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RE: Mechanical Equipment - Live or Dead/AFTER ANSI A58.1-82

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Syed,
The phrase is "You can't get there from here!"  I think I'm more
confused than when I started. Seriously, I have considered it a dead
load because of the service life of the units, but whether it is a live
or dead load, the best approach is to take the worst case condition and
make it work to this. Only then can I be sure I am out of a potentially
libelous situation.

It sure would have helped to have the original drawings. BTW, I think it
was Roger who suggested that if this was originally a Thrifty Drug
Store, then Thrifty should have the drawings. The problem is that the
store changed hands a few times in the last twenty years and because of
this the time it would take to find the drawings isn't worth the effort.
As for the building department, Blythe is a small town (at least as
large as La Quinta - about 25,000 people - but there are no surrounding
towns (other than a county prison) within nearly 30 miles and that is a
town of only a few thousand. Indo and La Quinta are the nearest and
these are 90 miles west.

In short - I wouldn't count on the building department either.

I'm going with the worst case scenario. The contractor verified the
beams today and some are larger, but his measurement on the claimed 7"
GLB is actually 7". Has anyone heard of a 7" GLB available in the early
70's?

Thanks
Dennis

Dennis S. Wish, PE
California Professional Engineer
The Structuralist.Net Information Infrastructure

Website:
http://www.structuralist.net

."The truly educated never graduate"
-----Original Message-----
From: syed faiz ahmad [mailto:syedfaiz23(--nospam--at)hotmail.com]
Sent: Tuesday, February 12, 2002 11:47 AM
To: seaint(--nospam--at)seaint.org
Cc: selkar(--nospam--at)aol.com
Subject: Re: Mechanical Equipment - Live or Dead/AFTER ANSI A58.1-82

Dennis,

Before I answer your question I would first draw your attention to ANSI
A58.1-82 (now replaced by ASCE-7/95 ??) which categorises DEAD & LIVE
loads
as follows:

  1) DEAD LOADS

     - It comprises the weight of all permanent
       construction including, walls, floors, roofs,
       ceilings, stairways & Fixed Service
       Equipments and the net effect of prestres-
       ing.

    As per clause 3.3 of ANSI A58.1-82, the
    Fixed Service Equipments include:

     - plumbing stacks & risers
     - electrical feeders
     - HVAC (heating, ventilation & airconditio-
       ning) system.

In the light of the above, answer to your first question is: The
equipment
loads are DEAD LOADS.

And, as for your second question, it is no more valid now because its
not a
LIVE LOAD.

However,  speaking strictly on the basis  of actual design practice that
Iam
familiar with (my own background); in the cases where we have specific
mechanical loads on the roof (like ACCU, AC PACKAGE UNITS, CHILLERS, AIR

HANDLING UNITS ETC) these loads are taken care of as DEAD LOADS.

But in the cases where we donot have such heavy mechanical loads on the
roof, we always take an allowance of some unforseen mechanical loads.
These
are taken as 0.50 KN/M2 or 10 psf and are always taken as LIVE LOADS.
This
live load basically takes care of:

    - any collateral load, like, exposed
      piping work on the roof,
    - loads due to maintenance workers,
    - or any other heavy construction
      equipments, tools & plants temporarily
      placed over the roof.

What I see is this approach is corroborated by ANSI A58.1-82; follow the

description of the LIVE LOADS as per ANSI.

   2) LIVE LOADS

   -  Live loads are  those loads produced by
      the use & occupancy of the building or
      other structures and donot include
      environmental loads such as wind, snow
      rain & the earth quake loads; or dead
      loads.,

   -  Live loads on a roof are those that are
      produced due to:

       - during maintenance by workers,
         equipment and materials,
       - during the life of the structure by
         movable objects such as planters and
         by people.

I hope Iam able to throw some light on the issue Which I hope you would
find
useful.

Regards,

SYED FAIZ AHMAD; MENGG, MASCE
SENIOR STRUCTURAL ENGINEER
SAUDI OGER LTD
RIYADH, SAUDI ARABIA.


>From: "Dennis Wish" <dennis.wish(--nospam--at)verizon.net>
>Reply-To: <seaint(--nospam--at)seaint.org>
>To: <seaint(--nospam--at)seaint.org>
>Subject: Mechanical Equipment - Live or Dead
>Date: Mon, 11 Feb 2002 18:21:35 -0800
>
>I know this is a dumb question and I should know better, but let me ask
>it anyway:
>
>Is a roof mounted A/C unit considered a Live or Dead Load?
>Is it added to the existing Live Load or does it replace the live load
>normally applied to that location?
>
>Dennis S. Wish, PE
>California Professional Engineer
>The Structuralist.Net Information Infrastructure
>
>  <http://www.structuralist.net> Website:
>  <http://www.structuralist.net> http://www.structuralist.net
>
>




SYED FAIZ AHMAD; MENGG, MASCE
SENIOR STRUCTURAL ENGINEER
SAUDI OGER LTD
RIYADH, SAUDI ARABIA.


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