County Road 47 over Trout Brook New York

<figure id='attachment_8140' style='max-width:1707px' class='caption aligncenter'><img class="size-full wp-image-8140" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of the Completed County Route 47 over Trout Brook Bridge." width="1707" height="1280" /><figcaption class='caption-text'> Figure 1. Completed County Route 47 over Trout Brook Bridge.</figcaption></figure>Location: St. Lawrence County, New York Owner: St. Lawrence County Year Constructed: 2013 National Bridge Inventory (NBI) Number: 3341880 Crossing Type: Roadway bridge over stream Superstructure Type: Steel Girders with precast concrete deck panels Span: 98 feet Maximum Wall Height: 11.6 feet Maximum Wall Face Width (edge to edge): 58 feet Skew: 30 degrees Facing Type: Concrete Masonry Unit (CMU) with split face Average Daily Traffic (ADT) (in 2002): 683 Contract Type: Design-Build (In-house) Unique Project Feature: The use of precast concrete deck panels with steel girders; instrumented to monitor performance during thermal expansionBackground: County Route 47 over Trout Brook Bridge (CR-47 Bridge) is located in the southern part of the town of Stockholm in St. Lawrence County, New York (see figure 2a and 2b). County Route 47 bridge provides a link between New York State Route 11B and U.S. Route 11 in the northern part of the New York state. Stockholm is a rural town with farms and forests close to the St. Lawrence River, Lake Champlain, and Lake Ontario. The town’s proximity to rivers and lakes as well as the Adirondack Mountains make it a great spot for various outdoor activities such as fishing, hiking, biking, boating, and skiing; all of these activities are within a 1.5 hour drive of Stockholm. Stockholm is also near four universities regularly visited by locals for informative lectures, music concerts, art exhibitions, and other cultural events. Given its location, one of the most unique features of Stockholm is its diverse population of professors, farmers, small business owners, factory workers, and others. The CR-47 Bridge is especially important to the town as it provides residents of Stockholm with access to their day-to-day destinations; the bridge is part of a network of 194 open bridges that connect local communities in St. Lawrence County.<figure id='attachment_8141' style='max-width:1019px' class='caption aligncenter'><img class="size-full wp-image-8141" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Sketches of the project location. To the left, location of St. Lawrence County, New York, to the right, location of the CR-47 over Trout Brook Bridge." width="1019" height="512" /><figcaption class='caption-text'> Figure 2. (a) Location of St. Lawrence County, New York and (b) CR-47 over Trout Brook Bridge. Source: Open Street Map, ESRI, FHWA.</figcaption></figure>The original CR-47 Bridge was built in 1967 by the New York State Department of Transportation (NYSDOT). Prior to replacement, the bridge spanned over three 14-foot wide, 8-foot high, and 92-foot long corrugated metal pipes (CMP) (see figure 3); the total span of the original bridge was 72 feet. In 2008, a bridge inspection revealed that the CR-47 Bridge was in immediate need for repairs due to its heaving floors, cracks along the floors and walls, and other forms of deterioration in all three pipes. In 2009, the pipes were repaired by installing a reinforced concrete floor as shown in figures 5a and 5b. However, these temporary repairs addressed only some of the issues with the bridge and the CR-47 Bridge still had deteriorating guide rails and head and toe walls (see figure 4). To ensure the safety of the public, the CR-47 Bridge was scheduled for a complete replacement in 2013.<figure id='attachment_8142' style='max-width:1160px' class='caption aligncenter'><img class="size-full wp-image-8142" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of the old CR-47 Bridge spanning over three corrugated metal pipes." width="1160" height="567" /><figcaption class='caption-text'> Figure 3. Old CR-47 Bridge spanning over three corrugated metal pipes. Source: NYSDOT Inspection Report.</figcaption></figure>Deployment: To replace the CR-47 Bridge, engineers decided to use Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) technology. By 2013, when the replacement occurred, the St. Lawrence County Department of Highways (County) had built 13 GRS-IBS bridges and were very familiar with the benefits of the method. St. Lawrence County particularly valued the cost-savings associated with GRS-IBS technology because it made it possible to replace more bridges with less funds.<figure id='attachment_8143' style='max-width:640px' class='caption aligncenter'><img class="size-full wp-image-8143" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of deteriorating toe wall at old CR-47 Bridge." width="640" height="480" /><figcaption class='caption-text'> Figure 4. Deteriorating toe wall at old CR-47 Bridge. Source: St. Lawrence County.</figcaption></figure>In the case of the CR-47 Bridge, the County applied for and received the Federal Highway Administration’s (FHWA) Innovative Bridge Research and Deployment (IBRD) grant to partially fund the project. According to the FHWA website, the “IBRD program provides funds to promote innovative designs, materials, and construction methods in the construction, repair, and rehabilitation of bridges and other highway structures”. The design of the CR-47 Bridge involved GRS-IBS and the use of steel girders as superstructure. The steel girders were combined with concrete footings and precast concrete deck panels to form a complete superstructure system. The new bridge featured a 98-foot span,11- to 12-foot high abutment walls constructed with split face concrete masonry unit (CMU) blocks, a 30-degree skew, a 0.5-percent slope, a four percent superelevation, and rip-rap countermeasures with a 3:1 slope (identical to original stream); the new bridge was designed for a 100-year flood and checked against the extreme condition of a 500-year flood. Additionally, the new CR-47 Bridge resulted in an additional 40 percent opening of the channel section allowing trout and other animals to cross under the bridge more easily.<figure id='attachment_8144' style='max-width:1184px' class='caption aligncenter'><img class="size-full wp-image-8144" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Two photographs. To the left, CMP before, to the right, after floor replacement at old CR-47 Bridge." width="1184" height="390" /><figcaption class='caption-text'> Figure 5. (a) CMP before and (b) after floor replacement at old CR-47 Bridge. Source: St. Lawrence County.</figcaption></figure>Project Challenges and Solutions: The challenges and solutions described below did not adversely affect the project. Rather, these challenges were predominantly the result of site conditions.First GRS-IBS bridge for NYSDOT As mentioned previously, the project utilized federal funding. As a result, NYSDOT had to provide oversite for the construction process. CR-47 Bridge was the first GRS-IBS bridge to be constructed by NYSDOT. To ensure the project proceeded smoothly and without delays, NYSDOT had to learn all the details about the technology very quickly. Engineers from St. Lawrence County and FHWA representatives were a valuable resource and ensured that NYSDOT engineers had all their questions answered in a timely manner. Great communication within the engineering team also facilitated the project and its resulting success.Scour design and excavation Evaluation of scour and creating a design to protect against it is always a concern at water crossings. For this project, due to stream bed material being a stiff glacial till, scour was not a major concern. The final hydraulic design called for the bottom of the reinforced soil foundation to be constructed below the calculated scour depth. Excavating this dense material was slightly challenging and required four to five passes for a large excavator to excavate a bucket-full of material. While excavation was difficult, the competency of the material allowed for nearly vertical excavation which minimized the amount of material to be disposed.Coffer-dam and dewatering Due to the need to excavate near a stream, a coffer-dam was required. Throughout construction, the excavation area was flooded several times with stream water flowing over the coffer-dams. The excavation-flooding was a result of unusually intense rainfall events that occurred during construction. Despite the flooding and the fact that excavation was nearly vertical, the walls did not cave in; this highlighted the competency of the glacial till. Despite the flooding, there were no significant delays because timely actions were taken by the contractor to dewater the excavation every time a flood occurred.<figure id='attachment_8145' style='max-width:609px' class='caption aligncenter'><img class="size-full wp-image-8145" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of Precast concrete panel lowered on top of steel girders." width="609" height="264" /><figcaption class='caption-text'> Figure 6. Precast concrete panel lowered on top of steel girders. Source: St. Lawrence County.</figcaption></figure>Precast concrete panels St. Lawrence County and NYSDOT engineers were new to precast concrete panels, but were quick to learn about the concept from the consultant on the project. Based on the advice of the consultant, precast concrete panels were chosen as a superstructure element to reduce construction time. The panels covered the whole width of the bridge and had exposed reinforcement at the joint sections (see figure 6); ultra-high performance concrete (UHPC) was used for the panel joints. The interface between the steel girders and concrete panels was composed of two steel angles welded onto girders to form a “channel” with the free ends of the angles topped with foam to provide a better seal. Within the “channel,” three rows of shear connector studs were welded into the girders. These studs were ensuring that the superstructure combined of steel and concrete acts as a composite material. As a final step, the “channel” was filled with cement grout to combine the concrete panels with the girders to form a complete superstructure system. The interface system is shown in figure 7. Although the use of precast concrete panels was successful in this project, resulting time savings were minimal. This experience taught the project team that using precast concrete panels does not always result in significant construction time savings.<figure id='attachment_8146' style='max-width:741px' class='caption aligncenter'><img class=" wp-image-8146" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of the steel girder and precast concrete panel interface." width="741" height="541" /><figcaption class='caption-text'> Figure 7. Steel girder and precast concrete panel interface. Source: St. Lawrence County.</figcaption></figure>Conclusion: The CR-47 Bridge was successfully replaced by St. Lawrence County with the help of NYSDOT and FHWA. To evaluate the performance of the bridge during thermal expansion and contraction cycles resulting from seasonal changes in temperature, the bridge was instrumented and monitored for eight months. During this time, the bridge superstructure and GRS abutments moved in unison in response to seasonal temperature changes. This demonstrated that the skew of the bridge had no effect on bridge performance related to thermal expansion and contraction.Between the completion of their first GRS-IBS bridge in 2009 and 2016, 19 GRS-IBS bridges and two bridge-style culverts have been completed in St. Lawrence County. In St. Lawrence County, the bridges have been completed at an impressive rate of three GRS-IBS bridges per year. The St. Lawrence County Department of Highways, who design and construct most of St. Lawrence County's bridges, were able to achieve this success by constantly learning from their experiences with GRS-IBS. St. Lawrence County has been consistent in reducing their bridge costs by approximately 50 percent compared to conventional bridge construction methods and have reduced project durations to five to six weeks. About a half of the 194 bridges owned by St. Lawrence County were identified as eligible candidates for GRS-IBS, and plans are in place to replace them using GRS-IBS technology. There are three GRS-IBS bridge projects in progress in 2017.Project Contact: Andrew Willard ‎Senior Civil Engineer St. Lawrence County Department of Highways AWillard@stlawco.org (315) 379-1542Project Technical Paper: A technical paper has not been published for this project.REFERENCES“CR 47 over Trout Brook Bridge”, (inspection report, New York State Department of Transportation, 2015).“Town of Stockholm, NY” (website article). Retrieved from: <a href="http://www.stockholm-ny.com/whystockholm.html.%20Accessed%20June%2026">…. Accessed June 26</a>, 2017.Andrew Willard, phone conversation with the author of this document, June 6, 2017.Daniel Alzamora, phone conversation with the author of this document, May 16, 2017Nicks, J. E., Adams, M. T., Stabile, T., and Willard, A. E., “Thermal Interaction of a Geosynthetic Reinforced Soil Integrated Bridge System in St. Lawrence County, NY”, Geotechnical Frontiers, 2017, GSP 278.Toby Bogart, “Geosynthetic Reinforced Soil Integrated Bridge System – A User’s Perspective” (presentation, St. Lawrence County Department of Highway, 2013).

Title

Technology

Mechanically Stabilized Earth Wall System