Bolts for casting into concrete?

[jh3141]

I'm building a pair of pillars which will be filled with concrete for strength. I'm going to need to place bolts at the top of each to attach a steel joist that will span the gap between them. I'd like to use the kind of bolt that you put in place before you pour your concrete, as I understand that this is the most reliable way of fixing to concrete and I'd really rather not have a quarter of a tonne of steel fall on me a few years down the line. Unfortunately, I've not been able to find any UK suppliers of these (I can find plenty in the US, where I understand they are widely used for fixing timber wall panels to concrete pads, as that I'm led to believe is the most common way of building a house over there, but obviously it's a bit less common over here). Does anyone know where I'd be able to get hold of them, or alternatively if there's another product that'll work in the same situation (I presume I can't use a typical expansion anchor bolt e.g. a rawlbolt for the job)?

 

[JohnD]

called ragbolts

I have more recently cast lengths of stainless studding into concrete, but I don't know how correct that is. I once heard a structural engineer saying that the wide end of a rag fixing was not correct, I think he meant it would only contribute once the bolt became loose.

 

[theprinceofdarkness]

I would use SS studding. Protect the exposed thread with masking tape and hit the buried end very hard with a hammer so you put a bend in it. Make a jig out of a piece of chipboard with holes drilled through it at the correct pattern - to support the threads in their correct positions while the concrete is being poured and is curing. Just thought its better to make the exposed ends too long, gives you something to handle and some tolerance for the stud to sink. If its an embarasment, cut them down after. Unless gravity changes its direction, you don't have to over do this bolting thing.
Just thought, stainless nuts on stainless studding will lead to the threads " galling", that is locking up when you try to undo them. Some lubricants claim to cure this. Best thing is to use mild steel nuts.
Frank

 

[^woody^]

Long coach bolts. Or a piece of all thread, and bend the end to make it an L shape.

You'll be messing about for ages trying to align these though. That steel only needs to be restrained laterally, not held down. So expansive bolts or chemical anchors will do.