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DTRT12-G-UTC16, Collisions between over height vehicles and bridges occur about 1,000 times per year in the United States. Collision damage to, bridges can range from minor to catastrophic, potentially requiring repair or replacement of a bridge beam. For prestressed concrete, beams, the traditional repair methods are strand splices and Fiber-Reinforced Polymer (FRP) wraps. A new material, Fabric, Reinforced Cementitious Matrix (FRCM), has been developed as an alternative to traditional FRP wrap., The first objective of this project was to damage, repair and test four beams retrieved during the demolition of the overpass of, Arcadia Road over Interstate 81 at Arcadia, VA. The repair techniques evaluated were strand splices, FRP, FRCM and a, combination of FRCM and strand splices. The beams were tested in the lab in simple span configuration with the repair location, placed in a region of constant moment. Loads were applied monotonically to failure. One beam was tested in an undamaged, condition as a control., Several methods were used to calculate strength and behavior. Simple methods from AASHTO and ACI were used for hand, calculations of flexural strength. Conventional strain compatibility was also used. Non-linear beam models and non-linear three, dimensional finite element models were also investigated as tools to evaluate repaired beams. Material characterization was, performed on the concrete, prestressing steel, splice chucks, FRP and FRCM. The material characterization was used to develop the, material models for the analyses., It was found that the greatest percentage of original strength was returned by the FRP repair and the repair with the combination of, FRCM and splice chucks. The lowest percent was returned with only splice chucks when eight of 48 strands were severed and, spliced. The FRCM proved to be a viable repair technique, but should be tested in fatigue before deployment on a bridge with high, truck traffic. The analysis methods were shown to provide good estimates of strength and load-deflection behavior.

87584, Studies show that the proper design of clearance intervals has significant implications for intersection safety. For, example, in 2001, approximately 218,000 red-light-running crashes occurred at signalized intersections in the United States., These crashes resulted in nearly 181,000 injuries and 880 fatalities and an economic loss of $14 billion. Driver behavior while, the driver is approaching high-speed signalized intersections at the onset of a yellow indication varies as a function of many, parameters. Some of these parameters are related to the driver’s attributes, e.g., age, gender, perception-reaction time, and, acceptable deceleration levels. Other parameters that relate to the intersection geometry include the approach speed, distance, and, time to the intersection at the onset of the yellow indication., This study developed a novice approach for computing the clearance interval duration that explicitly accounts for the, reliability of the design (probability that drivers are not caught in a dilemma zone). Lookup tables based on the limited data, available from this study are provided to illustrate how the framework could be used in the design of yellow timings. The, approach was developed using data gathered along Virginia’s Smart Road test facility for dry and clear weather conditions for, two approach speeds: 72.4 km/h (45 mph) and 88.5 km/h (55 mph). Each dataset includes a complete tracking of the vehicle, every deci-second within 150 m (500 ft) before and after the intersection. A total of 3,454 stop-run records were gathered. These, include 1,727 records (687 running records and 1,040 stopping records) for an approach speed of 45 mph and 1,727 records (625, running records and 1,102 stopping records) for an approach speed of 55 mph. Using these data, models that characterize driver, perception-reaction times and deceleration levels were developed., The application of the proposed approach demonstrates that the current design procedures are consistent with a, reliability level of 98%.

92733, Highway agencies continuously strive to expedite pavement construction and repairs and to evaluate materials and, methods to provide long-lasting pavements. As part of this effort, agencies have used precast concrete slabs for more than 10, years with successive improvements in processes and systems., The Virginia Department of Transportation recently used two precast systems along with conventional cast-in-place, repairs on a section of jointed reinforced concrete pavement on I-66 near Washington, D.C. One precast system, precast concrete, pavement (PCP), used doweled joints. The other precast system, prestressed precast concrete pavement (PPCP), used, transversely prestressed slabs post-tensioned in the longitudinal direction., Both precast systems are performing satisfactorily after 1.5 years of traffic, and the contractor was satisfied with the, constructability. In multiple locations, transverse expansion joints in PPCP were observed to be wider than the ½-in width, specified; excessively wide joints often compromise joint sealant performance, and erosion from water flowing through such, joints may result in eventual loss of support over time. There were a few cracks in the PPCP section, originating mainly from, grouting holes, cracks in the block-out patches, cracks and loss of epoxy at lifting hook holes, and corner breaks. There were, some mid-slab cracks in the PCP slabs immediately after opening to traffic, but they are still tight and stable after 1.5 years of, traffic., Even though the precast slabs initially cost more than the cast-in-place repairs to construct, the ability to construct the, pavement within a short period of lane closure per day and the probability of improved quality control of plant-cast concrete, warrant their use. Since this was the first application in Virginia, certain issues occurred and most were overcome, such as, matching of slabs and grout leakage. The project was successfully completed and further implementation is recommended.

Concrete bridge decks are susceptible to premature cracking and to corrosion of reinforcing steel. Low-permeability concrete does not always ensure durability if the concrete has excessive cracks that facilitate the intrusion of aggressive solutions. Cracks in concrete can occur when a restrained mass of concrete changes volume including drying shrinkage because of water loss. These types of shrinkage cracks can be counteracted with the use of shrinkage-compensating concrete (SC concrete). SC concrete is expansive cement concrete that when properly restrained by reinforcement can expand an amount equal to or slightly greater than the anticipated drying shrinkage., The purpose of this study was to investigate the effectiveness of SC concrete using Type K expansive cement in reducing cracks in bridge decks. The bridge deck on the Route 613 Bridge over the South Fork Shenandoah River in Warren County in the Virginia Department of Transportation’s Staunton District was selected for study. Restrained length change bar specimens showed expansion until the 7-day moist curing period (when tested in accordance with ASTM C878)., The results showed that a bridge deck with fewer transverse cracks than typically found in decks constructed with Type I/II cement can be constructed with Type K cement concrete. There were several longitudinal cracks (reflective cracks) caused by the differential movement of the beams at the keyway that could not be prevented by the use of SC concrete. No special construction equipment or techniques are required for satisfactory placement of SC concrete, but slump loss under hot weather conditions is a more serious problem in SC concrete than in normal portland cement concrete. Hence, for successful placement of Type K cement concrete, sufficient prior planning and proper mix design development are needed. Another concern is the availability and cost of Type K cement since it is not routinely used.

project no. RC00047, "The Federal Highway Administration has been encouraging states to improve their monitoring and tracking of the, mobility impacts of work zones. The use of mobility performance measures will enable agencies to assess better the, contribution of work zones to network congestion; to identify specific projects that are in need of remedial action; and, potentially to assess penalties to contractors creating excessive, avoidable negative impacts. Although the Virginia Department, of Transportation (VDOT) has defined allowable lane closure hours for the interstate system, VDOT has not defined specific, performance measures and thresholds for what constitutes “unacceptable” work zone mobility impacts. Performance measures, and thresholds have been developed by a number of other states, so there is a need to determine whether these could be adapted, for use by VDOT., This study explored issues related to a potential work zone mobility performance measurement program for Virginia., The issues investigated included identification of potential performance measures, definition of performance thresholds, and, recommendations for data sources for performance measurement calculations. This information was synthesized from, information regarding the experiences of selected states and experiences from a series of case studies that used data from, Virginia work zones. The review of experiences in selected other states found that delay and queue length were the performance, measures used most often by the states studied. The Virginia case studies focused on the use of private sector data to generate, mobility performance measures and found that the level of spatial aggregation in rural areas could inhibit the ability to generate, accurate performance measures, although granularity was better on urban roads. The level of temporal aggregation was also, found to influence performance measures., The research identified a number of key issues that VDOT should consider as a work zone mobility performance, measures program is developed. The report recommends that VDOT develop a pilot program that focuses on urban interstates, initially and convene a task group to develop formal policies and procedures for use in the state."

101477, The purpose of this study was to develop, demonstrate, and document laboratory procedures that could be used by the, Virginia Department of Transportation (VDOT) to evaluate non-tracking tack coat materials. The procedures would be used to, qualify candidate material formulations for field validation., The procedures were developed and were demonstrated through an evaluation of five “trackless” tacking materials and, two conventional tacking materials. The evaluation demonstrated that the trackless materials outperformed the conventional, materials in the laboratory tracking test and in the bond performance tests for tensile and shear strength., The study recommends that VDOT formalize the described laboratory procedures to produce a Virginia Test Method to, qualify candidate non-tracking tack coat materials for field verification. It further recommends that VDOT formalize the field, verification system and includes general direction on the elements to include in that process., This work is part of a program of research designed to support a move to performance-oriented specifications for the, interlayer bond for pavement construction. The non-tracking tack coat materials investigated in this study are expected to, facilitate the improved performance of this bond and, as a consequence, the pavement system as a whole. This work supports an, anticipated incremental improvement to an annual asphalt concrete program that is worth between $200 million and $400, million per year (not including new construction). When applied to investments on this scale, even nominal improvements, easily translate into considerable savings.

91336, The purpose of this study was to conduct a field evaluation of a highly skewed semi-integral bridge in order to provide, feedback regarding some of the assumptions behind the design guidelines developed by the Virginia Department of, Transportation. The project was focused on the long-term monitoring of a bridge on Route 18 over the Blue Spring Run in, Alleghany County, Virginia., The 110-ft-long, one-span bridge was constructed at a 45° skew and with no approach slabs. It incorporated an, elasticized expanded polystyrene material at the back of the integral backwall. Bridge data reflecting thermally induced, displacements, loads, earth pressures, and pile strains were acquired at hourly intervals over a period of approximately 5 years., Approach elevations were also monitored. Analysis of data was used to formulate design recommendations for integral bridges, in Virginia., Field results indicated that semi-integral bridges can perform satisfactorily at a 45° skew provided some design details, are modified. The relatively high skew angle resulted in a pronounced tendency of the semi-integral superstructure to rotate in, the horizontal plane. This rotation can generate higher than anticipated horizontal earth pressure acting on the abutment, wingwall. Study recommendations include modifying the structural detail of the backwall-wingwall interface to mitigate crack, formation and placing the load buttress close to the acute corner of a highly skewed abutment to reduce the abutment horizontal, rotation., The use of elastic inclusion at the back of the semi-integral backwall resulted in the reduction of earth pressures and, negligible approach settlements. The study recommendations include proposed horizontal earth pressure coefficients for design, and a revised approach to calculating the required thickness of the elastic inclusion., While recommending that the existing VDOT guidelines allow an increase in the allowable skew angle from 30° to 45°, for semi-integral bridges, the study also proposes a field investigation of the maximum skew angle for fully integral bridges, because of the inherently low stiffness associated with a single row of foundation piles., The study indicates that current VDOT guidelines can be relaxed to allow design of a wider range of jointless bridges., The implementation of integral design has been shown to reduce bridge lifetime costs because of the elimination of deck joints, which often create numerous maintenance problems.

93111, This project encompassed a research effort to establish the durability of pavement markings in an on-road installation. Six, marking technologies were installed on a portion of Route 460 in Blacksburg, Virginia. A human factors experiment in natural, rain conditions was performed to establish the visibility needs of the driver. The retroreflectivity of the markings was measured, at intervals of 2 to 5 months, with six measurements over the course of 23 months. The numbers of snow plow crossings and, chemical treatments were also measured., Although all markings lost a considerable amount of retroreflectivity after the first winter, the markings installed in, grooves or in rumble strips were shown to retain more retroreflectivity and receive less damage than markings installed on the, surface of the roadway. Twenty-three months after installation, the retroreflectivity for all markings in active rain conditions, had dropped below the 150 mcd/m2/lx minimum recommended from previous research. The reflective tape was the closest to, maintaining the minimum with a mean retroreflectivity of 137mcd/m2/lx in 1 in/hr rain. Several other markings maintained a, retroreflectivity above 84 mcd/m2/lx; this may still provide a benefit over standard paint., The study recommends that VDOT’s Traffic Engineering Division install pavement markings in grooves or in rumble, strips. VDOT will determine where the use of grooves or rumble strips is appropriate. Because pavement marking visibility is, more critical for high-speed roadways such as interstate roadways and major arterials, these roads should be the highest priority., Grooved markings may also be desired for high-volume roadways where markings may be exposed to higher levels of wear, from traffic. The study markings on Route 460 in Blacksburg should be monitored for two more years. The study team should, make the measurements after each winter through 2013 and report the findings to VDOT in a brief report. VDOT staff should, perform additional cost-benefit analyses to address standard VDOT policy, procedures, and practices and possible supplier, warranties