Red-Listed N.H. Bow-Concord Bridge Undergoes Long Awaited Replacement

Tue July 30, 2013 - Northeast Edition
Jay Adams


The replacement of the Bow-Concord, N.H., Bridge on Interstate 93 broke ground on Oct. 13, 2011.
The replacement of the Bow-Concord, N.H., Bridge on Interstate 93 broke ground on Oct. 13, 2011.
The replacement of the Bow-Concord, N.H., Bridge on Interstate 93 broke ground on Oct. 13, 2011. Traffic is still running on the existing northbound bridge, but is scheduled to shift to the second phase of the new southbound bridge sometime in late summer. Currently there is a bridge crew, drainage crew, site crew, and a layout crew. About 50 percent complete, the next phase includes constructing a traffic phasing crossover from southbound to northbound, median barrier and drainage work and complete construction and demolition of the northbound bridge.

The replacement of the Bow-Concord, N.H., Bridge on Interstate 93 broke ground on Oct. 13, 2011. Now mid-phase, the $14.7 million project is under the control of general contractor R.S. Audley Inc., in Bow, N.H.

Audley focuses on roads, bridges, utilities, large site work and unique structural projects throughout northern New England, with many projects in Maine and Vermont. This family-owned company has become one of the state’s largest, most successful heavy contractors. The company has completed, according to its Web site, more than $800 million worth of bonded projects in its history.

NHDOT, bridge owners, are overseeing the replacement of the I-93 northbound and southbound red-listed bridges over Interstate 89 and the Turkey River, some smaller repairs to the Collector Distributor Road Bridge and resurfacing nearly 1,650 ft. (502.9 m) of I-93 and reconstructing 4,050 ft. (1,234.4 m) of highway.

“The general contractor, R.S. Audley, based out of Bow, is a very well-known contractor in the state and is currently working on multiple NHDOT projects,” said Kyle Zorawowicz, CE II, and field support.

Audley’s current project, the Bow-Concord Bridge, is one of the two densely traveled north-south highways in the state. The highway lies about 1,100 ft. (335.3 m) south of the Grandview Road overpass. It extends northward about 1.1 mi. (1.8 km), to just south of Exit 12N on the Interstate.

According to Zorawowicz, steel beams on the southbound bridge lanes have just been put into place. Many sub-contractors have worked on this project, but R.S. Audley does its own site and bridge work. Continental Paving, Inc. is another New Hampshire based general contractor and has been contracted by Audley to perform all of the paving on the project. Delucca Fence & Guardrail, based in Massachusetts, has been contracted to install the entire new guardrail on the project. H. B. Fleming, based in Maine, has been contracted to install all support of excavation, and pile driving for each new bridge foundation.

HUB Foundations, based in Massachusetts, has been contracted to install the drilled shaft foundations for each new bridge pier. Insituform Technologies, a world-wide-based contractor, was contracted by Audley to install a steam cured-in-place pipe liner for a 6 ft. (1.8 m) culvert spanning underneath I-93 from one side to the other. JCB Colby, based in Vermont, has been contracted to perform all of the concrete flatwork and masonry headwalls on the project.

Currently there is a bridge crew, drainage crew, site crew, and a layout crew. All crews have been working days 6:30 a.m. to 4 p.m. unless night work is needed.

“Depending on the day, there can be upwards of 7-plus crews working on the project,” said Zorawowicz.

Structural steel came from Casco Bay Steel Structures Inc., based in Maine. All of the reinforcing steel came from Barker Steel, based in New Hampshire.

According to Zorawowicz, the existing bridges were constructed in the 1960s. The bridges have been high ranking red list bridges in the state for several years and have been in dire need of replacement. The first phase of the new I-93 southbound bridge is complete and traffic has resumed. The old southbound bridge has been demolished.

Traffic is still running on the existing northbound bridge, but is scheduled to shift to the second phase of the new southbound bridge sometime in late summer, according to Zorawowicz. Traffic will be travelling north and south, separated by an anchored jersey barrier, on the new I-93 southbound bridge while the existing northbound bridge is demolished and the new northbound bridge is constructed.

About 50 percent complete, the next phase includes constructing a traffic phasing crossover from southbound to northbound, median barrier and drainage work and complete construction and demolition of the northbound bridge. In addition, patching concrete scaling on the collector-distributor bridge that sends traffic northbound on Interstate 89 and takes traffic from I-89 southbound to I-93 southbound will be necessary.

“The existing bridges are of high-priority on the New Hampshire red-listed bridges list and have significant concrete scaling where there are multiple locations with exposed rebar on the piers and pier caps,” said Zorawowicz. “There were nets installed underneath the existing decks to catch any falling chips of concrete.”

The old southbound bridge carried only two lanes of traffic; the new bridge will carry three lanes. The existing bridges were both 5-span bridges. The two new bridges will be two-span bridges, and provide a cleaner look, according to Zorawowicz.

There are approximately 31,000 cars that travel on both north and southbound bridges daily. This number does not include the traffic that diverts off from I-93 south to I-89 northbound and from I-93 northbound to I-89 southbound.

The new northbound bridge will carry two lanes of traffic, but will be constructed with an extra-large 24 ft. (7.3 m) shoulder for possible future expansion. The extra-large shoulder will provide another lane for the traffic shifts performed during the two weeks NASCAR races in Loudon, according to Zorawowicz.

“One of the biggest sources of state revenue we have is the NASCAR races each summer in Loudon,” said Zorawowicz. “The two lanes up to Loudon get tight. Going north is easier as the fans usually go up to stay a week earlier, before the races. But when the races are over, southbound is much tougher. We currently have portable barriers and push the southbound traffic into the northbound, leaving a single lane northbound and multiple lanes southbound and it is still tight. We want very much to accommodate the traveling public without delaying them for hours and hours.”

NHDOT is making strides on local highways. Besides Bow-Concord, there is the Hooksett Toll Plaza project, a $22.9 million project with an anticipated completion of early October 2013.

This project consists of converting the Interstate 93 mainline cash and EZPass Toll Plaza in the town of Hooksett to an open road tolling facility. The project includes the widening and rehabilitation of the existing toll plaza, roadway widening and reconstruction and bridge rehabilitation.

Another major project is the widening of the Seabrook, N.H., road with an estimated cost of $6.3 million with a completion date of June 2014.

This project will widen N.H. 107 from the westerly limits of the Interstate 95 on and off ramps east to the intersection with U.S. 1 to accommodate the addition of two lanes. The N.H. 107 Bridge over I-95 will be widened 29 ft. (8.8 m) on the south side. Curbing, guardrail and fencing will be replaced on the north side. The existing deck will be rehabilitated using full and partial depth deck repairs and include the placement of new pavement and membrane.

The current NHDOT project Bow-Concord has required an impressive amount of materials.

Both northbound and southbound bridges will need 1.2 million lbs. (544,310.8 kg) of structural steel set on the project. Half of this amount was lifted into place in May and June.

The project total for concrete will be about 2,700 cu. yds. (2,064.3 cu m) and 1,000 cu. yds. (764.6 cu m) of that will be placed for solely the deck and the remaining 1700 cu. yds. (1,299.7 cu m) will and has been placed in the abutments, approach slabs, drilled shafts, piers, and pier caps according to Zorawowicz. There is 24,435 sq. ft. (2,270 sq m) of pre-stressed concrete bridge deck panels scheduled to be installed on the project and 26,000 tons (23,586.8 t) of asphalt to be paved on the project.

“We are currently on Phase Two of the bridge construction,” he said. “The northbound bridge has to come down now. We are currently building the second half of the southbound bridge. We left the deck rebar sticking out in order to do a closure pour. There is a big gap currently, but we will be forming the new bridge decks in Phase Two and tying in both bridges.”

Bow Brook had to be temporarily diverted in order to perform repairs and extend the 6 ft. (1.8 m) culvert underneath Interstate 93. Crews constructed a new stone-lined ditch for Bow Brook according to Zorawowicz. Bow Brook is now a new stream bed approximately 20 ft. (6 m) west of its original configuration.

“We even installed a custom babbling brook at the inlet with some handy excavator work and we also had New Hampshire Fish & Game come out on site to direct the installation of boulders in the stream line for trout and other fish to possibly live and lay eggs,” said Zorawowicz.

Years of meeting local officials in both Bow and Concord, public planning sessions, presentations, designs, bids and countless hours of public affirmations had to be performed before a single shovel went into the earth in October 2011.

Zorawowicz had great praise for the area, the officials and those who have to drive through it.

“I would like to thank the travelling public for bearing with all of the construction delays pertinent to the project,” said Zorawowicz. “I know it can be a pain to travel through on some days but it will ultimately benefit everyone in the end.”