I am also an avid fan of the hammerbeam but more of a fan of structures that stay standing without help down the line. A few articles, one specifically by Ed Levin, talk of the many hammerbeams seen with the dreaded steel tie bar added later to fix an obvious failure. This sure would be a disaster for a timber framing purist like myself. At the same time you are completely correct that a properly designed hammerbeam truss, well engineered and well executed will last and be beautiful to boot. I am by no means knocking the hammerbeam truss. I just dont feel confident enough to design one and I have a hard enough time finding decent frame plans that are simple, let alone one in which utilizes the more complicated hammerbeam truss.
