Structural support that absorbs vibrations?

Attrill · #1 Posted **Sep 17, 2007, 6:30 AM**

This is a pretty random question, but I'm doing some work on my house in Chicago and I've had a hard time finding any information on this.

We're adding some structual support to a large beam that runs the length of our house in the crawlspace. The beam plays a role in supporting all floors and load bearing walls (the house is brick with a stone foundation, built in 1879). The plan is to add concrete footers under the beam and then put some jacks in to give the beam more support. The tricky part is that we live VERY close to an El line and I'm looking to reduce vibrations being carried from the ground up through the structure. Are there any materials that we could use to dampen the vibrations? The ground vibrations are pretty serious, if you put a bucket of water on the ground in our backyard it ripples everytime a train goes by.

Canadian Mind · #2 Posted **Sep 17, 2007, 6:43 AM**

heh, I'm no professional, 17 years old, fresh out of highschool, but when we had 1.5 mile long freight trains going by within 50 feet of my house, we had no problem with steel poles supporting the centre-span support beam. I think all we had were thin rubber pads between the beam itself and the steel poles.

No, for a bit more radical thinking, and this is just me being stupid; fiberglass? it's a fairly absorbent material, so I wonder if it would work as a support structure in a house.

Attrill · #3 Posted **Sep 17, 2007, 2:55 PM**

Thanks - that's exactly the sort of thing I'm thinking of, but I'm wondering if there is a material that is more durable than rubber (maybe one made specifically for this type of application). I've used rubber in the past to insulate enlargers in darkrooms from vibration, but the rubber always seemed to degrade over time. I am considering cutting squares out of an old tire and putting those between the beam and poles.

Coldrsx · #4 Posted **Sep 17, 2007, 6:27 PM**

there are damper pads, both commercial and residential, that are available for this kind of use. They are synthetic and usually on the base near the footing and are sandwiched with steel "bread".They reduce lateral motion but also serve as vertical suppression with regards to vibration.

i dont have a link though....but i know there is stuff out there available to the public.

plinko · #5 Posted **Sep 17, 2007, 9:24 PM**

Coldrsx is right. Damper pads will be much cheaper for you than any other solution. I used to work on cleanroom designs and they would use fiberglas beams (highly expensive) set on vibration dampers for particular pieces of equipment.

Since the vibration comes from the ground, the dampers can be set between the beam and your footing, just make sure there is still sufficient anchorage.

I don't have any specific information beyond that either though...sorry.

Attrill · #6 Posted **Sep 17, 2007, 9:56 PM**

Thanks - Just having the term "Damper Pads" has pointed me in the right direction. A quick Google search has given me number of companies that have a number of products that will fit the bill. Thanks again!

Coldrsx · #7 Posted **Sep 18, 2007, 3:30 PM**

^best of luck.