Engineering Commons^™

Biodegradation And Landfill Settlement, Shailesh Pisolkar

Theses

The most widely used method for the final disposal of solid waste is landfilling, which is also economical and simpler than most other disposal systems. Long term settlement in a landfill occurs mainly due to biodegradation of the refuse which is a very slow microbiological process. However, if the rate of biodegradation is enhanced, it may be possible to achieve early stabilization, faster settlement, consequently more capacity of the landfill to handle waste.

The objective of this research is to study the effects of enhanced biodegradation on settlement and to compare these results to other models used for predicting landfill …

Solidification/Stabilization Of Petroleum Contaminated Soils With Cold Mix Asphalt Concrete, Nazhat Aboobaker

Theses

In this research Petroleum Contaminated Soils (PCSs) are recycled in Cold Mix Asphalt (CMA), to produce a useful product that can control potential environmental threats. The stability, durability, and hydraulic conductivity are three important engineering parameters that need to be considered when using petroleum contaminated soils (PCSs) in cold mix asphalt (CMA). In this research, stability, durability, and hydraulic conductivity due to the addition of six different PCSs into CMA is investigated. The stability test were performed to determine if cold mix asphalt made with petroleum contaminated soil can withstand heavy traffic. The freeze-thaw, and wet-dry tests were performed to …

Visual Inspection Of New Ramp Pavement At Bluegrass Airport Lexington, Kentucky, David L. Allen

Kentucky Transportation Center Research Report

Personnel from the Kentucky Transportation Center performed a visual inspection of newly constructed ramp pavement at the Bluegrass Airport in Lexington, Kentucky. The inspection was conducted in May, 1996 at the request of airport engineers. The inspection revealed a number of concrete apron slabs that had cracked. Attempts had been made (apparently by the contractor) to seal the cracks by epoxy injection. The visual inspection indicated that the epoxy may not have been performing as hoped, and that some of the cracks did not appear to be sealed. As a result, it was decided to obtain cores of the cracked …

Effect Of Bracing Stiffness On Buckling Strength Of Cold-Formed Steel Columns, Pratyoosh Gupta, George E. Blandford, S. T. Wang

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

A three-dimensional second-order analysis is used to study the effect of brace stiffness on the buckling strength of cold-formed steel columns. The finite element formulation uses an iterative updated Lagrangian scheme to include the second-order geometric non-linear effects in the space frame element as well as the connection element used to model a brace. Lateral brace stiffness required to achieve full bracing for a two-dimensional column, and lateral and torsional brace stiffnesses required for a three-dimensional cold-formed steel column are studied. The strength requirement for various brace components, the effects of column initial imperfections, and the impact of varying warping …

Interaction Of Flange/Edge - Stiffened Cold Formed Steel C - Sections, Colin A. Rogers, R. M. Schuster

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

A revision to the Canadian Standard (S136-94)[1] and the American Specification (AISI- 89)[2], in which the procedure to calculate the effective width of an edge-stiffened compressive flange is modified, has been proposed by Dinovitzer et al.[3]. The proposal involves a change of the equations for the flange plate buckling coefficients of Case II compressive elements, which eliminates a discontinuity in the effective width formulation. The modified local buckling procedure was compared with the current Canadian Cold Formed Steel Standard using a program of beam tests at the University of Waterloo[4] and data available in the literature[8,9, 10, 11,12]. Statistical results …

A New Aisi Cold-Formed Steel Design Manual, Richard C. Kaehler, Paul A. Seaburg

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

The Specification Committee of the American Iron and Steel Institute is currently developing a new Cold Formed Steel Design Manual. The work is being done under contract with Computerized Structural Design with oversight provided by AISI Subcommittee 26 - Design Manual. This paper describes the purpose and contents of this Manual. It is expected the Manual will be published in conjunction with the new edition of the Specification for the Design of Cold-Formed Steel Structural Members early in 1997. The Manual will contain the combined versions of the Allowable Stress Design and Load and Resistance Factor Design Specifications in addition …

Performance Of Self-Tapping Screws In Lap-Shear Metal-To-Metal Connections, Reynaud Serrette, Victor Lopez

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

The basic design requirement for screws in light gauge steel construction is the strength of the screw in a given application (metal-to-metal, wood-to-metal, or metal-to-wood) based on the body diameter of the screw. This statement is clearly obvious from the current AISI screw specifications for lap shear metal-to-metal connections. Recent research has shown that the performance of a screw fastener may also depend on other features of the screw including the head and thread style, and the method of installation (stripped versus unstripped screws). The data presented in this paper address these issues for lap shear connections designed with No. …

Cold Formed Steel Flat Width Ratio Limits, D/T And DI/W, Colin A. Rogers, R. M. Schuster

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

This paper reports the findings of an investigation of the flat width ratio limit for simple edge-stiffeners of channels in bending. Willis & Wallace concluded that the lip flat width ratio limit, d/t, should have a value of 14 based on a comparison of the 1980 and 1986 editions of the American Iron and Steel Institute (AISI) Cold Formed Steel Specification. This conclusion was made using the results of only three channel beam tests with various lip sizes, Case III flanges and locally unstable webs. The CAN/CSA-S136 Technical Committee adopted the recommendations of Willis & Wallace and included the lip …

Structural Design Study On A Light - Gauge Steel Portal Frame With Cold-Formed Sigma Sections, Pentti Makelainen, Juhani Kankaanpaa

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

Design study is conducted on a thin-gauge cold-formed steel portal frame with compound double (back-to-back) sigma sections in columns and rafters. Experimental study on the sem-irigid rafter-to-column connection behaviour is first carried out for two special bolted connection types based upon specific thin connection plates between the double sections. First connection plate studied was a compact corner plate bolted between double sigma sections of rafter and column end parts. Other connection plate type studied was composed of four together layered thin plates with the edges of two outer plates outwardly lipped at the free side of the corner plate. Connection …

Moment Rotation Behavior For Concrete Filled Shs Column To Composite Beam Connections, J. S. Lee, Young Bonb Kwon, K. S. Woo

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

A series of connection tests were carried out to study the behavior of connections between concrete filled Square Hollow Section(SHS) columns and composite W-section beams. The test connections were four different semi-rigid types selected for application to multi -story building frames. The initial flexural rigidities were estimated by different theories and compared with the simple beam. Moment-roration relations were simulated using a finite element program and a simple power model was proposed to predict the moment-rotation behavior of connections.

Strength And Stiffness Calculation Procedures For Composite Slabs, Budi R. Widjaja, Samuel W. Easterling

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

Two procedures for calculating the strength and stiffness of composite slabs based on a partial interaction model are introduced. The procedures rely on elemental test results for interfacial and end-anchorage behavior, and thus offer an alternate solution to the m and k method that relies heavily on full scale slab tests. Strength calculations made using the new procedures along with calculations from the Steel Deck Institute procedure are compared to a series of full size composite slab test results.

Strength Of Headed Shear Studs In Cold-Formed Steel Deck, John C. Lyons, Samuel W. Easterling, Thomas M. Murray

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

Results from 57 push-out tests of headed shear studs in cold-formed steel deck are presented. The results are compared to predicted strengths using the American Institute of Steel Construction Load and Resistance Factor Design Specification. The results indicate that the AISC specification does not accurately predict the strength of the shear studs placed in steel deck.

Residential Applications Of Cold-Formed Structural Members In Australia, Gregory J. Hancock, Thomas M. Murray

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

The design of steel framed houses in Australia is governed by a range of Australian Standards covering materials, strnctural design and performance and loading. The paper describes these standards and their applicability. Innovative building systems using high strength steel have recently been introduced into the residential construction market in Australia. A brief description of the members used in these systems is provided. The National Association of Steel Framed Housing (NASH) promotes the use of steel in homes and provides educational material to assist builders, suppliers, teachers and students.

Steel - The Clear Cut Alternative, Richard Haws

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

The current use of cold-formed steel owes its success to efforts which started 50 years ago. In 1946 AISI published the first specification for the design of cold-formed (then known as light gage) steel structural members. The specification was the end product of a doctoral thesis by Dr. George Winter which was initiated in 1939. Since 1946 AISI has continually updated and modernized the AISI Specification for the Design of Cold-Formed Steel Structural Members. The 1956 manual was the first design specification to have a companion commentary. In 1991 AISI published the LRFD version of the Design of Cold-Formed Steel …

A Study On The Effect Of Cold Forming On The Yield Strength Of Stainless Steel Type 304 - Hardness Test Approach, M. Macdonald, J. Rhodes, M. Crawford, G. T. Taylor

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

This paper describes a preliininary experimental investigation of the effects of cold forming on the material properties of stainless steel comer sections. The background and theory behind the research is briefly reviewed and is followed by a description of hardness testing. Hardness testing is used to postulate values for the increase in yield strength around the comers. The experimental findings are presented and the postulated increases in yield strength are compared with those predicted by two existing theories, and by other experiments carried out by the authors. It is concluded that the linear relationships found between yield strength and hardness …

An Explicit Approach To Design Of Stainless Steel Columns, Jacques Rondal, Kim J. R. Rasmussen

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

The paper describes a design procedure for stainless steel columns failing by flexural buckling. In the approach, the stress strain-curve is assumed to be expressed as a Ramberg-Osgood curve, defined in terms of the initial modulus (Eâ‚€), the 0.2% proof stress (σ₀.â‚‚) and the parameter n. It is shown that the column curve can be described in terms of the Ramberg-Osgood parameters by adopting a Perry-curve as basic strength curve and expressing the imperfection paranleter in terms of Eâ‚€, σ₀.â‚‚ and n. By using a Perry-curve, the design procedure is explicit. This contrasts the iterative approach described in the ASCE-LRFD …

The Strength Of Partially Stiffened Stainless Steel Compression Members, W. Reyneke, G. J. Van Den Berg

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

In this study the effect of the non-linear behaviour of stainless steels on the local buckling strength of partially stiffened compression elements is studied. The steel under investigation is a Type 304 stainless steel. Doubly symmetric hat section columns were manufactured by a press braking process and tested as stub columns to exclude overall buckling interaction. The different plasticity reduction factors' suggested in the ASCE stainless steel design specification for stiffened and unstiffened compression elements are used to compare experimental results with theoretical predictions. It is concluded that the ASCE and South African stainless steel design specifications overestimate the local …

Effective Width Of A Simple Edge-Stiffener Subjected To A Stress Gradient, Colin A. Rogers, R. M. Schuster

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

The most recent editions of the North American Design Standards present a unified effective width approach for the design of compressive elements. This paper outlines a comparison of various modifications to the existing procedure used to calculate the effective width of a simple edge-stiffener subjected to a stress gradient. The comparison involves three methods where the magnitude of the compressive stress is altered, and two stress gradient methods where the plate bucking coefficient is based on the ratio of compressive stresses at the top and bottom of the flat width of the simple edge-stiffener. Analysis of these methods was carried …

Design Of Thin-Walled Beams For Distortional Buckling, C. Jiang, J. Michael Davies

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

The bending behaviour of cold-formed steel beams is far from simple. The double symmetry associated with hot-rolled I-sections is generally uneconomical and the use of thin-walled slender elements means that local buckling of parts of the cross-section in compression may be a significant design factor leading to additional asymmetry of behaviour. Furthermore, the modern tendency to introduce additional folds in order to control local buckling and to produce more favourable global section properties also serves to aggravate the tendency towards distortional buckling. Generalised Beam Theory (GBT) has wide application to the analysis and design of cold-formed beams and can provide …

Determination Of Purlin R-Factors Using A Non-Linear Analysis, Catherine J. Rousch, Gregory J. Hancock

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

In both Australia and the U.S.A., the design procedure for purlins under wind uplift loading is based on the use of reduction factors (R-factors), which allow for the flexural-torsional or nonlinear twisting behaviour of purlins with screw-fastened sheeting. To date, all R-factors have been determined by testing. However, in the future it may be more efficient to obtain R-factors from numerical models to minimise testing. This paper shows how a numerical model of the twisting behaviour of channel and Z-section purlins can be used to generate R-factors. Comparisons between experimentally determined and numerically based R-factors are made.

Finite Element Analysis Of Hollow Flange Beams With Web Stiffeners, P. Avery, Mahen Mahendran

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 behavior has been shown to cause significant reduction of the available flexural capacity of HFBs. An investigation using finite element analyses and large scale experiments was carried out into the use of …

Experimental Research On The Behaviour Of Combined Web Crippling And Bending Of Steel Deck Sections, J. G. M. Kerstens, H. H. Snijder, Monique Bakker, H. Hofmeyer

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

At an interior support, sections of cold-formed steel are subjected to a concentrated load and a bending moment Existing design rules describing the section failure at an interior support are subject to improvement and are not based on the section's physical failure behaviour. In the last decade, several analytical models have been developed that predict the section ultimate concentrated load and directly include the influence of the bending moment, so that an empirical interaction method is not needed. However, the authors believe that these models are correct only for a concentrated load and a small bending moment In practice large …

Structural Detailing Of Openings In Sandwich Panels, Ton Toma, Wim Courage

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

European Recommendations [1] exist which provide calculation rules to determine the strength and stiffness of sandwich panels composed of two metal faces with a foam in between. In case of openings in such panels (e.g. for windows) an influence will appear with regard to the stiffness and loadbearing capacity. At the institute TNO Building and Construction Research this item has been studied (numerical and experimental) which has resulted in simple design rules in addition to the before mentioned calculation rules for panels without openings. The program has been executed with financial support of the European Community for Coal and Steel …

Dynamic Performance Of Light Gauge Steel Framed Shear Walls, Reynaud Serrette, Georgi Hall, Hoang Nguyen

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

The results of a series of reversed cyclic 4 ft. x 8 ft. (length x height) 15/32-in. plywood and 7/16-in. oriented strand board (OSB) shear wall tests are presented in this paper. The walls were framed with C-shaped 3-1/2 in. 20 gauge (0.036 in.) studs at 24 in. on center. Each wall was subjected to a sequential phase displacement time history at a frequency of 0.67 Hz. Performance of the wall was shown to depend on the type of sheathing material, the strength of the chord studs, and the screw fastener schedule. Although the hysteretic loops were significantly pinched (a …

Modeling Of Cold-Formed Purlins-Sheeting Systems, S. Kitipornchai, R. M. Lucas, F. G. A. Al-Bermani

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

Purlin-sheeting systems used for roofs and walls commonly take the form of cold-formed channel or zed section purlins, screw-connected to corrugated sheeting. This paper presents two nonlinear elasto-plastic finite element models, capable of predicting the behaviour of purlin-sheeting systems without the need for either experimental input or over simplifying assumptions. The first model incorporates both the sheeting and the purlin while the second, a simplified version of the first model, includes only the purlin. Both models are able to account for cross-sectional distortion of the purlin, the flexural and membrane restraining effects of the sheeting, and failure of the purlin …

Burst Strength Of Type 304l Stainless Steel Tubes Subjected To Internal Pressure And External Forces, J. Pretorius, P. Van Der Merwe, G. J. Van Den Berg

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

The findings of an investigation concerning the burst strength of cold-formed Type 304L stainless steel tubes subjected to internal pressure and static external forces are reported in this study. The use of cold-formed stainless steel longitudinally welded tube in pressurised processes in industry are limited due to the belief that seamless tubes have superior resistance to internal pressure. The primary objective of this study was to experimentally and theoretically describe the failure criteria for thin-walled longitudinally welded Type 304L stainless steel tubes subjected to internal pressure and static external point loads and torsion loads. Due to the diversity of the …

Golden Anniversary Of The Aisi Specification, Wei-Wen Yu, Don S. Wolford, Albert L. Johnson

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

The use of cold-formed steel members in building construction began in about the 1850's in the United States and Great Britain. However, such thin-walled steel members were not widely used for buildings until after 1946 When the first edition of the Specification for the Design of Light Gage Steel Structural Members was published by the American Iron and Steel Institute (AISI, 1946). This first design standard was based primarily on the research work sponsored by the Institute at Cornell University under the direction of Professor George Winter after 1939 (Winter, 1959a and 1959b). It was revised subsequently by the AISI …

The 1996 Aisi Specification, Roger L. Brockenbrough

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

The first edition of the AISI specification was adopted in 1946. Thus, the new specification represents fifty years of progress in the formal structural application of cold-formed steel. The continued efforts of the Committee on Specifications and the sponsorship of the American Iron and Steel Institute have made this fifty years of progress in cold-formed steel a reality. The new specification combines ASD and LRFD provisions in a single document. This affords the design engineer the opportunity to become familiar with both methods and facilitates the use of whichever method is preferred. In addition, the new specification includes a number …

A Probabilistic Examination Of The Ultimate Strength Of Cold-Formed Steel Elements, Benjamin W. Schafer, Mircea Gigoriu, Teoman Pekoz

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

This paper investigates the ultimate strength of cold-formed steel plates in uniform compression and pure bending with the goal of determining the statistical characteristics (mean and variance) of the ultimate strength. Plate thickness, longitudinal residual stress magnitude, and imperfection magnitude are considered as random variables. Based on existing data appropriate distributions are determined for these three random variables. Using ABAQUS for the strength prediction, two methods: Monte Carlo simulation and Taylor series approximation, are employed to determine statistical characteristics of the plates. The results are compared to the deterministic approach of the AISI Cold-Formed LRFD Specification.

Recent Research And Developments In Cold-Formed Steel Design And Construction, Roger A. Laboube, Wei-Wen Yu

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

Golden Anniversary of the AISI Specification - The 1996 AISI Specification - A New AISI Cold-Formed Steel Design Manual - Design of Cold-Formed Steel Stiffened Elements with Multiple Longitudinal Intermediate Stiffeners - A Probablistic Examination of the Ultimate Strength of Cold-Formed Steel Elements - Effective Width of a Simple Edge-Stiffener Subjected to Stress Gradient - The Effects of Perforation Length on the Behaviour of Perforated Elements in Compression - Interaction of Flangel/Edge-Stiffened Cold-Formed Steel C-Sections - Cold-Formed Steel Flat Width Ratio Limits, d/t and d/w - Comparison of the Distortional Buckling Method for Flexural Members with Tests - Design of …