Temporary Bridges Update #23
A Primer on Our New Temporary Bridges
One of the questions I’m asked most frequently is, “So what are these temporary bridges going to look like once they’re up and running on Main Street and Merchants Row?”
First, a little history. British engineer Donald Bailey designed a portable, pre-fabricated truss bridge during World War II that became known as the Bailey Bridge. Enabling troops to quickly cross rivers whose bridges had been destroyed, Bailey bridges proved instrumental in the Allied advance across western Europe.
Fellow Brit Bevil Mabey served in WWII. Recognizing the potential industrial applications of the Bailey Bridge, he engineered the purchase of government surplus Bailey Bridges by his father’s general building supplies business, Mabey & Johnson Ltd, at the end of the war.
Under strong family leadership, Mabey & Johnson grew in the post-war decades, and the company’s innovations put it at the forefront of major infrastructure projects. The Mabey Universal Bridging System became widely used in the U.S. starting in the 1970s.
Mabey in Middlebury. Mabey Bridges are modular steel truss bridges assembled in place. They can be noisy as vehicles pass over the paneled steel and so I’ve asked—and VTrans has agreed—that the bridge surface be paved.
Our Mabey bridges will sit about 18 inches higher than the high point of the two current roadways to provide the same vertical clearance for the railway, and so Kubricky will be building approaches from either side of the two bridges. The Main Street Mabey bridge will be two-lane traffic. The Merchants Row Mabey Bridge will be one-way only up the hill, the second lane being used for pedestrian access from lower to upper Merchants Row. More details on this as we get closer to launching the bridges.
Back to What They Look Like. Here’s a photo of a 150-foot-long modular steel truss bridge manufactured by Mabey Universal Bridge and owned by VTrans. This temporary bridge was installed in April 2017 over a failed culvert on Kimball Avenue in South Burlington.
How Temporary Is Temporary? The Main Street and Merchants Row temporary bridges will be replaced with a tunnel that runs roughly south to north, from the Battell side of Merchants Row to the Post Office side of Main Street. The central portion of the tunnel, between the two roadways, will become green space, restoring Middlebury’s Village Green to its original size before the arrival of the Rutland Railroad in the 1840s. Construction of the tunnel is scheduled to take place in Summer 2020, following construction of a new drainage system for the Village Green area in 2018 and excavation work below grade in the rail corridor in 2019.
Demolition Schedule. As I mentioned in my last update, the Main Street Bridge is scheduled to be demolished Friday-Sunday, July 21-23. The Merchants Row Bridge will follow suit the weekend of July 28-30. The temporary bridges for both roadways will be assembled on Main Street in front of the Post Office and on Merchants Row in front of the Village Green in the week following each bridge’s demolition. More details on schedules in future updates.
Bleachers Report? I’m looking into the possibility of putting up bleachers in Triangle Park, if it’s safe and if the Town agrees, so that boys and girls of all ages can watch the work taking place.
Update: Printers Alley. Printers Alley will be closed to pedestrians for a short period during the demolition of Main Street Bridge (it’s already closed to vehicles). I’m working on getting clear signage installed at either end of Printers Alley to clearly indicate how to get to Main Street from Marble Works and vice-versa, on foot and by car.
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.