The Peabody Road Overcrossing at the Vacaville/Fairfield Train Station showcases the significant benefits of building bridges with precast, prestressed California wide flange girders (CA WFG). Peabody Road, which carries traffic between Fairfield and Vacaville, as well as the Travis Air Force Base and numerous schools, needed an upgrade to support the area's urban expansion project, which calls for thousands of new homes to be erected in the Peabody Road area in the coming decades.
Precast, prestressed concrete for this project accelerated the construction schedule by two months with no disruption to rail service, enabling a reduction to the contractor and owner's expenditures typically associated with cast-in-place forming and scheduling.
This new overpass is a 3-span bridge consisting of 24 each of 48" CA WFG up to 100' span over an active railroad and under a 230 KW power line.
Contract drawings initially called for two spans consisting of 11 rows of 5' tall precast I-girders & exterior rectangular girders and one span on cast-in-place (CIP) box girders under the power line. Through value engineering, KIE-CON Inc. provided cost savings, accelerated construction, and constructability improvements by converting the I-girders, rectangular girders, and the CIP box girders to CA WFG. This eliminated three girder lines and reduced the structure depth by 12", thus providing the client with an extra 12" of height clearance.
The site's footprint was unavoidably constrained by a live power line that could not be removed and by the neighboring railroad. The first span of the project had a 230 KW live power line obstruction at 59' above the ground. To combat the site restrictions, the project's precast erector used an innovative solution to place the girders by utilizing two cranes with rolling outriggers while maintaining 21' of clearance from the top of the crane boom. The ability to set girders beneath power lines in a single day accelerated the construction schedule by two months.
The collaboration between the railroad, general contractor, and precaster to install the span over the live tracks without interrupting train service was a remarkable achievement. Trains could move between the precast girder lifts without difficulty.
The aesthetic versatility of precast concrete allowed the exposed girders to provide an attractive finish over the railroad adjacent to the train station. All 24 girders were erected in three consecutive days enabling the bridge to reopen early, resulting in savings between $3-$5 million dollars to the city of Fairfield. California wide flange girders have again demonstrated they are the most cost-effective cross-section through accelerating construction, overcoming site constraints, and providing real savings.