Narrows bridge, observatory nearing completion Fall opening seen for new Penobscot River span

It has been 966 days since officials broke ground on the $84 million Penobscot Narrows Bridge and Observatory.

That’s less than one term for a president, but the towers of the new link between Waldo and Hancock counties have risen almost to their full height – 420 feet above the Penobscot River – and the east and west deck sections of the main span are now just 60 feet apart.

With the time to completion now being measured in months, the 120 or so construction workers on the bridge are moving along at a steady speed.

“We’ve gained ground through the winter,” said Archie Wheaton, the Pylon 1 supervisor for the Cianbro-Reed & Reed joint effort that is building the bridge. “There was a learning curve, … but we’ve gained momentum during the winter.”

The bridge deck has been inching out across the river and back toward U.S. Route 1 from the two tall pylons that dwarf the old Waldo-Hancock Bridge that runs alongside it. Crews have poured the concrete deck segments in place – 12 feet each along the main span, 10 feet on the back span toward land.

The crews now average about four days between pours for the smaller main span segments, five days on the larger ones.

The larger segments are more complicated and take more time, Wheaton said, because they involve building the large anchor blocks that hold the cable stays, the long tubes holding the cables that support the weight of the bridge.

The process involves setting up forms and installing a meshwork of rebar, the concrete pour and tension tightening bars that pull and hold the deck segments together. Crews then move the form traveler, the large steel framework that rides on rollers and tracks and holds the forms.

Each pour also requires aligning the elevation of the deck – and tightening the cable stays – to ensure that the deck segments will meet correctly in the middle.

“Adjustments have to be made after every pour to keep things on track,” Wheaton said. “It’s been incredible how close we’ve been. The design is accurate, and if we do everything to the design, if we do things the way it’s supposed to be done, it comes out right. There’s no question in the world that it’s going to come out right where it’s supposed to be.”

Although work is moving right along, Wheaton said, a few major pieces still need to be completed. The eastern tower on Verona Island is at its full height, awaiting only the installation of the pyramidal roof resembling the top of the Washington Monument.

Subcontractors have been at work installing the elevator in the western tower on the Waldo County side that will carry visitors to the observatory atop that tower. Crews are working on the observatory platform, which must be completed before the elevator work can be finished. The design of the observatory will allow visitors to step out of the elevator to face a wall of glass that will extend around the entire observation deck providing a 360-degree view of the region.

The crews on the western pylon were completing the tensioning work on the bridge deck Thursday and soon will be ready to pour the final segment on that back span before the deck can be built out to meet Route 1. The eastern end of the deck will be attached to land about a week later.

According to Wheaton, the work on the western side has been a little tricky because the deck has to curve to match the curve on the newly designed approach on Route 1 in Prospect. That is called a “superelevation,” he said, which means crews have to bank the bridge deck and turn it into the curve.

Each end of the bridge also will include expansion joints, which will allow for movement on the bridge as the structure expands and contracts.

Once the ends of the bridge are attached, the focus will turn to connecting the two deck segments over the river. Crews still have to pour the two final 12-foot segments on both the east and west sides of the bridge deck.

Once that is completed and the two final cable stays are installed on each side, there will be about a 10-foot gap between the two ends. In order to pour the final segment, Wheaton said, crews will use a large jack to ease both sides of the bridge slightly apart.

“We’ll move the pylons up to 2 inches,” he said.

Once the concrete is poured and the tensioning work done, the jack will be released.

In addition to all the post-tensioning work done between the individual segments, each segment includes conduits that will hold long, larger post-tensioning bars that will run for 750 feet in the main span and 350 feet in each of the back spans.

After the bridge deck is connected in the middle and the cable stays tightened to the design specifications, the rest of the work will be typical of most bridge structures, Wheaton said.

The state Department of Transportation expects to open the bridge to pedestrian traffic for one day on Oct. 14. People will be able to walk on the bridge and ride the elevator to the observation tower for free on that day only. Nearby Fort Knox will be open free to the public on that same day. After Oct. 14, the observatory will be open to the public only on weekends through the end of October. A fee will be charged after Oct. 14, although that fee has not yet been set.

The bridge deck will remain closed to the public after the opening day celebration as crews complete work on the bridge.

DOT officials hope to open the bridge to vehicle and pedestrian traffic permanently on Nov. 16, the 75th anniversary of the opening of the Waldo-Hancock Bridge.