Engineering Commons^™

Sloped And Mitered Concrete Headwalls, Kean H. Ashurst Jr., Brad W. Rister, Eileen Grady, Jason K. Ward

Kentucky Transportation Center Research Report

The Kentucky Transportation Cabinet (KYTC) currently uses several pipe culvert end treatments, including standard headwalls, slope and flared headwalls, sloped and parallel headwalls, and safety metal ends. These treatments, however, can pose a safety hazard to motorists and those performing landscaping work (e.g., mowing). Crash statistics from 2012 through 2016 for Kentucky reveal that 49 fatalities and 148 incapacitating injuries occurred in incidents where culverts/headwalls were coded as the first harmful event on the police report. One solution to the safety hazards associated with standard pipe culvert headwalls is to use sloped and mitered concrete headwalls instead. To evaluate the …

Benefits From Constructability Reviews, Nikiforos Stamatiadis, Roy Sturgill, Kiriakos Amiridis

Civil Engineering Faculty Publications

Constructability review is a process used during project design to infuse construction knowledge into the design process. There is industry impetus encouraging early construction involvement in project development. State transportation agencies often have to abide by legislation restricting these procurement methods leaving construability review as the only opportunity for early construction involvement. Staffing and budgetary constraints lead to state transportation agencies being very cautious in the practices and processes they implement that seemingly lie outside the main missions of project development and delivery. Without straightforward and documented savings of constructability review processes, these methods may also be eliminated. After streamlining …

Transition Zone Design Final Report, Nikiforos Stamatiadis, Adam J. Kirk, Andrea Cull, Austin Dahlem

Kentucky Transportation Center Research Report

The purpose of this report is to document the activities of the research effort and present the findings of the work accomplished. Transition zone is the area in which it is communicated to drivers that the roadway environment is changing (i.e., from rural to built-up) and that their speed should change as well. This study evaluated treatments that could advise drivers to this. Based on the study findings, it is recommended to add additional speed warning sites to such transition zones.

Tools For Applying Constructability Concepts To Project Development (Design), Nikiforos Stamatiadis, Paul Goodrum, Emily Shocklee, Roy Sturgill, Chen Wang

Kentucky Transportation Center Research Report

The purpose of this report is to document the activities of Phases I and II of the research effort and present the findings of the work accomplished. Phase I developed the Constructability Review Database for the Kentucky Transportation Cabinet and Phase II conducted a benefit analysis of the constructability review process. The database provides the basis for entry and collection of constructability reviews and allows for the identification of trends leading to potential improvements of the process. The database can be used to summarize activities, generate reports for a project, and be capable of quantifying the benefits from the process. …

Tools For Applying Constructability Concepts To Project Development (Design), Nikiforos Stamatiadis, Paul Goodrum, Emily Shocklee, Chen Wang

Kentucky Transportation Center Research Report

The purpose of this report is to document the activities of Phase I of the research effort and present the development of the Constructability Review Database developed for the Kentucky Transportation Cabinet. The database provides the basis for entry and collection of constructability reviews and allows for the identification of trends leading to potential improvements of the process. The database can be used to summarize activities, generate reports for a project, and be capable of quantifying the benefits from the process.

A Case Study Analysis Of The Kentucky Transportation Cabinet’S Design/Build Pilot Projects, Paul M. Goodrum, Mohammad Moin Uddin, Bradley J. Faulkenberg

Kentucky Transportation Center Research Report

The current economic climate has forced transportation agencies to evaluate opportunities to save money. One possible opportunity lies in Design/Build (DB) delivery. In 2006, with the approval of the Kentucky General Assembly, The Kentucky Transportation Cabinet selected ten projects to be developed through the Design/Build method. DB delivery offers many attainable advantages, the most notable being expedited delivery. The research described herein presents a case study of these DB pilot projects in order to capture lessons learned on the use of the DB delivery method on future projects. In order to determine which projects are suitable for DB delivery, a …

Resilient Modulus Of Compacted Crushed Stone Aggregate Bases, Tommy C. Hopkins, Tony L. Beckham, Charlie Sun

Kentucky Transportation Center Research Report

In recent years, the American Association of State Highway Transportation Officials (AASHTO) has recommended the use of resilient modulus for characterizing highway materials for pavement design. This recommendation evolved as result of a trend in pavement design of using mechanistic models. Although much progress has been made in recent years in developing mathematical, mechanistic pavement design models, results obtained from those models are only as good as the material parameters used in the models. Resilient modulus of aggregate bases is an important parameter in the mechanistic models. The main goal of this study was to establish a simple and efficient …

Bearing Capacity Analysis And Design Of Highway Base Materials Reinforced With Geofabrics, Tommy C. Hopkins, Liecheng Sun, Mikhail E. Slepak

Kentucky Transportation Center Research Report

The primary objective of this study was to develop and implement mathematical bearing capacity models originally proposed by Hopkins (1988, 1991) and Slepak and Hopkins (1993; 1995). These advanced models, which are based on limit equilibrium and are operated together, can be used to analyze the bearing capacity, or stability, of early construction of loads on a single layer of material, two-layered problems involving a layer of base aggregate and subgrade, and a foundation involving multiple layers of different materials, such as a flexible asphalt pavement. A Prandlt-type shear surface is used in the model analyses of layered foundations. In …

Resilient Modulus Of Kentucky Soils, Tommy C. Hopkins, Tony L. Beckham, Charlie Sun, Bixian Ni

Kentucky Transportation Center Research Report

In recent years, the American Association of State Highway Transportation Officials (AASHTO) has recommended the use of resilient modulus for characterizing highway materials for pavement design. This recommendation evolved as of a result of a trend in pavement design of using mechanistic models, which are based on the theory of elasticity (layered elastic analysis) or linear and non-linear, finite elements (and finite difference methods), or a combination of both of those theoretical approaches. Although much progress has been made in recent years in developing mathematical, mechanistic pavement design models, results obtained from those models are only as good as the …

Pavement Design Guide: A Short Course, Kentucky Transportation Center

Kentucky Transportation Center Research Report

The purpose of this short course is to provide information to the registered engineer (with no previous background in pavement design or pavement technology) on the structural design of pavements. Included in this course is a summary of background information on the materials used in pavement construction and on the history and evolution of pavement design. Included with this course is an updated Design Guide or catalog to be used for designing new pavements in Kentucky. The intent of the guide or catalog is to provide the road\\ a) designer with a simplified, straightforward methodology for developing structural designs of …

Embankment Construction Using Shale, Tommy C. Hopkins, Tony L. Beckham

Kentucky Transportation Center Research Report

Shales have been used extensively in the construction of highway embankments, and other earthen structures, because of the vast amounts of these materials located in many areas of the country and the lack of economical and alternate available materials. Because shales exhibit a wide range of engineering properties and behaviors, many problems have occurred. Numerous shale embankment failures have occurred generally some 1 to 10 years after construction. Settlements of 1 to 3 feet (0.3 - 0.9 m) have been observed in many old embankments and required numerous asphaltic overlays. Shale embankments that settle continuously have been observed to fail …

Subsurface Drainage Of Highway Pavements, David Q. Hunsucker, Bobby W. Meade

Kentucky Transportation Center Research Report

Properly designed and constructed drainage layers can be used for effective control of surface water infiltration. Former pavement design methods often have resulted in base courses that have not drained well, thereby resulting in some premature failures of the pavement structure. The Kentucky Department of Highways is currently reviewing proposed guidelines for design of highway pavements. The guidelines propose the use of open graded, free draining, aggregate bases for controlling infiltrated surface water. However, interim design guidelines do not specifically address the design of aggregate drainage blankets. The purpose of this study was to develop recommendations relating to the specification, …

Cost Estimating And Forecasting For Highway Work In Kentucky [1996], James D. Stevens, Jennifer R. Walton

Kentucky Transportation Center Research Report

There is a need for better cost estimating and forecasting for highway work in the Commonwealth of Kentucky. KRS45.245 grants the Interim Joint Committee on Transportation oversight of the biennial highway plan, including a review of all authorized highway project phases that exceed their estimates by 15%. In recent years, the Kentucky Transportation Cabinet has suffered the loss of many resources necessary to produce good cost estimates.

Estimates developed using current methods are not sufficiently accurate to preclude cost overruns in excess of 15%. Over the 1992 and 1994 bienniums, 362 overruns totaling $162,487,511 have been submitted to the Committee. …

Best Practices For Commercial Vehicle Monitoring Facilities Design, Nikiforos Stamatiadis, R. Clark Graves, John E. Schmidt

Kentucky Transportation Center Research Report

The great technological advances that were made over the last decade in monitoring traffic and the increased emphasis on highway safety for truck traffic have prompted a need to determine more effective ways to monitor and inspect truck traffic. Commercial Vehicle Monitoring (CVM) facilities provide the highway community with the means of supervising truck traffic. However, in an era with limited funds and space for roadway expansion. some consideration must be given to the types of facilities needed and the most efficient way to spend the available funds. Hence, a research study was initiated to determine the successful practices for …

Modification Of Highway Soil Subgrades, Tommy C. Hopkins, Tony L. Beckham, David Q. Hunsucker

Kentucky Transportation Center Research Report

Major study objectives were to develop highway pavement subgrade stabilization guidelines, examine long-term benefits of chemical stabilizers, such as cement, hydrated lime, and two byproducts from industrial processes, and to establish a subgrade stabilization program in Kentucky. In developing a program, a number of design and construction issues had to be resolved. Factors affecting subgrade behavior are examined. Changes in moisture content and CBR strengths of untreated and chemically treated subgrades at three experimental highway routes were monitored over a 7- year period. CBR strengths of the untreated subgrades decreased dramatically while moisture contents increased. CBR strengths of subgrade sections …

Selection Of Design Strengths Of Untreated Soil Subgrades And Subgrades Treated With Cement And Hydrated Lime, David Q. Hunsucker, Tony L. Beckham

Kentucky Transportation Center Research Report

Selection of design strengths of soil subgrades and subgrades treated with cement or hydrated lime is a problem in pavement design analysis and construction because a variety of different types of soils may exist in a highway corridor and a wide range of different strengths may exist after the soils are compacted to form the pavement subgrade. The selected subgrade strength will largely affect the pavement thickness obtained from the design analysis, the future pavement performances, and the overall bearing capacities of the subgrade during construction and the pavement structure after construction. In developing the proposed selection scheme, a newly …

Bearing Capacity Analysis Of Pavements, Tommy C. Hopkins

Kentucky Transportation Center Research Report

A multilayered, mathematical model for analyzing the ultimate bearing capacity of soil subgrades and asphalt pavements is presented. Theoretical considerations and mathematical derivations of limit equilibrium equations, based on plasticity principles, for analyzing the ultimate bearing capacity of soil subgrades and partially completed asphalt pavements, and the extension of these equations to the analyses of asphalt pavements composed of multiple layers, are presented. The model is unique since shear strength parameters, Φ and c, (the angle of internal friction and cohesion, respectively) are used to describe each layer of material of the pavement structure and a factor of safety against …

Excessive Beam Deflections On The Ky-52 Bridge Over Dix River (Boyle-Garrard County Line), Theodore Hopwood Ii, Vishwas G. Oka, David Q. Hunsucker, James H. Havens

Kentucky Transportation Center Research Report

Upon rehabilitation, beams and deck of the Ky 52 bridge over Dix River were observed to have excessive deflections. An investigation of the problem included field inspections, structural analyses, and interviews with relevant KYDOH and other personnel.

Field measurements were made of the beam deflections. Those were compared to construction field measurements and dead-load calculations.

The beam deflection problem is attributed to 1) a failure to provide for sufficient camber in the beams to accommodate for construction dead loads, and 2) pre-existing sags in the beams when placed prior to casting the deck. Part of the deck deflection problem can …

Design Of Highway Embankment On Unstable Natural Slopes, Charles S. Bishop, Donald W. Armour Jr., Tommy C. Hopkins

Kentucky Transportation Center Research Report

Sections of the new Alexandria-Ashland (M) highway in northeastern Kentucky must be located on and through natural slopes of the Kope and Crab Orchard Formations that consist mainly of shales. Numerous highway embankment and cut slope failures have occurred In these two geologic formations In past years. The shales of these formations have very poor and undesirable engineering properties. Many stability problems encountered with the Kope and Crab Orchard shales are caused primarily by the tendency of those shales to breakdown when exposed to water and produce clays and clayey silts of relatively low shear strengths. Construction of highway embankments …

Stability Of Embankments On Clay Foundations, Tommy C. Hopkins

Kentucky Transportation Center Research Report

Ninety-one well-documented geotechnical failures are reviewed. The case studies involved the failure of embankments, footings and load tests, excavated slopes, and natural slopes. Seventy-five of the geotechnical failures had been analyzed using total stress analysis. Sixteen of the case failures had been analyzed using effective stress analysis. Based on a review of these case studies, there are discrepancies between predicted and actual stabilities of geotechnical structures and there is a tendency tu overestimate the factor of safety. Differences that may arise between predicted and actual performances are discussed and examined and guidelines are proposed for evaluating the potential of successfully …

Long-Term Movements Of Highway Bridge Approach Embankments And Pavements, Tommy C. Hopkins

Kentucky Transportation Center Research Report

Long-term movements of highway bridge approach embankments and pavements are described and factors that may lead to settlement of highway bridge approach pavements are discussed. Six case histories are presented. The bridge approach sites were observed at different times during the period 1966 to 1985. At four sites, lateral movements, measured from slope inclinometers, of the approach embankments were monitored over time periods ranging from 8 to 14 years. Settlements of the highway bridge approaches were monitored some three to four years after paving. Estimated and observed settlements of the foundations at the study sites were obtained for a length …

Unstable Subgrade, I 65, Hardin County (I 65 - 5 (17) 92; Fsp 047-0065-091-0396), Tommy C. Hopkins, Gary W. Sharpe

Kentucky Transportation Center Research Report

During construction of the southbound lanes of I 65, Stations 120+00 to 218+00, in Hardin County, Kentucky, near Elizabethtown, large deformations were observed when dense-graded aggregate (DGA) base courses were loaded with construction traffic. Rutting and cracking of the DGA also was noticeable. A study was performed to determine the causes of the unstable subgrade and base, recommend remedial actions, and evaluate the effectiveness of the remedial measures. The stability, or bearing capacity, of the unstable pavement was determined for different construction stages and combinations of pavement layer thicknesses using a relatively new stability model HOPK-I. The stability of the …

Pavement Management In Kentucky, Gary W. Sharpe, Robert C. Deen, Herbert F. Southgate, Rolands L. Rizenbergs, James L. Burchett

Kentucky Transportation Center Research Report

The principal objective of this paper is to summarize current pavement management activities in Kentucky. Early pavement management activities generally were decentralized (involving a number of transportation functions such as planning, design, construction, maintenance, and research) and involved long-term monitoring for skid resistance and ride quality (roughness).

Current pavement management activities may be categorized by evaluation, project selection, and development of recommendations for pavement rehabilitation strategies. Pavement evaluation activities at the statewide system level typically involve assessments of ride quality (ridesbility index) and estimated pavement serviceability, skid resistance, visual condition ratings, and the accumulation of traffic volumes and pavement fatigue. …

A Review And Analysis Of Pile Design, David L. Allen

Kentucky Transportation Center Research Report

A review of lateral load design of piles is presented. It appears many different methods and allowable lateral loads are permitted by the states. One particular method is discussed in detail, and from that method two charts are presented that relate pile deflection to lateral load. Recommendations are given on design criteria for lateral loads.

A review of allowable axial stresses is also presented. The results of a brief finite element analysis of pile tip settlement versus load for various conditions are also presented. These results are compared to data obtained from the literature. Recommendations on maximum allowable axial stress …

Thickness Design Curves For Portland Cement Concrete Pavements, Herbert F. Southgate, Robert C. Deen

Kentucky Transportation Center Research Report

Past experience indicates that thickness designs using portland cement concrete best agree with criterion used in the Portland Cement Association's design method for 18-kip EAL of 2 to 3 million or less. For EALs greater than 2 to 3 million, past experience best agrees with criterion developed from the AASHO Road Test. Research herein indicates the two criterion become asymptotic to each other at approximately 2.5 million EAL. For a variation in thickness and elastic moduli in portland cement concrete, dense-graded aggregate, and sub grade elastic modulus, research indicates that a general conic equation (included herein) very closely duplicates the …

Highway Sizing, Joseph D. Crabtree, John A. Deacon

Kentucky Transportation Center Research Report

A critical examination is made of the conventional method for highway sizing, that is, determination of lane requirements. Ranked hourly traffic volume distributions, obtained from 1977 Kentucky volume stations are examined to test certain assumptions common to the conventional approach. Several of these distributions have no distinct "knee" and, for those which do, the knee is most frequently found outside the normally anticipated range. Of equal importance, the knee location can be arbitrarily altered simply by changing the number of highest volume hours that are examining.

The fundamental fallacy of the conventional procedure is its focus on a single design …

Overlay Recommendations For I 64: Rowan, Carter, And Boyd Counties, Gary W. Sharpe, Herbert F. Southgate

Kentucky Transportation Center Research Report

A method was developed in 1978 for designing asphaltic concrete overlays for flexible pavements. This procedure utilizes Kentucky's theoretical flexible pavement design curves, estimates of pavement fatigue from traffic data, estimates of subgrade strengths, and estimates of the structural capacity of the existing pavement. Overlay designs were recommended for the asphaltic concrete pavement sections of I 64 in Rowan, Carter, and Boyd Counties. Road Rater deflection data were used to estimate the subgrade strength and the effective worth of the pavement structures. Pavement rutting and roughness were also considered in determining the final overlay thicknesses.

Design System For Asphaltic Concrete Overlays, Herbert F. Southgate, Gary W. Sharpe, Robert C. Deen

Kentucky Transportation Center Research Report

A method of designing asphaltic concrete overlays has been developed from (1) Kentucky's theoretical design curves, (2) an estimate of future traffic and the associated fatigue (five procedures are presented according to types of information available), (3) strength of subgrade on subject project (laboratory CBR tests or results of dynamic in-place tests such as the Road Rater), and (4) present condition of the existing pavement (from dynamic in-place tests, roughness measurements, or present serviceability index). Deterioration has been expressed as reduced or effective thicknesses of new-quality materials producing the same measured dynamic deflections. The total thickness required for the future …

Loads On Box Culverts Under High Embankments: Analysis And Design Considerations, David L. Allen, Rick L. Russ

Kentucky Transportation Center Research Report

Pressure and design analyses of five reinforced concrete box culverts are presented. Three of the culverts were constructed with the imperfect trench. Measured pressures on the culverts are compared to pressures predicted by the theories of Marston, Spangler, and Castes. Also, comparisons are made between measured pressures and calculated design pressures using AASHTO's Standard Specifications for Highway Bridges, 1.2.2(A). It is noted that the imperfect trench is, apparently, effective in reducing pressures on the top slab. The AASHTO design formulas underestimated the pressure on the top slab of the culverts without the imperfect trench.

Effects Of Water On Slope Stability, Tommy C. Hopkins, David L. Allen, Robert C. Deen

Kentucky Transportation Center Research Report

A brief state-of-the-art review of the effects of water on slope stability and the techniques for analysis is presented. The effective stress principle and basic considerations of slope stability, including design factors of safety, are discussed briefly. The derivations and effects of seepage forces and rapid drawdown on effective stress are also presented. Various conditions of external loading produce changes in effective stress. These changes are discussed and limiting conditions which should be analyzed are mentioned.

Limitations of total stress analyses are discussed in detail. It appears that, for soils having a liquidity index of 0.36 or greater (normally consolidated), …