Rick Contreras' workday began at 6:15 a.m. yesterday, and his first task in the dark, single-digit coldness at the Maumee River Crossing construction site was to get a huge crane warmed up and running.
“She started a little hard this morning,'' the crane oiler from Fremont said. But by mid-afternoon, bright sunshine had taken the edge off the daybreak chill, and Mr. Contreras' big crane was in position to lift the first of nearly 3,000 precast bridge segments into place.
This morning figures to be about as cold as the 3-degree low the National Weather Service reported yesterday at Toledo Express Airport - so Mr. Contreras can expect moisture to be frozen in the crane's air lines again when he gets to work today.
While most road construction in the region has ended for the season, the $220 million I-280 bridge's timetable offers no winter respite. At the main bridge site, pier construction and a concrete pour for the central tower's foundation proceeded apace yesterday, while at a yard a mile away on Front Street, the daily cycle of bridge-segment casting continued.
By late March, passing motorists on the freeway should see the central tower's base jutting above the Maumee's waterline, Don Curtis, the project manager for Ballwin, Mo.-based Fru-Con, Inc., said yesterday. All foundation shaft drilling on the East Toledo approach should be finished and some preparatory work will have begun on the North Toledo approach by the time spring arrives, he said.
Keeping concrete warm enough to maintain its required strength as it sets is the biggest challenge that winter's chill poses to bridge construction, Mr. Curtis said. At batch plants, the concrete is mixed with hot water so that its temperature is at least 50 degrees when delivered to the site, and the wooden forms and reinforcing steel are heated before each pour.
Freshly poured structures are kept warm by heaters and shrouded with blankets and plastic sheets to maintain a 40-degree minimum until the concrete has cured.
Cold is an issue at the casting yard too, project engineer Mike Tsichlas said. Small heaters are placed in each mold to maintain a temperature between 110 and 120 degrees during casting.
The warmer temperature keeps the casting yard on a schedule that requires one completed bridge segment per day from each of eight casting machines. So far, more than 200 of the bridge's segments have been cast.
On one part of the job, Mr. Tsichlas noted, the cold is helpful. Big-batch concrete pours for the central tower's footings - 5,600 cubic yards at a shot - generate a lot of heat, he said. Letting a little cold air down the shafts helps that heat dissipate, and below the riverbed the ground's natural warmth means there's no risk of freezing later on.
A minimum temperature of 20 degrees is required to use the epoxy that seals bridge segments together once they are assembled. While that work is about to start, it will begin slowly, so cold-weather delays are tolerable, Mr. Curtis said. “We really didn't plan on erecting a lot of the bridge before spring,” he said.
While not specifying what the threshold is, Mr. Curtis said there is a point at which it would become too cold to continue any construction.
“If it gets too cold and miserable, it gets too expensive to heat everything,'' he said, later adding that extreme cold also would be hazardous to workers' health.
Yesterday's chill seemed of little concern to most of the bridge construction workers, who took it as just part of the job.
“It's a little chilly,” Fru-Con foreman Greg Scroggs said matter-of-factly. But after two previous winters of working outdoors, the cold is mainly an inconvenience now, he said.
“It ain't too bad - the sun's out,” Billy Nelson, a pile-driver operator from Findlay, agreed while taking a break at the mid-river site where the central tower's foundation is being built. “We have a trailer we can go to if we need to warm up.”
Larry Millimen of Adrian said it's usually plenty warm inside the crane he operates.
“I just get in my cab and turn the radio up,” Mr. Millimen grinned. “As long as these guys can cope with it, we get it done.”
First Published December 4, 2002, 11:57 a.m.
