shape the top of a Glulam ridge beam

[sbebuilder]

The EOR for a commercial building that I'm framing, is asking me to shape the top of a Glulam ride beam. 10:12 pitch, 5 1/8 x 13 1/2 24F-V4", I was always under the impression that you couldn't shape the top of a Glulam beam because you would be removing the compression cord of the GluLam beam and then it would just be a pile of lumber with some glue holding it together.

Can you shape the top of a Glulam ridge beam?

Sim

 

[DaveTN]

You should never notch, cut, bevel, etc. a glulam. I would consider using a 4x6 cap beveled and ripped to match the width of the beam.

 

[msquared48]

Adding the ripped 4X6 cap that you can bevel is a good idea.

However, small holes and beam seating end notches are common with glulams. The structural engineer of record should be contacted by the contractor regarding the plumbing holes, but seldom is.

The top flange is usually not as critical, except in V8 beams, as the bottom flange, the tension flange. To cut any tension flange, top or bottom, is always a no-no.

Mike McCann
MMC Engineering

 

[dik]

If the section is designed for this by the glulam supplier, the stresses shouldn't be a problem: the glulam manufacturer can be involved with this.

Often with glulam, they use better quality material for the outer fibres and by cutting off the 'good stuff' you may weaken the beam.

Dik

 

[woodengineer]

It depends how the laminations are positioned. In a uniform beam lay-up, the grade and stress values of the laminations in the compression zone, the tension zone and the inner zone are the same throughout. "Glulam Uniform" is used mainly for resisting axial loads. In this case, I'd imagine you could chamfer the top. Check with your manufacturer.

woodengineer

 

[RARWOOD]

I would ask the EOR if he has analyzed the glulam with the bevel that is being requested. A 10/12 bevel on 5 1/8 seems like a lot to remove.

Beveling is commonly done. My person preference as an engineer is to add bevel blocking. Suppliers like to bevel the beam because it cost less than to add the blocking. If the plans show a 6 3/4" x 24" beam they base there bid on that. If they have to add blocking later it is an additional cost.

 

[swsengineer]

I am an engineer for a custom glulam manufacturer. We put top cuts on ridges, hips, eaves, and valley beams all the time. You must engineer the beam for the cut and often times we modify the layup to include extra tension/compression lams on the top. If you put a cut on a beam that the layup has not been modified your creating a beam with a lower layup and basicaly you are reducing the design values that can be assigned to that beam. Depending on how stressed the beam is it may not be a big deal or it may be.