R.S. Audley Utilizes Link-Belt Lattice Crawlers for New Hampshire Bridge
R.S. Audley, Inc. of Bow, New Hampshire was awarded the contract for replacement of four northbound lanes of Little Bay Bridge, a nine-span steel girder bridge that carries Route 4, NH Route 16, and Spaulding Turnpike over the Piscataqua River in southeast New Hampshire. Little Bay Bridge carries well over 70,000 vehicles each day and is forecasted to carry 94,000 vehicles by 2025.
In order to complete the project, R.S. Audley had to remove over three million pounds of old 1960’s era steel using several cranes from their fleet, including a Link-Belt 110-ton (99.79-mt) 218 HSL lattice crawler crane.
By mid-2016, the replacement of steel for the refurbished northbound lanes of Little Bay Bridge had begun. Steel erection was done by working from both ends of the new bridge structure [1,589 ft. (484 m) in length] to the center, five girders across with diaphragms connecting and strengthening the superstructure over the existing piers.
R.S. Audley purchased a new Link-Belt 238 HSL 150-ton (136-mt) lattice crawler crane and rented a 298 HSL 250-ton (227-mt) from Link-Belt distributor, Wood’s CRW to complete the final steel work for the bridge.
One of the most difficult elements to the steel replacement was the natural element of wind gusting up the bay from the Atlantic Ocean. For lifts toward the center of the bridge, both Link-Belt cranes were used in the early morning before winds picked up – one crane for each 100 ft. (30.5 m) beam. The 155 ft. (47.2 m) long center beams weighed 78,000 lbs. (35 380 kg) each. The cranes lifted in unison and the beams were adjoined in the middle to form the center span. Steel diaphragms were installed the rest of the day to space the beams alongside each other.
“Aside from the wind, the 3 percent grade change coming up the bridge is something else to take into consideration, you must adjust each pick point a little bit to make sure the beam is hanging correctly for final placement. Using two 25-ton Crosby beam clamps, the operator is able to reach out to the predetermined point, make sure it’s hanging correctly, pick it up and swing it out into position and marry it up to the previously set field splice,” explained Scott Stevens, Vice President with Audley.
In order to work up and down the bridge deck meant R.S. Audley Inc. only had the working space of two lanes at a time, which was 28 ft. (8.5 m) wide, to operate the two Link-Belt cranes. The new span went five girders across with diaphragms connecting and strengthening the superstructure over existing piers.
“The only weight restriction we had was keeping the “moving” load of our cranes down below 300,000 lbs. We were able to do this by removing counterweights as necessary during travel between pick locations. The stacked counterweights of the 238 and 298 made this a simple and straightforward process,” said Stevens.
Link-Belt Cranes, with headquarters in Lexington, Kentucky, USA, is a leader in the design and manufacture of telescopic boom and lattice boom cranes for the construction industry worldwide.