| Applies To | |||
| Product(s): | AutoPIPE, | ||
| Version(s): | ALL | ||
| Environment: | N/A | ||
| Area: | Load | ||
| Original Author: | Bentley Technical Support Group | ||
Problem:
Should the Wind Shape Factor Multiplier be 1 or 0.7 when using the ASCE wind specification type?
Does ASCE wind specification type, force coefficient factor take the place of the wind shape factor multiplier?
Is it "double dipping" by using 0.7 for the Wind Shape Factor Multiplier and 0.7 for the Force Coefficient when using the ASCE wind specification type?
Solution:
The intent of Wind shape factor multiplier on the 1st screen of the Wind load case dialog is to provide a uniform factor that is applied to ALL wind load cases.
However, AutoPIPE provides another more flexible method of applying this factor to the individual wind load cases; ASCE refers to this shape factor as "Force Coefficient Cf" and the UBC refers to it as "Pressure Coefficient Cq".
Using these coefficient values on the individual load case dialogs enables the user to create a more accurate wind load based on the objects shape by providing different values for different wind directions (i.e. W1: Cf or Cq.= .7 for global X wind direction but W2: Cf or Cq = .9 for global Z wind direction).
Using both Factor and coefficient values would reduce the wind load by the product of both values, which is incorrect.
Therefore, either the Wind shape factor is modified and the coefficients are set to 1 or the Wind shape factor is set to 1 and the coefficients are modified.