Database-Assisted Design for Wind: Veering Effects on High-Rise Structures. NIST Technical Note 1672

摘要

Atmospheric boundary layer winds experience two types of effects due to friction at the ground surface. One effect is the increase of the wind speeds with height above the surface. The second effect, called the Ekman layer effect, entails veering--the change of the wind speed direction as a function of height above the surface. In this study a procedure is developed within a database-assisted design (DAD) framework that accounts approximately for veering effects on tall building design. The procedure was applied in a case study of a 60-story reinforced concrete building, which also considered the dependence of veering effects on the orientation of the building. Comparisons are presented between response estimates that account and do not account for veering. Results show that veering effects on demand-to-capacity indexes for structural members are significant for certain building orientations, and that they increase with the length of the mean recurrence intervals (MRIs). However, for this case study veering effects on inter-story drift and rooftop accelerations were found to be negligible.