OPEN STRUCTURE WIND FORCE ON DIAGONAL DIRECTION
OPEN STRUCTURE WIND FORCE ON DIAGONAL DIRECTION
(OP)
ASCE figure 6-23 has Cf factor calculation for open trussed tower. Does anybody know how to calculate the wind force if the wind blows from other direction? Say, digonal direction.
ASCE says to use 75% wind force simultaneously on both orthogonal directions. That's true for enclosed building. But if I follow the Figure 6-23, I will get a much higher result. Here is the calc.:
Say, I have a 4 column square tower. I assign wind force on the windward 2 columns according to the Figure. If i look at the diagonal direction, there are 3 columns exposed to the wind direction. That's means all the 3 columns must be assigned.
I wonder is there any guideline for calculating the diagonal wind force on open structure.
Thank you
ASCE says to use 75% wind force simultaneously on both orthogonal directions. That's true for enclosed building. But if I follow the Figure 6-23, I will get a much higher result. Here is the calc.:
Say, I have a 4 column square tower. I assign wind force on the windward 2 columns according to the Figure. If i look at the diagonal direction, there are 3 columns exposed to the wind direction. That's means all the 3 columns must be assigned.
I wonder is there any guideline for calculating the diagonal wind force on open structure.
Thank you






RE: OPEN STRUCTURE WIND FORCE ON DIAGONAL DIRECTION
RE: OPEN STRUCTURE WIND FORCE ON DIAGONAL DIRECTION
RE: OPEN STRUCTURE WIND FORCE ON DIAGONAL DIRECTION
Mike McCann
MMC Engineering
RE: OPEN STRUCTURE WIND FORCE ON DIAGONAL DIRECTION
RE: OPEN STRUCTURE WIND FORCE ON DIAGONAL DIRECTION
To me, this implies that if you are considering all four legs of the tower, the structure as a whole, then all the members of both the front and rear faces of the tower need to be considered for normal wind forces.
Correspondingly, if you are looking at in diagonal direction, then the projected area of all four sides needs to be considered, but the resultant wind force multiplied by 0.707 to account for the diagonal inclination of the sides of the structure - a wind shedding effect as it were.
Mike McCann
MMC Engineering