic guidelines for the use of geometric imperfections …

Buckling Experiments On Hollow Flange Beams With Web Stiffeners, Mahen Mahendran, P. Avery

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

A new cold-formed and resistance welded section known as the Hollow Flange Beam (HFB) has been developed recently in Australia. In contrast to the common lateral torsional buckling mode of I-beams, this unique section comprising two stiff triangular flanges and a slender web is susceptible to a lateral distortional buckling mode of failure involving lateral deflection, twist and cross-section change due to web distortion. This lateral distortional buckling behaviour has been shown to cause significant reduction of the available flexural strength of HFBs. An investigation using finite element analyses and large scale experiments was carried out into the use of …

Comparison Of Tests Of Purlins With And Without Cleats, Michael Celeban, Dan Popovic, Gregory J. Hancock

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

The paper describes a series of tests on Z-section purlins lapped over three spans and subject to wind uplift loading. The purlins were not attached to the rafters by cleats. Sheeting was screw-fastened to the purlins and a range of bridging (bracing) members was used to prevent lateral deflection and twisting. The results of the tests are compared with earlier tests with the same configurations but including cleats at the supports.

Deflection Design Of Cold-Formed Rhs Steel Beams, Xiao-Ling Zhao, Kwong-Ping Kiew

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

The moment-deflection results of cold-formed RHS (rectangular hollow section) steel beams are examined. A simple design approach is proposed to account for the effect that material nonlinearity has on deflection. A general expression is also derived to predict the deflection of cold-formed RHS steel beams.

Comparison Of The Distortional Buckling Method For Flexural Members With Tests, Colin A. Rogers, R. M. Schuster

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

For thin-walled flexural members composed of certain geometric proportions and/or made of high-strength steel, a mode of buckling at half-wavelengths intermediate between local buckling and flexural-torsional or flexural buckling can occur. The mode is most common for edge (lip) stiffened members such as C and Z-sections, and involves rotation of the lip-flange component about the flange-web junction. This mode is commonly called distortional buckling. Presented in this paper is a design method for distortional buckling of flexural members recently submitted for ballot with the AISI Specification Committee for Cold-Formed Steel Structures. Currently, the North American Cold-Formed Steel Design Standards do …

Flexural Strength Of Cold-Formed Steel Panels Using Structural Grade 80 Of A653 Steel, Shaojie Wu, Wei-Wen Yu, Roger A. Laboube

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

Cold-formed steel decks made of the Structural Grade 80 of ASTM A653 steel (formerly ASTM A446 Grade E steel) are currently designed according to the AlSI specification, using 75% of the specified minimum yield strength of the steel or 60 ksi (413.7 MPa), whichever is less, due to the lack of ductility of the steel. To further evaluate the flexural strength of the cold-formed steel decks using such a steel, a total of seventy-two deck panels with hat-shaped sections were designed and tested under simply supported and two-point loading condition. The test results indicated that for the panel specimens with …

Lower Cost Lightweight Cold-Formed Portal Frames, B. W. J. Van Rensburg, G. P. De Vos

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

Southern Africa has a dire need for housing small industries and people, and concomitantly the creation of employment. It is common to use hot-rolled steel sections for industrial structures, which are pre-manufactured and then bolted together on site. In this paper an alternative structural concept for low-rise portals for light industries is proposed, whereby the total frame is made up of standard cold-formed sections which are cut and welded together on site. The cladding material is employed as an integral structural component through the principles of stressed skin diaphragm action. A short pile footing is proposed to provide a degree …

Non-Linear Buckling Analysis Of Thin-Walled Metal Columns, C. Jiang, J. Michael Davies

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

Uniformly compressed cold-formed metal columns are susceptible to instability in a variety of modes. In the stability analysis of such a column, using any of the available numerical methods with the exception of the eigenvalue method, the perfect geometry of the column must be ' seeded' with an imperfection in order to cause it to collapse. If the member buckles in a global mode, it is easy to introduce an appropriate imperfection in form of a suitable displaced shape. However, it is more difficult to define the imperfections for the distortional and local buckling modes due to the unknown nature …

Towards A Numerical Procedure For Composite Slab Assessment, Howard D. Wright, Milan Veljkovic

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

Composite slab design relies upon adequate shear bond resistance between the steel and concrete. This is achieved by friction between the materials and the mechanical interlock of embossments pressed in the steel. The behaviour of this shear bond resistance is complex and is obtainable only from model tests. This paper explores the potential for numerical modelling to provide the required design information.

The Modulus Of Elasticity Of Steel - Is It 200 Gpa?, Mahen Mahendran

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

In cold-formed steel construction, the use of a range of thin, high strength steels (0.35 mm thickness and 550 MPa yield stress) has increased significantly in recent times. A good knowledge of the basic mechanical properties of these steels is needed for a satisfactory use of them. In relation to the modulus of elasticity, the current practice is to assume it to be about 200 GPa for all steel grades. However, tensile tests of these steels have consistently shown that the modulus of elasticity varies with grade of steel and thickness. It was found that it increases to values as …

Design Models Of Continuous Sandwich Panels, Paavo Hassinen, Lassi Martikainen

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

Static behaviour and failure modes of single-span lightweight sandwich panels are well known in general and several design guidelines and recommendations have been published concerning the determination of the resistance values for the design. At intermediate supports continuous sandwich panels are loaded by high bending moments and transverse support reactions simultaneously, which leads to nonlinear interactions between the stresses caused by the bending moment arid support reaction. The interaction failure modes have not been introduced on acceptable level in the current recommendations. The paper presents experimental and analytical results concerning the static behaviour and strength of the intermediate support area …

Stability Of Standing Seam Roof - Purlin Systems, James M. Fisher, Joe N. Nunnery

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

Presented in this paper are the design considerations of purlins which support standing seam roofs. To properly design purlins attached to standing seam roofs the AISI Base Test must be conducted. The AISI anchorage equations can be used for standing seam systems provided that it can be shown that the standing seam diaphragm system has sufficient stiffness to meet the requirements of the diaphragm as specified in Section D3.2.1 of the AISI Specification. The stiffness of standing seam roofs can be determined from conventional diaphragm tests. The stiffness and strength of the standing seam diaphragm can be enhanced by the …

Ole Miss Engineer 1996

Ole Miss Engineer

No abstract provided.

The Oligonucleotide Probe Database, Elizabeth Wheeler Alm, Daniel B. Oerther, N. Larsen, David A. Stahl, Lutgarde M. Raskin

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Characterization Of Rainfall Runoff Quality From A Shipyard Drydock, Peter Pommerenk

Civil & Environmental Engineering Theses & Dissertations

Water quality and hydrological data were collected during seventeen rain events and additional data was obtained from laboratory experiments to characterize the quality of stormwater runoff from a drydock located on the Elizabeth River in Norfolk, Virginia.

The results indicated that the concentrations of dissolved constituents in drydock runoff increased with decreasing flow rate, while solids concentrations exhibited positive correlation to flow rate, suggesting that the mobilization of particulate matter is velocity driven. Approximating the runoff hydrograph due to a storm event using a simple model enabled derivation of the average time that rainwater resides on the drydock surface before …

Bs News

Building Services Engineering

No abstract provided.

The Crash Simulation And Analysis Of The Friendly Mobile Barrier, Bryan Edward Marz

Mechanical & Aerospace Engineering Theses & Dissertations

Mass transportation is an ever increasing alternative being researched and evaluated in today's society. With the increase of demand for such transportation, an increase in safety is also needed. This research entails the analysis of a new idea, The Friendly Mobile Barrier, in railroad crossing barrier design. The design is meant to prevent any approaching vehicle from crossing a railroad track and be survivable for those impacting the barrier.

Research conducted involves the crash simulation and analysis of the Friendly Mobile Barrier. The Friendly Mobile Barrier was analyzed structurally using finite element analysis. An advanced lumped-mass mathematical model software, Crash …

Modeling A High-Efficiency Ozone Injection Contactor, L. Bernard Garrett Jr.

Civil & Environmental Engineering Theses & Dissertations

Significant research over the last several years has focused on applying modeling equations for estimating design parameters of ozone contactors. Much of this research has focused on fine bubble diffusers, which are the more widely used injection system for ozone contactors in the U.S. A recently developed design incorporates a new ozone injection system called a sidestream venturi injector (SVI) which is used with a co-current downflow column to achieve very high ozone mass transfer efficiencies. A pilot study conducted at the Harwood's Mill water treatment plant in Newport News, Virginia, from June to December 1993 demonstrated the high mass …

Traffic Flow And Safety Evaluation Of Fayette County Schools, Samantha S. Jones, Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

In cooperation with Fayette County Schools, an evaluation of traffic flow and safety was conducted at school sites in Fayette County. The purpose of this evaluation was to eliminate potential safety risks currently existing at a number of schools and to reduce traffic congestion in and around school properties.

The evaluation was completed in two main phases. First, each school in the district was asked to respond to a survey questionnaire. Second, six schools were identified by Fayette County Schools as having traffic flow or safety problems that could benefit from detailed evaluation. The responses to the survey questionnaire were …

Rubberized Asphalt Membrane, Kamyar C. Mahboub

Kentucky Transportation Center Research Report

This document reports findings of a study involving the use of scrap tire chips in an asphaltic membrane. The research project was designed with two objectives in mind. First, to investigate the effectiveness of an asphaltic membrane on top of a subgrade for maintaining moisture equilibrium in subgrade, and second, to study the potential use of scrap tire chips in asphaltic membranes. The effectiveness of the membrane as a moisture barrier needs to be evaluated over a long period of time (i.e. several years). However, the method proved to be a feasible alternative for recycling waste tires in pavements. It …

Analysis Of Traffic Accident Data In Kentucky (1991-1995), Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

This report includes an analysis of traffic accident data in Kentucky for the years of 1991 through 1995. A primary objective of this study was to determine average accident statistics for Kentucky highways. Average and critical numbers and rates of accidents were calculated for various types of highways in rural and urban areas. These data can be used in Kentucky's procedure to identify locations that have abnormal rates or numbers of accidents.

The other primary objective of this study was to provide data which can be used in the preparation of the problem identification portion of Kentucky's Annual Highway Safety …

A Comprehensive Modeling Environment For The Simulation Of Groundwater Flow And Transport, S. J. Owen, Norman L. Jones, J. P. Holland

Faculty Publications

A comprehensive graphical modeling environment has been developed to address the needs of the computer simulation of groundwater flow and transport. The Department of Defense Groundwater Modeling Systems (GMS), developed at the Engineering Computer Graphics Laboratory at Brigham Young University, is part of a multi-year project funded through the Department of Defense, Department of Energy and Environmental Protection Agency. GMS is a graphically based software tool providing facility through all aspects of the groundwater flow and transport modeling process. Facilities include geometric modeling of hydrostratigraphy, two- and three-dimensional mesh generation, graphically based model input for specific flow and transport codes, …

Bs News

Building Services Engineering

No abstract provided.