The San Dieguito River Park Joint Powers
Authority (SDRP) was formed in 1989 to help develop a park along
the San Dieguito River Valley, which stretches some 55 miles
from the ocean to the foothills of Volcan Mountain. The Coast
to Crest Trail is a multi-use path that allows hikers, cyclists,
and equestrians to enjoy the natural open space of the River
Park. The SDRP is currently working to complete one of the remaining
components of the 55-mile long trail by constructing a 1,000’
long bridge over Lake Hodges west of I-15 and providing connecting
trail segments.
T.Y. Lin International (TYLI) performed numerous bridge concept
studies including a steel truss, timber bridge, prestressed
concrete bridge, suspension bridge, and a cable stayed bridge.
A unique alternative was also evaluated – a stress ribbon
bridge. This alternative has only been used in four locations
in North America, two of which have been designed by TYLI.
The stress ribbon bridge uses two very robust abutments to
anchor prestressing steel cables draped over the intermediate
bents. Precast deck panels approximately 14 feet wide, 16
inches deep, and 10 feet long, are placed onto the cables
and slid into place. Secondary prestressing steel cables are
then placed and stressed, creating a rigid, cable/concrete
structure.
For this site the stress ribbon bridge provides
a highly dramatic and graceful three span bridge over Lake
Hodges. The superstructure is a remarkably thin 16”,
carrying each of the three 330’-long spans. With a total
bridge length of nearly 1,000 feet, this extremely long stress
ribbon bridge would be one of the longest in the world, providing
the San Dieguito River Park, and the region, a landmark structure.
