Pour stainless steel pipes with concrete?

Hello,

I would like to support my wooden terrace with stainless steel pipes (DN130, 2mm thick). The material used is 1.4301. The pipes are to be placed in frost-resistant foundations.

I have 2 questions regarding this:

1. Does this stainless steel have any issues with direct contact with concrete? Can I insert the pipes directly into the foundations or should I paint them or similar?

2. If I completely fill the pipes, which protrude about 1m from the ground, with concrete, do I have to expect damage from frost since moisture can hardly escape from the pipes? The background is that I need to cast a concrete anchor on top as a holder. Possibly, I would press a Styrofoam plug about 30cm from the top edge of the pipe and pour concrete over it to hold the concrete anchor.

Thanks for your help!
Regards...Rainer

Structural calculation by a professional

Hello Rainer,

it sounds very interesting, although these are questions that actually only a structural engineer can calculate precisely. Unfortunately, your message does not indicate how severe the point load on the respective supports of the terrace is. Which area needs to be supported? How many supports are required?

One thing must be taken into account. The pipes alone, in DN130 and with a thickness of 2.0 mm (are these chimney pipes?), are by no means suitable or sufficient for structural purposes. Even because of the weld seam, which can ultimately also represent a so-called predetermined breaking point. Embedding the stainless steel pipes in concrete has no negative effects on the surface. However, care should be taken that the steel reinforcements, which are usually rusty, do not come into contact with the stainless steel. Otherwise, contact corrosion occurs, and this also causes the stainless steel to rust! You won’t be able to remove this later by pickling.

I would recommend obtaining the appropriate information from a local structural engineer. It would be a real shame for the beautiful terrace if something were to happen.
Have fun.

Hello,

thank you very much for the detailed response! I was out of the country for a few days, hence the late reply.
I am using an aluminum complete construction system for the terrace, for which a company calculated the specifications for me. The stability of the pipes was assessed as more than sufficient. I will additionally fill them with concrete.
The majority of the water should have diffused out by the next winter, which hopefully is still a long way off.
I was only concerned about stress corrosion cracking, which plays a role in chemistry, for example.

So once again, thank you and all the best!
Rainer