Subject: RE: 1920's 9 story concrete frame building
Date: Thu, 13 May 1999 14:36:21 +0800
If you are asking about the 1-2-4, it's the mixture of concrete. That's 1
bag of cement for 2 ft^3 of sand to 4 ft^3 of gravel. I think that's around
3000 psi or a Class - A concrete.
I hope this helps and not add to your confusion.
> From: Jeff Smith[SMTP:smthengr(--nospam--at)sirius.com]
> Reply To: seaint(--nospam--at)seaint.org
> Sent: Wednesday, May 12, 1999 9:37 PM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: 1920's 9 story concrete frame building
> Well, the client showed up with some plans and to my surprise the first
> floors have square columns with #3 spiral ties at 1.5 to 3" pitch. The
> vertical reinforcing ranges from 6 3/4" dia. to 10-7/8" dia bars. Above
> sixth floor there are basically 4 bars with # 2 ties at 10" o.c. Concrete
> was a 1-2-4 mix for the heavy columns (what does that mean again?)I left
> plans at my office so the details are a bit sketchy. Bob, I am sure you
> other SEAONC members would recognize the original Engineers, another
> colleague did. Werner (maybe) someone, someone and Russell I believe.
> offices were on Pacific. Even though I am amazed with the amount of
> reinforcing, I still would be very nervous in that building,it is very
> with the pan joists. The aspect ratio is closer to 2.5:1 and it is sort of
> "z" shaped in plan. I have a client who is equally concerned about seismic
> safety and the view, meanwhile a frenzy is building and other bidders are
> lining up without any consultant review what so ever. Maybe my client
> out about the sale too late or maybe the sellers are note allowing enough
> time for buyers review, I am not sure.
> Jeff Smith
> |-----Original Message-----
> |From: Robert J Bossi, PE [mailto:rjbossi(--nospam--at)sonic.net]
> |Sent: Tuesday, May 11, 1999 5:54 PM
> |To: seaint(--nospam--at)seaint.org
> |Subject: Re: 1920's 9 story concrete frame building
> |I agree, particularly if the non-ductile concrete frames are in the short
> |direction. This building probably also has a height to width
> |ratio of 3-4. Even
> |if you had plans, you probably won't find the column steel tied
> |with anything
> |more than #2 (two) smooth ties at 12" oc.
> |Jeff Smith wrote:
> |> A past client of mine is putting in a bid for a condo flat in Pacific
> |> Heights S.F. Million dollar views, very exclusive. It has a
> |concrete frame
> |> in the short direction and property line infill walls in the
> |long direction.
> |> It could be on bedrock. The floors are concrete pan joists. The
> |building is
> |> 9 stories with single units per floor. My initial reaction without any
> |> analysis is....not a good idea. Is there any possibility that a
> |> like this could have any margin of safety during a near fault 7.0
> |> earthquake? Building plan records are available, but not until
> |after the bid
> |> date is due. My only comment will be that this building is not
> |expected to
> |> do well during a credible seismic event.
> |> Regards,
> |> Jeff Smith