Civil and Environmental Engineering

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[Khaled El-Mokdem]

Evaluation of Oklahoma Department of Transportation (ODOT) Retroreflective Sheeting Policy

Nighttime visibility of traffic signs is usually accomplished through the use of retroreflective sheetings on the sign face. When illuminated by the vehicle's headlamps, signs appear bright in proportion to their ability to reflect the incident illumination back toward the driver. The primary objectives of this research were to evaluate ODOT's policy on use of retroreflective sheeting products and to identify any necessary changes to this policy based on driver visibility needs, durability of sheeting materials, life-cycle cost, and other practical considerations.

Sponsors: Oklahoma Department of Transportation and the Federal Highway Administration
PI: Samir Ahmed
RAs: Fred Myers, Derek Garvin, Ian Cyr, James Rosson, and Sean Kelly

Fatigue Performance of Tubular Connections

Offshore structures are being designed for the Gulf of Mexico and other deep water locations where the drill string between the platform and the ocean floor will see heavy wave forces during severe storms. The connections between segments of casing must be able to withstand these fatigue loads for 40 or more years. Tests are being conducted to develop information about the basic fatigue characteristics of standard American Petroleum Institute (API) connectors as well as modified or premium connectors. Four-point bending tests will be conducted for pipe with outside diameters ranging from 4 1/2 to 11 3/4 inches. In addition to pipe size and style of connector, tests will consider the influence of mean bending stress and stress amplitude.

Sponsor: Shell Offshore, Inc.
PI: John P. Lloyd
RA: Robert Ingram

Quality Assurance of Highway Construction

As part of the ODOT quality initiative, the department has accelerated the use of statistically-based quality assurance specification in their highway construction projects. The objectives of this study are: 1) to determine the relative magnitudes of variation in the measured quality characteristics of asphalt pavements due to materials, sampling, and testing, 2) validate the ODOT's QA specifications, particularly the allowable tolerances and pay factors used for product acceptance, and 3) evaluate the nuclear gauges for asphalt content and roadway density determinations.

Sponsors: Oklahoma Department of Transportation and the Federal Highway Administration
PI: Samir Ahmed
RAs: Angela Williams and Khaled El-Mokadem

Carbon Fiber Reinforced Concrete Mix Design Development

Numerous fibers have been considered to reinforce portland cement mortar and concrete. Although carbon fiber has excellent strength and durability, the high cost of the fiber has restricted research in the area of structural concrete. This project will investigate the techniques required to incorporate fibers into concrete and the resulting influence on material properties. Attention will be given to applications where a high performance concrete containing carbon fibers will permit a reduction or elimination of conventional steel reinforcement.

Sponsor: DuPont
PI: John P. Lloyd
RAs: Khaled El-Mokadem and Jenny Wright

Corrosion Fatigue Strength of Tubular Connection

This study will evaluate the fatigue performance of a 10 3/4 inch tubular connection subjected to axial fatigue while the connector and sacrificial anode are submerged in sea water. A rheostat will be used to maintain the potential of the connector slightly below the desirable level.

Sponsor: Shell Development Company
PI: John P. Lloyd
RA: Orin Johnston

Improving Accuracy of Early Estimates

For any capital investment adventure an early estimate is prepared to enable the business unit to make reliable decisions regarding the economic feasibility to justify pursuing the project. An early estimate is prepared based on limited scope definition and little information regarding the specific parameters that will be needed in the completed facility. The purpose of this research is to provide a methodology to improve the accuracy of early project estimates to allow the business unit to make better decisions. The scope of the research involves identification of estimating indices for projects in the oil and gas industry and to correlate the indices with the accuracy of estimates. A computer model will be developed to identify the accuracy range of an early estimate based on the estimating index. This research will also develop a best practices guide to improve the accuracy of early estimates.

Sponsor: Construction Industry Institute
PI: Garold D. Oberlender
RA: Steven M. Trost

In Situ Volatilization: Evaluation of Volatilization Models

Technologies used for the remediation of hazardous waste sites have recently been developed that rely on the injection of an airstream into the subsurface environment. Depending on the technology utilized, air can be injected into the unsaturated zone (bioventing) or the saturated zone (air sparging). Many mathematical models that simulate these technologies are appropriate for clean-up based on specific conditions (i.e., site geology, contaminant chemicals).

Sponsor: U.S. Army Waterways Experiment Station
PI: John N. Veenstra
RA: Mansour S. Bader

Instrumentation and Evaluation of Bridge Approach Embankments--U.S. 177 Bridges Over Salt Fork River

A problem shared by all state transportation departments involves the "bump at the end of the bridge." Specifically, the problem involves localized settlement of approach embankments whether caused by settlement of the approach embankment itself, settlement of the foundation soils, or a combination of both. The research project involves evaluation of different approach embankment construction procedures. Five of the six approach embankments for the three new bridges on U.S. 177 have been constructed using different procedures. The procedures used include: geotextile reinforced wall, controlled low strength backfill, dynamically compacted granular backfill, flooded and vibrated granular backfill, and a control section using conventional compaction of unclassified borrow. Evaluation of the performance of the different approach embankments will be based on measured stress and deformation values taken from instrumentation installed under and in the backfill materials. Instrumentation used includes total pressure cells in the back of the abutment wall, settlement gages beneath the backfill, inclinometers through the backfill, and piezometers. Surface movement points will be installed following paving to further monitor overall settlement. To date, all approach embankments have been constructed and all instrumentation, except surface movement points, have been installed and are being monitored.

Sponsor: Oklahoma Department of Transportation
PI: Donald R. Snethen
RAs: John M. Benson, Shannon Koeninger, and Shannon Hudson

Automation and Characterization of an Environmental Field Site

This project is part of a large, collaborative effort involving investigators from the University of Oklahoma, Oklahoma State, and Tulsa University. Its primary focus is on the development of the landfill in Norman, Oklahoma into an automated research facility. This will result in the development of a detailed database for this landfill, which has been selected by the United States Geological Survey as a site for its Toxic Substances Hydrology Program. A variety of research projects are associated with this effort, including one in the School of Civil and Environmental Engineering, in which a number of organic landfill contaminants are being investigated for their biodegradability by the anaerobic microorganisms present in the shallow aquifer adjacent to the Norman landfill. A number of important factors are being tested for their effect on toxic substance biotransformation, including different electron acceptors, the presence of other, more readily degradable substances, and the presence of inhibitory metals.

Sponsors: National Science Foundation and Oklahoma Center for the Advancement of Science and Technology (Applied Research)
PIs: Gregory G. Wilber and William W. Clarkson

Quantitative Structure-Activity Relationships for Environmental Contaminants

The goal of this project is to make a significant contribution to the rapidly evolving field of quantitative structure-activity relationships (QSARs). With QSARs, we seek to develop correlations between measurements of a compound's chemical reactivity, biotransformation, or other "environmental behavior", and the structural characteristics of the chemical. With this information, models can be developed which allow predictions of a chemical's environmental fate without the extensive testing currently needed. Specifically, these studies are investigating the anaerobic transformations of two sets of environmental contaminants by two distinct types of reactions. A series of nitrogen-substituted benzene compounds, as well as a series of chlorinated amide-based herbicides, are being investigated. The fate of these compounds is examined under two different conditions: in anaerobic enrichment cultures and in a buffered, sterile anaerobic medium containing bisulfide, a common, reactive constituent in anaerobic environments.

Sponsor: Oklahoma Water Resources Research Institute
PI: Gregory G. Wilber

Edge Distance, Spacing, and Bearing in Bolted Connections

Recently a change was proposed to the specifications for edge distance and spacing in bolted connections. During consideration of the proposed change by the Research Council on Structural Connections, it was determined that the current specifications are based entirely on tests with one-bolt connections. Since most structural connections are fabricated with multiple bolts, it was decided that a series of tests should be conducted with two-bolt connections to evaluate the accuracy of the existing and proposed specifications. The outcome of these tests will directly impact the design procedure for structural bolted connections in the United States.

Sponsors: American Institute of Steel Construction and W&W Steel of Oklahoma City
PI: Farrel Zwerneman
RA: Brian Lewis

Fatigue Assessment of Bridge Members Based on In-Service Stresses

Structural designs are necessarily based on conservative assumptions regarding support conditions, loads, and load distributions. Typically, these same assumptions are used to calculate stresses in existing structures, resulting in calculated stresses higher than the true stresses in the structure. The first objective of this project is to develop a data acquisition system that the Oklahoma Department of Transportation (ODOT) can use to measure the stresses in a functioning highway bridge. The second objective is to develop an analytical procedure allowing ODOT to use the acquired data to more accurately assess the structural status of the bridge. This more accurate assessment will both improve safety and help direct maintenance funds to locations where they are most needed.

Sponsors: Oklahoma Department of Transportation and Federal Highway Administration
PI: Farrel J. Zwerneman
RA: Orin Johnston