Structural steel goal post construction
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- Опубліковано 10 вер 2024
- What is steel goal post construction? In this video a structural engineer shows you why removing a rear wall makes a property unstable, and how to remedy that with a structural steel goal-post frame.
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**Disclaimer:**I'm a chartered civil engineer with a specialism in structural engineering. None of the things I say or teach in my videos should be construed as "advice", and you should always have your designs checked by a competent, experienced, registered or chartered engineer.
Hi Rob ! Your teaching is great !
Wich type of foundation you use for this case ? ‘Cause if you use bending connection between column and beam... will appear a moment in foundation. Or is it better use a shear connection between column and beam ?
Thanks Gustavo. Some engineers use moment resisting bases and foundations, others use moment resisting beam to column connections. Or both. Depends on whether the foundations can resist the moments.
In this scenario I would consider a "picture frame" design with a beam encased on concrete placed on the foundation. Moment due to lateral load is resisted by moment connections within the steel like a little portal frame. With stiff joints top and bottom!
@@17michaelboyd do you distribute the load along the strip below im evenly as on the top beam? Also, if that was the case, do you analyse it considering soil springs at the bottom? If using pads without reinforcement instead, the columns would need to be stiff enough to not transfer moment to the footing, right?
@@manuelmendez2483 - i also adopt the picture frame method. for the ground beam i model the section on springs based on the original wall loading at foundation level now removed for the frame
I love how you textured the box in Sketchup to match your real world demonstration, keep up the great work 👍🏻
Thanks Adam!
Thanks, really nice clear explanation!
This is such an excellent video...extremely useful. Thanks Robin
You're very welcome!
These videos are brilliant,thanks. I commission structural design on a weekly basis for my projects and like to understand as much as possible, I could never figure the logic of the connection details from column to beam but have always felt silly asking, this has really helped me understand...thanks
Hi Philip - that's great to hear!
Glad I’ve found your videos rob very interesting 👍 I’ve recently just put a doorway into an integral garage,it’s a 3 storey middle townhouse,the wall where the new doorway is,is the separation wall from garage to a bedroom and is single skin 140mm blockwork ,it supports the first floor joist but the wall does not continue up as the 1st floor is open plan with a big steel beam going the
full length of the house(steel holds second floor joist up)the steel is pretty much inline with the buttress wall on GF.The doorway opening is 920mm and the lintel is a concrete 140x140mmx1200mm and has a bearing each end of around 125mm,the new doorway is close to the rear external wall and is of traditional build 100block 100cavity 100stonework 3 storey high (think it’s classed as a supporting wall) and the new opening is in the buttress wall , the nib that is left is around 530mm closest to the supporting wall. Am I right in thinking this is ok, it has been passed by bc but after reading into approved doc A a nib has to be minimum of 550 with one opening being in the buttress wall . Wher as mine has the opening in the buttress wall 530mm buttress nib then the external supporting wall has a doorway either side of the centre line of the nib and both external nibs left and right are about 300mm.is this ok🤔 sorry if it doesn’t make sense but any info would be great before I consult an SE ,cheers 👍👍
Great video. Thanks.
Great explanation!
I am a welder this is just a question wouldn’t it be more Ideal to set the lateral beam on top of the columns? I would think you would have more downward support for the dead weight, rather than relying on just bolts
Hi Anthony. Great question! Often the columns are slimmer than the beam, so you would not get as much depth between bolts for the moment connection. Let me know if that makes sense! 👍
I was thinking the same thing
What's the difference between a goal-post and a box-frame system Robin? In what instance would you use a box-frame? Thanks
Hi Ahmad. I think you are referring to a beam also along the ground level. This would give you four moment resisting connections, so in some ways it could be more effective.
great good sketchup animation
Good info.👍
Great video. When designing a goal post frame do you use a tie rod below the opening to restrain the base of the columns from 'kicking out' or do you design the foundations to take the horizontal loading. I normally design with a tie at ground floor level but I have recently had queries from Architects saying that other Structural Engineers do not put these in. If you design the foundations to take the horizontal load it can make the pad foundations quite large! Just wondering what you would normally do.
Good job
Thanks, and well done with your youtube channel!
Thoughts on the beam sitting on top of the column instead of connections to the columns flange?
That could work equally well Cory.
@@RobindeJongh Wouldn't that make that a simple connection on top and then you'll have to design your base as a moment connection?
@@efy5aru The top connection would still be a moment connection - it's just working in reverse.
Hi Rob! By putting the steel inside the cavity, what implications would occur in terms of thermal bridging?
HI Manuel. There are ways to avoid thermal bridging by adding insulation around the frame.
Good video. Is it acceptable to use bolts to connect the beams like this? What is the benefit to that rather than placing the beam on top of the columns?
Hi Steve. It all needs to be calculated by a structural engineer; especially the bolted connection. The beam could go on top of the columns .
Hi Rob, Could you compare goal post with box frame often use in UK ?
Very interesting, thank you.
One question, how should you go about tying the columns to the inner leaf of masonry which sits either side of each column?
Something like frame cramps tek screwed to the column could do it, or tabs / straps welded to the column.
Great Video, what is deemed a good acceptable masonry at either side to warrant non goal post design.
Hi Heston. UK building regs say a minimum of 665mm or 1/6 of the opening, whichever is greater. Then the wall also has to be checked for the load of the beam.
Also, for the connection of the column back to the wall wouldn't you put slotted holes to allow for some possible settlement of the goalpost system?
Slotted holes would be necessary if the goalpost frame had seperate foundations. However, they are usually used as a replacement to existing walls which already have a foundation.
@@RobindeJongh Did one on a house with existing corbelled brickwork foundations, no way I was going to land on that. Put a new pad in and underpinned the existing.
Hi Robin. Great content, thanks for taking the time to make it. On a related matter, if an internal wall is being removed that doesn't provide restraint against wind loading (e.g. wall in mid terrace house) then posts aren't needed and the beam to replace the wall can generally be supported on the masonry walls perpendicular to it? Speaking in a general sense of course. All the best.
Hi. I'd think that's correct in a lot of cases, yes.
@@RobindeJongh The depth of the terraced house needs to less than 9m front to back otherwise the internal wall between is a butressing wall to the brickwall which maintains stability against wind load. If greater than 9m between front and back walls then the internal wall will require some kind of moment frame.
I'm a recent subscriber and I'm enjoying the videos.
What software did you use for sketching in this video?
Hi Stuart. It's SketchUp Pro.
Quality video! What software do you use was that google sketch up? Also, when I look at structural goal posts solutions, a lot of Americans always use a bottom beam tying the bottom of the columns together? - Why is this ? I see no benefit to it at all.
Hi Liam - glad you're liking the videos. With a moment resisting frame, basically you can resist the moment anywhere you like - either at the base, at the connections at the top, or as you mentioned, with a tie beam at the bottom. The beam at the bottom will have the benefit of keeping moment away from the foundations, which for american houses (usually timber) will not be as robust as UK foundations.
@@RobindeJongh Thanks Robin, I still don’t get how it takes moment away from the foundations in all honesty. I guess it depends on the connection more than anything. I usually keep the moment in the beam/column connection.
I'm just doing one of these where the load on the columns is 17kn ......and there is an existing assumed 1m x 0.6m trench fill foundation. I'm just wondering about the connection to the foundation and the point load . Is there a simple way of checking this , I know its not massively heavy just like to check :)
The problem isn't the structure - Asda decaf just doesn't have the strength. Try a decent Yorkshire tea, brewed 5 mins, add sugar, and your house will stay up fine.
Hi Laurence. I'm currently drinking Yorkshire tea and feel like a new man 😂
Just had drawing through for mine and getting slightly confused, one end is a 1mx1mx1m concrete pad that’s cool, the other it says an L shaped concrete spreader but not sure where that goes, I get the rest and the wall ties but just the last foundation bit 😂
Beats me, Jamie! 😂
Think that goal post frame for that teabag box is over designed ;)
Haha! Did you also notice my expensive taste in branded tea?