Usage of shearheads in flat slabs

[BeFEA]

Dear All! I was wondering if someone of you has experience in using "shearheads" for punching shear resistance in flat slabs.

My actual question is: Are shearheads commonly used in Europe?

According to guide ACI 421.2R-10, shearheads are not common in North America, even though the ACI code permits them. In Europe, Eurocode does not even mention "shearheads". However, I was wondering if there is any experience in using them in Europe.

p.s.: shearhead = steel profiles embedded in the slab at slab-column joint.

 

[pappyirl]

I would not say they are common but they are used in Europe. The ACI code covers the design process quite well and i would follow the same methodology adapted to EC2. Typically used if steel stanchions support an RC slab or if there is a punching shear issue in a slab less than 200mm in depth. Shear links would be the most common form of punching shear enhancement, although this I suspect you already know.

 

[BeFEA]

Thanks @pappyirl for your reply. I know about shear links and headed studs, but I need to know the European experience in shearheads. Are you aware of any paper or website describing the usage of shearheads in any project in Europe?

 

[PicoStruc]

FYI It's quite common in new building in canada.

Here Shearhead means "stud-rail reinforcement AROUND column" NOT "embedded steel profiles in slab joint.

 

[BeFEA]

Really (PicoStruc)? I didn't expect it to be so different from the USA, sorry for writing "North America" in my first post. Very confusing. I am pretty sure that ACI code defines "shearheads" as structural steel profiles placed inside the slab (wording is mine, not from ACI). Are these "steel profiles inside the slab" used in Canada?

 

[PicoStruc]

Only Headed Reinforcements (Studs) and Stirrup reinforcement are covered by canadian CONCRETE code, thus the difference in reinforcing wording definition.

 

[pappyirl]

I have been involved in two projects that used steel shear heads, not on any website or paper unfortunately. Not sure I can mention the projects either, sorry.

One was for a steel stanchion supporting an RC slab, stanchion was continuous through the slab. The other was to allow openings to be cored at a future date close to the column location without compromising the slab capacity.

 

[rapt]

In Europe, Stud rail and other types of shear reinforcement are not allowed in slabs under 200mm thick (for very good reason, allowing for cover etc the studs are simply too short). Hence the need for a structural steel shear head!

 

[DETstru]

I would disagree about stud rails being uncommon in North America. In my experience, they are very common in multi story, flat slab buildings (PT and non-PT).

I would agree they are not common when you consider all buildings (there are lots of steel buildings, wood buildings, other construction types, etc) but when it comes to two-way concrete, they're all over the place.

 

[hokie66]

DETstru,
Stud rails are common, but the question was about fabricated shear heads. Different things.