Natural Bridge, Virginia: Complementary Geotechnical Investigation and Analysis Methods for Mobility Planning

2020 ◽  
Vol 26 (2) ◽  
pp. 141-148
Author(s):  
Brian S. Bruckno ◽  
Chester F. Watts ◽  
George Stephenson ◽  
Christopher Mau
Keyword(s):  
Cultural Resources ◽  
Department Of Transportation ◽  
Geotechnical Investigation ◽  
Non Invasive ◽  
Transportation Corridor ◽  
Historic Landmark ◽  
Potential Risks ◽  
Potential Damage ◽  
Virginia Department ◽  
Privately Owned

ABSTRACT Natural Bridge, in Rockbridge County, Virginia, is a geological arch carrying U.S. Route 11 over Cedar Creek. The area has significant historical and cultural importance; it is listed on the National Register of Historic Places and is a Virginia Historic Landmark. Until 2015, the arch and area below were privately owned and operated, with only the pavement structure of U.S. Route 11 held by the Virginia Department of Transportation. Since then, the arch and area below have been leased to the Virginia Department of Conservation and Recreation, potentially transferring liability to the Commonwealth. As part of the Commonwealth's due diligence and to help ensure that the arch is preserved for future generations, the Department of Transportation, in partnership with Radford University, completed a comprehensive, non-invasive geological and geotechnical investigation in 2017 and 2018. A complementary variety of geophysical, laser, optical, seismic, and traditional geological methods of study were used to allow for integrated data analysis. The investigation revealed potential risks to the integrity of the arch, which may eventually reduce its suitability for use as a transportation corridor. The investigation methodology allowed planning for protection of the environment, cultural resources, and local economies while avoiding any potential damage to the arch. As of the date of this article, plans are under way to relocate U.S. Route 11 onto an alternate alignment entirely, thereby helping to preserve this valuable cultural, historical, and geological asset.

Bridge Substructure Repairs with Self-Consolidating Concrete and Galvanic Anodes

2018 ◽  
Vol 2672 (27) ◽  
pp. 56-64
Author(s):  
H. Celik Ozyildirim ◽  
Stephen R. Sharp
Keyword(s):  
Chloride Content ◽  
Visual Observation ◽  
Department Of Transportation ◽  
Corrosion Activity ◽  
Self Consolidating Concrete ◽  
Reinforced Concrete Bridge ◽  
Form Pressure ◽  
Virginia Department ◽  
Narrow Area ◽  
Chloride Contaminated

Historically, the Virginia Department of Transportation (VDOT) has repaired chloride-contaminated reinforced concrete bridge substructure elements that contain vertical and overhead sections with either shotcrete or a conventional A3 (3,000 psi) or A4 (4,000 psi) concrete. This study investigated using self-consolidating concrete (SCC), which has a high flow rate, bonds well, has low permeability, and provides smooth surfaces, as another option. The study also explored the use of galvanic anodes to control corrosion activity in SCC repairs. In VDOT’s Lynchburg and Staunton Districts, SCC repairs were made with and without the use of galvanic anodes. This provided a means for determining the benefit of using the anodes. The needed repair areas were determined by visual observation and sounding. After 7 years of service, SCC repair areas with and without anodes did not exhibit corrosion activity; small vertical cracks were evident in the SCC but did not affect performance. The anodes can provide protection to the steel immediately adjacent to the repair areas. However, unrepaired concrete areas away from the patched area with anodes now require additional repairs. SCC can be successfully placed; however, attention should be paid to form pressure and slump loss. Selection of repair areas should be based on corrosion-related measurements such as half-cell or chloride content, rather than sounding. Progression of corrosion demonstrates the necessity of removing all chloride-contaminated concrete not just adjacent to, but also away from the reinforcement, as anodes in the repair area will provide protection only in a narrow area around the patch.

Performance of Virginia’s Early Foamed Warm Mix Asphalt Mixtures

2018 ◽  
Vol 2672 (28) ◽  
pp. 178-189 ◽  
Author(s):  
Stacey D. Diefenderfer
Keyword(s):  
Dynamic Modulus ◽  
Permanent Deformation ◽  
Warm Mix Asphalt ◽  
Department Of Transportation ◽  
High Dynamic ◽  
Repeated Load ◽  
And Performance ◽  
Virginia Department ◽  
Performance Grading ◽  
Air Void

The Virginia Department of Transportation began allowing the use of warm mix asphalt (WMA) in 2008. Although several WMA technologies were investigated prior to implementation, foamed WMA was not. This study evaluated the properties and performance of foamed WMA placed during the initial implementation of the technology to determine whether the technology had performed as expected. Six mixtures produced using plant foaming technologies and placed between 2008 and 2010 were identified and subjected to field coring and laboratory testing. Coring was performed in 2014, resulting in pavement ages from 4 to 6 years. Three comparable hot mix asphalt (HMA) mixtures were cored at 5 years for comparison. Cores were evaluated for air-void contents and permeability and were subjected to dynamic modulus, repeated load permanent deformation, and overlay testing. In addition, binder was extracted and recovered for performance grading. Similar properties were found for the WMA and HMA mixtures. One WMA mixture had high dynamic modulus and binder stiffness, but overlay testing did not indicate any tendency for premature cracking. All binders had aged between two and three performance grades above that specified at construction. WMA binders and one HMA binder aged two grades higher, and the remaining two HMA binders aged three grades higher, indicating a likely influence on aging of the reduced temperatures at which the early foamed mixtures were typically produced. Overall results indicated that foamed WMA and HMA mixtures should be expected to perform similarly.

Measuring Smoothness of Virginia’s Asphalt Overlays

2000 ◽  
Vol 1712 (1) ◽  
pp. 86-92
Author(s):  
Kevin K. McGhee
Keyword(s):  
South Dakota ◽  
Asphalt Pavement ◽  
Critical Assessment ◽  
Department Of Transportation ◽  
International Roughness Index ◽  
Roughness Index ◽  
Virginia Department ◽  
Asphalt Overlays ◽  
Special Provision

In the summer of 1996 the Virginia Department of Transportation (VDOT) initiated the pilot of a new special provision regarding the smoothness of asphalt pavement surfaces. This special provision is based on the international roughness index (IRI) and is administered with a laser-equipped South Dakota–style inertial road profiler. A critical assessment of the nontraditional equipment and methods used to administer the special provision is provided. Issues addressed in the critique include provision exemptions, the ability to identify and contend with construction variability, and peculiarities of the equipment that affect the ability of VDOT to administer a modern acceptance provision.

Initial Approach to Performance (Balanced) Mix Design: The Virginia Experience

2019 ◽  
Vol 2673 (2) ◽  
pp. 335-345 ◽  
Author(s):  
Stacey D. Diefenderfer ◽  
Benjamin F. Bowers
Keyword(s):  
Performance Testing ◽  
Performance Criteria ◽  
Mix Design ◽  
Department Of Transportation ◽  
Innovative Methods ◽  
Asphalt Mix ◽  
Performance Additives ◽  
Virginia Department ◽  
Selection Of

Performance mix design (PMD) of asphalt mixtures, often referred to as balanced mix design, is a design methodology that incorporates performance testing into the mix design process. The Virginia Department of Transportation (DOT), like many owner agencies, is interested in ways to specify asphalt mix designs better in an effort to make its roadway network more sustainable, longer lasting, and more economical. By adding performance criteria through a PMD framework, that goal can be achieved. Further, a PMD framework should allow for the development of new, innovative methods to increase pavement recyclability, new performance additives, and other means to enhance pavement performance. This paper provides details and documentation of the approach being taken by the Virginia DOT in their efforts to develop a PMD specification. Aspects of development presented include PMD method options, selection of performance tests, and determination of acceptance criteria. A discussion about validating specifications with in-service performance data and addressing quality control and quality assurance is also provided. Although additional work is needed for full development and implementation, the methodology being applied has been found to provide useful outcomes for the Virginia DOT even in the initial stages of development.

247 SUCCESSFUL ARTIFICIAL INSEMINATION IN THE CORN SNAKE (ELAPHE GUTATTA), USING FRESH AND COOLED SEMEN

2007 ◽  
Vol 19 (1) ◽  
pp. 240 ◽  
Author(s):  
J. K. Mattson ◽  
A. T. DeVries ◽  
S. M. McGuire ◽  
J. Krebs ◽  
E. E. Louis ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Isoamyl Alcohol ◽  
Invasive Technique ◽  
Non Invasive ◽  
Microcentrifuge Tube ◽  
Tuberculin Syringe ◽  
Potential Damage ◽  
Corn Snake ◽  
Phosphate Buffered Saline ◽  
Parentage Test

The purpose of this investigation was to develop a non-invasive technique to artificially inseminate snakes using the corn snake, Elaphe gutatta, as the model representative for this taxon. Semen was collected by first applying pressure to the lower abdomen in a continuous distal motion toward the cloaca to remove any feces or urates. The cloaca was then gently washed using phosphate-buffered saline, and a more localized pressure was applied to each side of the vent to evert the hemipenes and, subsequently, the ejaculate. The semen was collected using a sterile transfer pipette and placed into 70 to 90 �L of medium (TL-HEPES solution; Cambrex Bio Science, Inc., Baltimore, MD, USA04–616F) in a sterile microcentrifuge tube, and then analyzed for overall motility, rate of forward progression (RFP, 0–5), and concentration. Based on a previously reported procedure, 10 females were inseminated with either fresh (n = 5) or cooled semen (n = 5; refrigerated for 3 days) one week after recovering from a hibernation period required to stimulate reproduction in this species. The overall sperm motility and concentration for females inseminated with fresh or cooled semen was 92%, 9.6 million sperm mL-1; and 85%, 6.1 million sperm mL-1, respectively. Immediately prior to insemination, the same method for expressing feces and urates in the males was applied to the females. The insemination dose (50 �L semen per oviduct) was drawn into a 1-mL latex- and silicone-free tuberculin syringe (Norm-Ject; VWR, Batavia, IL, USA) that was connected to a feeding/dosing needle (EJAY International, Issaquah, WA, USA) with a ball tip to prevent any potential damage during the insemination. The tip of the needle was then moved around the inner tissue of the vent to relax the cloaca, and the insertion continued until resistance was found indicating the vicinity of the oviducts. The extended semen was carefully deposited on both sides, and then the needle was slowly withdrawn. The offspring were tested for parentage to verify the success of the insemination. Blood was collected from the dorsal aorta posterior to the cloaca and stored in 10 mM Tris at 4�C. The DNA was extracted using a phenyl : chloroform : isoamyl alcohol (PCI) extraction method. Eight microsatellite loci were used for the paternity exclusion analysis: Eob�1, Eob�3, Eob�10, Eob�13, Eob�16, Eob�34, Eob�366, and Eob�373 (IDT, Coraville, IA, USA). All males and females in the collection were tested, and parental candidates were excluded if 2 or more allele mismatches occurred. From the total number of females inseminated, 3 females laid 51 eggs. Two females inseminated with cooled semen laid 36 eggs, of which 5 eggs were hatched, and the remaining were either unfertilized (n = 25) or non-viable (n = 6). All 5 hatched eggs were laid by one of the females. The third female inseminated with fresh semen laid 15 eggs, resulting in 5 hatching and 10 unfertilized eggs. The parentage test validated the AI a success as the alleles correlated between the adults and the offspring. In conclusion, artificial insemination was successful using both freshly collected and cooled (3 days) semen. Further studies are underway to improve the success rate in order to maximize the efficiency of this technology, and thus assist in the genetic preservation of endangered snake species.

Effect of Speed, Flow, and Geometric Characteristics on Crash Frequency for Two-Lane Highways

2000 ◽  
Vol 1717 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Nicholas J. Garber ◽  
Angela A. Ehrhart
Keyword(s):  
Department Of Transportation ◽  
Deterministic Models ◽  
Crash Frequency ◽  
Crash Rates ◽  
The Past ◽  
Speed Flow ◽  
Lane Width ◽  
The Mean ◽  
Virginia Department ◽  
Made In

Although during the past several years significant progress has been made in improving safety on U.S. highways, the frequency and severity of crashes continue to be of concern. A better understanding of the factors associated with crashes will facilitate the identification of suitable countermeasures that could further reduce the occurrence of crashes. Results are presented from a study that determines how the characteristics of speed, flow, and geometry affect the crash rates for two-lane highways. Deterministic models that relate the crash rate with the mean speed, standard deviation of speed, flow per lane, lane width, and shoulder width are presented. The multivariate ratio of polynomials method was used to develop the models. Research was limited to two-lane roadways in Virginia with speed limits of 89 km/h (55 mph). The data were obtained from speed-monitoring stations established by the Virginia Department of Transportation and from police accident reports from January 1993 to September 1995.

Asphalt Permeability Testing in Virginia

2000 ◽  
Vol 1723 (1) ◽  
pp. 83-91 ◽  
Author(s):  
G.W. Maupin
Keyword(s):  
Future Development ◽  
Laboratory Tests ◽  
Large Percentage ◽  
Acceptable Level ◽  
Permeability Test ◽  
Department Of Transportation ◽  
Asphalt Mixes ◽  
Air Voids ◽  
Virginia Department ◽  
Made In

Because of high air voids, long-lasting damp spots on pavement surfaces, and problems that other states have had with permeable coarse Superpave mixes, the Virginia Department of Transportation (VDOT) decided to investigate the permeability of its Superpave mixes. As part of this study, VDOT also tested other asphalt mixes. Falling-head permeability tests were performed on pavement cores to determine the general permeability of the mixes. The permeability of some of the pavement cores was compared with the permeability of specimens made in the laboratory through the use of mixtures sampled during construction to determine whether laboratory specimens could be used to predict pavement permeability. The primary purpose of this investigation was to determine the general magnitude of permeability for mixes being used by VDOT, with an emphasis on Superpave mixes. A large percentage of the field cores contained excessive voids, resulting in excessive permeability. Each mix had a unique voids-permeability relationship. Mixes that were composed of large aggregates required fewer voids to achieve an acceptable level of permeability. In four of five cases, the results of laboratory tests were generally quite successful in indicating field permeability. The preliminary permeability testing demonstrates the importance of achieving low voids in the field and will help in the future development of density specifications and possibly in the establishment of permeability requirements. It is recommended that the permeability test continue to be used to help set such limits.

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