Oak beam versus steel/concrete lintel strength comparison

[jfb]

Does anyone know of the comparative strengths of steel beam/reinforced concrete lintel versus oak beam for an above doorway lintel application?

 

Engineer specified a 2N 152 x 152 x 23kg UC or 3N 100 x 140dp precast concrete lintel

 

I have a seasoned oak beam that is 160 x 130 and would like to know if it is comparable.

 

I have the engineer coming back at the weekend to go through it but I would like to be well informed.

 

Anyone know of any resources out there as I can't find any?

 

Lintels are 1.4m

Edited August 10, 2022 by jfb

[markc]

Far too many variables to make a direct comparison especially with an unknown timber beam.

also a 152x152 UC is a horrendously big lump for 1.4 metres.

[Mr Punter]

The UC will be a bit lighter than even 1 concrete.  Cost may be similar.

 

I can't help on the oak.  SEs like softwood with a known strength grade.  I was surprised when an engineer recently specified 3 ply 220 x 45 C24 to support a loadbearing wall 1.5m span.

[George]

While steel and timber aren't really comparable in terms of yield strength or modulus of elasticity (springiness), timber lintels can work fine, especially for a short span. The trouble with timber is getting it graded.

 

The lowest strength class for hardwood is a D30, oak is normally D40.  If the engineer made some conservative assumptions and checked for any major knots, I don't see why they couldn't at least attempt the calculation check. 

 

 

[Temp]

Have you considered a concrete structural lintel set above a decorative oak beam? If its only one or two short spans the cost would be modest. Possibly less than getting new calculations done?

 

The conc lintel would probably need to be slightly longer as it rests on pad stones either end of the oak beam. Oak beam carries no weight so could be cheaper lower grade with knots for character etc. Possibly even Green oak if you don't mind filling shrinkage gaps in a year or two. 

 

 

Edited August 11, 2022 by Temp

[Temp]

This is our dining room ceiling. None of the oak is structural. It's got steel and concrete B&B floor above it. Ignore the cobwebs.

 

[jfb]

On 11/08/2022 at 12:35, Temp said:

Have you considered a concrete structural lintel set above a decorative oak beam?

I have done that on one side of the opening.

 

On the other side its a bit trickier to use concrete as I have joists to deal with hence why steels were suggested originally.

But I'm hoping the engineer will ok it as is because it will be a pain to redo!

 

Pic 1 is side with concrete and pic 2 is without.