Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Pier and grade beam foundation systems

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Assuming these two cases:

1. If your grade beam & pier system is not exposed and on grade, then
you should be able to justify that shear can be transferred from the
wall to grade beam and to slab-on-grade and then to soil.  unless you
have some heavy seismic axial loads due to short shear wall, then your
pier has to be closely tied and designed for that.

2.  If your beam& pier system is exposed, you can either design your
piers to be cantilever system or frame system.

John Buchanan wrote:
> To all:
> I have a general question regarding a foundation system for residential
> wood structures founded on a pier and grade beam foundation system.
> A college of mine has received a plan check comment from a locale building
> official stating that the pier and grade beam system should be considered a
> reinforced concrete frame structure and designed per the requirements of
> section 1921 of the 1994 Uniform Building Code.
> The standard of care for the area has always been to use an 8" x 18" or 24"
> deep concrete grade beam with #3 ties and 2 #5 bars top and bottom. The
> beam reinforcing varies per the vertical load. Typically the piers are
> spaced at eight to twelve feet on center.
> The grade beams are tied to the piers with four #5 bars from the grade beam
> to the top of the pier.
> The piers are reinforced with six number five bars and #3 ties at 10" o.c.
> with 4 #3 ties at two inches o.c. at the top of the pier.
> So the question is should the pier and grade beam system be considered a
> frame system a be detailed per the requirements of chapter 21?
> If the consensus is no, how does one confront the building official? (There
> is a board of appeals)
> My college has called the ICBO and they do not offer any help.
> Calls to ACI have been relatively unresponsive and they try to defer the
> question to others.
> (makes you want to be a member Ha!!!!)
> Have a call into EERI to discuss the project but no return phone calls as
> of yet.
> So does any one have any comments?\
> John Buchanan
begin:          vcard
fn:             Tom  Chiu
n:              Chiu;Tom 
org:            Thomas Engineering
email;internet: Tomchiu(--nospam--at)
title:          Principal, SE
tel;work:       (714) 221-3663
x-mozilla-cpt:  ;0
x-mozilla-html: FALSE
version:        2.1
end:            vcard