Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

ASCE7-05 6.5.12.2.1 gives huge pressures to design for, is this correct? 2

Status
Not open for further replies.
ProLuke

ProLuke

Structural
Joined
Mar 8, 2012
Messages
21
Location
US
Hello,
I am designing a 5 story wood framed hotel building approx 53' x 180' footprint. I am ending up with large pressures to design my plywood shearwalls for, and no difference in pressure between interior and corner zones. Is this correct?

Here are some details about the project:
I am using ASCE7-05, category II building, Exposure C, 130 mph, h = 65 feet

So because this building is over 60 feet tall, I am using the general MWFRS equation in ACCE7-05 6.5.12.2.1
I am ending up with 63 psf acting at the top of the building down to 55 psf acting at the bottom of the building.

I am used to using the lambda value and Figure 6-2 that has much lower interior zone pressure values.
From figure 6-2 for a low-rise 60 foot tall building, the pressure would be 60 psf at the corner zones and 40 psf at the interior zones.

Is it correct that there is no reduced pressure at interior zones on non-lowrise buildings?

Thank you for your time!

--Luke
 
Sort by date Sort by votes
I figured out what I was doing wrong to get such large pressure values using ASCE7-05 equation (6-17).
Hopefully this can save someone the weekend stuck in the office I have had :)
You are supposed to use + or - 0.18 for your internal pressure coefficient to determine the windward and leeward pressures. I was independently finding the worst case of both the windward and leeward separately, then combining those two values to get the total force on the building at each level. What I learned is that you should have two cases, one for + 0.18 and one for -0.18 internal pressures, and find the windward and leeward for each case. This give me a max pressure at the top of the building of 46 psf instead of the 63 psf I had before.

This is what helped me figure it out - they have nice wind design table layouts that I used for my calculations:
--Luke
 
Upvote 0 Downvote
In general (there are exceptions), I do not include the internal pressure in the MWFRS loads, because internal pressures do not result in a net lateral pressure.

DaveAtkins
 
Upvote 0 Downvote
...unless the building has an expansion joint, then the internal pressures may be relevant but the windward and leeward may not combine in the same structure.


Check out Eng-Tips Forum's Policies here:
faq731-376
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

E
  • Question Question
HOW TO DESIGN A SHEAR WALL DESGIN USING EUROCODES 2 AND 8
Replies
2
Views
3K
engTByazid
E
E
  • Question Question
shear wall design eurocode 8
Replies
0
Views
3K
engTByazid
E
E
  • Locked
  • Question Question
New RC wall to Existing RC wall Interface connection design
Replies
1
Views
1K
JAE
JAE
Awesomer
  • Locked
  • Question Question
First time going for structural design and coordination interview
Replies
0
Views
872
Awesomer
Awesomer
Olivaw
  • Locked
  • Question Question
Preliminary Design for Shear Wall Buildings
Replies
5
Views
2K
lexpatrie
lexpatrie

Part and Inventory Search

Sponsor

Back
Top