Re-evaluation of seismic torsional provisions

✍ Scribed by Tso, W. K.; Smith, R. S. H.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 245 KB
• Volume: 28
• Category: Article
• ISSN: 0098-8847
• DOI: 10.1002/(sici)1096-9845(199908)28:8<899::aid-eqe846>3.0.co;2-q

✦ Synopsis

Traditionally, seismic torsional provisions have been evaluated based on the assumption that the strength of the lateral load resisting elements can be adjusted without changing their sti!ness. There is an important class of elements that a change of their lateral strength implies a corresponding change of sti!ness, as exempli"ed by reinforced concrete #exural walls. This would imply that when torsional provisions are applied to adjust the strengths of these elements, the sti!ness distribution, and also the eccentricity of the system, will change. This paper re-evaluates the consequences of applying the torsional provisions of the Uniform Building Code (UBC, 1997) and also the Eurocode (Eurocode 8, 1994) to single mass eccentric systems supported by elements having such characteristics. In conjunction with the results based on the traditional assumption, the e!ectiveness of the two provisions to mitigate torsional e!ects is discussed from a broader perspective.