Huge concrete bridge beams riding on barges from as far away as the Bahamas will wend their way up the Intracoastal Waterway today.
Their destination: the Belleair Beach Causeway, where two massive cranes are waiting to hoist them into place Thursday to become the 530-foot center span of the $72.2-million Belleair Beach Causeway Bridge now under construction.
"This bridge is really unique. It is only the second bridge in the U.S. to be built this way," says Meg Korakis, Pinellas County spokeswoman for the project.
The construction method has a name — "incremental launching" — which means that the main sections of the bridge are constructed off-site and then lifted and "cranked" into place using large cranes and a hydraulic system applying 33,000 pounds per square inch of pressure.
It will take about three weeks to complete this part of the bridge, according to project manager Tony Horrnik.
The five concrete beams for this portion of the bridge were constructed in a plant in Tampa near the Gandy Boulevard Causeway and were to be barged down Tampa Bay and then up the Intracoastal Waterway, according to Horrnik.
Beginning Thursday, the beams will be joined to form three spans — one that is 200 feet long over the center channel, and two flanking anchor beams of 165 feet long on either side of the center span.
Each of the concrete beams is connected by high-tension steel tendons.
"We picked this method for a number of reasons," says Korakis. "It saved nearly $125,000, it has the least impact on the environment, and is safer for construction workers."
The only other U.S. bridge constructed using this method spans the Iowa River and is considered a landmark, Korakis said. It was built in the mid 1990s and, at the time, was the longest free-cantilever bridge in the country.
Other work that will be done on the bridge during the next few months includes:
• Completing the north half of the new relief bridge.
• Installing drill shaft foundations, pier footings, columns and caps throughout the length of the new main channel bridge.
• Constructing a new road west of the relief bridge.
• Completing retaining walls on the west end of the main channel bridge and east and west ends of the new relief bridge.
• Shifting traffic onto the relief bridge and newly constructed road.
• Demolishing boat ramps and beginning new ones.
During construction, traffic is often reduced to a single lane, and delays can be lengthy. Occasionally bridge traffic stops, but those periods are usually confined to 11 p.m. to 5 a.m., Korakis said.
Work to replace the 50-year-old drawbridge began a year ago. Construction on the new high-span bridge is on schedule, Korakis said, and should be complete by the spring of 2010.
The construction cost is covered by Penny for Pinellas funds and a federal grant. Because the bridge is considered a main evacuation route, FEMA requirements forced the high-span design.
The new bridge, which is expected to last about 75 years, will rise 75 feet over the channel. Features will include 12-foot travel lanes in each direction, 8-foot sidewalks, and 10-foot-wide shoulders with designated 5-foot bicycle lanes.
Bridge construction details, traffic schedules and a live Web cam can be viewed on the bridge Web site: belleaircausewaybridge.com.