Spanning over 2,200 miles and covering 52 counties, 2 peninsulas and 3 states, the REACH-3MC project has seen its fair share of terrain over the past 2-plus years. Protected shorelines, critical habitats, streams and wetlands are all par for the course. Most water crossings on the project have typically involved smaller streams and brooks, unless of course you consider the fibers Merit obtained across the Mackinaw Bridge–or REACH-3MC’s recent crossing of the Grand River.
That’s right. The longest river in Michigan has a new addition. Conduit that will soon house advanced fiber-optic cable has a place beneath the Grand River’s bed. Though the fiber only crosses at one important interval, it seems fitting for a project that covers as much ground as REACH-3MC to touch the river that stretches from Hillsdale County all the way to Lake Michigan. What’s more, the work it took to install it is perhaps just as impressive as the feat itself.
On a hot Monday morning in July, crews from REACH-3MC construction contractor, Western Tel-Com, and sub-contractor, Utility Contracting Company, gathered in Comstock Park, positioning themselves on one side of a lengthy four-lane bridge in the Grand Rapids suburb. Their task was to perform a directional bore beneath the riverbed that would reach a designated location on the other side of the bridge on the opposite bank. After completing the bore, they would then pull conduit back through to where they started.
Fiber construction crews often joke that by installing advanced fiber-optic cable they are on the low-tech end of a high-tech industry. But really their work requires a good deal of skill. And the process is a testament to modern engineering and the incredible technology that has been developed to deploy telecommunications and other vital infrastructure when crossing waterways, roadways or other environmentally sensitive or congested areas.
With the directional boring machine placed with enough distance from the shore to reach a suitable depth to cross beneath the water, the process begins by drilling a bore head attached to the first of a series of hollow steel rods into the ground at an angle. As one ten-foot rod is drilled into the ground, a member of the construction crew then gathers the next rod from a nearby stack and loads it on to the machine. For each rod successfully drilled into the ground the process repeats. For long bores, dozens of rods are needed–all placed in the ground one after another. Drilling fluid, a mixture of bentonite, clay and water, is added to improve performance and ensure the integrity of the tunnel created by the bore.
In order to track the location and trajectory beneath the ground, a sonde, or transmitter, is placed behind the bore head. It then tracks angle, rotation and directional data of the drill that is sent via electro-magnetic signals to a handheld receiver at the surface. So as the bore makes its way beneath the surface to its intended location, another member of the construction crew follows it above ground, usually on foot, with a receiver. They can then radio back to the bore machine operator to make adjustments like pitch and directional changes. And when crossing a waterway as big as the Grand River, things can get interesting.
That’s right. A member of the REACH-3MC construction crew was out in a row boat on the river with the receiver, tracking the bore’s progress and calling in adjustments to shore. For each ten-foot length of steel rod, he paddled closer to the opposite bank. In part because of the favorable composition of the ground beneath the river, the process went smoothly, and was completed in what seemed like no time at all.
When the initial bore beneath the river had reached the opposite bank, a fresh reel of new conduit awaited, ready to make its own crossing back to the other side. This time the bore head was used to attach to the end of the conduit reel so as to pull it back through hole that had just been drilled. Once the boring machine operator received the radio call from the opposite bank that the conduit was attached, he reversed the process.
The task then from the other side of the bridge was to pull each steel rod back out of the ground with the same machine that drilled them in. Whereas a crew member previously loaded the rods on to the machine as they were installed, now he waited near the boring machine to remove each rod as it was unearthed. As the rods are removed and the conduit pulled through the new path beneath river, the importance of drilling fluid comes into play. The bentonite mixture is critical to ensuring a smooth passage for the conduit.
On the first day on site in Comstock Park, the construction crew successfully bored under the river to reach their designated location on the other side of the bridge. Picking up where they left off, by afternoon of the second day, the last of the steel rods had been removed from the ground, pulling with it the first portion of the conduit that was now successfully deployed beneath the Grand River.
Though the event likely went relatively unnoticed by passersby rumbling over the bridge in their vehicles, the installation of conduit beneath the Grand River has been one of the more exciting achievements of the REACH-3MC project of late. Like many accomplishments of the project, our construction crews had little time to celebrate and reflect as they were at work that very afternoon installing more conduit heading north toward Big Rapids and Reed City. And of course, as we near the project’s completion there is still more to come for REACH-3MC.
About Merit Network
Merit Network Inc., is a nonprofit corporation owned and governed by Michigan’s public universities. Merit owns and operates America’s longest-running regional research and education network. In 1966, Michigan’s public universities created Merit as a shared resource to help meet their common need for networking assistance. Since its formation, Merit Network has remained at the forefront of research and education networking expertise and services. Merit provides high-performance networking and IT solutions to Michigan’s public universities, colleges, K-12 organizations, libraries, state government, healthcare, and other non-profit organizations.
For more information: www.merit.edu
The REACH Michigan Middle Mile Collaborative (REACH-3MC) will build 2,287 miles of open-access, advanced fiber-optic network through rural and underserved communities in Michigan’s Lower and Upper Peninsulas. The network will also provide backhaul to key connection points in Wisconsin and Minnesota. Led by Merit Network, Michigan’s research and education network, REACH-3MC includes sub-recipients from the private sector to make broadband readily available to households and businesses that lack adequate service options in the 52 counties that make up the project service area. REACH-3MC is funded by a two grants (Round I and Round II) from the Broadband Technology Opportunities Program (BTOP) as part of the American Recovery and Reinvestment Act of 2009 (ARRA), commonly referenced as the Stimulus Package.
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