To: Honorable Mayor and Members of Town Council
Through: David L. Corliss, Town Manager
From: Dan Sailer, PE Public Works Director
Title
Emergency Bridge Repairs along Castle Oaks Drive
Body
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Executive Summary
The purpose of this memo is to provide information about the upcoming closure of a bridge along Castle Oaks Drive. Because the bridge may not safely last through this winter, bridge repairs need to be conducted prior to then.
The work will require a full bridge closure for approximately 18 days, with a targeted period of October 11–28, 2025 (weather dependent) to take advantage of the School District’s Fall Break. The closure is necessary to replace the deteriorated bridge deck and ensure the bridge remains safe and serviceable for the next 20 years. Please see the vicinity and detour map which is included at the end of this memo.
Discussion
The Castle Oaks Dr. bridge, constructed in 1975 is slated for replacement under the October 2015 Development Agreement (DA) for the Terrain Community. The DA calls for realigning of Castle Oaks Dr. which would eliminate the existing bridge. As a result, ongoing bridge maintenance was not included in the Town’s annual BMP. However, due to development slowing and based on discussions with Development Services, there is currently no timeline when this work will occur, and these repairs can no longer be deferred.
In 2014, pavement was placed on the bridge, replacing its prior gravel surface. While the bridge surface was gravel, water was able to infiltrate and reach the metal decking that spans across the girders, accelerating corrosion. Since paving, traffic volumes have increased significantly with the growth of the Cobble Stone Ranch and Castle Oaks neighborhoods. The pavement has now deteriorated, allowing water to again reach the metal decking, which has caused rapid deterioration.
Although the Streets Division has been repairing potholes, the frequency and scale of required repairs have exceeded department capacity. Without major repairs before winter 2025–2026, the bridge could require a complete and prolonged closure for public safety.
Due to the required installation layout of the new deck panels and the limited width of the bridge, a full closure is necessary to complete the bridge work safely and efficiently. This approach ensures the safety of both construction crews and the traveling public. Other options were explored such as fully replacing the pavement only but were found to have limited success due to the deteriorated metal decking that supports the pavement. Furthermore, the use of a temporary pavement detour was evaluated. However, it was determined to be cost prohibitive due to constructing a temporary
structure over the drainage way and the associated storm water requirements that would double the project cost.
The proposed approach is the recommended method to ensure the work is completed correctly and to maximize the bridge’s remaining service life. With these repairs, the bridge is expected to have another 20 years of serviceable life. Since it is not known when the developer will complete their obligation, it’s important that this work not be deferred.
Schedule and Traffic Impacts
To reduce disruption, work is scheduled to begin during Douglas County School District’s Fall Break (October 13–17), lowering traffic volumes during the start of construction and allowing residents’ time to adjust to detours before school resumes. The October timeframe is also likely to have favorable weather for paving and related work.
Staff anticipates the work will take approximately 18 days, from October 11 – 28 to complete. A 24-hour operation was explored. Due to the critical aspect of identifying defects in the girders, the ability to provide adequate lighting under the deck is critical to secure the new decking to the girders. Additionally, there would be limitations on material delivery at night. Therefore, this option was eliminated. This project will include removing the existing bridge deck, preparing the bridge girders for the installation of the new bridge decking, placing the new pavement and completing necessary guardrail repairs.
The designated detour will route traffic via Highway 83 and Highway 86 (please, see the detour map at the end of this memo) adding approximately 12 miles and 18 minutes to travel time. Fire and Police have been consulted and will receive further coordination once the project is approved. The contractor has committed to the shortest possible closure window, working every weekday and both weekend days while adhering to Town ordinance for allowable work hours:
- Monday–Friday: 7:00 a.m.–7:00 p.m.
- Weekends: 8:00 a.m.–5:00 p.m.
Extended hours may be requested if beneficial to expedite completion.
Communications
The Town’s Communications team will develop and implement a public notification plan regarding traffic impacts. Message boards will be placed on Castle Oaks Drive in advance of construction to inform residents and travelers.
Attachments
Vicinity and Detour Map