New structure on top of an existing roof

[aeroelastic1]

Hi all,

In a project that I am working on, the client wants to have a small (4mx4m) building build on top of an industrial building roof. The existing roof is covered with pre-cast concrete planks. Columns of the existing building are 4m apart hence the proposed building size. Looking at the as-built drawing, the pre-cast planks have been laid on top of the column.

What is the best way to connect the new building column to the top of the existing one for load transfer? The pre-cast planks is about 200mm thick.

Thanks in advance.

 

[TehMightyEngineer]

Industrial precast planks are usually lightweight concrete in my experience and generally don't take kindly to loads of any kind, especially if they are old and have been exposed to steam causing decalcification. Carbonation and other corrosion issues are often present as well. Usually these planks are lightly reinforced. I'd remove the plank and replace them with metal deck if able. If not, perhaps you can resupport the edges of the plank and demo above the columns, connect to the column, then repour the plank with cast in place concrete?

Maine EIT, Civil/Structural.

 

[ztengguy]

I would use epoxy anchors. Design for your loads, concrete strength.