| Key Facts |
| Bridge Name | Facility Carried / Feature Intersected | Location | Structure Type | Construction Date / Builder or Contractor | |
|---|---|---|---|---|---|
|
Ponakin Bridge
| Ponakin Road Over Nashua River | Ponakin Mill: Worcester County, Massachusetts | Metal Pinned Post Through Truss, Stationary | 1871 By: Watson Manufacturing Company of Paterson, New Jersey |
| Technical Facts |
| Rehabilitation Date | Main Span Length | Structure Length | Bridge Width | Main Spans | Approach Spans |
| 1978 | 100 Feet (30.5 Meters) | 100 Feet (30.5 Meters) | 20.7 Feet (6.3 Meters) | 1 | 0 |
This bridge is one of two known Post truss bridges in the country: both are in Worcester County: the other is the Atherton Bridge. However, the Ponakin Bridge is the only one that also follows and displays the patented connection and structural details that Simeon Post filed a patent for and received in 1863. Post never did patent the actual truss configuration. As such, although each of these two bridges are among the most important truss bridges in the country, the Ponakin Bridge is slightly more significant for displaying both the truss configuration and the patented details. The Ponakin Bridge is also significant as a bridge with cast iron members, placing it in another small, elite group of historic truss bridges.
As the last remaining exact replica of the Post truss, and one of only two following the general Post configuration, with end post and top chord made of cast iron, and with excellent historic integrity despite how old it is, this bridge is truly a priceless historic artifact.
HAER thoroughly documents the unusual design, history, and details of this bridge. Be sure to look to their documentation for a complete history of the bridge.
Given a relatively higher attention given to historic bridge preservation in Massachusetts (and several other northeastern USA states) than is seen in the country as a whole, one would seem to expect to see the last Post through truss in the country restored. However, this bridge has just been abandoned and allowed to be overgrown, which is obviously better than the demolition that this bridge might have received had it been located in another state, yet a bridge this rare deserves so much more than abandonment. Rather than wait for a bad flood or a large falling tree to spell doom for this cast iron bridge, this bridge should be relocated and restored for pedestrian use. Any restoration of the bridge should be undertaken with the greatest care to retain all original material possible, and any replaced material must be exactly replicated, right down to the rivets on the bridge.
