Two precast concrete culvert projects in the Northeast offer durable, long-lasting solutions for one of the nation’s most concerning issues.
By Mason Nichols
Since 1880, average sea levels across the globe have increased by 8 inches, with 3 of those inches gained in just the last 25 years, according to the National Geographic Society. At first glance, that difference may seem inconsequential, but even a small change can have a devastating impact on habitats, including erosion, an increase in dangerous tropical weather and higher rates of flooding.
The question then is, what can communities do to help mitigate flooding? Specifiers are turning to precast concrete, a durable, resilient building material that is designed to not only meet current needs but continue to provide an optimal solution for years to come.
A river “Runnins” through it
The towns of East Providence, R.I, and Seekonk, Mass., are separated by the Runnins River, an approximately 9-mile waterway that forms part of the boundary between the two states. For years, extreme storm events meant flooding issues for residents in the area. As a result, East Providence officials applied for and received a flood prevention and mitigation grant to solve a major issue for the crossing at Warren Avenue – one of the area’s busiest thoroughfares.
According to Jan Greenwood, P.E., senior project manager for lead engineering firm Woodard & Curran, the existing culvert at the crossing was insufficient, necessitating a change.
“A hydrologic/hydraulic analysis of the river revealed that the existing culvert at Warren Avenue is undersized,” she said. “Under high flow conditions, the water rises above the existing culvert and backs up into an upstream neighborhood.”
To solve the issue, Woodard & Curran partnered with local general contractor J.H. Lynch & Sons and Scituate Concrete Products of Marshfield, Mass., to supplement the outdated culvert with the addition of two runs of 3-foot-tall, 7-foot-wide precast concrete box culvert. The new precast culverts provide additional flow area for the water to pass, reducing backup into the flood-prone neighborhood.
As a design-build project, the three entities involved worked closely, collaborating from the onset of the work to identify various culvert configurations. And while deciding on the ideal approach was relatively straightforward, getting the final go-ahead from officials was not.
“This project was delayed for over a year due to some issues between East Providence and Seekonk regarding who had jurisdiction,” said Bill Griffin, sales representative for Scituate Concrete Products. “But the culvert was made ahead of time, so we were ready to go when they were.”
With the approvals in place, J.H. Lynch & Sons got to work in Summer 2019. Because the Warren Avenue crossing is a heavily used roadway, the local department of transportation allowed a maximum of 30 days to complete the job. The bulk of that time was spent performing prep work, including excavation, demolition, grading and dewatering. But according to Chris London, P.E., project manager with J.H Lynch & Sons, the precast culvert installation only took a few days, which was vital in ensuring the work was completed ahead of the DOT-specified timeline.
“This project would not have been possible to build in the manner that we did without precast concrete,” he said. “If we were casting these culverts in place, it would have taken far more than 30 days, and in that scenario, we probably wouldn’t have been able to detour the roadway. That would have resulted in a greater impact on traffic and a higher cost to the public as well.”
Greenwood agreed with London.
“The precast products were instrumental in this project because of their quick installation time,” she said. “It was important to minimize the time working adjacent to the river since rainstorms would cause a rise in the water level that could make the work more difficult.”
Thanks to the use of precast, the entire project was completed in fewer than four weeks, meeting the DOT’s stringent schedule and providing area homeowners with much-needed flood relief.
A Culvert for the ages
Approximately 400 miles to the southwest, citizens of Ellicott City, Md., were dealing with their own flooding problem – but on a much larger scale. While 2018 saw a record amount of rainfall for the state overall, May 27 was a particularly catastrophic day for the city. In the span of just three hours, more than eight inches of rain fell, with some areas receiving more than 10 inches.1 The storm came just two years after the city experienced another devastating rain event that caused severe land erosion and massive damage to buildings.
At the intersection of Main Street and Ellicott Mills Drive, an aluminum culvert installed in 1970 was all that stood between the roadway and the torrential rainfall. But as the storm continued to pound the city, the culvert failed, resulting in the loss of a 25-foot portion of the Ellicott Mills roadway.
According to Thomas Butler, P.E., deputy director for the Howard County Department of Public Works, the culvert failure – along with other residual damage generated by the storm – resulted in more than 200 cars being swallowed by the water. Faced with an emergency and the need to quickly rebuild the roadway, Howard County officials turned to precast concrete for the replacement culvert.
“The decision to go with precast was twofold,” he said. “The weight of precast in the channel forever and a day is going to be a better product than what was there previously. Precast was also an optimal solution due to ease of construction – we needed to rebuild the roadway quickly.”
Howard County officials got to work selecting their project partners, which included Oldcastle Infrastructure for the precast concrete and Allan Myers for the general contracting work. Oldcastle’s plant in Fredericksburg, Va., produced the precast. Larry Ramsburg, Oldcastle’s director of manufacturing, northeast region, said the assembled box culvert was approximately 200 feet long.
“This was produced as what we call a Type II culvert, or clamshell,” he said. “You have the floor and half the height of the wall as one piece and the roof with half the wall on the other piece. These go together as a top and base, open-ended, and then there are 5-foot section lengths that go together end-to-end to make up the 200-foot run.”
As Butler explained, the intersection needed to be rebuilt fast because it serves as a major connection for emergency responders and is located at a critical point along the city’s evacuation route. With a short timeline, close-knit teamwork and collaboration were key to ensuring a successful project. According to Jeff Dremel, senior project engineer for Allan Myers, all three parties recognized this and operated accordingly.
“Through the design phase and with the selection of the culvert, everyone worked together,” he said. “Even during the shop drawing review process and any of the changes that were made, everything went smoothly.”
Oldcastle set up operations in Fredericksburg so a top and a base section could be poured each day. For easier installation in the field, the base sections were shipped upright, even though they are normally manufactured on their side. After production was completed, 59 loads – including accessories – were shipped from Virginia to Maryland over the course of seven days.
To prepare the site for the precast culvert installation, Allan Myers team members removed the debris, performed excavation work, prepped the subgrade and installed a pump-around system to handle the existing stream. While this system was essential to allowing the installation to occur, due to the geographic conditions in the area, any significant rainfall would be too much for the pumps to handle, causing slight delays in the work. Even with hiccups caused by rain, installation was completed in less than two weeks.
“First and foremost, precast expedited the installation, and even with the days that we lost due to weather, we were able to come back and just regrade the stone,” he said. “Beyond that, we didn’t have cure times, we didn’t have to worry about shoring and re-shoring, and we didn’t have formwork or rebar in the existing channel that we had to clean up or worry about losing.”
Ramsburg tacked onto Dremel’s assessment, noting precast’s extreme durability as paramount for the continued service of the roadway.
“Typically, a precast concrete culvert has about a 100-year life expectancy before you have to do anything to it,” he said. “In the long run, if you want to put something in that will withstand the test of time, precast is definitely the route to go.”
To ensure roadways remain intact and transportation systems stay in operation, architects, engineers, general contractors and specifiers require a building material with the durability and resiliency necessary to fight back. Precast concrete culverts meet these needs, providing the long-lasting service life to support communities, the quick installation times required of emergency work and the flexibility needed to make nearly any imaginable project possible.
Mason Nichols is a Grand Rapids, Mich.-based writer and editor who has covered the precast concrete industry since 2013.