KITTERY — Aided by the tides, construction crews installed a lift span Wednesday on the new Sarah Mildred Long Bridge, a major step toward completing one of the biggest and most expensive bridge construction projects in Maine’s history.

A 4 million-pound structural steel span the length of a football field was floated over the Piscataqua River on two barges Tuesday and maneuvered into place at the center of the new bridge that connects Kittery with Portsmouth, New Hampshire.

The operation was timed to take advantage of the 9-foot-plus tidal range on the Piscataqua.

The span rose into place with high tide Wednesday morning and dropped onto bearings on the bridge’s lower deck as the tide went out in the afternoon. The modular two-level bridge has a lower deck for locomotives that need to access the Portsmouth Naval Shipyard and an upper deck that carries vehicles on Route 1 about 56 feet above the river.

Crews install the 4 million-pound concrete lift span, center, approximately the length of a football field, on the Sarah Mildred Long Bridge connecting Kittery to Portsmouth, N.H. At $160 million, it’s expected to be the most costly bridge construction in state history.

Installation of the lift span is one of the last few steps before the bridge opens to traffic in mid-November, according to the Maine Department of Transportation. An old bridge in the same location had been closed to traffic since August 2016, when it malfunctioned and was stuck in the elevated position. That bridge was demolished last October.

After the span is fully installed, crews will race to complete paving, said Joyce Taylor, chief engineer at MDOT. Construction began in 2015.

“We are kind of dependent on the weather right now,” Taylor said. “We are trying to maneuver around the cold weather we know is coming.”

The bridge has a four-pulley system on four 200-foot concrete towers that raises and lowers the span when a vessel needs to pass through. It is higher above the river than its predecessor, and designed to cut by two-thirds, from 3,000 to 1,000, the number of times it needs to be raised to allow ships to pass through.

Because of the construction work, the U.S. Coast Guard has closed the river about a thousand feet around the bridge to all vessels until Oct. 27.

The project is expected to cost $160 million, the most expensive bridge construction in state history, Taylor said. Construction is a joint project of the Maine and New Hampshire departments of transportation, with the Maine team leading the project. The cost is shared between the two states, said MDOT spokesman Ted Talbot said.

“This is a state-of-the-art bridge, very complex,” said Peter Vigue, president and CEO of Cianbro, the Pittsfield company contracted to build the bridge.

Working with tides is a common way to install lift-span bridges, but the Piscataqua tides are particularly intense, he said.

The Sarah Mildred Long Bridge is one of three that connect Kittery and Portsmouth. A taller bridge to the west carries Interstate 95, and the smaller Memorial Bridge to the east connects downtown Portsmouth and Kittery village. The bridge’s namesake, Sarah Mildred Long, was a 50-year employee of the Maine-New Hampshire Interstate Bridge Authority.

Drivers accustomed to using the bridge have been detoured to I-95 for more than a year. The bridge carried 14,000 to 15,000 vehicles a day before it was closed.

The new bridge has a 100-year life expectancy. The old bridge was 76 years old when it was demolished. Officials opted to pay for higher-cost materials and build it with concrete, not steel, in an effort to moderate future maintenance and repair costs, Taylor said.

“It’s a beautiful bridge I think, but we weren’t looking for the prettiest bridge in the world,” she said. “We wanted it to stand the test of time.”

Peter McGuire can be reached at 791-6325 or at:

pmcguire@pressherald.com

Twitter: PeteL_McGuire

This story was updated at 10:30 a.m. on Oct. 19 to correct the type of material used in the bridge span.

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