EFFECT OF 85 YEARS OF SERVICE ON MECHANICAL-PROPERTIES OF TIMBER ROOFMEMBERS .1. EXPERIMENTAL-OBSERVATIONS

Peirce Hall, a building constructed on the Purdue University campus in 1904, was razed in 1989. The structural system of this building was h eavy timber trusses supported by masonry walls. During the destruction of Peirce Hall, 11 structural timbers were salvaged from the roof sys tem. Part 1 of this paper focuses on the experimental evaluation of ti mbers. Part 2 is an analytical study of the duration-of-load (DOL) eff ects through the use of several available DOL models. The roof system was found to be subjected to design magnitude loads at least twice dur ing the life of the structures. Additionally, although some members in the roof system were oversized relative to current design standards, some members were sized as if designed today. Determination of the pos t-service life mechanical properties of the Peirce Hall timbers was th rough experimental evaluation of the material. The post-service life p roperties were then compared to estimates of original material propert ies, which were based on historic research data. The comparison showed little difference between original and post-service life properties, thus indicating no DOL effects present in the material.