ASCE 7/37 Wind Loads
ASCE 7/37 Wind Loads
(OP)
thread507-307748: Wind Speed Conversion Factors
See the reference thread.
I am working on developing some wind pressure profiles for temporary applications. I am running into the same question as the original poster for the referenced thread.
ASCE 7-05 (as well as previous versions) provides a table (C6-7) in the commentary allowing one to adjust the basic design wind speed for various Mean Recurrence Intervals. ASCE 37-02 provides a table based on the construction period, also allowing for basic design wind speed adjustment. The issue I see is that the values for similar time periods do not match up. For example, out of ASCE 7-05, for a mean recurrence interval of 5 years, the reduction factor would be 0.78. ASCE 37, however, recommends a factor of 0.9 for a construction period of between 2 and 5 years. Why the discrepancy?
I understand that there are two different committees responsible for the development of these documents. However, ASCE 37 references ASCE 7, and as such, one should be able to reasonably assume that the design standards jive. Can anyone provide any clarification?
See the reference thread.
I am working on developing some wind pressure profiles for temporary applications. I am running into the same question as the original poster for the referenced thread.
ASCE 7-05 (as well as previous versions) provides a table (C6-7) in the commentary allowing one to adjust the basic design wind speed for various Mean Recurrence Intervals. ASCE 37-02 provides a table based on the construction period, also allowing for basic design wind speed adjustment. The issue I see is that the values for similar time periods do not match up. For example, out of ASCE 7-05, for a mean recurrence interval of 5 years, the reduction factor would be 0.78. ASCE 37, however, recommends a factor of 0.9 for a construction period of between 2 and 5 years. Why the discrepancy?
I understand that there are two different committees responsible for the development of these documents. However, ASCE 37 references ASCE 7, and as such, one should be able to reasonably assume that the design standards jive. Can anyone provide any clarification?






RE: ASCE 7/37 Wind Loads
RE: ASCE 7/37 Wind Loads
In determining the wind speeds to use for construction periods in ASCE 37, the idea is NOT to determine the MRI for shorter and shorter recurrence intervals (which is what Table C6-7 in ASCE 7-05 does), as this would be essentially designing for smaller and smaller storms, the idea is to match the PROBABILITY that the storm damage that you typically design the building for during its 50 year life for will occur during a much shorter reference period (the duration of construction). I believe that is the distinction you may have been missing. We are not reducing the size of the wind event (MRI), we are just trying to match the reduced probability that this same size event will occur during a very brief reference period of time as compared to the 50 year presumed life of the structure
RE: ASCE 7/37 Wind Loads
RE: ASCE 7/37 Wind Loads