Engineering Commons^™

Comparison Of A Non-Linear Purlin Model With Tests, Catherine J. Rousch, Gregory J. Hancock

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

A non-linear elastic analysis has been developed for determining the lateral deflections of, and stresses in, the unconnected flanges of simply-supported and continuous channel and Z-section purlins screw-fastened to sheeting and subject to either wind uplift or gravity loading. The analysis incorporates a model, based on a combination of those developed by Pekoz and Soroushian, and Thomasson, which depicts the unconnected purlin flange as a beam-column. The restraint against lateral deflection is provided primarily by the sheeting, and is represented by a linear extensional spring of stiffness k located at the level of the unconnected purlin flange. To verify the …

Bending And Shear Behavior Of Web Elements With Openings, Roger A. Laboube, Ming-Yang Shan, Wei-Wen Yu

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

Cold-formed steel C-sections are frequently used as wall studs and floor joists in both commercial and residential construction. To facilitate installation of ancillary systems such as electrical wiring and plumbing, the C-section is manufactured with a web opening. Although the opening offers construction advantages, it may degrade the structural integrity of the member. To quantify the degrading effect of a web opening, a study has been conducted at the University of Missouri-Rolla (UMR). The UMR study included the loading conditions of bending, shear, web crippling and the combinations thereof. This paper summarizes the results of an experimental study of the …

Perforated Webs Subjected To End-One-Flange Loading, Roger A. Laboube, James E. Langan, Wei-Wen Yu

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

A study of structural behavior was conducted and a design equation was developed that accounts for the degradation in web crippling capacity caused by web openings for unreinforced single web cold-formed steel flexural members subjected to the End-One-Flange (EOF) loading condition. The research findings enable the current EOF design provisions for sections without web openings to be modified by a reduction factor equation to obtain the web crippling capacity for sections with web openings. The modified capacity is considered for the web crippling capacity in the absence of bending moment for the same cross section and load bearing length.

Reference Section Method For Local Web Buckling, T. K. Sooi, Reynaud Serrette, Teoman Pekoz

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

The present AISI effective width approach for determining flexural section capacities of sections with slender webs requires an iterative approach. A simplified method, called the Reference Section Method or RSM, which eliminates the need for iteration is presented and discussed. The reference section is defined as one that is similar to the actual section except for the web height. This simplified method is based on the premise that the flexural capacity of a section with slender webs is proportional to that of a reference section with compact web. The ratio of the web height of the actual section to that …

Flexural Capacity Of Continuous Span Standing Seam Panels: Gravity Load, Reynaud Serrette, Teoman Pekoz

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

The standing seam panel is one of the most practical and economical roofing systems developed in recent years. Construction of the roof system requires that the panel legs be overlapped and crimped. Under gravity load, the crimped outstanding leg of the connected panels may be subject to distortional buckling. A design method was previously suggested for estimating the distortional buckling strength of the outstanding leg of a single simply supported standing seam panel. In this paper, an approximate method is present for estimating the capacity of a system of interconnected continuous span standing seam panels. Experimental results for three full-scale …

Multiple Stiffened Deck Profiles, M. Sommerstein, R. P. Papazian, R. M. Schuster

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

CAN/CSA-S136-M89 and the AISI Specification on Cold Formed Steel Design use different methods to determine the effective width of multiple stiffened compressive elements when no local buckling in the sub-elements occurs. Both methods replace the multiple stiffened element with a flat plate element centered at the neutral axis of the multiple stiffened element. The methods differ in assigning an equivalent thickness to the straight line element. The AISI method provides sufficient thickness to match the moment of inertia of the multiple stiffened element, while the S136 method makes use of orthotropic plate theory, however, dealing only with the elastic buckling …

Buckling Behaviour Of Cold-Formed Thin-Walled Members By Spline Finite Strip Analysis, Joachim Lindner, Y. L. Guo

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

Local,distortional and overall buckling (including overall flexural buckling and overall flexural-torsional buckling) behaviour of cold-formed thin-walled columns is presented which is based on an inelastic spline finite strip analysis. The columns are loaded centrally at the ends. The increment of yield stresses in the corner area due to cold-forming work, together with a more real stress-strain curve of material, that exhibits continuous strain hardening for the stress above the proportional limit of material, are involved in the analysis. The cold-formed section is divided into two different types of strips, one is a flat plate strip on the central part of …

Cold-Formed Steel Sections For Transmission Towers, David Odaisky, Dimos Polyzios, Glenn Morris

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

Hydro-electric transmission towers are traditionally built using hot-rolled angles. However cold formed angles are becoming more popular as replacements for hot-rolled angles, especially in the smaller angle sizes. In addition to conventional 90° angles, a wide range of shapes can be produced, in sizes to suit individual project requirements. In particular, cold-forming can be used to provide stiffening lips to prevent local buckling of thin wide elements, to optimize shapes so that longer unbraced lengths can be used, and to create shapes such as 60° angles for triangular towers. A research project was carried out at the University of Manitoba …

Elastoplastic Large Deflection Analysis Of Cold-Formed Members Using Spline Finite Strip Method, Shi-Lin Chen, Shao-Fu Li, Shan-Feng Fang

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

The elastoplastic large deflection behaviour of cold-formed members is analysed by a nonlinear spline finite strip method. The method is developed using the principle of virtual work, based on the total Lagrangian description. It is used to deal with problems of geometric and material nonlinearity. The displacement function of a strip is expressed as the product of transverse interpolation polynomials and longitudinal B3-splines. The effect of arbitrary initial imperfections is taken into consideration. The influence of cold-bending residual stress on the local and overall behaviour of cold-formed lipped angle columns is investigated especially. The numeric examples show that the method …

Behavior Of Concrete And Slender Reinforced Concrete Columns Under Cyclic Axial Compression With Bidirectional Eccentricities, Byong Youl Bahn

Dissertations

A rational analysis of reinforced concrete (R/C) structures requires satisfactory modeling of the behavior of concrete under general loading patterns. The behavioral characteristics of concrete dominantly depends upon its load history. For the study of concrete behavior, parametric study and experimental investigation into the behavior of concrete under load history of random cycles are performed. Through parametric study, the applicability of the previous concrete models is examined and a physically motivated modeling for the cyclic stress-strain relationships is proposed. The present modeling of concrete under general cyclic loading is initiated to provide substantial applicability, flexibility of mathematical expressions and furthermore …

Theoretical Evaluation Of The Break Off Test For Concrete, Arjuna Priyara Ranasinghe

Dissertations

Strength of concrete is normally measured using the standard cylinder or cube. The measured strength is used for design. The accuracy of concrete strength is frequently challenged, particularly in large concrete structures where size effect of the test specimens is attributed for the differences. Many nondestructive tests were developed to evaluate concrete strengths. In recent years, it was obvious that these tests are unreliable. As the infrastructure decays, more nondestructive tests are required to evaluate the existing structures.

The Break Off Test is a recently developed nondestructive test. Although substantial amount of experimental investigations have been carried out on this …

Ole Miss Engineer 1994

Ole Miss Engineer

No abstract provided.

Predicting The Future Fate Of Pcbs In Lake Hartwell, Alan W. Elzerman, Kevin J. Farley, Frank M. Dunnivant, Craig Cooper

Publications

No abstract provided.

Analysis Of Motor Vehicle-Deer Accidents In Kentucky, Kenneth R. Agent

Kentucky Transportation Center Research Report

An analysis of motor vehicle-deer (deer) accidents for the five-year period of 1989 through 1993 was conducted. There was an average of about 2,800 deer accidents per year. This type of accident was generally not severe with almost 96 percent property-damage-only accidents. Trends were noted in time and date of the accidents. The highest percentage of deer accidents occurred between 6 and 10 pm and in November and December. The percentage of this type of accident was highest in western and northern Kentucky and lowest in southeastern and central Kentucky. The accident rate for this type of accident was highest …

Particle Trapping In Estuarine Tidal Flows, David A. Jay, Jeffery D. Musiak

Civil and Environmental Engineering Faculty Publications and Presentations

Particle trapping in estuarine turbidity maxima (ETM) is caused primarily by convergent mean and/or tidal fluxes of sediment. The result is an approximately bell-shaped along-channel distribution of vertically integrated, tidal cycle mean suspended sediment concentration. Observations from the Columbia River estuary suggest that (1) strong two-layer or internal along-channel residual and overtide flows are generated by time-varying stratification and (2) correlations between the near-bed velocity and the suspended sediment fields at these frequencies are important in landward transport of sediment. A new spatially and temporally integrated form of the sediment conservation equation has been derived to analyze this trapping process. …

Development Of A Knowledge-Based System For Wastewater Pipeline Rehabilitation, David Allen Reaves

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this thesis is to study and develop a knowledge-based system to make decisions for the rehabilitation of wastewater pipelines. Development includes justification for the use of an expert system, data acquisition from knowledge experts, program model development, model testing, implementation and future considerations including expansion. The model is developed and implemented using an expert system shell called XIPlus ®.

This knowledge-based system is designed specifically for the Navy Public Works Center Utilities Department at Norfolk Naval Base in Norfolk, Virginia for making decisions for the rehabilitation of the 50-year-old wastewater collection system. Recent sewer collapses and a …

The Influence Of Seawalls On Beach Responses To Storms, Seasonal Transitions And Long-Term Erosion, John Marshall Hazelton

Civil & Environmental Engineering Theses & Dissertations

It has been argued that seawalls have a detrimental effect on the adjacent beaches. These effects may only be noticeable over a period of years or may be short-term effects associated with storms or with seasonal transitions of the beach. Many theories on beach and seawall interaction have been speculative and have lacked actual field or laboratory evidence for their basis.

This study uses four years of monthly and post-storm beach profile data to examine what influences the seawalls at Sandbridge, Virginia have on the adjacent beaches. Long-term effects of the seawalls are analyzed using fourteen years of profile data. …

Bs News

Building Services Engineering

No abstract provided.

Analysis Of Traffic Accident Data In Kentucky (1989-1993), 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 1989-1993. 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.

Another 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 Plan. County and city …

1994 Safety Belt Usage Survey And Evaluation Of Effectiveness In Kentucky, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objective of this study was to establish 1994 safety belt and child safety seat usage rates in Kentucky. The 1994 survey documents the results from enacting a statewide mandatory safety belt law. Data were collected at 100 sites and combined based on vehicle miles travelled for a given type of highway, rural or urban location, and county population category. Also included in this report is an analysis of accident records evaluating the effectiveness of safety belts.

The data show that enactment of the statewide law had a dramatic effect on usage rates. The usage rate for drivers increased from …

Simulation Of Hydrologic Influences On Wetland Ecosystem Succession, Robert A. Pompilio

Theses and Dissertations

This research focuses on the development of a simulation model to determine the effects of hydrological influences on a wetland ecosystem. The model allows perturbations to the inputs of various wetland data which in turn, influences the successional development of the ecosystem. This research consisted of converting a grassland ecosystem model to one which simulates wetland conditions. The critical factor in determining the success of wetland creation is the hydrology of the system. There are four of the areas of the original model which are affected by the hydrology. The model measures the health or success of the ecosystem through …

A Preliminary System Dynamics Model Of A Constructed Wetland For The Mitigation Of Metals In Usaf Storm Water, Mark P. Smekrud

Theses and Dissertations

This thesis determines the potential removal and corresponding accumulation of trace metals from Air Force storm water in a constructed wetland through the use of a System Dynamics model. The goal is to determine whether constructed wetlands used as storm water best management practices provide efficient metal removal while creating only benign accumulations of such pollutants. Its purpose is to allow Base Civil Engineers and Environmental Managers a better tool to assess the long-term effects of a constructed wetland used as a storm water mitigation technique. The research is limited to the assessment of typical metal concentrations found in Air …

Evaluation Of Edge Drains Headwalls And Outlets On Western Kentucky Parkway And Pennyrile Parkway, L. John Fleckenstein, David L. Allen

Kentucky Transportation Center Research Report

On May 10, 1994, the Kentucky Transportation Center conducted a routine edge drain and outlet inspection on the Pennyrile Parkway in the vicinity of Milepost 23. The edge drains had been in service since 1992. Two edge drain outlets were inspected with a "Cues" pipeline inspection camera. One of the outlets was 85 percent blocked by rock and debris. District 2, operations personnel concerned with the findings requested that the Kentucky Transportation Center evaluate all 364 outlets on the project plus an additional 49 edge drain outlets that were being installed on the Western Kentucky Parkway.

This report documents the …

Evaluation Of Pavement Edge Drains And The Effect On Pavement Performance, L. John Fleckenstein, David L. Allen, Jack A. Harison

Kentucky Transportation Center Research Report

This report documents the performance of highway edge drains in Kentucky. Approximately eighteen high edge drain installations were inspected. The report also documents the laboratory testing, construction, short-term and long-term performance of these systems. Construction inspection and maintenance are addressed.

It is apparent that the panels are distressed more under the old method of installation using excavated trench material and dynamic type compaction. It is apparent that using the sand slurry reduces the chances of installation damage. Proper density needs to be achieved during installation of the sand backfill or damage will occur due to trench settlement. In most cases, …

Modeling Trihalomethane Formation Potential From Wastewater Chlorination, Carol A. Mccormick

Theses and Dissertations

The deletion of federally mandated fecal coliform limits has led many states to review and modify their wastewater disinfection requirements. One issue in analyzing wastewater disinfection is the discharge of potentially carcinogenic halogenated organics formed during the chlorination process. This research investigates the formation of one class of the halogenated organics, the trihalomethanes. The applicability of using drinking water trihalomethane formation models for use with wastewater effluent is examined. Three models are compared for predictive capability by using measured trihalomethane values from previous research data. The results show that a previously developed model is applicable for use based on assumptions …

Economics Of Chlorofluorocarbon (Cfc) Machine Replacement, Geoffrey D. Rudderow

Theses and Dissertations

Continued use of chlorofluorocarbon CFC refrigerants may have a severe financial as well as operational impact on the users of air-conditioning and other refrigeration equipment as price increases continue and production is phased out. With production of CFCs coming to a halt on 31 December 1995, the two major refrigerants that have been used in commercial and industrial cooling applications will no longer be available. The phase out of production is a result of national and international agreement that these, as well as other CFCs, are a primary cause of the depletion of the stratospheric ozone layer. To help the …

Optimal Pulsed Pumping For Aquifer Remediation When Contaminant Transport Is Affected By Rate-Limited Sorption: A Calculus Of Variation Approach, Richard T. Hartman

Theses and Dissertations

The remediation of groundwater contamination continues to persist as a social and economic problem due to increased governmental regulations and public health concerns. Additionally, the geochemistry of the aquifer and the contaminant transport within the aquifer complicates the remediation process to restore contaminated aquifers to conditions compatible with health-based standards. Currently, the preferred method for aquifer cleanup pump-and-treat has several limitations including, the persistence of sorbed chemicals on soil matrix and the long term operation and maintenance expense. The impetus of this research was to demonstrate that a calculus of variations approach could be applied to a pulsed pumping aquifer …

Design And Analysis Of Constrained Layer Damping Treatments For Bending And Torsion, Kimberly J. Balkema

Theses and Dissertations

In this dissertation, different aspects of constrained layer damping treatments on beams of various geometries are studied. First, the optimal length of a constrained layer damping treatment mounted on a surface in linear strain is identified as a function of the relative stiffnesses of the damping layers and the non-uniformity of the surface stain. The analysis extends previous work that considered the case of uniform surface strain. Sixth order sandwich beam theory is then modified for use with a rectangular beam covered with a segmented constrained layer damping treatment. Non-dimensional variables are used to simplify the form of the problem. …

Decision Support Model To Compare Hazardous Waste Site Remediation Process Alternatives, Christopher E. Findall

Theses and Dissertations

This research focuses on the development of a decision support model to identify the preferred methods of site characterization and treatment technology identification using the principles of decision analysis theory. The model provides an effective decision making tool to evaluate and compare the feasibility of using alternative methods of completing the RIFS process. Given a specific site remediation project, the users of this model can enter site- specific cost, duration and likelihood values to determine the expected value for various alternative processes. This thesis postulates that the alternative having the highest expected value is considered the preferred alternative. In calculating …

An Analysis Of Alternative Methods Of Measuring Hazardous Waste Reduction Progress At The Air Force Materiel Command's Air Logistic Centers, Edward C. Finke

Theses and Dissertations

his study investigated the relationship between aircraft related maintenance activity and the amount of hazardous waste (HW) disposed of by Air Force Materiel Command's (AFMC) Air Logistic Centers (ALC). These ALCS, along with the Aircraft Guidance and Meteorology Center, generate approximately 76 percent of the HW generated by the Air Force. The activity indexing and least squares curve fitting methods were used to predict the amount of HW that would have been disposed of based on the relative level of aircraft related maintenance activity had no pollution prevention efforts been implemented. These predictions were then compared to what historically occurred …