Covered Bridges on Two Wheels

The bridge was closed in 1993 after a vehicle struck the inside of the bridge and caused structural damage. In addition, deterioration over the years had caused the bridge to sag. It was rehabilitated in 2003 to 2004 during which work had to be halted at least a couple times in the fall of 2003 due to high water. The multiple kingpost with Burr arch bridge is one of the longest spans in Vermont with this design and one unique touch is how the top of the siding arches to match the curve of the Burr arch.

Also notice how the bridge curves slightly (you can see this by looking at the bottom of the siding in the first photo). This is called 'camber' and helps deflect weight of the live load (traffic) crossing the bridge. This is similar in principle to why some dams on rivers are curved... the pressure of the water on the curve of a dam actually makes it stronger. Camber is a good indicator of the condition of the bridge. Although not all covered bridges are built with a camber, ones that are can be monitored to see if the camber if no longer there. If a bridge was known to have been built with a camber, and the camber is gone, the bridge may be failing. In the case of the Poland Bridge, before rehabilitation its original camber of 12" had deteriorated to a negative 18" (meaning the center was sagging in the middle instead of being higher than the ends).

Despite the outward appearance of a healthy bridge, it had been closed once again fairly recently. In the fall of 2010, a vehicle accident which resulted in the cracking of a beam prompted a full inspection. The beam that was hit had been displaced, making the entire bridge unsafe. The engineers performing the inspection declared that the beams making up the arches are too small. Because they play such an integral role in the support of the trusses, it would have required a major undertaking to replace them. It was also decided that the curbing in the bridge (which the car was able to jump over) was insufficient and they were replaced with higher ones to better protect the trusses. The bridge, which is normally closed in the winter anyway, was not reopened the following spring.  It remained closed for quite some time while plans to fix it were drawn up and put into action.  Repairs have been made, and the bridge had been re-opened... briefly.

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In early 2017, the bridge was closed again. But not for any kind of structural failure.  The conversion of the old railroad line into a recreation trail (the Lamoille Valley Rail Trail) has generated more traffic, both vehicular and pedestrian. The trail passes just outside the southern portal and there is a lot of foot and bicycle traffic crossing the road at the bridge, which raised concerns regarding limited sight-lines when exiting the bridge to the south. The town had closed the bridge for these pedestrian safety concerns while it contemplated a solution.  Initially, the apparent solution based on chatter online would be to make the bridge one-way from south to north, but instead they have installed speed bumps at each portal to keep speed down.