Balfour Beatty US is the general contractor responsible for the delivery of the Topsail Island Bridge Replacement project on NC 50/210, which is on schedule for completion 300 days ahead of contractual requirements. The high-profile bridge project involves the complete replacement of the existing steel truss swing-span bridge with a two-lane, fixed-span, high-rise bridge over the Intracoastal Waterway (ICW) and associated approaches at beach end. The new bridge is currently under construction just south of the existing bridge. When it opens to traffic in 2019, Balfour Beatty will demolish the original structure.
Originally built in 1954, the existing, functionally obsolete bridge is one of two bridges that provide access to and from Topsail Island. Traffic must be stopped and the bridge mechanically turned 90-degrees to allow large vessels to travel the ICW because of the bridge's low clearance a process that can stop traffic for as much as 30 minutes.
The new 3,700 foot, 29-span, high-level Topsail Island bridge has a 65-foot clearance to accommodate marine traffic below without disrupting vehicle traffic above.
Since the shallow depths of the wetlands and adjacent waters of the ICW prohibit the use of barges for material deliveries to the project area, the team had to put the trestle in place in its entirety to access the 3,700-foot bridge deck. By using drivel piles, Balfour Beatty was able to complete the 4,000-foot-long trestle within the in-water work window of October 1, 2016, to March 31, 2017, to begin construction on the bridge structure. If the team did not complete the trestle prior to the start of the fish moratorium on April 1, 2017, the delivery of the entire bridge could have been delayed by a year.
Balfour Beatty made creative adjustments to the schedule to drive the piles and complete the trestle while meeting in-water work limitations. To start, the team worked double shifts seven days each week to drive approximately six 30-inch steel pipe piles per shift and installed the trestle structure to gain access to the next pile locations. With limited storage on-site, the team scheduled pile deliveries for on-time delivery staggering the deliveries of piles sourced from existing projects in Wilmington, N.C., Savannah, Ga., and Milledgeville, Ga., to exactly the right the amount of piles needed each day.
In addition to this complex coordinated scheduling effort, the team had to work with the Coast Guard to redesign access across the ICW to solve inadequate access issues present in the original design documents. Balfour Beatty successfully completed the redesign and drove 39,870 feet of piles within the first six months of the project. Working with the U.S. Army Corps of Engineers, the North Carolina Department of Environment and Natural Resources and the North Carolina Division of Coastal Management, Balfour Beatty was able to complete the work using environmentally sensitive methods. Throughout it all, the team has not incurred any environmental violations, lost-time or recordable safety incidents.
Originally contracted for completion by 2020, Balfour Beatty is on schedule to open the Topsail Island Bridge to traffic in 2018 300 days ahead of the contractual schedule. This extraordinary feat would not be possible without the use of driven piles.
All eyes are on this critical infrastructure project as the new Topsail Island Bridge winds its way across the ICW. To date, the existing bridge, providing the only southern point of access to the island, is functionally obsolete and structurally inefficient. Its low clearance and swing-span design cannot simultaneously accommodate vehicle and marine traffic as it must be mechanically-turned every hour to allow marine vessel passage. Residents and visitors are anxiously awaiting the delivery of the new bridge, which will increase traffic capacity and allow for safe marine passage without affecting vehicle traffic flow.
Special innovation in construction techniques, equipment and/or materials
Designing a temporary trestle to support pile driving and bridge construction is no easy task particularly when there are access and schedule restraints, and the trestle provides the only access to the bridge for construction. Upon the award of the project in August 2016, Balfour Beatty immediately recognized insufficient access at the ICW to build the trestle and the bridge. With only six months to complete all in-water work, including the 4,000-foot trestle and its 39,870-feet of driven pile, Balfour Beatty had to act fast. The team worked with the Coast Guard to redesign the access and commence pile driving efforts as quickly as possible. However, delayed right-of-way acquisition and regulatory issues delayed the team's access to the site even further. The team did not mobilize the pile driving and trestle installation effort until November of that year, which cut the already-tight, in-water work window by a third. To recover this blow to the schedule, Balfour Beatty engaged the team of 40 field employees to work two 12-hour shifts each day, seven days each week.
The trestle is divided into two parts: one trestle extends to the ICW from the mainland side and another trestle extends from the island side. With the access issues resolved by the team's initial redesign and coordination with the Coast Guard, Balfour Beatty still had to maintain clearance through the waterway. To do so, the trestle does not meet in the middle. This allows marine traffic to safely move through the construction site on its way through the existing bridge. The team coordinates work on each side of the trestle each day to avoid delays associated with crossing the existing bridge to access the other side.
The temporary trestle was the only point of access to construct the bridge deck, and the compact work site provided no material storage space. Looking ahead, Balfour Beatty designed the temporary trestle system to support immediate equipment traffic and subsequent use of two 275-ton cranes that would be necessary to set the 180,000-pound horizontal bridge girders in place in March of 2018. Balfour Beatty also devised a complex, staggered delivery schedule for the 90-foot piles to be driven in rapid succession. With daily deliveries of piles, the team had to move the 90-foot piles from the trucks to the trestle quickly and safely to drive them into the riverbed each day. If the team encountered delays in its daily pile driving quota, they would have no space to store additional piles on the compact work site.
Construction problems and creative solutions
The annual fish moratorium and site access issues contributed to the challenging execution of this pile driving and bridge construction project. The team completes daily work on the bridge from two compact site locations and is further challenged by the large volume of vehicle and marine vessel traffic that interacts with the project area on a daily basis.
Ranked number two on the ENR 2017 list of Top Contractors in the Southeast, Balfour Beatty regularly delivers complex infrastructure projects in challenging locations. The team used its lessons learned from similar roadway and bridge over water projects built throughout California to develop and adhere to a strict daily schedule of tasks for the Topsail Island Bridge replacement project. By following and adjusting the schedule as necessary, Balfour Beatty has been able to stagger deliveries for all construction materials to avoid storage issues. The team also avoids incurring time delays related to driving across the existing bridge to access the other side. At the start of each shift, after the job briefing and safety discussion, Balfour Beatty ensures that the correct field forces are in place on each side of the divided trestle and equipped with the correct materials to execute the day's work without wasting time traversing the site. This coordinated approach to on-time material delivery and an emphasis on lean construction enabled Balfour Beatty to drive piles as they arrived on site and ultimately expedite the entire project schedule.
The new high-level bridge will be almost 4,000-feet long and 53-feet wide. Balfour Beatty is currently completing phase one of the project to construct the 29-span bridge, roundabout intersections, MSE walls and approaches that will connect the new bridge to the existing roadways on the mainland and the island. Once complete, the team will begin phase two, which involves tying in the roadways and switching traffic onto the new bridge. During phase three, Balfour Beatty will remove the existing swing bridge, reduce the roads from three lanes to two and add a new 10-foot-wide multi-use pedestrian path. Constant attention to the short-term and long-term schedules is a key component of the team's successful delivery of these multiple project components.
Cost saving measures
Expediting the overall project schedule enabled the Balfour Beatty team to avoid unexpected project costs. By meeting the initial in-water work window at the start of the project, Balfour Beatty is on track to open the high-level bridge to traffic nearly one year ahead of schedule. This type of achievement is nearly unheard of in infrastructure project delivery and it stands to infuse millions of dollars back into the local economy. With increased traffic capacity and improved commuter times, the new Topsail Island Bridge will bring tourists to the beach destination more quickly each day. It will make the area a more attractive destination for vacations, events and the retail businesses needed to support the increase in consumer traffic.
Innovative project management
Led by Balfour Beatty's area operations manager Jay Boyd, superintendent Mike Ewell and project engineer Robert Mann, the team has worked together to coordinate multiple project components to keep the bridge project on schedule. The established team has worked together on many similar marine projects with restricted work windows such as the nearby Wilmington Bypass project in Wilmington, N.C., a previous PDCA Project of the Year Award Winner. These proven team relationships provided a strong foundation to implement similar strategies and methods to deliver a successful bridge project for the residents of Surf City and Topsail Island.
Located just 30 miles northeast of Balfour Beatty's southeast region headquarters in Wilmington, N.C., the management team filled other critical staff and production positions with personnel familiar with projects with pile driving efforts of this magnitude. Coupled with the understanding and familiarity with the local subcontracting community, this team continuity has enabled Balfour Beatty to drive 37,980 feet of piles, install 4,000 feet of trestle and nearly complete the structure of the new bridge in record time.
Additionally, for the complex operation to put the 180,000-pound horizontal girders in place in the spring of 2018, Balfour Beatty coordinated with the Coast Guard and law enforcement to shut down the ICW to get these girders across the channel. Teammates Mike McDermott, Mike Ewell and Robert Mann contributed to the in-house planning efforts to self-perform the lifts over a meticulously planned two-day operation.
Management or mitigation of environmental considerations
Balfour Beatty is committed to delivering every project with Zero Harm to people and to the environment. Throughout the delivery of the Topsail Island Bridge Replacement project, the team has maintained that commitment and instilled a strong Zero Harm culture on-site.
The team is familiar with the intent of fish moratoria and the adverse effects that large infrastructure construction projects can have on the environment when contractors do not exercise extreme care throughout project planning and delivery. From the moment of project award, Balfour Beatty worked closely with the U.S. Army Corps of Engineers and the North Carolina Division of Coastal Management to learn about the environmental considerations specific to the stretch of the ICW running through the Surf City, N.C., area. They met all of the permit requirements for the six-month window that prohibits bottom-disturbing construction activities in the shallow water of the site's stretch along the ICW, and they have not incurred any environmental citations throughout the project's lifetime.
Balfour Beatty has full-time environmental inspectors assigned to the project and the team coordinates monthly environmental inspections from the U.S. Army Corps of Engineers, North Carolina Division of Coastal Management and North Carolina Department of Environment and Natural Resources. These monthly inspections are instrumental in successfully minimizing delays and ensuring all environmental conditions in the permits are strictly followed. Team safety discussions at the start of each work shift include updates on environmental conditions and considerations for construction activities that could disrupt local wildlife or pollute the water in any way. As part of the project environmental mitigation plan, the team also carefully monitors operations to ensure that materials and trash have not fallen into the water.
Together, with this focus on Zero Harm and a consistent attention to detail, Balfour Beatty has met the permit requirements and maintained environmentally sensitive construction practices for the environmental health of the project area.