This Emergency Swing Dam has global significance as the last
remaining structure of its kind in the world, a bridge-like dam that can swing
out over the water, and lower wickets and shutters down into the water to reduce
the flow of water. Although this bridge has only been called into service once,
the bridge proved that one time to be a valuable asset. If a boat breaks the
locks and releases torrents of water, this dam allows for a temporary slowing of
that water flow so that the locks can be repaired and closed once again.
This is not a bridge in the sense that it was not built to
facilitate the crossing of something. However, that is where the dissociation
with the word "bridge" ends. This structure is in terms of design a swing truss
bridge, and for that reason it appears on this website as one of the finest and
most unusual bridge structures in Canada. It was built in 1896 by
the Dominion Bridge Company, which was based in Lachine, which is part of
Montreal, Quebec. This company also built the nearby fixed spans of the International Railroad Bridge, according to builder plaques on that structure.
The Emergency Swing Dam features a Baltimore style truss
configuration. Most connections are pinned, although some are riveted. Compression members on the bridge are built-up with substantial v-lacing and lattice used. There are an unusually large number of
different steel mill stamps on this bridge including some from the U.K. There are Carnegie stamps, Burbach
stamps, Consett stamps, and finally a mark reading "A.H.A.V. 1891" to
me. The 1891 might refer to some sort of patent date, or when the iron was actually rolled at the mill. The bridge itself was
erected in 1896.
The bridge retains a high degree of historic integrity, with
some exceptions. The deck beams are huge on this bridge and are likely not
original. Nor is machinery house, which houses the motor and other machinery. Also, some floor beams have steel welded to them and to some rollers below that
handle the chain. This apparently was to strengthen the rollers. There is a
weird i-beam that runs the length of the east side of the bridge and is attached
to a weird arrangement of bracing in front of the portal bracing. All of this is
riveted, but it does not look like it fits in although it appears to be
original anyway. It is definitely old,
and is visible in a 1909 historic photograph. The bridge has been maintained very well, and there is no
major structural deterioration. It is good to see this wonderful structure being
maintained for future generations. The informative sign near the bridge shows
that Ontario is indeed recognizing the historic nature of it and wants to help
educate the public about this bridges fascinating history and operation.
This bridge was only used once, way back in June 9, 1909.
The Accident at the Canadian Canal, Sault Ste. Marie,
Ontario, 1909
There was a major accident on June 9, 1909 at the
Sault Canal. Downbound from Lake Superior, the Canadian passenger vessel
Assiniboia was waiting in the lock at the Sault to be lowered to the
Lake Huron level of the St. Marys River. Behind the Assiniboia, the
Pittsburg Steamship Company's steamer Crescent City was just entering
the lock. Captain Frank Rice was asked to lock down with the Canadian
Pacific passenger vessel Assiniboia.
The Canadian canal was fourteen years old in September 1909, having been
officially opened on September 7, 1895. The lock was built between 1888
and 1895.
On June 9, 1909, the Perry G. Walker, owned by the Gilchrist
Transportation Co. of Cleveland, Ohio, proceeded up the St. Marys River
intent on locking through the American canal. Captain Moshier was
impatient. He could see several vessels ahead of him also awaiting
upbound passage. He began moving his vessel towards the Canadian canal,
intent on a quick lockage. The vessel continued up the lower approach.
The master, ignoring previous instructions to moor at the southeast pier
to await passage, kept moving upwards.
Finally the order to reverse engines was sounded. The Captain made an
effort to reverse the engine but there was a misunderstanding of the
signals and the engineer did not reverse the engine. It was too late to
stop the vessel which was moving at eight or nine kilometres per hour
and was within 70 metres of the lock gates.
The Walker struck the south main gate, forcing it back and allowing the
force of water to push the north main gate over. The rush of water threw
the Walker back, her bow swinging to the south. The Assiniboia was
carried down against the Walker, striking the starboard side.
The Crescent City dropped onto the upper wall carrying away the timber
work. Leaving the lock, she surged ahead. Suddenly the Assiniboia
dropped her anchor, swinging her stern over towards the north pier and
the Walker. Immediately Captain Rice called for full speed astern.
Slowly the Crescent City responded, swinging her stern to starboard at
the last moment. She struck her starboard beam on the Assiniboia and
avoided the Perry Walker.
Either the Assiniboia or the Crescent City in their downward drop struck
the south main gate, breaking it diagonally in two. Surprisingly no one
was hurt during this accident.
With the gates being swept away, it was necessary to bring the Emergency
Swing Bridge Dam into operation. This was the first time the structure
was required in an emergency situation. The emergency swing bridge dam
stopped the flood of water, allowing repairs to be done on the canal and
the lock.
There was extensive damage to the valves, the wooden gates, the
stonework and the timber on the lock floor. All of the repair work was
completed by June 21, 1909, and the canal was reopened.
The canal had been closed for repairs for a total of twelve days.
Considering the damage done, the repairs were made in a short period of
time thanks to the successful operation of the Emergency Swing Bridge
Dam.
Above: View of the damage to the locks.
Above: View of the swing dam in operation.
Excerpts taken from:
Harrison, R. "The Break at the Canadian Canal, Sault Ste. Marie,
Ontario, 1909". Inland Seas. Volume 34, No. 2, Summer, 1979. pgs
104-109.
This bridge is tagged with the following special condition(s): Unorganized Photos
Original / Full Size Photos For the best visual immersion and full detail, or for use as a desktop background, this gallery presents selected overview and detail photos for this bridge in the original digital camera resolution. This gallery offers photos in the highest available resolution and file size in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer
Mobile Optimized Photos A collection of overview photos that show the bridge as a whole and general areas of the bridge. This gallery features data-friendly, fast-loading photos in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer
Mobile Optimized Photos These photos are mainly to document the design, construction, and materials of the bridge. They provide a detailed look at how this bridge was built, and what was used to build it. This gallery features data-friendly, fast-loading photos in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer
Mobile Optimized Photos These photos show the various parts that worked to move the bridge, and also to create the dam. This gallery features data-friendly, fast-loading photos in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer
Original / Full Size Photos A supplemental collection of photos that are from additional visit(s) to the bridge and have not been organized or captioned. This gallery offers photos in the highest available resolution and file size in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer
Mobile Optimized Photos A supplemental collection of photos that are from additional visit(s) to the bridge and have not been organized or captioned. This gallery features data-friendly, fast-loading photos in a touch-friendly popup viewer. Alternatively, Browse Without Using Viewer