Distribution of actions (loads) between two beams

[As-Lag]

Hello

I have a glulam beam that has failed in bending-moment and deflection and I want to add a steel beam below to take up the slack. Do I distrubute the actions between the two baems in a ratio of their stiffness (EI) for both bending and deflection.

Thanks

 

[SWComposites]

Only if you can unload the original beam before installing the new beam.

 

[JAE]

And if the upper GLB is "failed" then I might simply design the steel beam to take 100%.

 

[rb1957]

has it failed installed (like under the loads it is seeing) or has it failed under the code loads (and you're looking to reinforce it) ...

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[HTURKAK]

A sketch is necessary .Pls Post a dimensioned sketch to get better responds.
It is not clear if the existing beam failed , how the GLB connected to steel beam etc.

I would consider adding two channels at both sides to get combined action .
......

He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..

Luke 6:48

 

[As-Lag]

Thanks for all your enquiries.

The Glulam Beam is the sole-plate for a timber-framed extension that is to sit onto the wall-plate of an existing bungalow making the house three-storey. The Glulams are to span several openings and I have the task of checking those openings. My first opening is over some bi-fold doors and I concur that I shall ignore the beam for this example but I have other openings not so wide (2.5m say. The Glulams may only just fail so I woild like to share the actions between the Glulam and Beam.

As requested, I attach a drawing showing the beams.

I am not trying to over egg the problem, just share the actions and I am minded to use the stiffness of the beams as the ratios as in a flitch beam.

 

[SWComposites]

You are not going to connect the two beams? Why?
If this is a new design, why not just size one beam that will work?

 

[As-Lag]

Thanks everybody

I asked a technical question about distribution of actions between two beams. I will use my own experience and distribute the actions by stiffness.

As for the design, it was not mine so I do as I am asked.

Thanks again.

 

[SE2607]

I asked a technical question about distribution of actions between two beams. I will use my own experience and distribute the actions by stiffness.

If you are not going to shore the beam thus relieving the existing beam of the loads imposed on it prior to reinforcement, you need to analyze the existing beam as unreinforced (pre-loaded). If you add reinforcement (such as channels on both sides, as HTURKAK suggests, bolted at fairly close spacing (12" or so), then you can distribute the superimposed loads (those that are added after reinforcement). Then you superimpose those stresses on the existing beam.

 

[As-Lag]

My task is to analyse the beams as in the drawing - one above the other. I am unable to flitch the Glulams.

 

[XR250]

I am unable to open your attachment but for a 2.5m span, there must be a shit-ton of load to fail a GLB. Seems like it would be easier to just design the steel beam for the entire load as JAE mentioned. Probably cheaper overall to do it that way.