Breyer's, Wood Structures, 6th Ed.

[flyinghigh]

Good morning. On p2.40, Example 2.10, Wind Force, Components & Cladding, Wall Forces for regions b and c (Interior Zone 4) for effective wind area of 10 sf: Pnet30 = 14.6 psf and -15.8 psf.
Q1: There is no zone 4 in ASCE 7 Fig. 6-3.
Q2: Where does he get 14.6 and -15.8?
Ditto p2.41, Wall Forces for region d, 14.6 and -19.5? Thanks.

 

[FSS]

I'll take the bait on this one since both Breyer's text and ASCE are front and center on my desk. Zone 4 is interior wall and is referred to in ASCE 7 Fig 6-3. Obviously you need to look a little closer and you will find it. The 14.6 and 15.8 pressures are straight from Figure 6-3 for interior wall pressures.

Class dismissed....

 

[flyinghigh]

Yeah, that was a stupid question. I saw the answer right after I posted it. Duh. My bad. Sorry.

 

[flyinghigh]

The following are less stupid ?'s (hopefully). 1) On p2.71, he shows wc = 90 psf. He does not define wc, nor is it in Definitions, pxxv, nor xxvi. He merely equates wc to 90 psf, coincidently the same as the wind speed V, 90 mph. Is this a slight of the hand or is this conversion correct?
2) At the btm of the page, he shows ap = 1 and Rp = 2.5, from ASCE 7, p 146, Table 13.5-1, maybe 3rd group fm the top, at Exterior Non-structural Walls. However, his Fig. 2.20 clearly shows the wall IS structural. So how can these Rp's be used?
3) Then on the following p, he must have used Rp = 1, to get the wu2 = 108 psf, because with Rp = 2.5, wu2 =43 psf. Did he hit the wrong button on his calculator?

 

[BadgerPE]

I will try to answer these:

1) I believe wc should read wp based upon the definition of wp on the previous page. The problem states that the brick wall weighs 90 psf so I think this is what was used in the calculation. I doubt the wind load would be used in this step as you are determining the diaphragm forces due to seismic loading.

2) I agree with the author on the use of the values of the variables given. This is a parapet wall with the bracing to the structure provided above the wall's center of gravity.

3) I would tend to agree with you that there is a typo and that wu2 should equal 43.2 psf

 

[flyinghigh]

Good morning, 1) yes, I initially overlooked the identical weight of the wall. 2)Ok, 3)Thx for the note.