Please pardon the hiatus, the current gig and it’s long commute wrapped around a long day – demands much and additionally, much too much of my time and those days not devoted to it are demanded by other projects, including other writing projects…
So we will now take up the baton with one of the themes and constant wonders this weblog is wound around.
That being how will we, in the unfolding present and the unpromised future continue to perpetuate this trade? The reality of this is that for the trade to carry forward, there must be work for those who have interest in it to engage in, so those who have mastered it can share those unique skill sets and the nuances and subtleties that separate it from its allied trade of Timber Framing to up and coming generations of practitioners.
This work is found in two forms, the rehabilitation and restoration of historic examples and occasionally with the replication of the loss of one of history’s examples. Such loss is sadly borne of tragedy, be it the whimsy of raging weather or the raging stupidity of a destructive personality. The ironic upsides of such loss is the refusal of some to accept such and their demand that what was stolen, be returned to them. Borne of this refusal and the demand it spurs are these historic replications.
And this ironic upside is key to this perpetuation of knowledge that can carry this trade forward, there is only so much that can be conveyed in the maintenance and rehab of our historic stock. Some methodologies, among these, specialty rigging techniques, what achieving desired camber demands of the layout process, and how approach in cutting joinery minimizes the potential crush the constant and cyclical always massive forces clear span trusses must bear, can only be conveyed in the full blown construction of traditionally joined wooden through truss bridges.
And when a wheel spins and spins well, I am admittedly confused by the never ending drive to reinvent that wheel.
Joined timber through truss bridges are not simply proof positive of the service life of wood as a material. Our standing almost two century old examples also provide to us a stunning example of the suitability of wood to wood joinery for this purpose.
The occasional new builds of covered wooden through truss bridges are invariably designed with nontraditional connections. Whether the driving of the decisions creating this dynamic are borne of a wish to reduce cost by designing a construction any typical general contractor can build or if this is an aspect of how few structural engineers are trained in wood and fewer still are trained to understand wood to wood joinery, or if this is simply lack of familiarity and failure to research or liability driven fear, matters but little.
New Builds of traditional design will seemingly never again come to market in numbers which might help sustain our specialty trade and convey our chain of knowledge into the future.
Sustaining this Trade is then in large measure dependent upon future Replications.
So it was with some sadness that I came to understand that one of the replications currently in the offing saw significant changes in design before being let out to bid. This being to my mind particularly sad in that this was a rare truss type (of which there is now but one surviving historic example) and a truss type which can be described as a Bridgewrights truss, being that it is ripe with and wholly dependent upon, complex timber joinery.
Some of that joinery was changed in the redesign. Most notably in the Bottom Chord tension splices which now are reliant not on the well executed work of highly trained individuals but on the the easily quantifiable values of mechanical fasteners.
With that, none of the Bridgewrights I am familiar with chose to bid on this replacement. Meaning there has perhaps not only been the irreplaceable loss of this Mother example time had handed us, this formerly Brown Truss bridge, the work of patent holder Josiah Brown and its Bridgewrights Jared Bresee and Joseph Walker, but the ironic upside of a once in a blue moon opportunity to continue to forge a chain of knowledge through it’s saddening loss, is perhaps also lost.
Again, my ultimate aim in all the work I do is not simply to preserve our joined timber truss built transportation heritage but also to preserve the skilled trade that made them possible.
Bids are due on this project within a coming few days and we will soon find out who will be building the replacement. Will it be a group of people well versed in joined timber clear span trusses and their apprentices, people who will take what they learn from the project and convey it into the future?
Or will there sadly be no Bridgewrights? And with another missed opportunity the sadly stunning realization that without a continuum of work to serve as the foundations of our future there may again one day be, no Bridgewrights.