Road work outside historic Fairbanks church requires careful digging

by Dermot Cole/ cole@newsminer.com Fairbanks Daily News Miner

A crew from HC Contractors uncovers the water lines running into Immaculate Conception Church just past the north end of the Cushman Street bridge.

To help protect the church from excessive vibration, electronic monitoring equipment has been set up inside the building that will send an alarm to a structural engineer when the movement reaches 40 percent of the level that a building of that age is able to handle.

Structural engineer Keith Korri, of Anchorage, is keeping close tabs on the building via the equipment that is set up to give him an alert on his mobile phone when the 40 percent level is reached. So far the movement has been below that standard, which he said provides a good margin of safety.

He has also told the church workers to talk to HC Contractors if and when something seems amiss.

Inside the church the first sign that vibration preparations are an issue is the temporary removal of the crucifix from the front of the church.

In addition, the statues of Mary and Joseph have been removed from their elevated perches and placed on the main floor of the church.

Korri has monitored the vibration levels in the church on three previous occasions, going back to the early 1990s.

When the heavy equipment is operating within six feet of a building and right next to a fire hydrant and water pipes, the mechanical arm has to be handled by an operator who knows that every inch counts.

Regarding the vibration inside the church, the industry standard for movement is 0.5 inches per second for a building like ICC, Korri said. The machine he has installed in the crawl space is set to go off when the movement is 0.2 inches per second. He said he wants to solve any problem before it becomes a problem and the 40 percent threshold offers that protection.

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Road work outside historic Fairbanks church requires careful digging