Concrete Pad Spec for Gate Piers

[Dan F]

We've ordered some automated gates, and the drawings show concrete pads 400mm BGL which the gate post steelwork then screws down into. 

 

Is there a rule of thumb as to the size these pads should be and/or if they should incorporate any rebar or mesh?   The gate supplier doesn't specify any of this, and groundwokers has just suggested 600mm deep 1x1m pads with no steel or even mesh.   Do I need a strucutral design for these, or are there some general rules which can be followed?

 

Thanks!

 

 

 

 

Edited April 22, 2022 by Dan F

[Dudda]

1x1m and 600mm deep is huge. Overkill and more than enough for the gates and you don't need steel. I'm currently using the exact same size pads (designed by a structural engineer) for a large steel frame outdoor canopy that's built on reclaimed land and less than 1km from the Atlantic so will also have huge wind uplift. If my pads are fine you're will be no problem.

[Temp]

My neighbour had some fantastic hinged iron gates on 8ft brick pillar constructed last year. They lasted a month before he had to get the builders back to fix them. That involved taking down the brick pillars and rebuilding them stronger. important to get it design right.

 

Are your gates going to be sliding or hinged?  

 

Found..

 

https://community.screwfix.com/threads/iron-gate-footings.211575/

 

 

 

[markc]

Base size and configuration depends on the loads being imposed. A canopy has mass (weight) to distribute and uplift or overturning moments that need to be held down.

a swing gate is a cantilever and produces a rotation load onto the pillar and it’s base. So the posts need to withstand bending and the foundation must have sufficient bearing on the ground to prevent it ‘cutting through’ the earth.

brick pillars need to be massive or be brick around a steel or concrete core

[tonyshouse]

I like a cube of concrete with an an RSJ buried in it dead plumb and in the right place, temporarily fix RSJ before pouring concrete, 800x 800 ,800 

[Mr Punter]

From the drawing, the pad looks about 1200 x 1200.  The goal post design will do a lot of the work.  The gate type, size, weight, soil type etc will all impact what is needed.  Can you get the supplier to give you more of a steer?

[Dan F]

8 hours ago, Temp said:

Are your gates going to be sliding or hinged? 

Gates are hinged.  Posts use a goalpost design with steelwork (which also acts as a conduit) between the two posts.  Posts are fixed to the top of the pad.

 

4 hours ago, Mr Punter said:

the gate type, size, weight, soil type etc will all impact what is needed.  Can you get the supplier to give you more of a steer?

The gates are 1.8m x 1.8m each and made from 50x50 SHS with Iroko infill.  Ground is good.  I guess they should be able to answer some questions on weight at least, if not loads too.  I'll try to ask them

 

8 hours ago, Temp said:

https://community.screwfix.com/threads/iron-gate-footings.211575/

3ft square and 3ft deep is even bigger than groundworker suggested!

 

 

 

[Dan F]

All I got from gate supplier is that gates are approx 150kg each.

[Dan F]

Anyone any idea roughly what I should expect to pay for two concrete pads 1000x1000x600mm deep (400mm below finnised ground level) with a 400mm deep trench between them and and blockwork up to ground level?  South-east prices unfortunately.

[Onoff]

5 hours ago, Dan F said:

Anyone any idea roughly what I should expect to pay for two concrete pads 1000x1000x600mm deep (400mm below finnised ground level) with a 400mm deep trench between them and and blockwork up to ground level?  South-east prices unfortunately.

 

Are you not up to getting it dug then shuttering it up yourself and getting a ready mix lorry along? 

 

I wouldn't know ref South East prices as I DIY everything. 

[Mr Punter]

There is a fair amount of work in automatic gates.  A specialist firm may be a better bet than DIY.