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P.A.T.H. Subway Expansion

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Vibration monitoring critical while tunneling in a highly urbanized area

Kilduff Underground Engineering, Inc., was hired to perform design, construction management and vibration monitoring for a new subway cross-passage tunneling project for the Port Authority Trans-Hudson (P.A.T.H.) in Jersey City, NJ.  


Vibration monitoring before and during tunnel excavation was specified below grade at the existing subway platforms the tunnel would be connecting, as well as along the densely urbanized street some 60 feet overhead. Kilduff turned to Inzwa to ensure the excavation activity did not create any adverse impact to existing structures — including P.A.T.H.'s headquarters directly above the excavation site.

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"Three Inzwa Veva III vibration monitors up, one down"

Shrey Arora, lead engineer for Kilduff on this project, placed one Inzwa Veva III vibration monitor at the excavation site in close proximity to the subway platform.  He placed three additional Veva III monitors at street level along the length of the tunnel site. The devices' small size and integrated, long-lived battery made them ideally-suited to these applications.

"The thing that was really attractive about Inzwa for us was that you don't have to have a power source," Shrey explained.  "It has a built-in battery system, it's portable, it's light, it's small, and you don't need additional data loggers like you have to add on to other vibration monitors," he added.  

Kyle Scanlan, also with Kilduff, agrees. "What I like best about it is it’s lightweight, it’s really easy to install and set up, it provides long-lasting battery life, especially for these projects that go on for multiple months, and it sends the monitoring data via 4G LTE directly to the website that we’re managing daily.  Inzwa’s done a great job designing a product that can be unboxed and set up in minutes," he added.

Another important consideration was how to maintain monitoring integrity where these devices needed to be installed — essentially along a busy sidewalk with hundreds of people passing by daily. The Veva III's compact size and ease of installation made the solution to this challenge simple.

"The biggest hurdle that we face when we’re installing vibration monitoring in a densely populated area such as Jersey City is keeping the device out of the way of passersby and ensuring that theft is not an issue," Scanlan explained. "What we really like about this device specifically is that it has this 5/16” diameter cutout in the center, so all we need to do is pound a threaded bolt into the sidewalk, drop a utility box on top of it, and then mount the device inside it. It provides that peace of mind and comfort knowing that the vibration monitor isn’t going to be tampered with while construction goes on," he concluded.  

"It has a built-in battery system, it's portable, it's light, it's small, and you don't need additional data loggers like you have to add on to other vibration monitors."

"Really nice job, Inzwa."​

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To hear Kyle for yourself, watch the video below.

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