Need a book? Engineering books recommendations...

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

Re: HIGH CLEAR HEIGHT CONCRETE WALLS

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Thanks Harold.
 
I have used vertically post-tensioned precast before, this is also a high seismic area with bad soil. I am not sure what R value to apply for a vertically post-tensioned precast system, I think I would need to get a good amount of mild steel continuity in the walls to reach the special concrete shear wall ductility levels.
 
I was also contemplating composite steel instead of all the rebar as well. I will put in an option for the long spanning precast.
 
Will Haynes

On Wed, Nov 9, 2011 at 11:13 AM, Harold Sprague <spraguehope(--nospam--at)hotmail.com> wrote:
Will,
Reconsider shipping precast.  Even with an escort, it would be likely easier than constructing this with cast in place concrete.  Reinforcing 10" walls with 2 curtains of rebar will get very crowded and difficult to construct.  The wall elements spanning horizontally would be easy in precast in 8' wide segments.  Hollow core spanning horizontally would reduce the wall mass.  AASHTO girders supporting the precast walls would be easily constructed.  You could also consider structural steel or composite structural steel spanning vertically supporting the precast which would be spanning horizontally.  It would greatly ease the rebar congestion.  Another consideration would be post tensioning the vertical element.  Precast girders with post tension (PT) can be spliced in the field with relative ease especially if you use bonded PT.  Bridges spanning interstates often use field spliced girders with bonded PT.  Obviously, you can field splice structural steel easily with welding. 
 
Given what you are proposing to construct, SCC would not be a problem for consolidation even in very crowded rebar, but your heat of hydration will be very large.  Insulating and controlling the heat of hydration would be a challenge.  With what you have drawn up, I would suggest slip forming.  And as mentioned, form pressures would be very large. 

Regards, Harold Sprague
 

Date: Tue, 8 Nov 2011 20:05:19 -0500
Subject: Re: HIGH CLEAR HEIGHT CONCRETE WALLS
From: gtg740p(--nospam--at)gmail.com
To: seaint(--nospam--at)seaint.org

I have some very high lateral loads also and I was going to create pilasters (in the 3 ft x 4 ft square range) integral with the wall to cut down on the reinforcing and concrete required. But, now I am trying to figure out what to do about tying all the vertical bars in the pilasters and whether it should meet column tie reinforcing requirements. The pilasters are functioning primarily but are needed to assist the 10" wall since it can't nearly make it 90 feet. I would specify SC concrete but I am still not confident it will get down in between the layered vertical bars. Here is the conceptual detail of the wall in plan:

http://structuraldetails.angelfire.com/


Will
 

On Tue, Nov 8, 2011 at 2:27 PM, Rick Stone <rwsmadconc(--nospam--at)aol.com> wrote:
I have successfuly gone 65 ft with tilt-up, and 73 feet in single lift pours. In the latter case, used self-consolidating concrete (no way to vibrate internally that far down, and external vibrators rejected due to the sketchy conditions with the bracing shaking loose) and did a lot of set time testing to control the form pressures.........


-----Original Message-----
From: gtg740p <gtg740p(--nospam--at)gmail.com>
To: <seaint(--nospam--at)seaint.org> <seaint(--nospam--at)seaint.org>
Sent: Mon, Nov 7, 2011 6:49 am
Subject: Re: HIGH CLEAR HEIGHT CONCRETE WALLS


It's not planned for one pour.

WH

On Nov 6, 2011, at 3:52 PM, Jay Shilstone <j2008.s(--nospam--at)shilstone.com> wrote:

I hope you aren't planning on placing in a single pour. That would be
a recipe
for disaster. You will need multiple pours or slip form.

Can't respond to engineering aspects since I am not an engineer.

You might want to include a comment on the geometry of the building.
I figure
rectangular but round is easier to brace.

Jay Shilstone
Sent from my iPad

On Nov 6, 2011, at 2:05 PM, William Haynes <gtg740p(--nospam--at)gmail.com> wrote:

Can anyone tell me what construction difficulties may be encountered
for a
building that is around 90 feet clear height using poured concrete? Shipping on
precast this long would be an issue and I don't see it practical to create
continuity in precast if using stacked modules. I am concerned with the cost of
bracing the high poured walls during construction as they are being built and
figuring this cost into a preliminary cost estimate.

Will Haynes

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
*
*   This email was sent to you via Structural Engineers
*   Association of Southern California (SEAOSC) server. To
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
*   send to the list is public domain and may be re-posted
*   without your permission. Make sure you visit our web
*   site at: http://www.seaint.org
******* ****** ****** ****** ******* ****** ****** ********

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
*
*   This email was sent to you via Structural Engineers
*   Association of Southern California (SEAOSC) server. To
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
*   send to the list is public domain and may be re-posted
*   without your permission. Make sure you visit our web
*   site at: http://www.seaint.org
******* ****** ****** ****** ******* ****** ****** ********


******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* *   This email was sent to you via Structural Engineers *   Association of Southern California (SEAOSC) server. To *   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you *   send to the list is public domain and may be re-posted *   without your permission. Make sure you visit our web *   site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ********