steel and hanging joists

[Colin3322]

Hello everyone,
Ive just taken over a bodge job.


Issue
The floor joists spans 2m from front to back. While one end is secure, sitting in the steel web end, the other end lacks proper support. Unfortunately, using the top of the steel is not feasible since large 3 track sliding door will sit on the top side, leaving insufficient bearing for the joists.

One solution…. welding steel plates at every joist load point. However, there is concern that this may induce a twisting load effect on the existing steel structure. Another option is introducing a second steel for the floor only , but it comes at a $$$$cost – 7.2m length of 203 uc 46.

The new floor joists, specified by the owner, 225x75. They plan to tile above and demand zero deflection.
Will seek advice from a structural engineer. wanted more thoughts before I do.

Thank for any advice!

 

[freddiemercurystwin]

What height are the joists supposed to end up at in relation to the beam? (which seems a bit slender for that span?) Why have they been notched - was the idea to sit that notch on the top flange?

 

[George_engineer]

You'll need the engineer to check torsion but I'd have thought something like this could be made to work

Otherwise splicing bits onto the end of the joists would be less work than welding steel. Would probably need an engineer design for that too.

 

[noseall]

You'll need the engineer to check torsion but I'd have thought something like this could be made to work

View attachment 324197


Otherwise splicing bits onto the end of the joists would be less work than welding steel. Would probably need an engineer design for that too.

Wouldn't fixing the same timber to the ends of the joists (thus lengthening them all), rather than adding it to the blocking-out timbers work better?

 

[George_engineer]

Wouldn't fixing the same timber to the ends of the joists (thus lengthening them all), rather than adding it to the blocking-out timbers work better?

That would be better - less torsion. Make a 'floating' ledger.

Given the cut outs I'd perhaps beef up the connection by using joist hangers from the joists to the ledger.

 

[Colin3322]

You'll need the engineer to check torsion but I'd have thought something like this could be made to work

View attachment 324197


Otherwise splicing bits onto the end of the joists would be less work than welding steel. Would probably need an engineer design for that too.

thanks for taking the time out to draw this
makes alot of sense

 

[Colin3322]

What height are the joists supposed to end up at in relation to the beam? (which seems a bit slender for that span?) Why have they been notched - was the idea to sit that notch on the top flangend location of teh steel is for it to sit alot lower, taken over teh job but it seems at one point the beams where notched to sit part into the steel, the steel height was incorrect resulting in the joists sitting higher.