Category Archives: Long Truss

Model of Improvement

I had long heard of a model of Col. Long’s Truss in the collection of the The New Hampshire Antiquarian Society, and long had it in mind to arrange a visit as part of research in piecing together my multiple blog entries on the Colonel and his Truss. Though I did not work to do so until coming upon this curious passage in an article titled – An Hour in the Antiquarian Room in Vol XXXII No. 1 of The Granite Monthly, published in 1902.

That initial inquiry to the Antiquarian Society was spurred by some seeming confusion found in the passage, (none of the Childs brothers have or had C.B. as their initials, nor where any of them still living in 1902) and a curiosity as to if there was any possibility that the Society perhaps also had in their collection a model of a Childs truss.

As it turns out, it was a Childs (likely Horace – visit the search bar to the right for information on the man and his truss, or for greater information on the good Col. Long) who donated this Long Truss model to the society, this sometime in the 1870’s. This would stand to reason being that Horace was a cousin of the Colonel’s and his bridge building firm was counted as among the earliest of those named as agent and sanctioned to build Long Trusses, and such a model would have been a useful tool in selling bridges of this truss type.

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Col. Long’s Bridge – The Model fits in its box like a hand in a glove

It was a rare thrill to examine the model, which is truly joined with well executed wood to wood joints and holds features I have not yet seen (such as the upper lateral bracing details, and the thrust blocks on the terminal ends of iron rod wind stays) on any still standing Long Truss bridge. It was also an honor and a privilege to examine this tiny construction, it being perhaps wrought by, and likely held by the hands of one or both of these storied bridge truss patent holders.

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The Bridgewright Blog would like to thank the NHAS / Hopkinton Historical Society for their willingness and cooperation in providing access to this rare piece of both area and wooden bridge history.

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Genuinely joined and richly detailed

 


A Theme and its Variations

Several years back I became highly familiar with The Bement Bridge in Bradford New Hampshire, this in a series of surveys while preparing a Structural Condition Assessment. That hard look was the genesis of a deep exploration of its named Truss Type, and a bit of a bio-exploration of its engineer patent holder, (and tangentially a running theme of an on-going wonder in how someone with no bridge building background might have come to design the complex joined timber truss that he did ) that exploration in large measure unfolded here on the pages of The Bridgewright Blog.

The Bement has recently recaptured my attention with my again working just a skip down the road from it, and with an area historical society recently making available several photographs which predate alterations made in recent decades. Changes structural and aesthetic.

The Bement with its original far more elegant Portal Trim - Image courtesy Hillsborough Historical Society - MPM Collection

The Bement with its original far more elegant Portal Trim – Image courtesy Hillsborough Historical Society – MPM Collection

In again skipping this stone of interest into the waters under this bridge, two ripples surface once more. Who was it who built it, and just what Truss Type is it? Individual Panel components typical to the named type are all there, and I am going to continue calling it a Long, while acknowledging it is a Variant. Many truss types are found in an array of variations, this perhaps driven by a desire to avoid the cost of patent royalties, or as explorations of capable minds guiding capable hands in looking for a better way.

The Bement while fitting the typ Panel component configuration of the type, varies markedly from Long’s patent, both in the number of these components – Single as opposed to double Posts, and not three, but four Chord Lams. Additionally the components vary completely in how they are joined to one another. The Braces and the Counters are reversed in their configuration and their number. And perhaps the most striking variation / departure from the patent are the absence of the pre-stressing wedges at the Counter Braces, a key feature of the type and the Colonel’s patent itself.

Double Daps and a reversal in number and purpose

Double Daps and a reversal in number and purpose

The Counters in the Bement fully join and pass through the Chord Lams in reciprocal double Daps, (simple notches) and do not simply abut the Chords & Posts with one wedged end as is typical to the typology – As if intended to act in tension as opposed to the norm of compression.

I point these features out for a number of reasons, foremost among these being that of a form of kudos for the bridge itself. There are other Long Truss bridges and Long variants still existing, and I have a deep appreciation for their detailing in how they are joined, yet find the simplicity of this little bridge intriguing, and worthy of admiration.

Secondly the historian in me thinks it just may be time to put to bed the oft repeated notion, that The Colonel himself built this bridge. The record does not seem to suggest where this bit of mis-information was first floated, but it is simply that. For Long’s whereabouts for the whole of the year, are well recorded in his work for and travels demanded by his position on the Board of Engineers for Lakes and Harbors and Western Rivers – He was nowhere nearby. And had he been in any way involved in its construction, I think it reasonable to suggest it would not have been a variant, but a textbook (Series of Directions to Bridge Builders) example.

So who did build the Bement? I think it safe to assume it was someone from the immediate area if not a local. There is not a ten mile distance from the Childs Brothers framing yard in Henniker to where the bridge stands, and there had by this time been a multitude of covered spans built all up and down the Warner River for both Railroad and highway use. There were those in numbers in the area with the necessary skills and knowledge to have designed and built it.

The Tie has been modified to carry a Flying Plate, the Rafter Seats now sits abandoned

The Tie has been modified to carry a Flying Plate and the altered Steplap Rafter Seats now sits abandoned

An interesting aside is the sometimes mention to the Bement’s Counter Braces and their joined relationship to the Chords as having similarities to Paddleford’s – The Bement shares (or did share) another even more uncommon feature, one found almost exclusivly in Paddleford’s, that of the Rafters joining the Ties in Steplapped Rafter Seats – Philip “Henry” bridged the Merrimack at Sewell’s Falls (but thirty miles to the east) in Concord just the year prior. (1853) Could our Bridgewright have maybe served on his crew and borrowed a detail worthy of repeating. I find it not improbable, and a smile rising with the realization and the on its head irony, that perhaps a Long variant was modified with influences driven by a Paddleford.

Here can be seen the Steplap Rafter Seats still serving their original purpose - Image courtesy Hillsborough Historical Society - MPM Collection

Here can be seen the Steplap Rafter Seats (Click to enlarge) still serving their original purpose – Image courtesy Hillsborough Historical Society – MPM Collection

Should you need a short span bridge, why should we not build a variation of The Bement, over another waterway, and set yet one more story in motion?


Commonly Un Common

The Square Rule is, as I suggested in the last entry, not just back on my current, but it is now my actual horizon. A part of my here is now everyday. As is this wondering as to why it was the people who chose to use it, this Square Rule, chose to do so.

It is a funny place to be in in more ways than one. As is the fact that I might gaze through a window few can share – I know what it is to wonder after the efficacy of which system to use for any given Timber Framed construction. To ask which system of Timber Layout, Scribe or Square Rule is the more, or even the most appropriate. This a window common to a few of my contemporaries. Though one last wide open for but a brief while, centuries ago now, when this rapid shift from the Scribe to the Square was yet underway.

And I think the perspective I view all this through, is far from common. To know traditional versions of both systems of layout is not common even among framers. To have a working sense of both historical framing of buildings, and those of bridges is maybe even more so. All this is a circumstance and a happenstance and a perspective, which was once commonly shared. The once sense of everyday of a common country carpenter, but now some of the little explored vagaries of a hyper niche carpenter. That said, I still see myself as a common country carpenter. Perhaps it is the every tree is a timber, commonality traditional timber framing has with the sawlogs we are often involved in “converting” – It is in this work, none so uncommon to choose timber in the woods and on the stump. Something we have done here as part of the Bernhard Barn restoration, the two Tulip stems which will serve as species in kind replacements of the one piece fifty foot hewn from the round Wall Plates still stand in their forest and yet touch the sky, and do not yet know that they will be part of the next chapter in the ongoing story that this Barn will continue to tell.

It often crosses my mind that this thing of being a Framer with an inter-discipline sense of things is an all too small club, one with a membership far far too short in numbers.

So, all that, and with the other high horizon focus, The Blenheim, seem to bring us back to where this blogging adventure began, with Long Trusses and The Square Rule and who might have taught who what, when it came to bridge framing, (see the May & June ’11 archives) now swings back and over into a parallel and perhaps as seemingly and an almost equally unanswerable exploration. Who was it who brought the roots of Square Rule to the table, and where was that place that they called home?

Semi parallel interwoven puzzles and a wonder after both, send us in search of clues to either, and we find yet another letter of shameless self promotion from the good Col Long –

All this information for but three pence, the price of a nail so small, most might think of it as a tack.


What Was Lost…

The entry here on the the Bridgewright Weblog which has seen more readership than any other, (and is still clicked in on with regularity) is now some thirteen months old. A piece titled Lost to Evermore, written in part in reaction to the devastation wrought by Irene. Some of which, as I put pen to paper in those first few days after the storm, I had already seen firsthand. Some, in the hard-hit Schoharie Valley of New York was at that point, less than fully known, to myself nor most anyone from outside the immediate area. Lines of communication were then down, and travel in and out of the valley was so hindered that little information about the level of damage had yet reached the wider world. What was known was that The Blenheim had been washed from its abutments.

With less than little known about the level of damage done to the Bridge, and with this blog being Bridgewright-centric, (for the most part but not limited to, an exploration of the works and work of Bridgewrights – Builders of wooden bridges, both past & present) my piece was as much about the builder of the Blenheim, as it was about the bridge itself.

The Bridgewright Nichols Powers – Photo courtesy of Schoharie Historical Society

Information then available suggested the bridge was not only lost, but had been all but erased – Even weeks later, in a group of folks at a Regional Gathering of Timber Frame Carpenters many of whom knew and had spent time on, in and under The Blenheim, (It being to the North American Timberframing Community among the greatest of timber works to be seen, a built heritage pilgrimage of sorts somewhat akin to Chartres, the Parthenon or Pont du Gard) no one knew either what was lost or what might yet be found.

Many of us from outside the area assumed that the needs to replace and repair homes and businesses, to restore livelihoods and a sense of normalcy were the demands of the day for those directly affected by the floods. It was seen as perhaps not even reasonable to wonder after the post flood state of the Bridge.

Yet despite all this much to do, locals somehow made time for their Bridge. A recovery effort was organized, advantage was made of the seeming irony of a mild, almost snow free winter, and regular efforts in search and retrieval were made.

This gained a sense of urgency when the Blenheim’s National Historic Landmark Status was seen as in jeopardy, and it was suggested that any effort at rebuilding would have to include 51% of the original “fabric” to retain Landmark status. A lower than typical Spring Melt also cooperated with efforts towards recovery, and activity intensified as the weather warmed.

And more recently even as recovery efforts saw the transfer of sections both large and small to a common staging area, another setback. A FEMA determination that the The Blenheim, because it no longer carried vehicular traffic, is ineligible for funding. An appeal of this decision was recently heard, the finding and a final decision is yet to be determined.

Some of you may remember the shot of the Bottom Chord Scarf (Splice) I included in the Evermore piece. I no longer see the Bridge as lost, (If I ever did, the piece was about circumstance and reaction) or the situation as evermore. I do still see that magnificent Scarf, that startlingly beautiful and complex bit of cooperative workmanship, as being a yet unbroken connection still tying the Bridges past, to its future. I see this as area residents do – The need is to rebuild.

Preparations for rebuilding began, but will not end, with recovery and retrieval.

The following shots were taken on a recent non-related timberframe restoration trip into the area – Several of Powers chosen multiple abutment “Trait de Jupiter” (Bolt ‘O Lightning) Scarfs are seen here also…

The Bridled Tenons which control the Wedge where the Counter joins an Arch

Double Mortises and a Flatting cut perpendicular to the axis of the Counter Braces in an Arch section to receive a Counter and its Wedge

An Oaken Angle Block & a Cleat to receive a Set of Lower Lateral Braces and the Tie Rod which controlled them

The Blenheim materializing out of the mist on an early morning visit in the Autumn of ’07