College of Engineering Unit:
Clear Creek bridge is located on US Highway 26 approximately 12 miles south of Mt. Hood. The bridge was originally constructed in 1932 and widened in 1959; however, the current bridge needs improvement. The concerns that will be addressed in our design are structural, water resources, and transportation related. The bridge has a poor superstructure and substructure which warrants concern over the load rating and scour potential. Clear Creek runs from Clear Lake to the White River and is an important fish passage for Rainbow trout and Brook trout, thus pollution into the creek should be minimized. US Highway 26 is a major freight route which has large volumes of heavy traffic traveling on it daily. The daily volume of traffic over the bridge will increase in the future and the bridge must have an appropriate road design to manage future traffic. Our team’s goal is to design a new bridge structure, construct a culvert and stormwater system, and plan the alignment and surface design of the bridge roadway.
New features of the bridge include an abutment with wingwalls which will help support the new bridge while the current piers in the creek will be removed. Reinforced concrete girders will help support the dead and live loads of the now longer one span culvert.
The culvert that will be installed in Clear Creek will replace the current bridge structure that has poor substructure, a weak load rating, and scour potential. A concrete slab culvert that is 30 feet wide by 10 feet tall will be placed in the creek. A slab culvert was chosen for this project because it does not have an artificial bottom to it. This allows the natural streambed material to be undisturbed. A culvert that allows the natural streambed to stay in place is ideal for fish passage. The slab culvert is also strong enough to support the heavy loads of the freight vehicles that will be traveling over the culvert. Whenever a structure is placed in a body of water, there is concern of scour occurring. To prevent scouring, the footing of the culvert will be buried beneath the streambed.
Stormwater management on this project is a high priority concern as it is in a location with substantial amounts of rainfall and snow melt. Conveyance systems must be implemented along the roadway surrounding the culvert to redirect the flow of water and prevent erosion and flooding. Since a conventional inlet drainage system was incapable of preventing clogging, a larger method that requires less maintenance would need to be implemented. An existing ditch was analyzed, and it was determined to be able to safely handle peak discharges in the modern day.
To protect Clear Creek from pollution during construction or from traffic, a silt fence and bioswale will be installed. The silt fence will serve as a temporary sediment control device that will prevent construction debris from entering the creek. The bioswale will be a long-term pollution control device following construction. Designs will protect life in the stream and preserve the stream’s overall water quality.
With a new culvert being designed for Clear Creek, a new roadway alignment and pavement design is needed to support the heavy traffic. The new alignment consists of a spiral curve along with a sag curve to match the elevation. New pavement will be created to withstand the heavy truck loads and harsh weather, along with new subgrade layers. To ensure drivers are safe, new signage and guardrails will be implemented along the road. Reinforcement layers were also incorporated to ensure the pavement layers are sufficient and provide a quality ride to users of the highway.
Project Communication Piece(s):
|Group CE.C1 Expo Poster||701.11 KB|