Wall End zone distance ASCE7-05

[cg3375]

Quick question if anyone can help or give an opinion.

MWFRS - Method 1 (Figure 6-2 pg 37 in ASCE 7-05)

To calculate the area of end zone for horizontal pressure, notice on the longitudinal diagram that the area A is given as a distance of 2a. Below in notation 10 "a" is calc'd three different ways. For simplicity of discussion lets say I can use 3 feet.

Now note on the drawing we have shown "2a" as the distance.

2 x 3 = 6

Is my area of end zone wall (2a), 6 feet for the whole wall or 12 feet (2a on each side...2a = 6 feet each end x 2 corners)? When I throw half of the load to each longitudinal wall I'd like to know if I'm including enough for the end zone. I've seen it done both ways with just 3' used on the end and also 6 feet used on the ends.

Any thoughts or opinions?

Thanks.

 

[KBVT]

I think based on ASCE-7, you only have to use an end zone at one corner at a time, but to simplify calculations most engineers assume the corner zone at both ends and analyze the direction one time.

 

[cg3375]

I agree that I only use one endzone when I throw the load into the diaphram and then to the supporting wall, but is the end zone in my example 3' feet or 6' (2a)?

Thanks.

 

[DaveAtkins]

For MWFRS, the end zone is "2a" wide (6' in your case). For C & C, the end zone is "a" wide.

DaveAtkins

 

[KBVT]

Dave is correct, 2a for your MWFRS calculations, a for your C&C calculations.

 

[cg3375]

Thanks to everyone. Input, explanation & opinion are appreciated.

CG