Converting Wind to ASCE 7-05 from Ultimate
Converting Wind to ASCE 7-05 from Ultimate
(OP)
ASCE 7-10 and the 2012 IBC use ultimate wind speeds
In ASCE 7-10 "Table C26.5-6" shows that to convert 7-10 speeds to 7-05 speeds, you divide the 7-10(ultimate speed) by sq.rt. 1.6
In IBC 2012 the equation provided to convert to Vasd, is to multiply the 7-10(ultimate speed) by sq.rt. 0.6
Am I correct in thinking Vasd is the same as ASCE 7-05 design wind speed?
If so, it looks like ASCE 7-10 ans IBC 2012 back calculate wind speeds differently. Does anyone know why?
Which is the proper way to back calculate ultimate to nominal wind speeds?
Any help is greatly appreciated!
In ASCE 7-10 "Table C26.5-6" shows that to convert 7-10 speeds to 7-05 speeds, you divide the 7-10(ultimate speed) by sq.rt. 1.6
In IBC 2012 the equation provided to convert to Vasd, is to multiply the 7-10(ultimate speed) by sq.rt. 0.6
Am I correct in thinking Vasd is the same as ASCE 7-05 design wind speed?
If so, it looks like ASCE 7-10 ans IBC 2012 back calculate wind speeds differently. Does anyone know why?
Which is the proper way to back calculate ultimate to nominal wind speeds?
Any help is greatly appreciated!






RE: Converting Wind to ASCE 7-05 from Ultimate
Are you concerned by the 2% difference?
If you need the ASCE 7-05 wind load, why not use ASCE 7-05?
The wind force is related to velocity squared, and it's much more straight forward to convert wind force to service levels (for deflection calculations). Would this work for your situation?
RE: Converting Wind to ASCE 7-05 from Ultimate
2% will make a difference due to a cost competitive field.
If I use ASCE 7-05 wind speed from ATCouncil I do not get the added benefit of the new contour wind lines.
That is why I need to convert the ultimate speed back to 7-05.
Does anyone know why the methodologies are different?
What is the correct way to convert based on my situation?
RE: Converting Wind to ASCE 7-05 from Ultimate
RE: Converting Wind to ASCE 7-05 from Ultimate