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RE: Shear Walls

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Sir, 
Thank you very much for your suggestions. I intend to use a dual system to
provide sufficient rigidity for lateral deformations and forces. 
With regards to the forces, I use STAAD for 3-D analysis but the results are
in stresses (kPa and psi) and not forces (KN and lbs). Previously, I
determine the wall forces manually (assuming that the walls are cantilever
beams with each story forces) with the resulting conservative design. I
intend to use STAAD but I need a confirmation on the results. I presume that
the results are to be multiplied to the wall dimensions to obtain the
moments and forces. 
Any suggestions and comments are most welcome. Thanks.
By the way, do you know any other structural engineering programs, aside
from STAAD and ETABS, which are user friendly and efficient? Thanks again
!!!!

> ----------
> From: 	T. Eric Gillham PE[SMTP:gk2(--nospam--at)kuentos.guam.net]
> Reply To: 	seaint(--nospam--at)seaint.org
> Sent: 	Monday, March 29, 1999 6:36 AM
> To: 	seaoc list
> Subject: 	Fw: Shear Walls
> 
> Allan:
> 
> Kumusta!
> 
> I would say that keeping the shaft R/C AND keeping it connected is the way
> to go.  Dual systems, IMO, are the best R/C configurations for seismic
> resistance.  The SMRF, if properly detailed, provides an excellent energy
> absorbing system, and it can accomodate some pretty high drift levels.
> The
> shear walls, depending on the configuration and sizes, provides some
> measure
> of deformation control.  Given that the frames are taking most of the
> vertical loading, axial load on the walls is usually pretty low, allowing
> them to exhibit good hysteretic behavior.
> 
> On the other hand, if the walls are in such a configuration that they
> bring
> about a lot of torsional response, you might look at using soft walls, but
> for a 7 storey structure I would think it wouldn't be too much of a
> problem.
> 
> Besides, I think the PI is similar to Guam in that R/C is the prevelant
> material.  Best to keep things simple (read: leave it R/C), rather than
> introduce some separation detail or switch to another material which may
> result in construction headaches.
> 
> My .02 pesos.
> 
> T. Eric Gillham PE
> GK2 Inc.
> PO Box 3207  Agana, Guam  96932
> Email - gk2(--nospam--at)kuentos.guam.net
> Ph:  (671) 477-9224
> Fax: (671) 477-3456
> -----Original Message-----
> From: Francis.Ang(--nospam--at)toyota.com.ph <Francis.Ang(--nospam--at)toyota.com.ph>
> To: seaint(--nospam--at)seaint.org <seaint(--nospam--at)seaint.org>
> Date: Friday, March 26, 1999 11:52 AM
> Subject: Shear Walls
> 
> 
> >I am designing a building that is seven story high. And here in the
> >Philippines, we are required to use elevators for 5-storey high
> structures.
> >Can anybody out there offer me suggestions? I intend to use the elevator
> >housing as a shear wall. That is based on my experience.  For a change, I
> >was thinking of providing an elevator housing but is not connected to the
> >Lateral Force Resisiting Element.
> >The structure would act as a special space moment resisting frame rather
> >than a dual structure.
> >Suggestions are most welcome.
> >I know that by using a shear wall, there is a need to consider many
> things
> >in the seismic analysis.
> >Thanks in advance guys !!!!!
> >
> >Allan Yango
> >Structural Engineer
> >
> >> ----------
> >> From: Charles Greenlaw[SMTP:cgreenlaw(--nospam--at)speedlink.com]
> >> Reply To: seaint(--nospam--at)seaint.org
> >> Sent: Thursday, March 25, 1999 6:17 PM
> >> To: seaint(--nospam--at)seaint.org
> >> Subject: Re: Residential Flexible/Rigid Diaphragm Analysis
> >>
> >> Responding to Dennis Wish's recent solicitations:
> >>
> >> Dennis, if you are gleaning prior postings for an Online article, I
> >> submitted quite a bit on the diaphragm rigidity issue in 1998 on Aug 29
> >> and
> >> Nov 18 and 21.
> >>
> >> I still think the code's demand that we regard diaphragms as conforming
> in
> >> reality to the extremes that human-invented figures of speech suggest
> >> ("rigid" and "flexible") is the dumbest thing since when young ladies
> were
> >> similarly divided into two distinct categories. You remember, there
> were
> >> "good girls" and "bad girls". And nothing else. The first kind were
> good
> >> for
> >> marrying and bearing your children. The second kind were good for other
> >> purposes we need not specify here.
> >>
> >> Like with this spurious code expectation that we can tell the
> difference
> >> in
> >> diaphragms and rely on the result, telling the difference between good
> and
> >> bad girls hasn't been all that certain. My great-grandfather F.B.Ogden
> in
> >> Oakland wouldn't let his daughters wear any red clothing, because it
> was
> >> "the sign of the fallen woman". His judgment seems quaint now, but the
> >> voters back then kept re-electing him as a superior court judge.
> >>
> >> In my own youth, the girls themselves, when it came to being good or
> bad,
> >> seemed to sort out behaviorally as "rigid" or "flexible", so to speak.
> >> Performance-based evaluation, we might proudly call it now.
> >>
> >> But back then, the girl classifications were just for guideline
> purposes.
> >> You didn't get sued or lose your license and retirement savings if you
> >> mistook one kind of girl for the other and made a poor choice. But with
> >> the
> >> building code, mistaking rigid for flexible is disastrous as soon as an
> >> adversary's expert opines you got it wrong. The fact that the building
> >> itself didn't care is only a curiosity. You are into an expensive
> defense
> >> for violating a regulation intended to protect people from injury.
> Serious
> >> business.
> >>
> >> So how did this pitfall come to be inflicted on us? I suggest looking
> to
> >> Mark Gilligan's posting on 2-27-99, the pertinent part of which is:
> >>
> >> >I have observed that a number of code provisions have been adopted
> with
> >> >little technical data backing them up.  The SEAOC Seismology committee
> >> has
> >> >generally done a good job but ultimately the individuals find
> themselves
> >> >having to make decisions on subjects that they have not seriously
> >> >researched.  In this context people use their  best judgement.  I
> believe
> >> >that the provisions on redundancy probably fell in this catagory. The
> >> >problem is that what may seem rational occasionally isn't.
> >>
> >> I discussed Mark's implication in early March at a SEAOC dinner meeting
> >> with
> >> another regular code formulation participant, who is with a state
> agency
> >> keenly concerned with seismic codes. He confirmed that code language
> very
> >> often comes from one person on a committee, usually an energetic and
> >> forceful advocate, and gets approved with little or no validation in
> >> depth.
> >> Usually voting committee members shoot from the hip on little
> >> knowledgeable
> >> debate, because the agenda is too full, and was distributed too close
> to
> >> the
> >> meeting date to absorb and find flaws in. And the plane home leaves too
> >> soon. This is what my own experiences confirm. On the few issues I can
> get
> >> up to speed on and find big defects in, it is still hard at the meeting
> to
> >> get an edge in wordwise. I have in past writings referred to these
> >> committees as "empires" and been told that is an understatement.
> >>
> >> I do better at Board of Registration meetings. I have spoken on
> >> enforcement
> >> issues and pointed out an anomaly:   The Board disciplines individual
> >> engineers for failure to fulfill the duty of due care, such as
> mistakenly
> >> making a code violation, on a single element of a single building. But
> the
> >> code provision itself was originated with less care than taken by the
> >> offending engineer in its use. And the code doesn't just affect that
> one
> >> building, it affects all buidings. With less care taken. How do you
> Board
> >> of
> >> Registration members want to discipline that??  Blank stares follow; no
> >> complaints were received so they have no idea. But why should the
> >> struggling
> >> code users suffer the burdens? Why not the code originators? The
> stories
> >> of
> >> code formulation proceedings are plainly stories of failure to render
> due
> >> care.
> >>
> >> Questioning "authority" itself, not the orders disseminated by
> authority,
> >> is
> >> where this subject's inquiry should head.
> >>
> >> Charles O. Greenlaw, SE    Sacramento CA
> >> Vietnam Vet who hasn't forgotten what can happen
> >>
> >>
> >>
> >>
> >
> >
> >
> 
> 
> 
>