NORTH BEND — For more than a year motorists have rumbled past construction workers while crossing the McCullough Bridge. As the months have dragged on, they’ve watched workers replace decades-old concrete rail, endured nighttime lane closures, and have been led across the span by pilot cars.

But that’s just a hint of the four-year restoration project.

Those who venture beneath the belly of the bridge find a much different view as one of the McCullough’s sweeping arches have been enveloped in a structure of tin and steel. Behind the metal panels that rise 100-plus feet into the air, crews like worker bees perform the most critical part of the project: to extend the life of the 1936 bridge.

Employees of Great Western Corporation are preparing the bridge’s concrete pieces for a process known as cathodic protection, in which the concrete will be sprayed with a zinc layer. It will eventually receive a continuous controlled electric charge of about 0.2 milliamps per square foot. Doing so saves the rebar inside from corrosion brought on by sea air, said James Garrard, an Oregon Department of Transportation employee who designs bridge protection systems.

Don’t worry, he said, people won’t get electrocuted if they touch the bridge.

“It’s very low. You can’t feel it,” he said.

The electricity pushes chloride ions away from the rebar and each zone of about 5,000 square feet will have its own power supply. The coating itself lasts about 20 years.

Out at the ODOT staging site, Ted Bennison, the project coordinator for ODOT, stood in the shadow of the bridge as he discussed the work taking place. About seven people from Springfield-based Hamilton Construction Co. are replacing the rail with replicas, installing deck drains and performing seismic retrofitting. Another 19 people from Great Western of North Bend are doing the cathodic protection.



“There is never no work being done in there. It’s a continuous 24-hour process,” Bennison said.

Discoveries

Prior to coating the concrete, crews must first find any metal bits left in the concrete when the bridge was first constructed 73 years ago. If not, the metal could short the electrical system, Bennison said. This may sound like an opportunity to find some interesting artifacts, but Bennison said that hasn’t been the case. Workers have found only old nails and tie wires.

“It kind of surprises me, too, because usually we find things,” Bennison said.

He noted that during a similar project on the Isaac Lee Patterson Memorial Bridge in Gold Beach, workers found old chisels, nails and other items buried within the concrete.

Archaeology aside, Bennison said the project has run smoothly and the crew has overcome obstacles, such as removing more delaminated, or bad, concrete than expected.

The next step will be to roll the enclosure about 200 feet north on the mile-long bridge.

Bridge traffic

On the McCullough’s deck, Oregon State Police troopers have kept an eye on drivers to ensure they obey a 35-mph speed limit and respect workers’ safety.

OSP Patrol Sgt. John Keeler, said when the project began motorists continued to speed, but many have since changed their habits. Lately, there hasn’t been much trouble beyond the occasional stall out, he noted.

“Initially, we were sending extra troops out,” Keeler said. “Once (drivers) get used to the construction going on and stuff ... it kind of sinks in.”

Troopers stepped up enforcement in the summer and fall of 2008 when more out-of-towners crossed the bridge.

“It wasn’t just local citizens,” he said. “It was a combination of tourists visiting our area.”

Drivers might eventually forget what it was like to drive 45 on the bridge, as the project is expected to last another four years.

Bennison explained that the first four years deal with only south end of the bridge to where the steel span begins. ODOT likely will restore the northern side, but that is dependent on funding and solving logistical issues involved in working over water.

“It depends what they draw up in Salem,” he said.