Case Study - Bois D’Arc piers

Occasionally, an engineering firm will request that we excavate near the piers that support a foundation in order to expose them for testing. We received such a request in 2009. Plans were being drawn up to remodel the 120 year-old Fannin County Courthouse, built in 1888 in Bonham, TX. The engineering firm needed to know if the three story building really was constructed on Bois D’Arc (pronounced “bodark”) wood piers, and, if so, was there anything left of them.

Two five foot-square holes were dug at two different corners of the building, with the excavation taking us to the seven-foot depth. We encountered ground water in both holes. At five feet, as required by OSHA, we began using professional shoring. This photo demonstrates how that shoring keeps personnel safe when entering the hole.

Much to our surprise, the wood piers that had been submerged in wet mud for over a century, holding up a three story building, were firm, hard wood that was still performing its job.