Shelburne Farms National Historic Landmark : Doug Porter

BREEDING BARN

The Shelburne Farms Breeding Barn, a National Historic Landmark, is a monumental example of the estate architecture that appeared in North America near the end of the nineteenth century. Constructed for training new breeds of horses, the building features an enormous riding ring (measuring 72 ft. x 360 ft.) spanned by composite trusses of wood and iron. Structural engineers have called attention to potential overstresses in roof-frame members.

Under the direction of architectural conservator Doug Porter a multidisciplinary design team was assembled to assess the current condition of the barn and design repairs. Survey work was conducted in October 2005, employing a combination of non-destructive and quasi-nondestructive technologies. Results were used to determine rational design values for structural elements, reduce factors of safety to reasonable levels, and quantify overstresses through testing, modeling, and analysis. Results of resistance drilling of deteriorated wooden elements, strength testing of iron tension members, load tests of the principal truss, and data produced by 3-D laser scanning were used to develop designs for structural repairs.

Preliminary conditions assessment and documentation of the barn was organized as a field training project involving the design team, members of the Timber Framers Guild, and students from Historic Preservation and Engineering at the University of Vermont. Laser scanning and development of project drawings was accomplished in partnership with Texas Tech. University. School of Engineering faculty and students participated in load testing of principal trusses in 2006 and 2007.

Investigation and analysis of the barn were featured topics at the 5th International Conference on the Structural Analysis of Historical Constructions in New Delhi in 2006 and at the 2007 meeting of the ICOMOS International Wood Committee in Florence, Italy. (Read the paper (PDF) here » )