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Articles 5131 - 5160 of 6327

Full-Text Articles in Engineering

Construction Work Zone Safety, Christopher Ryan Huebschman, Camilo Garcia, Darcy M. Bullock, Dulcy M. Abraham Jan 2003

Construction Work Zone Safety, Christopher Ryan Huebschman, Camilo Garcia, Darcy M. Bullock, Dulcy M. Abraham

JTRP Technical Reports

The need of maintaining safety of motorists and workers during periods of construction activities on interstates has prompted the Indiana Department of Transportation (INDOT) to initiate a study aimed at improving the safety in work zones on rural interstates. The two main objectives of the project are 1) determine if active warning devices or improved signing have an impact in work zone safety and 2) determine if it is appropriate to consider temporary roads and bridges during construction activity on interstates in an effort to maintain two lanes open at all times. This report describes the methods used to meet …

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Development Of A Database And System For Analyzing The Actual And Potential Impacts On The Environment Of Existing And Planned Indot Sites, Lynn A. Corson Jan 2003

Development Of A Database And System For Analyzing The Actual And Potential Impacts On The Environment Of Existing And Planned Indot Sites, Lynn A. Corson

JTRP Technical Reports

The objectives of this research were: 1. to identify the source, character, currency and format of environmental, ecological, geological and other data for each existing facility site and organize it in a “hard copy” and/or computerized framework to aid the prioritization and planning process for facility upgrades to protect the environment, for regulatory compliance, and for potential replacement or relocation of existing sites; 2. to identify and assess the criteria currently employed by INDOT to select locations for new and/or relocated facilities, including the ASTM Phase I and II Environmental Site Assessment criteria, and to recommend additional criteria including those …

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The Effectiveness Of Maintenance And Its Impact On Capital Expenditures, Samuel Labi, Kumares C. Sinha Jan 2003

The Effectiveness Of Maintenance And Its Impact On Capital Expenditures, Samuel Labi, Kumares C. Sinha

JTRP Technical Reports

With ever increasing traffic loadings, highway pavement maintenance needs continue to outpace the availability of resources, and transportation agencies seek cost-effective maintenance practices. This study investigated the effectiveness of maintenance treatments in the short-term and the cost effectiveness of maintenance strategies over entire pavement life. The study also analyzed the relationships and trade-offs between maintenance and capital investments such as pavement rehabilitation, and the trade-offs between preventive and corrective maintenance. These analyses were carried out through a work sequence that included analyses of historical trends, literature review, and a questionnaire survey. The study found that there are significant benefits associated …

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Guideline Specifications For Construction And Maintenance Equipment For Street And Highway Work, Indiana Ltap Jan 2003

Guideline Specifications For Construction And Maintenance Equipment For Street And Highway Work, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

The purpose of this guide is to provide a useful tool for county engineers and supervisors and city and town street commissioners in purchasing equipment.

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Simplified Meta-Analysis Of Clinical Trials In Resuscitation, Charles F. Babbs Jan 2003

Simplified Meta-Analysis Of Clinical Trials In Resuscitation, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Objective: To present and demonstrate a new simplified method for synthesizing results of multiple clinical trials in resuscitation research. Methods: The mean difference across studies in the proportion of favorable outcomes between experimental and control groups is calculated. This difference is shown to have a t-distribution. Its significance can be ascertained with a simple t-test. The analysis can be implemented in a one-page computer spreadsheet. Results: Simplified meta-analysis provides high sensitivity and can be extended to include weighting of studies according to size or quality, comparison of subgroups of studies, tests for outliers, and calculation of the power of the …

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Interposed Abdominal Compression Cpr: A Comprehensive Evidence Based Review, Charles F. Babbs Jan 2003

Interposed Abdominal Compression Cpr: A Comprehensive Evidence Based Review, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Interposed abdominal compression (IAC)-CPR includes all steps of standard external CPR with the addition of manual mid-abdominal compressions in counterpoint to the rhythm of chest compressions. IAC-CPR can increase blood flow during CPR about two fold compared to standard CPR without IAC, as shown by 6 of 6 studies in computer models and 19 of 20 studies in various animal models. The addition of IAC has clinical benefit in humans, as indicated in 10 of 12 small to medium sized clinical studies. The technique increases the frequency of immediate return of spontaneous circulation for in-hospital resuscitations from roughly 25% to …

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A Simple Quantum Mechanical Treatment Of Scattering In Nanoscale Transistors, Rajesh Venugopal, Magnus Paulsson, Sebastien Goasguen, Supriyo Datta, Mark S. Lundstrom Jan 2003

A Simple Quantum Mechanical Treatment Of Scattering In Nanoscale Transistors, Rajesh Venugopal, Magnus Paulsson, Sebastien Goasguen, Supriyo Datta, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

We present a computationally efficient, two-dimensional quantum mechanical simulation scheme for modeling dissipative electron transport in thin body, fully depleted, n-channel, silicon-on-insulator transistors. The simulation scheme, which solves the nonequilibrium Green’s function equations self consistently with Poisson’s equation, treats the effect of scattering using a simple approximation inspired by the “Büttiker probes,” often used in mesoscopic physics. It is based on an expansion of the active device Hamiltonian in decoupled mode space. Simulation results are used to highlight quantum effects, discuss the physics of scattering and to relate the quantum mechanical quantities used in our model to experimentally measured …

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Quantum Mechanical Analysis Of Channel Access Geometry And Series Resistance In Nanoscale Transistors, R. Venugopal, S. Goasguen, Supriyo Datta, Mark S. Lundstrom Jan 2003

Quantum Mechanical Analysis Of Channel Access Geometry And Series Resistance In Nanoscale Transistors, R. Venugopal, S. Goasguen, Supriyo Datta, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

We apply a two-dimensional quantum mechanical simulation scheme to study the effect of channel access geometries on device performance. This simulation scheme solves the nonequilibrium Green’s function equations self-consistently with Poisson’s equation and treats the effect of scattering using a simple approximation inspired by Büttiker. It is based on an expansion of the device Hamiltonian in coupled mode space. Simulation results are used to highlight quantum effects and discuss the importance of scattering when examining the transport properties of nanoscale transistors with differing channel access geometries. Additionally, an efficient domain decomposition scheme for evaluating the performance of nanoscale transistors is …

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An Investigation On Transversely Prestressed Concrete Bridge Decks, J. A. Ramirez, Jhon Paul Smith Jan 2003

An Investigation On Transversely Prestressed Concrete Bridge Decks, J. A. Ramirez, Jhon Paul Smith

JTRP Technical Reports

This study is concerned with the development of design specifications for the use of transverse post-tensioning in concrete bridge decks. The ultimate goal behind this proposal is to improve the durability of concrete bridge superstructures. Experimental results from previous studies are used to validate the analytical models implemented in the development of the design specifications. It is found that the required distribution of transverse post-tensioning is such that different application levels of prestressing are required in regions containing the interior and exterior (or outermost) diaphragms. It is also concluded that the magnitude of such transverse forces is a function of …

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Investigation Of Novel Acoustic Barrier Concepts Phase I: Concept Development And Preliminary Evaluation, Luc Mongeau, J. Stuart Bolton, Sanghoon Suh Jan 2003

Investigation Of Novel Acoustic Barrier Concepts Phase I: Concept Development And Preliminary Evaluation, Luc Mongeau, J. Stuart Bolton, Sanghoon Suh

JTRP Technical Reports

In a previous research project [SPR 2418; "Study of the performance of acoustic barriers for Indiana toll roads,"] the influence of environmental factors and of advanced sound barrier concepts was investigated. The presence of temperature gradients over pavements was found to have a strong influence on sound propagation. Refraction of sound waves emitted by tire-road interactions in the vicinity of the ground also affects sound barrier performance. Modified ray tracing model suggested that prevailing winds have an influence on barrier performance at large distances. Randomized edge configurations were found not to improve barrier performance for traffic noise. Random edges simply …

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Maintenance Quality Assurance Program, Bob G. Mccullouch Jan 2003

Maintenance Quality Assurance Program, Bob G. Mccullouch

JTRP Technical Reports

An INDOT maintenance QA program has been developed and implemented at the activity level. Every maintenance activity is checked and evaluated by QA guidelines. One area that has been considered as an ideal candidate for QA is at the management level of maintenance operations. This program uses a random sample population at a certain confidence level to evaluate the maintenance condition of INDOT roads. Five categories are evaluated: pavement, roadside features, shoulder, drainage, and traffic control. A field inspection program utilizes INDOT personnel and resources. A scoring program yields results that provides for category and individual item evaluations. Data collected …

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Traffic Signals In School Zones, Kevin S. Lee, Darcy M. Bullock Jan 2003

Traffic Signals In School Zones, Kevin S. Lee, Darcy M. Bullock

JTRP Technical Reports

Traffic signals are used to control the right of way at intersections. Strict engineering guidelines are published in the Manual on Uniform Traffic Control Devices (MUTCD) that engineers use to determine if a traffic signal is “warranted”. The warrants provide consistent national balance between mobility, safety, efficiency, and costs. However, signalized intersections are often viewed by the general public as safer then unsignalized intersections. This belief is often heightened when there are personal injuries and even higher when children are involved. Parents, city officials, and local interest groups often vigorously request the installation of a traffic signal. After these requests …

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Weigh-In-Motion Data Checking And Imputation, Ting Wei, Jon D. Fricker Jan 2003

Weigh-In-Motion Data Checking And Imputation, Ting Wei, Jon D. Fricker

JTRP Technical Reports

There are about 46 weigh-in-motion (WIM) stations in Indiana. When operating properly, they provide valuable information on traffic volumes, vehicle classifications, and axle weights. Because there are great amounts of WIM data collected everyday, the quality of these data should be monitor without further delay. The first objective of this study is to develop effective and efficient methods to identify missing or erroneous WIM data. The second objective is to develop a data imputation method to update the missing or erroneous data. This report describes the WIM data checking process on both a monthly and a daily basis. The Weigh-In-Motion …

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Simplified Shear Design Of Prestressed Concrete Members, Robert J. Frosch, Tyler S. Wolf Jan 2003

Simplified Shear Design Of Prestressed Concrete Members, Robert J. Frosch, Tyler S. Wolf

JTRP Technical Reports

Design methods for the shear resistance of reinforced and prestressed concrete beams are based on empirical evidence. Due to different approaches in their development different equations are used to calculate the shear strength of reinforced and prestressed concrete. Recent research conducted by Tureyen has proposed a simplified shear model for reinforced concrete which is primarily based upon mechanics and corresponds well with a wide range of test results. The objective of this research was to determine the applicability of the shear model to prestressed concrete. The applicability of the shear model was evaluated by a comparison of its results with …

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Use Of Modulus Of Rupture, Fatigue Resistance And Maturity In Determining Opening To Traffic Time For Concrete Pavements, J. Olek, Menashi D. Cohen, Charles F. Scholer, Deepak R. Mandrekar Jan 2003

Use Of Modulus Of Rupture, Fatigue Resistance And Maturity In Determining Opening To Traffic Time For Concrete Pavements, J. Olek, Menashi D. Cohen, Charles F. Scholer, Deepak R. Mandrekar

JTRP Technical Reports

The main objective of this experimental and analytical research project was to develop maturity-based guidelines for early opening-to-traffic of concrete pavements in the state of Indiana. Currently, the Indiana Department of Transportation (INDOT) specifies that pavements can be opened to traffic when the concrete reaches the strength of at least 3.8 MPa (550 psi). During this study modulus of rupture (MOR) and maturity data were collected and strength gain characteristics were analyzed. Also, fatigue experiments were performed at different stress levels and ages. Based on the experimental results, modulus of rupture of concrete was correlated with corresponding fatigue life for …

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2002 Statewide Bridge Sufficiency Rating Report, Indiana Ltap Dec 2002

2002 Statewide Bridge Sufficiency Rating Report, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This report contains information specific to the county of interest, plus summary tables relating information about all Indiana county bridge conditions and funding levels.

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Performance Projections For Ballistic Carbon Nanotube Field-Effect Transistors, Jing Guo, Mark Lundstrom, Supriyo Datta Apr 2002

Performance Projections For Ballistic Carbon Nanotube Field-Effect Transistors, Jing Guo, Mark Lundstrom, Supriyo Datta

Other Nanotechnology Publications

The performance limits of carbon nanotube field-effect transistors 􏰎CNTFETs􏰁 are examined theoretically by extending a one-dimensional treatment used for silicon metal – oxide – semiconductor field-effect transistors 􏰎MOSFETs􏰁. Compared to ballistic MOSFETs, ballistic CNTFETs show similar I–V characteristics but the channel conductance is quantized. For low-voltage, digital applications, the CNTFET with a planar gate geometry provides an on-current that is comparable to that expected for a ballistic MOSFET. Significantly better performance, however, could be achieved with high gate capacitance structures. Because the computed performance limits greatly exceed the performance of recently reported CNTFETs, there is considerable opportunity for progress in …

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2002 Directory Of Indiana State, County, City And Town Officials Responsible For Road And Street Work, Indiana Ltap Mar 2002

2002 Directory Of Indiana State, County, City And Town Officials Responsible For Road And Street Work, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Directory

Contact information for agency officials and employees responsible for Indiana’s local road infrastructure.

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An Evaluation Of Innovative Transportation Financing Techniques For Indiana, Kristine Drike, A. Vincent Genetti, Kumares C. Sinha Jan 2002

An Evaluation Of Innovative Transportation Financing Techniques For Indiana, Kristine Drike, A. Vincent Genetti, Kumares C. Sinha

JTRP Technical Reports

Innovative financing techniques can complement current methods of financing highway projects in Indiana. Annual federal apportionments and Indiana state revenues are not sufficient to maintain and improve state highways, so innovative approaches in transportation project financing should be sought. There are several available innovative financing techniques associated with the use of federal funds. Although, they do not provide new sources of revenue and cannot create enough funds for all identified projects, they provide flexibility in the use of available funds that can expedite the implementation of individual projects. The main objective of this study was to evaluate the major innovative …

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Design Of Durable Concrete Railroad Crossings, Anthony J. Lamanna, Charles F. Scholer Jan 2002

Design Of Durable Concrete Railroad Crossings, Anthony J. Lamanna, Charles F. Scholer

JTRP Technical Reports

Existing precast concrete railroad crossings in the state of Indiana are experiencing too short a life expectancy. This study proposes methods that can be used to produce durable concrete railroad crossings with satisfactory rideability, durability, and longevity. Thirty-two precast concrete railroad crossings were visited in central and northern Indiana. Failures were determined to belong to three major categories: structural capacity causes, environmental causes, and material property causes. A concrete mix was evaluated at three different polyolefin fiber contents and without fibers. Beams were tested in flexure, and modulus of rupture and first crack deflection were recorded for each beam. Cylinders …

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Design Of Mse Walls For Fully Saturated Conditions, Antonio Bobet Jan 2002

Design Of Mse Walls For Fully Saturated Conditions, Antonio Bobet

JTRP Technical Reports

The current design of MSE walls, which is based on limit state analysis, does not apply to undrained conditions. Laboratory and numerical pullout tests are performed to determine the relation between drained and undrained pullout capacities for different soil types (clean sand, 5, 10, 15 and 35 % silty sand), overburden pressures (30, 100 and 200 kPa), and scale and permeability effects in the dissipation of excess pore pressures. The results of the pullout tests show that both drained and undrained pullout capacities change as silt content changes since the pullout capacity increases as the internal friction angle of the …

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Effectiveness Of The Borman Expressway Its Program On Local Air Quality, Timothy M. Labreche, Robert Bertram Jacko, Barry K. Partridge, William H. Schneider, Ahmed S. Soliman Jan 2002

Effectiveness Of The Borman Expressway Its Program On Local Air Quality, Timothy M. Labreche, Robert Bertram Jacko, Barry K. Partridge, William H. Schneider, Ahmed S. Soliman

JTRP Technical Reports

Particulate Matter less than 2.5 μm in diameter (PM2.5), carbon monoxide (CO), and meteorological parameters were monitored at 10 second averaging intervals adjacent the Borman Expressway in Northwestern Indiana before and during the implementation of an Intelligent Transportation System. Traffic data was collected from sensors on the expressway. The high-resolution data permitted the expressway contribution to local air quality to be separated from background components of local air quality and significant correlations were made between pollutant flux and traffic flow and pollutant flux and highway occupancy. Traffic incidents (accidents / congestion) were shown to have a rapid impact on local …

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Effects Of Heavier Truck Loadings And Super-Single Tires On Subgrades, Rodrigo Salgado, Daehyeon Kim Jan 2002

Effects Of Heavier Truck Loadings And Super-Single Tires On Subgrades, Rodrigo Salgado, Daehyeon Kim

JTRP Technical Reports

Due to their efficiency and economy, super-single tires have gradually been replacing conventional dual tires in the trucking industry. According to recent studies, super-single tires generate much higher vertical contact stresses than do conventional dual tires, resulting in larger deformations and more severe damage to the subgrade. In order to better assess the higher stresses generated by super-single tires and their effect on the subgrade, analyses are done taking into account soil plasticity rather than simple elastic analysis. In this study, the effects of super-single tires on subgrades for typical road cross-sections are investigated using plane-strain (2D) and 3D static …

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Fatigue Behavior Of Beam Diaphragm Connections With Intermittent Fillet Welds, Part I, Volume 1, Field Evaluation, Tammy L. Canna, Mark D. Bowman Jan 2002

Fatigue Behavior Of Beam Diaphragm Connections With Intermittent Fillet Welds, Part I, Volume 1, Field Evaluation, Tammy L. Canna, Mark D. Bowman

JTRP Technical Reports

This report is the first of a two-part, three volume final report presenting the findings of the research work that was undertaken to evaluate the behavior of Indiana highway bridges with diaphragm members welded directly to the web of the primary beams and girders. Fatigue cracks have been observed at several bridges that utilize the welded diaphragm connection. The seriousness of the cracking and the corresponding potential risk on the integrity of the bridge superstructure were assessed. Inspection and repair guidelines for bridges with the welded diaphragm connections were also developed as part of the research effort. This volume presents …

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Guidelines For Use And Types Of Retaining Devices, Antonio Bobet Jan 2002

Guidelines For Use And Types Of Retaining Devices, Antonio Bobet

JTRP Technical Reports

A large number of types of retaining devices are currently available but their limitations, recommendations and guidelines are scattered in the technical literature. A synthesis study has been made in which different technologies have been investigated to develop guidelines for the use of the different types of retaining devices. For this purpose, an extensive literature review has been performed and a new classification has been proposed. An electronic database with 207 selected cases from the technical literature and INDOT archives has been created. The database stores the following information: (1) Type of Retaining Device; (2) Geometry (3) Soil conditions; (4) …

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Improving Efficiency Of Indot Traffic Data Collection Using Gps Devices, Shuo Li, Karen Zhu, Boudewijn H. W. Van Gelder, John Nagle, Carl Tuttle Jan 2002

Improving Efficiency Of Indot Traffic Data Collection Using Gps Devices, Shuo Li, Karen Zhu, Boudewijn H. W. Van Gelder, John Nagle, Carl Tuttle

JTRP Technical Reports

INDOT has utilized many new technologies to reduce travel delay, mitigate traffic congestion, and enhance public and employees’ safety. Many projects are underway, including re-timing of most existing traffic signals and pavement maintenance and rehabilitation. To evaluate signal system performance, prioritize alternatives of improvement, conduct before and after studies and investigate work zone safety, it requires a large amount of traffic data such as travel time, speed and delay. Issues, such as safety, efficiency and cost, may arise associated with the current methods. For the current manual or automatic data collection, it usually requires two operators, a driver and a …

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Internet-Supported Evaluation Of Highway Safety, Andrzej P. Tarko, Brian Desalle Jan 2002

Internet-Supported Evaluation Of Highway Safety, Andrzej P. Tarko, Brian Desalle

JTRP Technical Reports

Few current methods of identifying hazardous locations take into account the perspective of highway users. It is generally accepted by human factor experts that user feedback can provide valuable insight into safety at highway locations that is not obtainable through the use of crash data. However, little research has been conducted in the highway transportation area, and the relationship between user perception and actual safety at a location is not well known. Currently, motorist feedback in Indiana is gathered by individual highway agencies through the use of a phone and mail collection process. A centralized feedback collection would not only …

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Mid-Panel Cracking Of Portland Cement Concrete Pavements In Indiana, Hung-Ming Chen, Yunus Dere, Elisa D. Sotelino, Graham C. Archer Jan 2002

Mid-Panel Cracking Of Portland Cement Concrete Pavements In Indiana, Hung-Ming Chen, Yunus Dere, Elisa D. Sotelino, Graham C. Archer

JTRP Technical Reports

Portland cement concrete slabs are a common form of highway pavements in Indiana. As a result of their widespread use, the economic impact of their maintenance and life span is therefore tremendous. In Indiana, these types of pavements have been experiencing premature random transverse mid-panel cracking. This phenomenon has been observed under a variety of environmental and traffic conditions. Also, it has been found that the cracking occurs in conjunction with the opening of the lanes to traffic, within months of construction. In this project, a research synthesis was carried out to determine exactly what the current state of knowledge …

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Load Tests On Pipe Piles For Development Of Cpt-Based Design Method, Kwangkyum Kim, Rodrigo Salgado, Junhwan Lee, Kyuho Paik Jan 2002

Load Tests On Pipe Piles For Development Of Cpt-Based Design Method, Kwangkyum Kim, Rodrigo Salgado, Junhwan Lee, Kyuho Paik

JTRP Technical Reports

This research focused on the drivability and load-carrying capacity of both open and closed-ended steel pipe piles. Two pipe piles (one open-ended, the other closed-ended) were installed in a sandy soil to the same depth. The site was extensively characterized. SPT and CPT tests were performed both before and after pile installation. A variety of soil indices and shear strength parameters (such as the constant-volume friction angle) were measured in the laboratory. The piles were fully instrumented, permitting separate measurement of shaft and base capacity for the closed-ended pile and shaft, annulus and soil plug capacities for the open-ended pile. …

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Performance-Related Specifications For Concrete Bridge Superstructures, Volume 4: Bond Of Epoxy-Coated Bars With Thicker Coatings, J. A. Ramirez, Michael K. Appelhans Jan 2002

Performance-Related Specifications For Concrete Bridge Superstructures, Volume 4: Bond Of Epoxy-Coated Bars With Thicker Coatings, J. A. Ramirez, Michael K. Appelhans

JTRP Technical Reports

In Volume 4 of the final report, the results of an evaluation of the bond performance of epoxy-coated bars with a coating thickness up to 18 mils are presented. The experimental work on the bond performance of epoxy-coated bars with thickness up to 18 mils indicates that the current AASHTO requirements for development length of epoxy-coated bars up to #8 could be safely extended to coating thickness of up to 18 mils. Thus, no change to the bond specifications is recommended in order to implement the use of bars with diameters up to a #8 with epoxy-coating thickness up to …

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