Lightly Loaded Steel Beam Connection to Mason/Concr Wall + Steel to Timber Nailer Connection Detail?

psychedomination · Mar 4, 2021

Hi there, I was recently told by the architect that they need a 4” lintel in order to fit the door frame in for a small building.

I have never designed a lintel so shallow before but I believe a 4” (W4x13) steel beam may work. All of the normal checks seem to be fine, bending capacity, shear capacity and deflection. I am assuming that the top flange is restrained (resistant to lateral-torsional buckling) as I will be connecting the steel beam top flange to the wall plate above.

Is there anything that I should be worried about when using a 4” section for a lightly loaded lintel?

Essentially this lintel is only supporting the roof structure. There is a timber wall plate above, which will bear onto the lintel (shown in the attached site image). The rafters are already connected to the wall plate with skew nails.

I would like to get opinions on how I can make the attached detail better and easier for site placement. Also a forgiving detail for a potentially inexperienced contractor.

I am also wondering if I need the CIP anchors bolts (concrete/steel) shown in the attached detail for these relatively short spans (6’8” and 4’). There may be slight uplift loads in high winds if someone leaves the door open but the dead load from the slate roof should hold it down. I am wondering whether this detail is overkill or not for these spans?

I am aware of the poor pull out capacity of J bolts, so I am thinking of changing the CIP anchor to just have the nut and washer (same size as the top) also on the concrete side?

The bolts welded to the top flange of the steel beam are mainly there to ensure the timber wall plate is engaged on the lintel and to also restrain the top flange from lateral-torsional buckling.

Quite a lot of these details are nominal so any advice would be appreciated for best standards.

dik · Mar 4, 2021

Can you use an angle? or a double angle, back to back... slotted into the masonry? or on the face of the masonry if it can be exposed?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

BAretired · Mar 4, 2021

I suggest adding stiffeners at each end of each lintel to prevent rollover. I think the J-bolts are likely adequate, but if in doubt, increase the diameter and the embedment or use a more positive anchor.

BA

psychedomination · Mar 6, 2021

Thanks Dik, that is a good point. I haven't really looked into steel angles. I am not too familiar in using those for lintels but I think that may work for the short 4' span. I am still a bit stumped on what the detail would be. If a steel angle is used would a decent detail be placing it against the face of the timber wall plate and through bolting (see the attached sketch)? Or what would be a standard detail for this? Also would it be suitable to have the same connection to the concrete as shown previously with the 4" beam?

On another note, I took another visit to the site yesterday and it seems that they would like a steel beam for a 15' span as well now. I will spec an 8", so I still would need to use the original detail (or similar with the revisions to make it better).

Thanks BAretired, that is a good idea and noted, over supports, I will include web stiffeners.

From a constructability perspective, I am trying to visualize the sequence as there is not a lot of headroom for the contractor to work with. They have the jacks for the roof, which Would they :

1. position the beam under the timber wall plate and jack it up to the timber to mark the drill positions for the steel to timber connections.
2. drill the holes in the timber to connect the welded threaded studs.
3. jack the steel beam up, aligning with the holes and screw the nut/washer on the top of the wall plate. Keep steel beam jacked up.
4. drop the CIP concrete anchors in
5. form up the wall and pour.
6. remove jacks from the steel beam when the concrete reaches sufficient strength.

Or is it easier to form up the concrete wall first, level the beam with grout or steel shims and then drill and put chemical anchors in after?*

I am not sure if this is the right sequence but any input would be appreciated just so that I am aware.

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Lightly Loaded Steel Beam Connection to Mason/Concr Wall + Steel to Timber Nailer Connection Detail?

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