Structural welds on residential property

[Turbo]

That's a bad design of a joint imho. The long girder needs to be joined directly to the web of the short girder to form the strongest joint.

As it it the long girder is only joined to the edges of the side flanges of the short girder and the force will be acting on the weakest part of the I beam. It is relatively easy to bend the edges of the side flanges of an I beam.

To make the strongest joint you could profile the end of the long girder to fit into the short girder and you would get a nice weld to all sides of the short girder. It would make access for welding a lot easier.

The profiling could be done off site with a plasma/laser.
If that wasn't possible just add a plate to join the centre parts of both girders, either welded to both or welded to 1 on the ground and bolted to the other in place.

The 'engineer' that designed that joint doesn't understand I beams and in what way to join them for maximum strength.

 

[Farside]

a row of tacks and some savage inclusions are not whats needed ...

Oi, you been looking at my trailer?
In my defence, the voltage was low that day.

 

[Jelly_Sheffield]

Agree with much of what you've said.

I'd still have bolted the short piece on to the long piece. Maybe have gusseted the connection plate

Ultimately bolting is just way more practical for the installer, so it removes a potential source of error, especially when it's a general builder doing the install (no disrespect to general builders, but as a group their judgement and skill levels vary wildly)

The problem is very few of these structural engineers are good at steel detailing. They can read in a book ten different ways of doing things

A lot of structural engineers come from a civil engineering background and don't get anywhere near the same level of exposure to mechanical design or methods of manufacturing as other disciplines.

The good ones tend to be the people who went to work directly for contractors actually involved in making (or demolishing*) things after leaving uni... They are also often mechanical engineers who got lost on their way to get a job designing innovative tortures for car mechanics.

But the major pipeline for civils grads is in into consulting firms where they spend years focusing only on determining if someone else's design will stand up using maths...

Then if they're fast enough at calculations and good at office politics they get to move up in the world and redesign things architects dreamt up in a fever dream, so the eventual building won't immediately buckle under it's own weight.

*I never cease to be impressed by demolition engineers... Any fool can make something fall over, but making it fall down exactly where you want it to go, when you want it to, without hurting anyone takes real skill.

but they've probably never had to do the welding or the assembly onsite.

Literally why I learned to weld!

I was specifying lots of welded structural and pipe assemblies for process plants as part of a couple of different rebuild projects, and realised that seemingly inconsequential little design details could make a huge difference to the quotes I got back...

Turns out the cost difference was almost exclusively related to how easy or hard the thing was to make.

Also a lot easier to insist to a contractor that something awkward needs to be that way if you can demonstrate you understand that it is awkward to do, and you did consider the other approaches first.

Having the connection plate overlap the beam by 10mm top and bottom is certainly a bit of a new one

Yeah... It might suggest that the individual isn't super familiar with the range of possible welded joints.

I guess it makes it very obvious where to put the weld bead at least?

I'd weld a gusset to the centre back of the connection plate on the bench, then have the connection plate sized just right to sit on the very edge of the top and bottom flanges of the beam.
When welded to can do a 6mm fillet in one pass or 8mm in two passes.
You can then reach in (especially with a 450mm electrode) to weld the gusset vertically.

That's a very neat way to do it!

 

[Jelly_Sheffield]

Great explanation, when I did both my builds with steel, those drawings are far far better than I got from both the engineers used. Was all fairly vague to be honest, not even weld sizes, just a hint to use a competent onsite welder.

That always bugs me...

First of all, how the hell is Joe Bloggs, (or even Joe Bloggs' builder Stan D'round) going to know how to select a competent welder?

Secondly, even if they do find a competent welder, the guy is being selected for his ability to stick metal together...

They have hopefully learned what the best joint design to use in a given situation are, and how to choose between them properly...

But that's not at all guaranteed!

For every time-served welder who out of idle curiosity has accidentally taught themselves more materials science and mechanical design than most people with engineering degrees know...

There's someone who has tremendous skill with a torch/stinger and can perform any weld you tell them to perfectly... But who you wouldn't trust to make a gingerbread house without supervision lest they set fire to the kitchen.

And most everyone else sits somewhere in the middle.

 

[Easywelder]

My welder dues structural stuff all over London, he has seen it all, so many cowboys. He is usually correcting mistakes in the steelwork or other peoples welding. Sometimes there are serval days welding and he only hire got a day, he knows it so they can use his certs, for it all and get someone cheaper to do the rest. He takes photos of just the bit he does. Occasionally he will walk away from a job as he didn’t want his name on it. He is good, £400+ vat for a day in London.
Here’s a joint I did a couple years ago, how I would have thought the op’s joint should look a bit like

 

[tom2207]

My welder dues structural stuff all over London, he has seen it all, so many cowboys. He is usually correcting mistakes in the steelwork or other peoples welding. Sometimes there are serval days welding and he only hire got a day, he knows it so they can use his certs, for it all and get someone cheaper to do the rest. He takes photos of just the bit he does. Occasionally he will walk away from a job as he didn’t want his name on it. He is good, £400+ vat for a day in London.
Here’s a joint I did a couple years ago, how I would have thought the op’s joint should look a bit like
View attachment 522895

yep thats all you would want and you would be happy to sleep at nights

 

[fizzy]

Did the cat do it?

 

[addjunkie]

That always bugs me...

First of all, how the hell is Joe Bloggs, (or even Joe Bloggs' builder Stan D'round) going to know how to select a competent welder?

Secondly, even if they do find a competent welder, the guy is being selected for his ability to stick metal together...

They have hopefully learned what the best joint design to use in a given situation are, and how to choose between them properly...

But that's not at all guaranteed!

For every time-served welder who out of idle curiosity has accidentally taught themselves more materials science and mechanical design than most people with engineering degrees know...

There's someone who has tremendous skill with a torch/stinger and can perform any weld you tell them to perfectly... But who you wouldn't trust to make a gingerbread house without supervision lest they set fire to the kitchen.

And most everyone else sits somewhere in the middle.

Bout sums it up, we have a local Mr weld it all and anything from gates to just about anything you'd want, but I don't doubt that many folk who hire him, just assume he's a welder because it says so on his van. He used to do process pipework on offshore hook ups and boiler work so assume at some stage in the past he's been ASME IX.

 

[Pete.]

Tell the welder the welds are going to be inspected. You could even do it but it'll be a few hundred quid usually.

 

[Tigman]

Round my way , building inspectors won't accept welding on site , if you have to do it they require a certificate , most places I've been we are asked for it ! The certificate should be relevent to the positional welds executed , so vertical , overhead fillets !
I don't have a current Cert , so I use a company that has , the certificate is signed by the welder and has a picture on it , of the said welder ,

 

[sg66]

My ohh my I didn't read all the replies from the professionals and I'm by no means one of those but I've done better welds upside down in a farm yard in the rain on rusty diggers.

 

[Tigman]

To weld the inside of the steels are not easily accessible, very difficult , hence all the arc strikes very hard to see the joint through what looks like a 150mm gap , totally the wrong connection to be doing on site , drilled and cleated much better in that situation , in my opinion

 

[reb78]

I domt understand why it wasn't designed like this

Surely that's ideal? Even IF the welds and bolts all failed it still could catastrophically fall apart? Bit trickier to get the beam in as you'd have to insert it diagonally bit not impossible in the space in the original pics?

 

[Pete.]

Ideal is fin plates welded inside the web of the supporting joist and the secondaries bolted to it. I don't know why the structural engineer figured that a bolted connection could not carry the imposed load it's how the rest of the construction industry does it, and we're talking commercial buildings not residential. If a joist cannot be ficed up with bolts then something is under-specced.

 

[gaz1]

for what you have used it would have been better just to build a new concrete wall and fit a padstone on top of it for what its cost you to have those 2 beams fitted for the inner and outside walls on the original build of the house



as goes for beams ours was bolted for a shop



this one also bolted but the main holder is at front and a side one holding the bathroom/hallway floor concrete wall built the front is the mainbeam thats been lifted

 

[reb78]

I domt understand why it wasn't designed like this

View attachment 522912

Surely that's ideal? Even IF the welds and bolts all failed it still could catastrophically fall apart? Bit trickier to get the beam in as you'd have to insert it diagonally bit not impossible in the space in the original pics?

I meant 'could not catastrophically' above, only mentioning otherwise my post seems a bit silly.

 

[ash1356]

for what you have used it would have been better just to build a new concrete wall and fit a padstone on top of it for what its cost you to have those 2 beams fitted for the inner and outside walls on the original build of the house

View attachment 522924

as goes for beams ours was bolted for a shop

View attachment 522925

this one also bolted but the main holder is at front and a side one holding the bathroom/hallway floor concrete wall built the front is the mainbeam thats been lifted

View attachment 522926

Sorry should’ve said in my post - There is doorway going underneath the small beam. The design did initially have a large lintel above the doorway and then the two beams sitting on top of the lintel but we didn’t have the head room to play with so had to change the design

 

[nickk]

Fin plate or a pair of RSA cleats should be the specified method,SE was inviting poor workmanship.

 

[ash1356]

So I’ve now heard back from both building control and the structural engineer.

Both BC and engineer are happy with the welded connection. Only caveat to that is the top of the flanges and the inner flanges need to be welded.

The welder has not welded the top of one of the flanges due to access issues. See attached.

 

[skotl]

So I’ve now heard back from both building control and the structural engineer.

Both BC and engineer are happy with the welded connection. Only caveat to that is the top of the flanges and the inner flanges need to be welded.

The welder has not welded the top of one of the flanges due to access issues. See attached.

That doesn’t sound like a good outcome. Time to insist on another welder I think.