Pier design and tie-in to support 10.2m steel ridge beam for roof

[Jeffers_S13]

I have an old farm building that I want to re-roof with a load bearing steel ridge beam. Currently the roof comprises a few beefy king post trusses, approx. 8x5 (?) purlins and 4x2 rafters, all have had it. The building is around 5.5m wide and 10.2m long. I intend to support new 6x2 rafters off the steel and the walls to give me a fully vaulted interior. Roof angle is 45deg it it makes any difference. I will tile with modern concrete tiles like Marley Mendips.

I had the calcs done a long time ago by an SE, he determined a 254 x 254 x 107 UB.

The two end walls of this span are both solid 9" brick, except that one end has two windows that will need bricking up as I go that the pier at that end could be tied into. The other wall is an internal partition wall.

Can someone detail the internal piers I should build to support the steel and how I would tie it in to the two end walls, they would need to be around 5m high from FGL. Bricks, blocks, hollow blocks whatever.

No BC or planning, I just need it to be of sound design.

 

[^woody^]

Supporting piers should be bonded to the wall, not tied.

Material should be designed by the SE, but otherwise be at least as dense as the wall being attached to.

 

[cjcoffin]

I had the calcs done a long time ago by an SE, he determined a 254 x 254 x 107 UB.

Surprised it is a square profile, you do not need as much bending stiffness in the transverse direction so sub-optimal.
See here for a somewhat longer and heavier section beam which called for 325 x 440 piers. But still square.
My loft conversion people put 2 courses of engineering brick pads under the beams, but arguably not enough bearing length. I would think you need at a minimum 2 bricks wide and two deep i.e. 440 x 210 or maybe 325 x 325. If your SE did the calcs for the beam why did he not specify the piers to suit?

 

[Jeffers_S13]

Surprised it is a square profile, you do not need as much bending stiffness in the transverse direction so sub-optimal.
See here for a somewhat longer and heavier section beam which called for 325 x 440 piers. But still square.
My loft conversion people put 2 courses of engineering brick pads under the beams, but arguably not enough bearing length. I would think you need at a minimum 2 bricks wide and two deep i.e. 440 x 210 or maybe 325 x 325. If your SE did the calcs for the beam why did he not specify the piers to suit?

My original idea was to use steels to support the ridge too, which is what the SE specced up, but I'd now prefer to build the piers from block/brick.

So I'd like/I'm planning to use 440mm x 215 x 215 hollow blocks laid in alternating pairs (so a 440 x 440 pier, similar to yours) then change to 100mm solid blocks near the top then blues of padstone on top of them.

 

[Jeffers_S13]

Supporting piers should be bonded to the wall, not tied.

Material should be designed by the SE, but otherwise be at least as dense as the wall being attached to.

So this can only be done by chopping out bricks in the existing wall to allow me to tooth in with blocks or bricks every so often (?) or every other course, could you be more specific? do I just chop out halfway through the wall?

 

[cjcoffin]

So I'd like/I'm planning to use 440mm x 215 x 215 hollow blocks laid in alternating pairs (so a 440 x 440 pier, similar to yours) then change to 100mm solid blocks near the top then blues of padstone on top of them.

Sounds fine to me, good progression. Subject to others' advice on bonding to extg wall. Personally I don't like starter kits, however if you have got to tie modern brick/block sizes into an old wall it may be the only option.

 

[^woody^]

So this can only be done by chopping out bricks in the existing wall to allow me to tooth in with blocks or bricks every so often (?) or every other course, could you be more specific? do I just chop out halfway through the wall?

If a pier is deemed necessary to transfer the load downwards, then it should be bonded to the wall, as otherwise if just tied the load is just vertical on the pier.

Bond per course, or block bond every three courses.

 

[cdbe]

Sounds like a lot of messing to me when you could presumably just hoike in a couple of steels with your tractor and follow the approved design!

To my untrained eye the main issue will be the wind load trying to blow the whole thing over ,and the steel windpost will act in a far different way than a slender stack of bricks up the middle of the wall, however it's tied in - so unless the only purpose of the vertical steels was to transfer the load down I'd run your alternative design past another SE.

 

[George_engineer]

Was the wall ever checked without either a pier or steel column? The actual load on a ridge beam in a roof that has multiple trusses and purlins would not be very much.

Concrete tiles are heavier than clay if that has been checked.

The steel section sounds massive - sure it was a UC and not a UB?

 

[Jeffers_S13]

Sounds like a lot of messing to me when you could presumably just hoike in a couple of steels with your tractor and follow the approved design!

To my untrained eye the main issue will be the wind load trying to blow the whole thing over ,and the steel windpost will act in a far different way than a slender stack of bricks up the middle of the wall, however it's tied in - so unless the only purpose of the vertical steels was to transfer the load down I'd run your alternative design past another SE.

Alas, I don't have a tractor but I often look at them! I am not a farmer. Access in with any machine would be a PITA. My neighbour's posh top-spec telehandler (he's is a 'poor & hard-up' farmer...) will just manage to lift the ridge beam in from the side at full reach and at the limit of the specs, but I reckon I'd need a crane to lift the vertical ones in. The vertical steels were only intended to support vertical load of the ridge.

 

[Jeffers_S13]

Was the wall ever checked without either a pier or steel column? The actual load on a ridge beam in a roof that has multiple trusses and purlins would not be very much.

Concrete tiles are heavier than clay if that has been checked.

The steel section sounds massive - sure it was a UC and not a UB?

The wall has not been checked, as I say it's just a solid imperial 9" brick Flemish Bond wall, one of them has two large, arched windows in the middle-ish, where my pier will be.

The trusses, purlins and rafters will all be removed and burned on my living room fire not sure what you mean here (?) they've all had it. I will be fitting new 6x2 rafters to give full vaulted ceiling/roof space.

Regards your query about the UB or UC, the calcs state UC but the associated sketch he did says UB, I never noticed that before:

 

[bsr]

If the steels are 5m long and the building is 5.5m wide the could you not put them in flat through an opening, put the telehandler over the top of the walls and use a rope or block to lift the steel?

Otherwise the vertical steels could be made in two shorter pieces and bolted together.

Random thoughts, could you make a concrete pier by making a former out of ply and pouring in concrete from the top using the telehandler? That's how a lot of commercial construction is done. You could tie into the wall using resin bolts. Any SE who can advise?

How to Form a Custom Concrete Pier for a Porch - Fine Homebuilding

In this article, learn how to form a custom concrete pier for a porch including advice about footing and using a concrete block as a form.

www.finehomebuilding.com

CONCRETE BUCKET - Plant Hire GB

For 14 tonne excavators, this bucket is used for transportation and pouring of concrete and other materials when attached to an excavator quick hitch.

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[George_engineer]

The wall has not been checked, as I say it's just a solid imperial 9" brick Flemish Bond wall, one of them has two large, arched windows in the middle-ish, where my pier will be.

The trusses, purlins and rafters will all be removed and burned on my living room fire not sure what you mean here (?) they've all had it. I will be fitting new 6x2 rafters to give full vaulted ceiling/roof space.

Regards your query about the UB or UC, the calcs state UC but the associated sketch he did says UB, I never noticed that before:

View attachment 331571

Ah okay I'm with you. The UC makes sense as it's a 10.4m span. Seems a shame to get rid of king post trusses but is what it is.

I think best advice is go back to the original engineer and talk it through with them. The changes are substantial enough that I think it's gone beyond what forum advice can give.

 

[^woody^]

The wall has not been checked, as I say it's just a solid imperial 9" brick Flemish Bond wall, one of them has two large, arched windows in the middle-ish, where my pier will be.

The trusses, purlins and rafters will all be removed and burned on my living room fire not sure what you mean here (?) they've all had it. I will be fitting new 6x2 rafters to give full vaulted ceiling/roof space.

Regards your query about the UB or UC, the calcs state UC but the associated sketch he did says UB, I never noticed that before:

View attachment 331571

Those calcs look like they are from Superbeam. If so, I'd suspect the person who used that was not a proper structural engineer.

 

[Jeffers_S13]

Those calcs look like they are from Superbeam. If so, I'd suspect the person who used that was not a proper structural engineer.

Cost me £700 ! Was an independent guy somewhere in Leicester. He wouldn't explain how I was supposed to tie the footings in to the existing! Said it wasn’t his job and I should speak to my builder