Precast Double Tees

[Ben29]

I have an existing facility where the client wants to install a CMU block fire wall partition on the double tee slab. The building is circa 1973. The block wall will run parallel to the tees and will be centered between the tees. Is this something I can conservatively calculate based on minimum information that I have?

The second image below shows the cross section of the slab where it was cut for installation of a staircase. It is hard to tell if this is a 4 inch flange + 2 inch topping. What do you all think?

 

[bones206]

It's possible the topping is sloped and has varying thickness. You could be looking at a high point in the topping slab.

 

[DC_Engr]

I wouldn't recommend it. This could be unnecessary liability you assume, absent necessary information. Try to either get information on strands in DT via old drawings or on-site scanning to be able to do any evaluation. Walls parallel to stems are more critical than the perpendicular walls. Not sure if it would be possible, but is there possibility of building the wall using light-gage studs, etc?

 

[JLNJ]

If you know the geometry and the number of strands (usually from the existing drawings), then you can make a go of it.

If you don't know the geometry of the section or the number of strands, then you need to be able to explain it to the judge as to why you guessed.

If you know the geometry, maybe you can choose the most lightly reinforced section for that shape. You would need to be careful as not all manufacturers for precast use identical means and methods, especially if you are trying to squeeze every last ounce of strength from the section.