Messages and Online Forum Q&A

Re: 16' I-Beam

From: tonyines@aol.com
Category: Structural
Remote Name: 24.164.128.251
Date: 24 Oct 2005
Time: 10:52 AM

Comments

Question: I am finishing a basement and I am facing an area that spans 16 feet (from left to right as you face front-to-back) and the full depth of the house (about 30 feet). I have a steel I-beam that is 8” high by 4” in width and appears to be 1/8th “ in thickness. The beam is set back approximately 11 feet away from the front of the house and runs the full 16’ length. On one end it is supported by a corner of the poured foundation and the other end is tied to a 4” steel support. Another 10 feet further back in the house is another steel beam that runs parallel to the first. The main floor above rests on 2X10’s on 16” centers running front to back and joining (with a slight overlap) on each of the beams. The majority of the floor on the next level is open space with the exception of one segment of an archway that supports a second story support beam. This segment is placed about 1/3rd of the way back from the first beam to the second. My question is this: In the middle of the first 16’ beam I described is a 4” steel support beam, sunk in reinforced concrete footings below the basement floor. I would like to remove this support pole. That would leave the full 16’ span unsupported, but I see other sections in the basement where the I-beam runs as much as 13' unsupported. Is there reason to fear problems with a steel beam like the one I described running 16’ without a mid-point support?

Builders Websource Answer: Chances are good that the mid-point support is there for a reason: to minimize deflection from above and/or to transfer other loads from the roof or house above. While we can visualize your situation, we don't know how all the loads are transferred to the beams. As a result, removing the center support could cause the floor to sag above. Even worse, you could create a potentially dangerous structural condition that results in catastrophic failure. Before you remove any center steel supports, consult a licensed structural engineer who can evaluate your exact situation and make a recommendation. If you want a clear span, you may need to add another larger beam to take the load. Even if removing the beam support turns out to be structurally safe, your floor will bounce much more, which deteriorates the quality feel of the construction. There's nothing worse than a bouncy floor that flexes when you walk on it.

Builders Websource®

Article Tools

Builders Websource® is a corporate member of ASTM International—a non-profit engineering body dedicated in part to the standardization of building materials specifications, products, systems, and test methods for improved health, safety, and reliability of residential and commercial structures.

Copyright © 1999 - 2008 Builders Websource®, an InBuild™ company. All rights reserved.