×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Reinforcing Existing Wood Beams

Reinforcing Existing Wood Beams

Reinforcing Existing Wood Beams

(OP)
I'm currently working on an existing building where we need to reinforce the existing timber beams to accommodate the new loading condition. Our plan was to sandwich the existing beams with steel and bolt together.

However, due to historic preservation requirements they will only allow us to add steel to one side of the existing beams. Is there anything in the code that states the steel must be added symmetrically to allow for composite action? Can the steel be placed on one side of the existing beams?

Thanks.

RE: Reinforcing Existing Wood Beams

If the issue is the aesthetics of having wood due to the historic look, you could always do a flitch plate (wood-steel-wood). This would prevent any unsymmetrical rigidity.

RE: Reinforcing Existing Wood Beams

Removing the beam, reinforcing it, reinstalling it really isn't that hard (for an engineer to specify that is). Shoring is always doable

RE: Reinforcing Existing Wood Beams

Quote (ChamboEng)

However, due to historic preservation requirements they will only allow us to add steel to one side of the existing beams. Is there anything in the code that states the steel must be added symmetrically to allow for composite action? Can the steel be placed on one side of the existing beams?

Not likely any code other than Laws of Physics which will want the beam to rotate so that must be addressed.

RE: Reinforcing Existing Wood Beams

Why not reinforce the timber beams with additional timber? That's how I normally deal with alterations and "landmarks."

RE: Reinforcing Existing Wood Beams

What about a cable or rod on the bottom of the beam? What about suspending from above with hanger rods through partitions and a beam or truss in the attic? I know, that may be a completely different configuration than you can do but without seeing your building it's hard to provide a solution. A little imagination can go a long way & that's why you get the big bucks.

RE: Reinforcing Existing Wood Beams

What are the relative thicknesses of the wood and steel? Is the load delivered to the top of the beams? Will the bearing reaction in the steel be delivered to the support directly or will it be transferred back through the timber. Can blocking, bridging, or bracing be installed on either side of the beam?

One sided reinforcing is often fine in my opinion. You just need to rectify the torsion with blocking/bridging etc or give due account to the resulting torsional stresses.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Reinforcing Existing Wood Beams

Good suggestions by all, one additional thought: if you're concerned about unsymmetrical stiffness of a one-sided steel retrofit, you could look at designing your added steel such that it would have capacity to take all the load, presuming the design magnitude doesn't get out of hand. Therefore, the existing wood beam would simply be "sacrificial", and I think you could neglect any thought of potential torsion/etc. due to unsymmetrical stiffness.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources