FLITCH PLATE 3

[VBI]

I'm wondering if anybody can help me with this question...

EXISTING CONDITION - TOP PLATES OF BASEMENT COLUMNS FULLY SUPPORT BUILT-UP-BEAM (3-2x10'S)

PROPOSED CONDITION - ADD 3/4" X 9" PLATE AT EACH SIDE OF BUILT-UP-BEAM TO CREATE FLITCH PLATE (in order to remove a middle column)

PROBLEM? - THE NEW STEEL PLATES WILL NOT BEAR ON COLUMN (TOP PLATE). IS THAT A PROBLEM AND IF SO - ANY IDEAS ON HOW TO RESOLVE IT?

THANK YOU,
VBI

 

[SlideRuleEra]

If the three 2x10s are adequate for shear load (often a big IF), it does not matter if the steel plates have bearing or not.

With that said - there are a lot of other factors to be considered such as span, loading, tributary area, column material and size, column foundations (footings), 2x10 splice details, connection details between the steel plates and the 2x10, etc.

 

[Ron]

VBI...I'm assuming by your description that the flitch plates extend over the column, but that the built-up beam is the only part actually bearing on the column head. If my assumption is correct, then you need to check the compression load on the bearing sides of the built-up beam for comparison to limit on compression parallel to the grain. If this is OK (after column removal) then should be OK that the flitch plates do not actually bear on the column head. Have you checked the remaining columns for loading after removal of the one?

 

[dicksewerrat]

Make sure the steel will suport the increased moment at the middle of the span (largest moment). also look at what the compression loads on the remaining col. You will have to estimate the existing loads fairly well before doing the calcs. Start at the max the existing beam/cols. will hold.

 

[TFL]

Remeber you have to develop the bolting for two purposes. the bolting in the middle of the beam has to get the load from the wood into the beam over it's length and the bolting at hte end has to develop the full reaction into the wood

 

[boo1]

Typically the steel in flitched beams are undersided so the bearing load is taken by the timbers. Ron describes bearing check. Bolting patern is calculated so load being transferred from the timbers to the plate by the bolts over the main span, and then transferred back from the plate to the timbers at the bearings.

You MUST ensure that any flitch beam is provided with adequate bearing, fastening methods, and lateral restraint.

See:

http://www.destefanoassociates.com/tech/flitch.pdf

http://www.toolbase.org/docs/MainNav/WoodFrameConstruction/2947_flitchplate.pdf