Masonry, special reinforced R=5. Fire Station Apparatus Bay... see the pier description per original email.
I have no walls, just 4 ft piers.
--- On Thu, 2/5/09, David Topete <d.topete73(--nospam--at)gmail.com> wrote:
From: David Topete <d.topete73(--nospam--at)gmail.com>
Subject: Re: ACI 530 R=1.5
Date: Thursday, February 5, 2009, 8:57 AM
The exception in ACI 530 188.8.131.52 states that if you reduce the response modi. factor to 1.5 or less, then you can use masonry wall piers to resist lateral loads. What type of structure are you designing?
On Thu, Feb 5, 2009 at 8:42 AM, Rick <mohr2circle(--nospam--at)yahoo.com>
Look at ACI 530 184.108.40.206... it limits the R to 1.5, but only in the strength section. City of LA code references 530 to answer the other section.
I saw 220.127.116.11, and thought thats what they were origianlly referring to, but 18.104.22.168 is pretty clear. But nothing in ASD
From: Paul Feather <PFeather(--nospam--at)se-solutions.net>
Subject: RE: ACI 530 R=1.5
Date: Thursday, February 5, 2009, 8:35 AM
ACI 530 does not set or establish R factors. There are only two possible explanations that I am aware of: first if using strength design there is a provision for maximum area of flexural tensile reinforcement (22.214.171.124) where M/Vd greater or less than 1 and IF the design used an R of less than or greater than 1.5 is a trigger for additional design requirements. This is not an R factor limitation, just a trigger for other provisions. Second would be if they are somehow mis-interpreting the shear force required of 1.5V in ASD design, but this is an IBC requirement and not in ACI 530 either.
I would ask the Plan reviewer to specify which code provision he / she is referencing with his comment.
Paul Feather PE, SE
I have a City of LA Plan check comemnt that R = 1.5 "must" be used for masonry walls piers per ACI 530.
Can someone point me to the specific reference.
David Topete, SE