Sources: National Precast Concrete Association; Kie-Con Inc., Antioch, Calif.; CP staff
Kie-Con has shipped four of seven prestressed California Wide-Flange girders, which at 159 ft. 5 in. are the longest non-spliced, monolithic precast members delivered by trailer to a Golden State bridge site. The girders are 12 inches longer than similarly configured beams Oldcastle Precast–Perris is fabricating for the Santa Ana Freeway South Corridor in southern California.
The design for a new Porter Creek Road Bridge in Santa Rosa, north of San Francisco, called for a cast-in-place concrete crossing. Kie-Con proposed as an alternative prestressed concrete super girders—cast with 56 0.6-in. diameter strand and 9,000-psi design strength mixes—noting the feasibility of fabricating and hauling 78-in. tall members just under 160 feet long. A little over 100 miles, the plant-to-site route runs seven freeways and attendant on-and-off ramps, and challenging terrain on the final 20 miles.
A Kiewit Corp. subsidiary, Kie-Con credits project success thus far to quick alternate design approvals by lead contractor Gordon N. Ball Inc., Sonoma County officials, and engineer Mark Thomas & Co. The precast/prestressed spec has significantly reduced the contractor’s field schedule and curtailed concrete work in or around a sensitive waterway. The remaining three Porter Creek replacement bridge girders will be dispatched in mid-October.
Related article: Oldcastle Precast ships record-length Caltrans girders