Pitkins Curve Road Bridge and Rock Shed at State Route 1

This $29M Caltrans project realigned a 0.3-mile segment of State Route 1 along the Big Sur coast and constructed the Pitkins Curve Road bridge, Rocks Shed, and Pitkins Curve Road bridge north tieback wall. This stretch of highway is considered one of California’s most scenic drives; thus, in addition to providing vital transportation for local residents, it is also frequented by tourists. Susceptible to frequent, potentially deadly landslides, the Pitkins Curve Rock Shed helps deflect the large, vehicle-size boulders periodically falling onto the highway.

The 620-foot-long, 35.5-foot-wide, three-span, cast-in-place, pre-stressed concrete segmental box girder bridge, with a textured and stained concrete barrier rail, was constructed on reinforced concrete columns founded on large diameter cast-in-drilled-hole (CIDH) piles with permanent casings. The Rock Shed is the first of its kind constructed in North America. This 240-foot-long tunnel-like Rock Shed was constructed on CIDH piles with permanent and isolation casings and also included two retaining walls, two tieback headwalls, pre-cast concrete roof panel elements, and cast-in-place column and bent elements. Finally, the 314-foot-long by approximately 40-foot-tall soldier beam and timber lagging tieback wall contained three rows of concrete walers with steel soldier CIDH piles. The complexity of this project led to many technical submittals that required approval through engineering analysis. This included shoring and excavation, temporary trestles, an on-site concrete batch plant, numerous working drawings, mass concrete placement, falsework, large-diameter cast-in-steel-shell (CISS) piles, pre-stressed/pre-cast (PS/PC) structural panels, tiebacks, and post-tensioning. The construction site’s remote location and the need to keep the roadway open to traffic during construction brought additional challenges to project staging and construction.