Seismic performance of older steel frame mill buildings

Abstract

In the early 1900s, steel frame buildings were designed and constructed differently from the way they are today. Further, little or no consideration of seismic design was required. Many of these buildings remain in service as part of critical lifeline facilities, but engineers are unable to evaluate their seismic performance by modern evaluation methods. This paper applies various methods for seismic evaluation of existing structures to one of these buildings. It is shown that modern evaluation methods do not accurately simulate the seismic performance of the subject buildings. These modern methods suggest the existence of problems that are not observed in practice, while they ignore factors that may be detrimental to the seismic performance of some older buildings. As a result, dynamic response of the buildings is described, and the sequence of damage and yielding are noted. The factors that may limit the inelastic performance of the buildings are described. Finally, a simplified design model, which captures the dynamic response of these buildings, is summarized.