High-speed construction: Road projects present safety, schedule and engineering challenges
On any given day, nearly one million people drive through three construction projects that Wagman Heavy Civil is currently executing along the I-95 corridor.
Crews are working on two, major interchange upgrades — one at Route 152/Mountain Road, another just over the Delaware line and each valued at about $200 million. Meanwhile on the south side of Baltimore, crews are roughly halfway through a $30 million rehabilitation of the interchange at I-695.
Some of the challenges facing the Wagman teams and other companies working on highway projects are obvious and huge. They have to create massive infrastructure in the midst of kinetic and hazardous environments, and complete that work efficiently, safely and with minimal disruption to the travelling public.
Beyond the obvious challenges, highway construction teams are also contending with shrinking project schedules, expanded use of design-bid-build contracting, a burgeoning adoption of public-private partnerships, and the growing need to fit more traffic capacity into the same highway footprint. With funds from the federal infrastructure package finally getting released, the amount of bridge and highway construction work is expected to expand over the next two years.
In highway projects, “the biggest challenges are always traffic control and trying to keep our workers safe and motorists safe while traffic keeps moving and construction progresses,” said Kevin Thatcher, Vice President and Chief Estimator at Gray & Son.
An accident on I-695 in March 2023 delivered a horrifying reminder of the hazards of highway construction. Two speeding motorists collided. One car spun out, went through an opening in the concrete barriers around a construction site and killed six workers.
The tragedy prompted stand-downs and safety reviews in companies involved in roadwork.
It also spurred action by the state government. The Moore administration is now pressing the General Assembly to pass The Worker Protection Act, which would authorize multiple safety measures, including reducing the speed limit around highway construction sites to 45 mph and allowing crews to cordon off an additional lane to put more distance between drivers and workers.
Gray & Son, which is currently working on a four-year, four-phase project to renovate, modernize and widen I-695 between I-70 and I-95 on the northeast corner of the beltway, welcomes the changes. A 45-mph speed limit has already been imposed on part of the beltway during construction hours and Gray & Son is collaborating with state officials to post state police at the construction site whenever crews are doing night work, Thatcher said.
Protecting workers and drivers also requires construction companies to complete meticulous bidding and project planning, said Todd Becker, Senior Vice President at Wagman Heavy Civil.
“Safety of the public and our workers is the paramount concern,” Becker said. “Projects today also have to be delivered faster and we are limited in how much road we can shut down. Those are tremendous challenges and we have to consider all of them in the bidding process.”
Precise project planning is essential for meeting the schedule, finances and safety requirements of a project.
“If you are not carefully pre-planning, then you can put yourself in a position where you didn’t think of something and you are scrambling a little. You don’t want that situation in that environment, so you work to take that variability out of your operation,” he said.
That planning also aims to minimize nightwork, Becker said. Workers often can’t access needed services or supplies if equipment breaks or additional materials are needed at night, and that can impede construction.
Growing use of design-bid-build contracting is helping companies meet the challenges of highway projects.
Wagman has teamed up with engineering firms to secure several design-bid-build projects.
“We welcome the system,” Becker said. “Internally, we have some very creative and skilled people who can look at a job and identify different opportunities. Maybe it’s an opportunity to improve the staging of a project. Maybe our engineers can look at a proposed type of wall or foundation and propose better alternatives.”
Although the design and bidding process can take up to two years, construction of such projects tends to move more quickly and smoothly, Thatcher said. “The project plans are really new, as opposed to a plan that was pulled off the shelf from 10 or 15 years ago. Once you start construction, the drawings are complete and current so you don’t end up dealing with any large changes in the middle of construction.”
Highway projects in central Maryland, the District of Columbia and Northern Virginia, however, are facing an increasingly common design and engineering challenge. Traffic planners need to increase the capacity of major roads but typically don’t have the option of acquiring adjacent land to build new travel lanes.
Consequently, many projects — including the current I-695 renovation and the I-495 Northern Extension (NEXT) project near the American Legion Bridge — are, in places, converting existing shoulders into new travel lanes. That conversion can present geotechnical and structural challenges to project teams.
“Having a limited right-of-way to create those new lanes means we have to build supporting embankments steeper than we might like or add vertical retaining walls,” said Randy Wirt, Vice President and Director of Engineering at ECS Mid-Atlantic. ECS is the geotechnical engineering consultant on the NEXT project.
“From a geotechnical engineering perspective, it is a question of slope stability,” Wirt said. “We can’t build certain slopes at very shallow angles because we don’t have the room. The steeper you make the slope along the side of the highway, the more potential you face of having a slope stability failure. We have to look carefully at the kinds of materials we can put in the embankments to make sure they are safe long term.”
Projects along I-695, I-495, I-95 and other major routes also frequently raise the need for ground alternatives.
“For example, you have to deal with bridge abutments where the tallest portion of the steel or concrete bridge rests on a supporting abutment. You have fill material that goes behind the retaining walls of that structure,” Wirt said. “In some places, settlement is an issue so you can’t just place conventional soil and rock behind that wall. You have to use lightweight fill alternatives for stability and to prevent long-term settlement.”
Contractors expect to start tackling a lot more highway and bridge improvements in the region over the next two years. Increased funds from the federal infrastructure package are about to be released after a long delay.
“By the end of 2023, only about 25 to 30 percent of those funds had been put into the market,” Wirt said. “I think ’24 and ’25 will see more project contract opportunities and probably additional IDIQ-style (indefinite delivery/indefinite quantity), task-order based contracts with state departments of transportation.”
In Maryland, Thatcher expects a significant amount of new projects to focus on bridge rehabilitation.
“A lot of bridges in the State of Maryland are rated B, C or D … so one of the things the state needs to focus on is getting the bridges back in good structural soundness,” he said.