Night shift to set precast u-walls on north end of project starting Monday
Temporary impacts on night-time traffic on Seymour Street coming up
Downtown construction has progressed rapidly since a crowd gathered midday last Friday to watch the 300-ton crane lift and set the first piece of Middlebury’s new rail tunnel.
Over the weekend 50-plus bottom u-wall pieces were set in place south of Merchants Row as well as a handful of tunnel tops where Merchants Row will cross over the tunnel. (The tunnel consists of two precast concrete sections: a bottom u-wall and and a top u-wall.)
During the week, Kubricky extended the bottom u-wall sections up to the north end of the tunnel underneath Main Street. Kubricky now expects to complete setting all 94 precast tunnel pieces by Friday or Saturday. About two dozen tunnel tops were in place by late afternoon Thursday, when the photo below was taken.
Once the tunnel tops are in place, Kubricky and Bay Crane will break down and truck out the 300-ton crane that was assembled on Main Street just four weeks ago and quickly became a focus of attention downtown. The 200-ton crane on the south end of the project left town earlier this week.
As I mentioned last week, the rapid transformation now taking place downtown is something worth seeing. So if you have an opportunity to do so, I’d really encourage you to join the spectators young and old lining the walkway alongside St. Stephen’s and take a look for yourself.
If you aren’t able to make it downtown, VTrans has set up a link whereby you can view a regular feed from their time-lapse camera mounted on the roof of the Duclos Building. You can check that out here.
Before we move on to more construction details, I wanted to share the following photos taken from “down below.” I’ve included them here because I think they give a better sense of the size and scale of the rail tunnel. Viewed from the St. Stephen’s walkway, it can appear smaller than it really is. As someone said to me when the first tunnel piece went in, “Are you sure the train can fit through there?”
Tunnel Pieces Are In, What’s Next?
Setting the precast tunnel pieces in place is just the first step of many in building a working rail tunnel.
Each piece is joined to its neighbor with about 20 bolt connections and the bolt pockets are then sealed with grout. Each u-wall is triple sealed with butyl rubber, what's known as an expandable water stop, and a sheet membrane, all of which are designed to keep water out of the tunnel.
Next, a ballast mat is laid in place to protect the precast from the stone ballast that provides a bed for the rail track. In the photo below you can see the black ballast mat as well as an under-drain (the green pipe) whose purpose is to drain any stormwater that finds its way into the tunnel. The under-drain feeds by gravity into the drainage system that we’ve watched being built these past several weeks between the bridges.
Kubricky will begin backfilling the areas around the tunnel starting on Friday. Carrara’s concrete pump truck will be in town to pump flowable fill (a cement mix designed for backfill) into some areas while in others Kubricky will bring back excavated soil from Fifield Farm.
Next week we’ll see the start of restoring Merchants Row as Kubricky begins to form up the concrete bridge deck that will sit on top of the tunnel. The deck forms the foundation for the asphalt roadway. More on that next week.
North End Precast Next
Starting next Monday Kubricky will begin setting nearly 150 bottom u-walls on the north end of the project, starting at the Main Street end of the rail tunnel and running up to the old at-grade crossing across from Fire & Ice.
These pieces will be set on the night shift, which runs between 7 PM and 7 AM, to minimize disruption to traffic. Flatbed trucks carrying the u-wall pieces from Fifield Farm will turn into the Marble Works from Seymour Street at the at-grade crossing and then continue through Marble Works to the roadway running from the National Bank up alongside the rail corridor near Junebug.
At the far north end of the project, the final pieces will be set in place from Seymour Street. Again, this will be night work and will involve about two days of reducing night-time traffic on Seymour Street to a single lane of alternating traffic and one night when Seymour Street is closed to thru traffic. All businesses and buildings will be accessible during this period. I’ll have more details as we get closer to that part of the operation.
On the south end of the project, Kubricky will complete the final phase of excavation over the next few days, removing soil from the rail corridor and installing concrete retaining walls fabricated by SD Ireland that extend from the end of the precast on the south end to the trestle bridge over Otter Creek.
Downtown Is Calling
Before we wrap up I wanted to remind you how many of our local stores and restaurants are open downtown and would love to see you.
In central downtown there’s Sweet Cecily, Parlour, Autumn Gold, Middlebury Mountaineer, Buy Again Alley, Forth ‘n Goal, Edgewater Gallery, IPJ, Frog Hollow Bikes, Mister Up’s, Two Brothers, Taste of India, The Arcadian/Haymaker, and Shafer’s Market. Check hours but all open.
Vermont’s Own opens up on Saturday and Sabai Sabai reopens Wednesday, August 5.
Vermont Book Shop is doing a brisk online business with pick-up at the Stone Mill (which has its own public market plus Mad Taco), Main Street Stationery is doing curbside pick-up, and Kiss the Cook is in town on Saturdays for you to pick up your online orders.
Over in the Marble Works, there’s Junebug, Round Robin, Noonie’s, Flatbread, Otter Creek Used Books, Marble Works Pharmacy, and Costello’s. And right across the tracks Fire & Ice and Royal Oak Coffee on Seymour Street.
My apologies to anyone I’ve missed but you get the picture. Our businesses are open and construction is taking place in downtown Middlebury that we’ll never see again in our lifetime so come on down and check it all out.
One final note: remember the RiseVT program last summer that paired brief talks on healthy practices from Porter professionals with walks around town? RiseVT is now back with a virtual edition that kicked off this week. You can register and get details here.
That’s all for today. See you downtown.
Please keep your comments and questions coming. Send me an email at firstname.lastname@example.org and I’ll try to cover it in my next update.