ASCE 7-10 Fig 28.4-1 vs ASCE 7-05 Fig 6-10 1

[denoid]

I apologize if this has already been answered somewhere in a previous post, but I couldn't find it.

When you compare the two figures from the two versions of how to apply the wind load to wall and roof faces, the numbers of the wall/roof faces (1-6, 1E-6E) of the building are not the same between code versions. That is, in 7-05, the walls and roofs get renumbered when going between the transverse direction wind and the longitudinal wind, whereas in 7-10, this does not happen.

I do see that cases 5E and 6E must have been added in 7-10, since they don't show up in 7-05, but still, the generated load pressures and directions don't make sense to me.

Is this a mistake? If so, I couldn't find it in any of the supplements or errata to 7-10.

Any explanation for this is appreciated.

 

[ajh1]

Note that the edge strip orientations have also shifted between the two editions. For ASCE7-05, the numbering is basically 1: front surface exposed to wind, 4: back surface leeward wind effect, 5 & 6: surfaces that are parallel to the wind flow. The chart on the next page does not make any distinction between wind perpendicular to the ridge and wind parallel to the ridge.
For ASCE 7-10, the chart of numerical values distinguishes between load case A (perpendicular to the ridge) and load case B (parallel to the ridge). If you study the values you will see that with the exception of the 1E and 4E zones for load case B, the values are basically flip-flopped to account for the change in numbering. The net effect for the basic wall surfaces is the same between the two editions. The big change is in the orientation of the edge strips.

 

[denoid]

ajh1:
Thanks a lot. When I actually draw it out in isometric 3D and label the values, it makes more sense to me. I appreciate it.