Reinforced Concrete Structural Screed

[engstructural]

If a structural screed is used over precast planks (hollow core units) this increases the load capacity of the units. Is this just due to the composite action of the reinforced concrete screed with the planks below giving an incresded effective depth the the prestressed strands or is the increses load capacity resulting from different factors?

 

[hokie66]

Yes, composite action between the precast and cast in place.

 

[engstructural]

If this is the case, is the mesh reinforcement in the structural screed only anti-crack reinforcement?

 

[hokie66]

Mesh is not alway used in the topping. If it is used, its only benefit would be to control the longitudinal cracks above the joints between planks.

 

[Teguci]

I've never heard it called a screed - usually called "fieldtopped" or topping concrete.

Make sure you specify a raked surface on the precast so that you get a composite action. I have put reinforcement in the screed when needed for a seismic resisting diaphragm and for wierd areas around stairtowers. Otherwise, the screed stays in compression and doesn't need reinforcing.

 

[engstructural]

Cheers guys, very helpful. As i said i was trying to establish whether the increased strength was just due to the increases effective depth of if other factors came into play. Thanks.