Kealakaha Stream Bridge Replacement
|Client Name:||State of Hawaii, Department of Transportation, Hawaii District|
|Disciplines Applied:||Construction Management|
RMTC provided full construction management services for this FHWA-funded project. All records and documentation were prepared in accordance with FHWA requirements.
Kealakaha Stream gulch is over 600 feet wide and 170 feet deep. The replacement bridge is located makai of existing bridge, and measures 720 feet from abutment to abutment. The existing structure has been declared a Category I Historic Bridge by the State of Hawaii, DLNR Historic Preservation Division. Therefore, no alterations to bridge are permitted and the new bridge must be in addition to the existing structure which has been found to be deficient in width, curvature, sight distance and structural capacity in addition to non-conformance to current federal highway standards.
Kealakaha Stream gulch is over 600 feet wide and 170 feet deep.
The main structural components of the bridge are two box girder piers, one on each side of the gulch. Each pier is supported by eight 5-foot diameter reinforced concrete shafts, each 115 feet in length. These shafts were drilled in the side slope of the gulch such that the tip of each shaft was above the 100 year flood elevations of the stream. The bridge superstructure is supported by Friction Pendulum Seismic Isolation bearings. These bearings are placed at both abutments and at the box girder pier columns to protect the bridge superstructure from earthquake damage. These bearings are designed using the response characteristics of a pendulum. Each bearing consists of an articulated slider plate and a plate with a concave surface. The slider plate is attached to the superstructure and the concave plate is attached to the bridge foundations. During an earthquake, the slider plate slides along the concave surface to dampen the forces of the earthquake.