Posted by: fightclub74 ® 03/17/2008, 17:15:34 Author Profile eMail author Edit

Hello all, I desperately need help and short of paying $1200 for an engineer I am just looking for some basic answers from people who know. I have a ranch house, single floor with an attic, roof loads are on outside walls only. I am having my basement refinished, and am trying to remove one of the lally columns. Currently my girder is 3 -2 x 8's with a lally column every 7 1/2 feet. I need to remove one lally column to span the girder a total of 15 feet from block foundation to next lally column. The total length of joists that rest on the girder is 24 feet from end to end. From what I am told by two contractors and according to a flitch plate table, adding two 2 x 8 x 16 one inch steel plates on either side of my girders (lag bolted in a w pattern) will support the weight of removing the existing lally column. I understand you have to take into effect the footer size, but that withstanding, do these estimates seem correct? The roof is a 4 pitch. Thanks for anyones help, I really need it!!!

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: replacing lally column/ strengthening existing girder
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Posted by: JOPAPE ® 03/24/2008, 13:03:56 Author Profile eMail author Edit

Do not do it! Though the steel may be able to handle this load, the wood will fail miserably. By doubling you span, if using 30 psf LL & 15 psf DL, you have increased you actual moment nearly 4x and your actual shear load of the wood has more than doubled at mid span. Your wood is going to fail! I am not a licensed engineer, however, i have been performing structurlal engineering calculations for small commercial structures, under the stamp of a registered architect, for thirteen years, and i would not allow such a thing! If contractors could simply splice those girders together to begin with, think of the money they could save by not having to form and pour footings, and think of the desirable wide-open space people could have had for years! Why hasn't it been done in the past? Because it won't work! - My opinion!

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Posted by: marky ® 03/18/2008, 07:43:53 Author Profile eMail author Edit

Hi...welcome to the forum. This is one of those questions that I think the folks here will shy away from. Sounds like you're making room for a pool table. I think the 2 contractors answered your question. Nothing beats having someone in person looking at the issue. Good luck...send us a pic of the finished room I'll kindly pay you Tuesday..for a hamburger today....Whimpy

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Posted by: fightclub74 ® 03/18/2008, 08:10:15 Author Profile eMail author Edit

Exactly right, making room for the pool table. Alot of work for that extra 3 feet!! I understand the use of an engineer is the only real way to do it safely, but in NJ it is gonna cost me a minimum of $1000 or more to get one to do it. After looking at flitch plate systems and dealing with the salesman, it seems they recommend 3 2x8's with 2 plates of 1 inch steel to cover the 15 foot span. Just need an idea if this will hold the approximate 30lb live/15 lb dead load. Thanks!

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Posted by: marky ® 03/18/2008, 08:25:12 Author Profile eMail author Edit

If you are pulling the proper permits...your town engineer should help you. I'll kindly pay you Tuesday..for a hamburger today....Whimpy

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Posted by: zekeman ® 03/18/2008, 15:05:42 Author Profile eMail author Edit

I would not rely on the town engineer in general to help with any engineering problem. Their expertise may not be in structures. Nor would I allow a salesman to help. I will tell you that the new configuration assembled and connected properly can take the load ( the steel alone can handle the load), but the deflection would be a little higher at the center than with the original but should be OK, anyway. You still should not engage in DIY in this area, especially in designing the girder and its connections. If you screw up, you could cause serious damage and bodily injury and your insurance company will walk away from the consequences.

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Posted by: fightclub74 ® 03/19/2008, 14:13:50 Author Profile eMail author Edit

Thanks for the replies. Basically I just wanted to know if it could support the load with what I am being told.

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