Prestressed Concrete Bridge Beams with Microsilica Admixture
Microsilica fume admixture in concrete beams was used in two coastal bridges to reduce chloride permeability. Cylinders were cast from the beam mixture for strength and permeability tests.
The fabricator found no problems with making these beams, except for the reduction in slump. After the beams were cast and cured they were transported from Harrisburg to the Oregon coast.
The construction contractor reported no problems with the placement of the beams related to using microsilica. Although the results of the permeability test by AASHTO T277 were acceptable, they were higher than the silica fume supplier predicted. The producer obtained better results by using a steam cure method before testing the cylinders. The job was still considered a success and silica fume admixture is recommended for future concrete bridge construction.
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Evaluation of the Corridor Safety Improvement Program Phase I
This project is an analysis of Oregon´s Corridor Safety Improvement Programs implemented on Oregon Route 22 and Oregon Route 34. Improvements were made along each corridor in 1993.
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The project used a mail-out survey to determine the level of awareness and perception of safety among drivers due to the improvements made along each safety corridor. The results of the study show that most drivers are aware of the changes that were made to the corridors. In addition, most drivers also agreed that the changes made to the corridors were an improvement in safety. Most devices were said to be effective, but would eventually lose their effectiveness with repeated exposure.
Comparison of Skid Resistance Testing to Stopping Distance Testing
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This report is intended to statistically summarize the results of a side-by-side test of the skid resistance testing trailer utilized by the Oregon Department of Transportation (ODOT), and the stopping distance car utilized by the Oregon State Police (OSP). The ODOT skid trailer is used for testing skid resistance of pavement surfaces. The OSP method is used for collision reconstruction.
Silica Fume Latex Modified Concrete Bridge Deck Overlay - Tualatin River Bridge #1417N
The Oregon Department of Transportation has used either Silica Fume or Latex Modified Concrete (LMC) to lower chloride permeability in bridge deck overlays. On this project a new product combining both silica fume and LMC was used. The overlay was completed in July of 1993. Three years later, only a few cracks had developed. Chloride permeability measurements were low but not as low as the suppliers claimed.
One unexpected result was lower friction numbers on the deck surfacing. At this time it is unclear if the reduced friction was due to the modified cement or the smaller aggregates used in the mix design. ODOT plans further testing to determine the main cause of the reduced friction.
This product was difficult to mix and place and has since been discontinued by the producer.
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Future Transportation Trends and Technology
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This document was prepared as a resource for ODOT's 1997 Research Strategic Planing Meeting held in November 1997. Included in the paper are relevant socio-economic trends, including social, environmental, economic, and political. construction technology, condition assessment and monitoring, transport technologies, information technology, and human factors research are also discussed. finally, the results of a survey distributed to Department personals, local transportation agencies, and vendors regarding transportation issues and research needs are presented.
ET-2000 Extruder Guardrail End Terminal
An ET-2000 Extruder Guardrail End Terminal (GET) was installed in September 1993 along Highway 35 (ORE 42) near Roseburg, Oregon (M.P. 76). The ET-2000 GET was selected for this site to reduce accident severity and right-of-way cost. The Get was installed for a total cost of $3,000 in about two hours.
The performance of the ET-2000 GET was monitored for four years. No impacts were reported in this period. No maintenance was required.
ODOT will continue use of the ET-2000 GET or similar model. Other states, including Texas and Ohio, report large decreases in accident severity at their ET-2000 GET installations.
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Evaluation of Revised Left Turn Signalization
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Modified left turn signals had shown cost savings over the old style of traffic signals in initial installation and maintenance. This evaluation was conducted to determine whether those savings would be justified by no increase in the accident rates at the intersections where the new signals were installed. Eighteen intersections were selected for the evaluation and their accident rates before and after the new signal installation were compared. The results were statistically inconclusive, but since there was no indication of a significant rise overall in the accident rates, the evaluation committee determined that the savings already demonstrated would justify continuing to install the new signals.
Evaluation of DUII Sentencing Practices in Oregon
Oregon law requires motorists driving under the influence of intoxicants (DUII) to be sentenced with some sanctions, and allows judges the use of additional sanctions. Sanctions including drug/alcohol treatment, jail time, community service, etc., are not consistently and/or uniformly applied throughout the state. There is not a clear picture of which sanctions or combinations of sanctions are effective in reducing the recidivism, relapse into criminal behavior of DUII, and consequently, improving traffic safety. The trend represented in the January 1997 ECO Northwest report, DUII Sentencing Data in Oregon, is that the most severe sanctions are the least effective. There is a bias in the sentencing data, based on the fact that the most blatant offenders receive the most severe sanctions and are the most likely to repeat. These results are inconclusive and misleading.
For future research, start with a literature review that focuses on existing legislation. Then create a study design that addresses the objectives more directly and thoroughly. Study the databases of the OJD and the DMV, as well as others, to know exactly what information is available, and the relevancy of the available data. Next, produce a trial run through for a small number of cases, to gather initial trends, thereby detecting such issues as bias. Develop a better understanding of the sentencing practices in effect. Also, limit the research to ‘representative’ counties, freeing up time for database information verification with hard copy files. Gather multiple year data to increase the offender observation period for recidivism. Ensure the data collection process is halted and reengineered if there are any discrepancies. Develop methods to track the counseling utilized for the offender and their psychological profile. The diversion/counseling of the offender in relation to their background is possibly another project altogether.
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Snow and Ice Control
Alternative Snow and Ice Control Methods Field Evaluation
This document is the result of a two-year study to evaluate the emerging technologies in snow/ice control and determine their economic and operational effectiveness. Operational, environmental and economic factors were evaluated to compare Oregon’s "plow and sand" strategies to emerging chemical-based anti-icing strategies. The strategies examined included the use of calcium magnesium acetate (CMA) and magnesium chloride (MgCl2) known for their effectiveness, low corrosion, and low environmental impact. The ten evaluation sections in this study represented the various climate conditions found throughout the state.
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Results show that an anti-icing strategy, with either CMA or MgCl2, is effective and cost-efficient under a wide range of climatological and traffic conditions when compared to traditional "plow and sand strategies."
Polymer Modified Chip Seal Test on Oregon Route #22
In 1987 ten chip seal sections were constructed on Oregon Route #22 near Stayton in Marion County. CRS-2 emulsion with conventional asphalt was used in the control sections. Two other emulsions in the 1987 ODOT specifications were used in test sections: HFE-90 with conventional asphalt, and HFE-100S with polymer modified asphalt. Seven emulsions rarely or never used in Oregon were tried: CRS-2P, CRS-2R, CRS-2D, LMCRS-2H, CRS-2(P1) and CRS-2K. All seven used polymer modified asphalt.
In 1992, after five years of use, the seals were visually inspected and their friction numbers were measured. The condition of the seals were:
CRS-2(P1): excellent condition, functional. CRS-2 Calibration Section: excellent condition, functional. The calibration section's rating, however, was based on the amount of exposed surface asphalt, chip retention, and aggregate embedment, only. The seal's resistance to ravelling and ability to seal cracks was not known. HFE 100S, CRS-2D, and CRS-2K: fair condition, functional. CRS-2 Control Sections: poor condition, functional. CRS-2R: poor condition, failed after five years due to poor crack sealing ability. CRS-2P and LMCRS-2H: failed after four years due to poor crack sealing ability.
All seals had similar and adequate friction numbers. In addition, all seals which were still functional at the end of five years were considered successful, according to local maintenance personnel.
A double application of aggregate prior to the release of traffic onto the seals helped the performance of several test sections.
The comparative performance of these seals was influenced by other factors in addition to emulsion properties. As a result, the performance of some of the emulsions in this study may not represent their behavior.
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Recycled Plastics in Highway Construction and Maintenance
Installation and serviceability were examined for several products manufactures, in part, from recycled products. The following recommendations were reached:
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1. The type of recycled plastic snow pole employed in this study is not recommended for general use by ODOT.
2. Though the recycled plastic fence posts used in this study have higher initial cost than the more customary wooden posts and have greater labor requirements during installation, they should be considered when high quality wooden fence posts are unavailable.
3. The recycled plastic sign support posts used in this study, both hollow and solid core, are not suitable for use by ODOT.
4. The general use of the FHWA approved TREX (Timbrex) recycled plastic guardrail offset blocks is encouraged.
5. TRIMAX boards and Carsonite panels are suitable sound wall materials.
As the emphasis on using recycled materials increases, products suitable for highway construction and maintenance will become more common. The continued use of products with recycled materials should be encouraged and the successes and failures of such use publicized.
High Cycle Fatigue Crack Modeling and Analysis for Deck Truss Flooring Connection Details
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The Oregon Department of Transportation is responsible for many steel deck truss bridges containing connection details that are fatigue prone. A typical bridge, the Winchester Bridge in Roseburg, Oregon, was analyzed to assess the loading conditions, stress levels, and fatigue life of the connection details. The analysis included linear-elastic beam analysis, 2D and 3D finite element modeling, and fatigue modeling. A field identification methodology was developed to expand the analysis to other steel deck truss bridges. Five retrofit strategies were investigated to determine their effectiveness in reducing the stress ranges developed in the connection details.
Summary for 1996 LTPP Traffic Data Collection
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In 1996 the Research Unit continued to collect traffic data for the Long Term Pavement Performance Program, hereinafter referred to as the LTPP program. The LTPP program is essentially comprised of on-site computers that apply collected data to an algorithm in order to classify vehicle traffic on a given segment of the highway. Due to various equipment problems, on-line time was reduced from 90% in 1995 to about 86% in 1996. The system would shut down due to power surges and could only be reactivated by manually resetting the system on site. However, due to budget cuts, no extra effort was made to reset or repair equipment malfunctions.
Traffic data was collected by two different systems, the Automatic Vehicle Classifier (AVC and the Weigh in Motion (WIM). Classification data taken by the AVC and the WIM equipment was very similar with only one or two exceptions. For example, a three-axle bus pulling a trailer or a travel home pulling a car would be registered as a Class 11 (semi-truck) Appendix A contains a classification table based on numbers of axles and weight. Overall, traffic data collected was determined to be 90 percent accurate.
Armorform Articulating Block Mat Erosion Control System
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ARMORFORM® Articulating Block Mat (ABM) was used as part of a bridge replacement project at the Salmon Creek Bridge abutments in the summer of 1991. ABM was selected to replace riprap which was continually being undermined by the erosion of the streambed. ABM was selected due to its ability to maintain its structure (articulate) and withstand erosion. The original design requiring the mat to be keyed into the bank could not be constructed according to the manufacturer due to product limitations. Therefore, contrary to the original design, the flanks of the mat were not embedded into the bank to protect against undermining from bank erosion.
The ABM did work well during the flood event in February of 1996. Although the northwest corner was undermined, the blockmat articulated and changed slope to partially fit the void. Because the bank erosion stopped near the edge, it appears that the ABM also retards embankment erosion. However, the gap was not filled completely which allowed the rushing water to flank the mat increasing the damage. Downstream, some of the blocks were torn away from the mat while others were uncovered in the toe trench. Since the riprap placed by maintenance to retard the erosion is end dumped rather than keyed into the channel bottom and bank, the stream will probably continue to flank the ABM.
Future designs subject to similar flow conditions should consider keying the upstream edge 10 ft. (3 m) into the bank and burying the toe 8 ft. (2.4 m) into the channel bottom. In addition, the design should include riprap to protect the flanks of the mat. The ideal situation would be to construct the mat as designed with the fan shaped ends. The ABM appears to be most suited for active streambeds susceptible to erosions with slopes steeper than 1.5H:1V (steeper than is reasonable to place riprap).
Future designs should also consider the configuration of the ABM blocks. Consideration should be given to configuring the blocks so that there is no vertical alignment offset versus staggering the blocks. Aligned rows of blocks would allow articulation in all directions.
Latex and Microsilica Modified Concrete Bridge Deck Overlays in Oregon-Final Report
This final report presents information collected by ODOT personnel from bridge deck overlays constructed in Oregon between 1989 and 1995. Decks were placed on a variety of existing bridge types prepared using hydrodemolition, milling, and diamond grinding followed by sand, water or air blasting. Both latex and microsilica overlays were placed under a variety of environmental conditions. The study investigated causal relationships between construction and environmental factors and deck cracking and delamination and, where warranted, recommends procedures to minimize these distresses.
Statistical analyses of available environmental and construction information from several overlays constructed between 1989 and 1993 failed to clearly establish the cause(s) of delamination or cracking. Petrographic studies of cores taken from these decks appear to show increased microcracking in substrates prepared with milling compared to those prepared with hydrodemolition. Diamond ground substrates were not included in this phase of the study. This analyses supports increased use of hydrodemolition over milling.
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In an effort to establish the casual relationships, detailed environmental and material property data were collected during construction on five bridges in 1995. Statistical analyses of data provides information on the range of environmental conditions under which bridge deck may be placed, however, little cracking or delamination was noted in any of the five bridges. Thus, the cause(s) were not identified.
Repair of Studded Tire Damage Pilot Project MP 276-279 (I-5) Section
In 1996, a pilot project to repair studded tire damage on CRC Pavement was constructed on Interstate 5 north of Salem, Oregon. The test section was about 5km (3mi.) long on a three-lane section of highway. Rut depths on this section were about 20 mm (.80 in.) with most of the damage in the center lane. since the average daily traffic volume (ADT0 was greater than 45,000, the work was done at night.
Four different thin AC overlays were placed on the test section. The first was a standard open graded F-mix. The second was the same F0mic with mineral fibers added. The third was a 38 mm (1.5 in.) stone mastic course aggregate mix. finally, the last section was paved with a 25 mm (1.0 in.) lift of a fine stone mastic lift.
The work was completed near the end of the paving season and was delayed by a week due to rain. The night paving and the late season low temperatures caused some lay down problems. Lumping of the mix slowed the paving operation and produced a rough ride. Compaction was also low and inconsistent.
The section will be monitored for distress for two years. Raveling and/or rutting will be checked periodically.
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Low Volume Highway-Rail Grade Crossing Treatments for the Oregon High Speed Rail Corridor
This study defines how to gather information and how to obtain the communication and response necessary for safety at highway-rail crossings. It examines technologies for low-cost, high-safety treatments for low volume (less than 200 ADT) highway crossings of higher speed (130–200 kph) or (80-125 mph), rail. A full crossing closure and consolidation process for the corridor is a necessary first step. Current train control and crossing safety systems are also examined. Intelligent Transportation System technologies are evaluated to determine applicability in information gathering, communicating, and control functions of grade crossing safety. This study also presents guidelines for low volume crossings of the higher speed rail line in Oregon. Finally, a preliminary cost/benefit analysis is presented.
Above 200 kph (125 mph), a crossing closure or grade separation is required. In the range of 130–200 kph (80-125 mph), ITS technologies have the potential to enhance crossing safety at a much lower cost than grade separation. Advanced systems can provide train location and speed information needed for sophisticated crossing control. A traffic management center can receive train and crossing information, operate crossing systems, and grant clearance for train or highway users through the crossing. Remote lock gates provide safety at private crossings. Increased traveler information and four quadrant warning gates increase motorist compliance at public crossings. At train speeds above 175 kph (110 mph), barrier gates protect rail movements. Video monitoring and detection systems provide reliable, but redundant information should a vehicle become trapped in a crossing.
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Lock-Pin and Collar Fastening
Lock-Pin and Collar Fastening System
In 1993, a steel girder I-beam deck was extended to cross a new on-ramp at the Marquam Bridge Interchange in Portland, Oregon. The steel members of this new structure were fastened together using the lock-pin and collar fastening system.
These fasteners are quicker and easier to install than the standard threaded ASM 325 bolts. While the lock-pins are about the same lengthened strength as the standard bolts, the collars are not threaded but rather are swaged onto the lock-pin by a special hydraulic installation tool. Once the collar is swaged on, no additional tightening with a torque wrench is required. A simple sound test by pinging it with a hammer verifies the tightness of fit. While reports of nuts working loose on standard bolts are common, the lock-pin collar fasteners remained tight after three years of service.
Costs can be reduced with less labor by using this system. Since the lock-pins do not need to be torqued, the second and third tightness checked are eliminated. Material costs are about the same when torque indicator washers are used with standard bolts.
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