As many contractors know, it can be a hard enough task to adhere to a schedule that brings a project completion in on time.
But 17 months early?
That's what happened not long ago, when the Lowell, MA-based S & R Corporation found out that the $12.7-million Mass Highway bridge project they were working on had to be completed 17 months ahead of schedule.
It was in spring 2007 that the replacement project of the Route 1A Bridge over the Parker River in Newbury, MA, was awarded to S & R. The project was a multiphase construction sequence utilizing the existing bridge to maintain traffic during construction. The original completion date was September 17, 2010.
At the start of the project, it was discovered that the deteriorated condition of the existing structure would not permit safe travel of the public over the Parker River, and that the bridge would have to be taken completely out of service. Since Route 1A is a critical coastal roadway, the replacement of the bridge needed to be done at an accelerated rate. The accelerated project schedule required the bridge to be open to traffic 17 months ahead of the original completion date.
To achieve the new schedule, S&R and the Highway Department's project team modified the construction sequence and the methods of accessing vital work activities in the river such as demolition, control of water, shaft construction, and New England bulb tee erection.
The most challenging task was the erection of the 60-ton bulb tees from land – since construction of a temporary structure in the river to stage cranes for the big lifts would have required months of review and permitting to do the work.
The final plan called for two 300-ton-capacity Manitowoc 4100W ringer cranes – one to be assembled at each abutment. The bulb tees were then loaded onto a barge and floated into position, where they could be lifted off the barge and set into the final location using a single crane for each end span and a tandem lift for the center span. The bulb tee erection was completed in mid-September.
The project schedule included the 360-foot cast in place concrete bridge deck placed in early October followed by sidewalks, railing, utilities, and roadwork. With the major modifications to the work process behind the construction crew, the goal of opening the bridge to traffic in April 2009 is on schedule.