Civil Engineering Commons^™

Characteristics Of Fresh Municipal Solid Waste, Tashfeena Taufiq

Civil Engineering Theses - Archive

The characteristics of fresh municipal solid waste (MSW) are critical in planning, designing, operating or upgrading solid waste management systems. Physical composition, moisture content, compacted unit weight, permeability are the most important MSW characteristics to be considered in planning a system. When the landfill is operated as enhanced leachate recirculation (ELR) landfill, the physical and hydraulic characteristics are of particular interest in determining the amount of moisture to be recirculated and to design the leachate recirculation and gas collection systems. The current study presents the physical and hydraulic characteristics of MSW collected from the working face of Denton Landfill. The …

Development Of A Suction-Controlled Resonant Column Apparatus With Self-Contained Bender Elements, Eduardo Alfonso Suescun-Florez

Civil Engineering Theses - Archive

Small-strain soil stiffness properties such as shear modulus, shear wave velocity, and material damping, are key subsoil parameters for an adequate analysis and design of unsaturated earth structures subject to static and non-static loading. Most conventional geotechnical testing techniques, however, are not able to capture this small-strain behavior and, hence, enormously underestimate the true soil stiffness, primarily due to inaccuracies in small-strain measurements. Around the world, a great deal of research efforts has been dedicated to field and laboratory based measurements of soil suction, assessments of soil-water retention properties, and analyses of swell-collapse behavior. However, very few efforts have been …

Development Of A Preliminary Cost Estimation Method For Water Treatment Plants, Jwala Raj Sharma

Civil Engineering Theses - Archive

Reliable cost estimates for construction, and operation and maintenance (O&M) of water treatment plants are essential for their project planning and design. During the planning phases of the project, preliminary cost estimates are developed for major project components, and for screening of alternatives.Construction and O&M cost curves are widely used for developing preliminary cost estimates. This method is time consuming and there is possibility of human errors. Therefore, for this thesis, construction, and O&M cost equations were developed considering historical cost data for different unit operations and processes involved in a water treatment plant. These equations were developed from historical …

Modeling Studies To Assess Long Term Settlement Of Light Weight Aggregate Embankment, Seema Kalla

Civil Engineering Theses - Archive

Expanded clay and shale (ECS) is a low weight material derived from clay and shale, and has been used in large quantities throughout the world. Very few studies have been performed to investigate the behavior of ECS and how it can reduce the settlements of embankments when used as a fill material. This thesis presents research findings of numerical modeling to assess the long term settlements of ECS embankment on a soft clay deposit and supports both pavement and traffic loading. Observed settlements near the pavement of a light weight ECS embankment built on soft clay indicated that this material …

Field Investigations On Performance Of Short Drilled Shafts Under Inclined Loading, Richard S. Williammee Jr

Civil Engineering Theses - Archive

In the Kaufman County area within the Texas Department of Transportation's Dallas District, several short drilled shaft foundations supporting three-cable median barrier systems wereobserved to be distressed during severe winter storm conditions in late 2006 through early 2007. A research study was initiated at UT Arlington to determine and understand the mechanisms causing these shaft failures. The ends of the three-cable median barrier systems are fastened to a single drilled shaft foundation. In general, these shafts are short in depth and of the same dimensions, diameter, and depth. They are typically used in all soil conditions. This paper presents the …

Effect Of Frame Shape And Geometry On The Global Behavior Of Rigid And Hybrid Frame Under Earthquake Excitations, S.M. Ashfaqul Hoq

Civil Engineering Theses - Archive

The primary focus of this study is to present a shape which will improve building performance in earthquake excitations. The investigation started with 3-, 9-, 12- and 20-story rectangular frame. The seismic performance is observed for different earthquake data with different frequency content. Then, the Rhombus shape is introduced to compare with the Rectangular shape frames, keeping the height-to-width ratio and loading same. For the first part of the investigation, deflection and member forces are compared between rhombus and rectangular shape considering all connections rigid. In the second part of the study partially restrained connections are introduced in mid levels …

Investigation Of The Lower Bound Compressive And Flexural Strengths Of Conventional Concrete And Clay Masonry, Benchmark Henry Harris

Civil Engineering Theses - Archive

Conventional masonry is a handcrafted product in which units are placed by hand in a mortar bedding that is prepared during construction. TMS 402 Building Code Requirements for Masonry Structures (also referred to by the industry as the Masonry Standards Joint Committee or MSJC) and referenced standards consequently permit a range of various field conditions so as to allow practical construction (1). The primary objective of the testing program was to measure a statistically significant number of test results to investigate the lower bound compressive and flexural strengths of conventional concrete and clay masonry under simulated field conditions.96 compression tests …

Effect Of Leachate Recirculation On Methane Generation Of A Bioreactor Landfill, Shahed R. Manzur

Civil Engineering Theses - Archive

Municipal solid waste (MSW) disposal is of current concern due to the green-house effect and rising temperature all around the globe. Landfill gas is generated from aerobic & anaerobic biodegradation of organic materials in municipal solid waste (MSW) landfill. Along with leachate, generation of Methane happens to be a by-product of the entire biodegradation process in MSW landfills. Conventional landfilling or dry cell concept minimizes the amount of moisture infiltration into the waste. In contrast, Enhanced Leachate Recirculation (ELR) or bioreactor operation facilitates leachate recirculation and distribution through the landfill that leads both reduction of time for waste stabilization and …

Impact Of Hurricanes On Structures - A Performance Based Engineering View, Vijay Mishra

Electronic Theses and Dissertations

The magnitude of damage caused to the United States (US) coast due to hurricanes has increased significantly in the last decade. During the period 2004-2005, the US experienced seven of the costliest hurricanes in the country's history (NWS TPC-5, 2007) leading to an estimated loss of ~ $158 billion. The present method for predicting hurricane losses, HAZUS (HAZard US), is solely based on hurricane hazard and damage caused to building envelopes only and not to structural systems (Vickery et al., 2006). This method does not take into account an intermediate step that allows for better damage estimates, which is structural …

On The Use Of Polyurethane Matrix Carbon Fiber Composites For Strengthening Concrete Structures, Zachary Haber

Electronic Theses and Dissertations

Fiber-reinforced polymer (FRP) composite materials have effectively been used in numerous reinforced concrete civil infrastructure strengthening projects. Although a significant body of knowledge has been established for epoxy matrix carbon FRPs and epoxy adhesives, there is still a need to investigate other matrices and adhesive types. One such matrix/adhesive type yet to be heavily researched for infrastructure application is polyurethane. This thesis investigates use of polyurethane matrix carbon fiber composites for strengthening reinforced concrete civil infrastructure. Investigations on mirco- and macro-mechanical composite performance, strengthened member flexural performance, and bond durability under environmental conditioning will be presented. Results indicate that polyurethane …

Characteristic Dynamic Increment For Extreme Traffic Loading Events On Short And Medium Span Highway Bridges, Eugene J. Obrien, Daniel Cantero, Bernard Enright, Arturo González

Articles

More accurate assessment of safety can prevent unnecessary repair or replacement of existing bridges which in turn can result in great cost savings at network level. The allowance for dynamics is a significant component of traffic loading in many bridges and is often unnecessarily conservative. Critical traffic loading scenarios are considered in this paper with a model that allows for vehicle-bridge interaction and takes into account the road surface condition. Characteristic dynamic allowance values are presented for the assessment of mid-span bending moment in a wide range of short to medium span bridges for bi-directional traffic.

Integrated, Multi-Attribute Decision Support System For The Evaluation Of Underground Utility Construction Methods, John C. Matthews

Doctoral Dissertations

The dissertation research work described herein is comprised of three primary objectives: (1) the development of a rehabilitation method selection software (TAG-R) for the National Association of Sewer Service Companies (NASSCO) and its subsequent validation and combination with TAG (a sister decision support system (DSS) software developed by the author in an earlier work); (2) the development of a social cost calculator (SCC) and its validation; and (3) the development of a proposed framework for multi-segment optimization for construction methods selection using the tools developed in the first two objectives as well as additional project related data.

The selection of …

Effects Of Unbalanced Approach Volumes On Roundabout Operations, Marilyn Valdez

Open Access Theses & Dissertations

Modern roundabouts are increasingly popular in the United States due to their advantages in improving safety and reducing delay at intersections. A roundabout is an intersection in which traffic enters the intersection and travels in a circular counterclockwise motion around a center island. In a roundabout, priority is given to vehicles traveling in the circular roadway, and incoming traffic at the roundabout approach must yield to the circulating traffic. If there is an unbalance in approach volume, the approaches with higher input volumes may dominate the circulating flow preventing vehicles the other approaches to enter the roundabout. This may consequently …

Probabilistic Analysis Of Concrete Fracture, Mustafa Abushaala Aldalinsi

Open Access Theses & Dissertations

It is well known to civil engineers that fatigue leads to the bulk of structural failures. In plain and reinforced concrete structures, fatigue might account for excessive deformation, excessive of crack widths, de-bonding of reinforcement and rupture of the reinforcement, all of these can lead to structural collapse. Fatigue crack propagation can be a method to predict a remaining life of a structures. Herein will show some works that have been done in order to analyze the fatigue crack growth for plain concrete specimen. The goals of this study are to estimate the critical crack length and remaining life of …

Impact Of Moisture Content And Density On Stiffness-Based Acceptance Of Geomaterials, Lourdes Guadalupe Pacheco

Open Access Theses & Dissertations

Modulus-based quality management of compacted layers has been considered by a number of highway agencies. Even though simple in concept, the paradigm shift from density to modulus for quality acceptance has generated some technical and institutional challenges. One of these complications is that for a given density, the modulus can vastly vary depending on the moisture content at the time of compaction and at the time of acceptance. The results of a systematic study carried out to qualify and quantify the impact of compaction moisture content, moisture content at the time of field testing and density on the modulus and …

Pseudo-Probabilistic User Equilibrium Assignment In Travel Corridor Networks Containing Managed Facilities, Alireza Khaleghi-Soroush

Civil Engineering Dissertations - Archive

Throughout the years, transportation organizations and agencies have been unable to keep up with increasing demand for roadway facilities. Similarly, traditional public-sector funding such as motor fuel taxes is falling short in meeting the growing demand for new transportation infrastructure. With deficit financing and congestion problems common to many highways throughout the United States, DOTs are turning to tolling the roadway facilities as a means of financing transportation improvements for inter-urban and urban facilities.In turn, in order for managed facilities such as toll roads or managed lanes to be attractive and viable for the potential investors, the facilities must be …

Importance Of The Tail In Truck Weight Modeling For Bridge Assessment, Eugene J. Obrien, Bernard Enright, Abraham Getachew

Articles

To predict characteristic extreme traffic load effects, simulations are sometimes performed of bridge loading events. To generalize the truck weight data, statistical distributions are fitted to histograms of weight measurements. This paper is based on extensive WIM measurements from two European sites and shows the sensitivity of the characteristic traffic load effects to the fitting process. A semi-parametric fitting procedure is proposed: direct use of the measured histogram where there are sufficient data for this to be reliable and parametric fitting to a statistical distribution in the tail region where there are less data. Calculated characteristic load effects are shown …

The Influence Of Correlation On The Extreme Traffic Loading Of Bridges, Eugene J. Obrien, Bernard Enright, A. T. Dempsey

Conference papers

Accurate traffic loading models based on measured data are essential for the accurate assessment of existing bridges. There are well-established methods for the Monte Carlo simulation of single lanes of traffic, and this can easily be extended to model the loading on bridges with two independent streams of traffic in opposing directions. However, a typical highway bridge will have multiple lanes in the same direction, and various types of correlation are evident in measured traffic. This paper analyses traffic patterns using multi-lane WIM data collected at two European sites. It describes an approach to the Monte Carlo simulation of this …

Management Strategies For Special Permit Vehicles For Bridge Loading, Bernard Enright, Eugene J. Obrien

Conference papers

An examination of weigh-in-motion data collected recently at sites in five European countries has shown that vehicles with weights well in excess of the normal legal limits are found on a daily basis. These vehicles would be expected to have permits issued by the responsible authorities. It can be seen from the measurements that most of them are travelling at normal speeds. Photographic evidence indicates that, while many are accompanied by an escort vehicle, normal traffic is flowing alongside in other lanes. As European freight volume grows, the frequency of these special vehicles can be expected to increase. Hence, the …

Optimal Design Of Trusses With Geometric Imperfections, Mehdi Jalalpour, Takeru Igusa, James K. Guest

Civil and Environmental Engineering Faculty Publications

The present paper focuses on optimization of trusses that have randomness in geometry that may arise from fabrication errors. The analysis herein is a generalization of a perturbation approach to topology optimization under geometric uncertainties. The main novelty in the present paper is in the consideration of potential buckling due to misaligned structural members. The paper begins with a brief review of the aforementioned perturbation approach, then proceeds with the analysis of the nonlinear effects of geometric imperfection. The paper concludes with some numerical examples.