CBF Provisions for Seismic Evaluation and Retrofit of Existing Steel Buildings [U1]

Concentrically braced frames (CBFs) have been used as seismic lateral force resisting systems for many years. Current seismic design provisions were not instituted until about 1995, hence why many older braced frames in seismic regions do not meet current seismic design requirements.

The seismic rehabilitation design standard, ASCE 41, is nominally intended to address the seismic performance and retrofit of these older buildings. However, the ASCE 41 provisions for braced frames were developed in the early 1990s, which both preceded the development of current AISC 341 for SCBFs and current research on older and retrofitted CBFs.

The AISC 342 standard, currently under development, is planned to replace ASCE 41 provisions for seismic evaluation and retrofit of steel buildings. AISC 342 will update all steel provisions, particularly those for braced frames, due to extensive research on the seismic performance of braced frames in the past 20 years.

This session will show the background to these AISC 342 braced frame provisions, the changes made in the provisions, the consequences of the changes, and an example application of the new provisions.

Track: Seismic

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