Civil Engineering Commons^™

Unbound Pavement Base Courses: Parallel Study Of Stiffness And Drainage Characteristics, Moussa Issa

Doctoral Dissertations

The purpose of this project was to study the effects of fines (minus #4 sieve) on permeability and stiffness characteristics of unbound base materials and to propose an optimumgradation that will satisfy these two parameters. One type of highway base material--crushed limestone--was used in the study. A total of 75 laboratory tests were conducted and distributed--25 respectively on permeability, resilient modulus and unconfined compression. The permeability test data were collected using a low-head permeameter. The resilient modulus and unconfined compression test data were collected by the mean of the MTS (Machine Testing System) with a load cell capacity of 22-kips. …

Displacement-Based Analysis And Design Of Rigid Retaining Walls During Earthquakes, Yingwei Wu

Doctoral Dissertations

"This research focused on the analysis and design of rigid retaining walls subjected to earthquakes and considered nonlinear foundation soil properties. The simultaneous sliding and rocking movements of retaining walls were considered. Seven field conditions, including moist, submerged, perched and saturated backfill with a sloping drain, were specified by design codes. A computer program capable of computing displacement using real time history records or equivalent sinusoidal motions was developed. Finally, a dynamic design procedure was proposed for practicing engineers.

The study revealed that maximum shear modulus in foundation soil, maximum ground acceleration, and soil nonlinearity had significant effect on the …

The Effect Of Pipe Bursting On Nearby Utilities, Pavement, And Structures, Alan Atalah

Doctoral Dissertations

This dissertation has involved field and analytical studies of ground movements, ground vibrations and other design issues associated with trenchless pipe replacement (or pipe bursting, as it is commonly known). The process is used to replace an existing underground service pipe with a completely new pipe but without the disturbance and cost of excavating a trench from the surface. The process typically involves the insertion of a tool into the existing pipe that has a maximum diameter that is slightly larger than the existing pipe. This tool is used to break the existing pipe into pieces and to displace the …

Multiobjective Optimum Design Of Static And Seismic-Resistant Structures With Genetic Algorithm, Fuzzy Logic And Game Theory, Dan Li

Doctoral Dissertations

"The goal of this research is to develop a constrained multiobjective optimization method in the form of a robust, practical, problem-independent algorithm, and to investigate the effect of multiobjective optimization on structural design.

This research studies the properties and characteristics of multiobjective optimization and solutions. Design objectives, constraints and design variables as well as their effect on structural design and behaviors are investigated. Dynamic input energy for a multidegree-of-freedom structure is formulated. A multiobjective optimization algorithm based on game theory is developed. Fuzzy set theory is introduced to construct a fuzzy constrained environment. A Pareto genetic algorithm is developed based …

Implementation Of Alf Results To Designing Flexible Pavements In Louisiana, Ludfi Djakfar

Doctoral Dissertations

The Louisiana Transportation Research Center (LTRC) recently conducted a research effort using the Accelerated Loading Facility (ALF). The objective of the research was to evaluate a limited number of alternative base materials and construction techniques envisioned to provide a significant reduction in the occurrence of shrinkage and reflected block cracking in the cement-stabilized bases. Nine test sections were constructed for this research, using the same wearing course material but having different thicknesses of crushed stone and soil cement bases and subbases. The soil cement base is the most commonly used base material in Louisiana, whereas crushed stone is a preferred …

Time Characteristics Of Small Watersheds In Response To The Probable Maximum Precipitation, Brian Jay Swenty

Doctoral Dissertations

"The EPA Storm Water Management Model (SWMM) was used to perform single event simulations of Probable Maximum Precipitation (PMP) level rainfall events on the Loss Lake watershed in southcentral Missouri. Overland flow was simulated using kinematic wave routing and channel flow was simulated using dynamic wave routing.

Lag time was defined as the time between the centroid of the excess rainfall hyetograph and the centroid of the direct runoff hydrograph.

Rainfall depth, rainfall duration, and the distribution of rainfall intensity were found to be significant predictor variables for lag time. Defined as hydrologic parameters for this study, channel flow roughness, …

Development Of Design Criteria For Ferritic Stainless Steel Cold-Formed Structural Members And Connections, Pieter Van Der Merwe

Doctoral Dissertations

"This dissertation describes the development of the basic criteria needed for the design of structural members cold-formed from certain ferritic stainless steels. The Allowable Stress Design method as well as the Load and Resistance Factor Design method receive attention. The ferritic stainless steels under consideration are: Types AISI 409 and 430 as well as a modified Type 409 steel, designated 3CR12 steel, developed and produced by the speciality steel producing company, Middelburg Steel and Alloys in South Africa.

The mechanical properties needed for structural design are established. It is shown through an experimental study that the design provisions for the …

Structural Behavior Of Members Consisting Of Flat And Curved Elements, M. Brad Parks

Doctoral Dissertations

"Local buckling of stiffened and unstiffened curved elements has been investigated both experimentally and analytically. Stiffened curved elements are supported on all four edges while unstiffened curved elements are supported along three edges with one longitudinal edge free.

A series of stub column, beam, and shear tests have been performed for sections containing curved elements. The tested specimens were formed from sheet steels with yield strengths ranging from 27 to 88 ksi. The radius-to-thickness, R/t, values of the curved elements varied from 12 to 438 whereas the arc length-to-thickness, bit, ratios ranged from 23 to 218.

As a result of …

Web Crippling Of High Strength Cold-Formed Steel Beams, Chiravut Santaputra

Doctoral Dissertations

"The structural behavior of high strength cold-formed steel beams subjected primarily to web crippling was investigated analytically and experimentally. In this study hat sections and I-beams, formed from five different types of high strength sheet steels commonly used in the automobile industry, were investigated under various loading conditions. The yield strengths of these sheet steels vary from 58 to 165 ksi.

In addition to the test data gathered in this phase of study, the experimental results obtained from the beam tests conducted at Inland Steel Company and Ford Motor Company were carefully evaluated. The evaluation indicated that the present available …

An Investigation Of Signs For Median Crossovers, Gillian M. Worsey

Doctoral Dissertations

“This paper describes a study of advance warning signs for median crossovers on divided highways. Candidate crossover signs were identified from a literature review, survey of current State practices and discussions with FHWA personnel. Seven of these signs were selected for further testing in a laboratory study for legibility, understanding and driver preference. Sixty subjects representing a cross-section of drivers took part in the study, thirty at the Turner-Fairbanks Highway Research Center in McLean, Virginia and thirty at the University of Missouri--Rolla in Rolla, Missouri.

Two of the seven signs were word messages and five were symbolic signs. The results …

Structural Design Of Coal-Fueled Power Plant Ductwork, Stanley Pearce Rader

Doctoral Dissertations

"An absence of a comprehensive procedure for design of coal-fueled power plant ductwork currently exists in the publicly available literature. This dissertation presents such a procedure.

An overview of the ductwork design environment, including major components of the air and flue gas flow paths, design loads and temperatures, corrosion considerations, and physical configurations, is given. Design criteria for materials, corrosion inhibition, minimum plate thicknesses, temperature effects, allowable stresses and deflections, and vibrations are proposed. A detailed design procedure based on the allowable stress design philosophy is presented, and computer programs implementing the design procedure are provided. An alternate design procedure …

A Study Of The Permeability Of Clays Subjected To Organic And Inorganic Permeants, Janardanan O. Uppot

Doctoral Dissertations

"Two types of clays, a magnesium montrnorillonite and a kaolinite, were subjected to precise permeability tests in specially designed triaxial permeameters, using organic and inorgani c permeants, to study the changes in permeability due to the reaction between clays and permeants. The organic permeants were an acid (acetic acid), a base (aniline), a neutral polar fluid (methanol), a neutral nonpolar fluid (xylene), as well as EDTA and its sodium salt. The inorganic permeants were aqueous solutions of aluminum, magnesium, sodium, calcium, barium and strontium.

The clay samples were prepared by consolidating from slurry; they were subjected to back-pressure saturation and …

Load And Resistance Factor Design Of Cold-Formed Steel Structural Members, Boonsong Supornsilaphachai

Doctoral Dissertations

"In a traditional design, the Allowable Stress method has long been used for the design of cold-formed steel structures. In this design approach, the allowable stress is always used to prevent the possible structural failure by using an appropriate factor of safety selected primarily on the basis of engineering judgment and long-time experience.

Recently, the concepts of risk and reliability analysis have been successfully applied to many fields of engineering. By applying the theories of probability and statistics, the load and resistance design criteria for steel structures have been developed for the design of hot-rolled steel shapes and built-up members. …

Strength Of Cold-Formed Steel Beam Webs In Bending, Shear, And A Combination Of Bending And Shear, Roger A. Laboube

Doctoral Dissertations

"An extensive experimental investigation has been conducted to study the load-carrying capacity of cold-formed steel web elements subjected to bending stress, shear stress, and a combination of bending and shear stresses. Emphasis has been concentrated on the instability and postbuckling strength of beam webs.

In the study of beam webs subjected only to bending, the postbuckling strength of web elements and the effect of the compression flange on the moment capacity have been carefully evaluated for beams having stiffened and unstiffened flanges. Based on 84 test results, formulas have been developed to predict the ultimate moment capacity of cold-formed steel …

Structural Behavior Of Cold-Formed Steel Members Made Of Thick Sheets And Plates, Ai-Shen Liu

Doctoral Dissertations

"It is well-known that the current AlSI Specification for the design of cold-formed steel structural members has been developed mainly for thin steel sections. In order to extend the applicability of the specification for the design of cold-formed steel members thicker than 1/4 in., both analytical and experimental investigations have recently been conducted with special emphases on the effects of cold work on the mechanical properties of corners and the strength of bolted connections.

For the effects of cold work, previous investigations have shown that the phenomena of strain hardening and strain aging are main factors which affect the mechanical …

Nonlinear Optimum Design Of Dynamic Damped Structures, Mark E. Botkin

Doctoral Dissertations

"A method to optimize the weight of plane frames subjected to dynamic loads is presented. Restrictions are imposed upon the maximum dynamic stresses and displacements, desirable section moduli of the constituent members, and the range of values allowed for natural frequencies. Various considerations for rigid frame design include damping, the P-Δ effect, static girder loads, static column loads and girder shears transferred to the columns. A finite difference approach is presented to evaluate the shock spectrum which is used in conjunction with modal superposition to obtain the peak upperbound dynamic displacements and stresses for multistory and multibay frames. The displacement …

Analysis Of Continuous Curvilinear Structures By Infinite Matrix Series Methods, Trinh-Ngoc Rang

Doctoral Dissertations

"The objective of this dissertation is to present two methods of structural analysis for continuous curvilinear frames by using infinite matrix series as an extension of the well-known moment-distribution method. The sum of all unbalanced moments and thrusts relaxed at joints of a continuous system can be expressed in a compact and exact mathematical expression, which is in terms of the sum of a convergent infinite matrix series. With these unbalanced forces at joints, the final support forces may be calculated in a single stage of distribution and carry-over. The convergence of the balancing process is also demonstrated. Approximate results …

Dynamic Instability And Ultimate Capacity Of Inelastic Systems Parametrically Excited By Earthquakes, Wu-Hsiung Tseng

Doctoral Dissertations

"A procedure of analysis is presented for determining the dynamic instability and response of framed structures subjected to pulsating axial loads, time-dependent lateral forces, or foundation movements. Included in the analytical work are the instability criterion of a structural system, the finite element technique of structural matrix formulation, and the computer solution methods.

The dynamic instability is defined by a region in relation to transverse natural frequency, longitudinal forcing frequency and the magnitude of axial dynamic force. The axial pulsating load is expressed in terms of static buckling load for ensuring that the applied load is not greater than the …

Probabilistic Models For Construction Estimating And Bidding, James E. Spooner

Doctoral Dissertations

"Two probabilistic models are offered as a means for quantitatively determining contingency in a lump-sum bid. The first model is based on the isolated project and requires subjective evaluation of probabilities associated with the individual elements of the estimate. Contingency is defined as a function of the standard deviation of project field costs. Procedures are developed to obtain the variance of the total field cost from three-value estimates of the primary quantities. The second model considers the business as a stochastic process with an initial risk reserve and a positive risk loading, and contingency in this model is a function …

The Structural Behavior Of Cold-Formed Steel Members With Perforated Elements, Charles S. Davis

Doctoral Dissertations

"Analytical and experimental investigations have been conducted to study the influence of perforations on the structural behavior of cold-formed steel structural members. Since in many cases, the load-carrying capacity of cold-formed steel members depends on the buckling behavior of individual component elements, emphasis has been concentrated on the study of the instability and post-buckling strength of perforated elements. In this investigation, the buckling loads and post-buckling strength of stiffened and unstiffened compression elements having single circular and square holes have been studied analytically by using the finite element method. The effects of different holes on the buckling coefficient have been …

Computer Assisted Teaching Of Steel Design, Wendelin Henry Mueller Iii

Doctoral Dissertations

"A method for use in creating a university level course is presented. The specifics of each of the steps is given in general terms to allow its application to as many different topics as possible. This method is then specifically applied in the formation of a fundamental steel design course using the American Institute of Steel Construction Specification. The reasoning utilized in each phase of development is documented. A lecture style presentation complemented by a series of student oriented computer programs was chosen for use. The details of the course material in outline form is given along with the computer …

Dynamic Behavior Of Eccentrically Stiffened Plates, Charles Stuart Ferrell

Doctoral Dissertations

"The dynamic behavior of eccentrically stiffened rectangular plates is studied by the finite element method. The addition of stiffeners to a plate structure is a common method of increasing the rigidity of the structure with a minimum of weight increase. However, this stiffened plate configuration does not easily lend itself to analysis. This study is an approach to finding a rational method by which the dynamic behavior of such a stiffened plate structure may be determined. The governing differential equations for the finite element model are derived and the stiffness and mass matrices for the plate and stiffener elements are …

Transient Hydraulic Simulation: Breached Earth Dams, D. L. Fread

Doctoral Dissertations

"A conceptual method to alleviate flood damages due to over-topping failures of small earthfill dams is the incorporation of a relatively thin erosion retarding layer within the dam. This paper investigates the reduction in the reservoir release due to the hypothetical erosion retarding layer. In addition, the paper provides a method for the determination of an optimal location of the layer so as to minimize the maximum possible reservoir release due to a gradually breached earth dam. The transient reservoir flow is simulated by a numerical model, based upon the solution of the one-dimensional St. Venant unsteady open-channel flow equations. …

The Identification And Evaluation Of Toxic Effects Of Organic Micropollutants, John Warren Smith

Doctoral Dissertations

No abstract provided.

Matrix Computer Analysis Of Curvilinear Grid Systems, David Leon Fenton

Doctoral Dissertations

"A general equilibrium-stiffness method of matrix structural analysis was adapted and applied to the solution of the member end forces and moments of each of the members in a curvilinear structural grid system. A structural system of this nature is commonly used as the supporting framework for a "steel-framed dome", in addition to being a basic structural component in many aerospace applications. An integral part of the development of the analysis was the development of a computer program to perform the many complex operations required to obtain the solution. The engineer, by supplying the appropriate structural data and load data …