Monthly Archives: December 2014

Briggs – the Man – the Truss – the Enigma

Delays in obligation, delays in meeting self imposed deadlines – Holidays, power failures, and the resulting loss of hard-drives and research materials, and even passwords.

Time again to pick up the pen…

As I’ve worked here on the weblog to document all the various personalities with roots here in New Hampshire, whose lives works included the design of still recognized truss types, and/or the advocacy of wood as a building material in their construction (the spark for me in this adventure was in part the sheer number of individuals with this shared connection, numbers seemingly disproportionate for a state of this size, and not being simply that they chose to design in wood) – In research for this series, I have returned a time or three to the same name, only to hit the same dead ends, time and again.

This is both puzzling, and more than regrettable, a bit sad really. As the legacy of what can only be seen as a successful life’s work, should not end up like this, somehow, through the fog of time, shrouded in mystery.

Our subject in this look back, John C Briggs, was not only the builder of many short and long span bridges, and at some of the most famed crossings in the state. (Over The Merrimack at both Sewell’s Falls and Hooksett Village) He is the holder of two bridge patents.

The first of these dating to 1858, No. 22,106 though titled as a “Truss Bridge” and picturing Truss panels of several mongrel varieties, (and also a Strong-Arc type “Truss Beam”) is a patent for what he describes as his “having invented a new and Improved Mode of Giving Elasticity to the Compressed Joints of Truss-Frames” essentially this the idea that the addition of rubber shock washers to Angle Blocks and Cast Washers would somehow extend the life of these truss framing connections. We can’t know with certainty with what is left to us, but it does seem probable that the idea put forward in 22,106 was put to little use, seemingly even in bridges he himself went on to build.

Just five years later, in 1863 John was awarded patent No. 38,653 for a distinct Lattice Truss variant he describes in his Letters Patent as a “Triple Lattice” now known as the Briggs Truss. He successfully sold his truss locally (He advertised and began building this variation of his “Patent Bridges” well before the second patent was awarded – I will edit and add his advertisement to this entry after visiting a special collections library and upon securing a public domain copy) and built examples in numbers as both highway bridges and for area Railroads.

– Sadly, somehow none survive.

Henniker Road Bridge - Photo courtesy of The Library of Congress and the Historic American Building Survey - Photographed in May 1936 by L.C. Durette

Henniker Road Bridge – Photo courtesy of The Library of Congress and the Historic American Buildings Survey – Photographed in May 1936 by L.C. Durette

Happily, perhaps the last of these was documented by a HABS team (Historic American Buildings Survey) just months prior to its removal in 1936, and both photographs and a full set of as-built drawings were archived as part of their survey. (Click underlined text here and above to link to associated records)

A glimpse Through Time - Photo courtesy of The Library of Congress and the Historic American Building Survey - Photographed in May 1936 by L.C. Durette

A glimpse through time – The Henniker Road is a Briggs Truss example built the year before the patent was awarded – Photo courtesy of The Library of Congress and the Historic American Buildings Survey – Photographed in May 1936 by L.C. Durette

The almost greater irony in this story of patent holder and his truss, is how little is known of either his bridge building concern “John C. Briggs Civil Engineer – Builder of his own Patent Bridges” and likewise time has seemingly lost for us any real sense of just who John was. There seems to be no image of the man, no bio-piece in one of the who’s who of industry so common to the era, no obituary yet found. We do know through the unusual Lateral Bracing system seen on the Henniker Road Bridge, and the funky roof boarding detail described in his patent, that he was a man who thought outside the box.

The decade of the ’60’s was hugely successful for John, his truss, and his Concord based company, and then like physical examples of his Triple Lattice, he too, is somehow, almost lost to time.

Advertisements