The Overland Bridge Project is the largest transportation design-build in the history of Jacksonville, FL. Extending south of the Fuller Warren Bridge that carries I-95 over the St John’s River, the project includes replacement of a series of existing overpasses, widening of both the Fuller Warren Bridge and I-95, and replacement of an existing bridge spanning Florida East Coast (FEC) railroad tracks. The $277M project is phased over approximately 30 months in order to maintain adequate traffic flow along the I-95 corridor during demolition and re-building. Moretrench is sub-contracted to Archer Western Contractors Inc. of Tampa, FL for all three phases of the drilled shaft bridge foundations.
Phase One Construction Challenges
Work at both sites had to be accomplished in very restricted conditions while traffic flow along I-95 was required to be maintained at all times. At the Fuller Warren Bridge site, four of the 16 shafts were to be installed in the St. John’s River from a trestle, raising environmental concerns. Here also, drilling between the existing bridge span and exit ramp meant tight clearances and complex rigging requirements.
Drilled Shaft Design and Testing
Drilled shaft diameters ranged from 42 to 72 inches, with ultimate capacities ranging from 725 to 1,540 tons. Installation depths ranged between 55 and 95 ft below working grade. Prior to production work, three sacrificial shafts were constructed at +/- 700-ft intervals in similar soils along the corridor where production shafts were to be installed. Due to the large loads, Archer Western selected Statnamic load testing, conducted by Applied Foundation Technologies, to verify design assumptions.
Fuller Warren Bridge Widening
Construction at the Fuller Warren Bridge involves widening of the south end of the bridge to provide an additional south bound lane adjacent to the two-lane exit ramp. With drilling to be accomplished between the main span and the exit ramp, sophisticated high definition light detection and ranging (LiDAR) laser scanning was performed to calculate drill rig and crane clearances from the existing bridge pier. From the results of the scan, these were pinpointed to be as little as six inches in places, requiring extensive rigging and lifting pre-planning.