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Re: Removing Garage Pole 22' span
From: info@builderswebsource.com
Category: Structural
Remote Name: 63.198.181.43
Date: 16 Nov 2002
Time: 12:23 PM
Comments
Without having an accurate loading diagram, including intermediate point
loads and tributary loads, we can comment generally on your situation. Only an
onsite inspection can reveal all load sources and how they tie into the
structural shell. However, removal of the center garage pole has a huge impact
on the size of beam required to span the width of the garage. Furthermore, even
if your client will accept them as you suggest, bouncy floors are not good,
especially on long spans. They lead to a feel of poor quality and cause the
house to shake when you walk. Generally, the building code stipulates a maximum
live load deflection of SPAN/360, and a total load deflection of SPAN/240, using
a minimum of 40 psf for the live floor load, plus whatever other snow loads may
impact the equation. Normally, to span 20' clear with a second story load
requires a glulam or steel beam of substantial proportions. We always recommend
very stiff beams to minimize deflection and spongy feel. Sometimes glulams are
specified with a slight camber to help offset the dead load deflection,
providing a more level floor. We recommend that you design floors and structural
members with a maximum live load deflection of SPAN/480, or SPAN/720. While this
isn't required by code, it makes a better product. In order to engineer your
beam to proper specifications, you must hire a local licensed structural
engineer. It may be possible to buttress your existing 2x12 built-up beams, but
the size and spacing of bolts must be computed to ensure sufficient shear
performance. In addition, how the loads are transferred from the end of the beam
to the walls is also important. You will probably need to additional studs
and/or column posts, along with suitable column-beam fastening saddles or
brackets. Depending on the loads, some exterior foundation reinforcement may
also be required to properly distribute the added load on either side of the
garage. Ask your structural engineer to look at this too. Builders Websource.
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