Superimposed Dead Load Definition and References

[BeamMeUpStudent]

I have a couple questions:

1. How do you differentiate between dead load and superimposed dead load? What criteria do you use to categorize them?

2. How are you estimating superimposed dead loads in your designs? For example, consider a faux sloped roof built with steel or wood studs over a concrete roof slab, or an insulated metal panel system. What dead load values do you typically use for these? Do you have any reference materials or resources you rely on?

Looking forward to your insights!

 

[BulbTheBuilder]

1. First thing, super-imposed dead load is a type of dead load. So, is there a dead load that isn't super-imposed? Yes, the self of the structure. After you have the self-weight dead load, you have additional dead loads (e.g. ceilings, waterproofing, CMUs, floor finishes) you are imposing on your structure.

2. You have to know the weight of the material or object. Now, there are standard weights for certain materials and object so you can always refer to handouts (check the back of AISC/EC3 and ASCE/EC1). Like how we all say the weight of reinforced concrete is 150PCF or 24Kn/m³
There are other objects like roof top units (RTUs) which the supplier /mechanical engineer will provide you with the loads to design your structure.

For your faux sloped roof built, you can compute the weight of the steel since we know the density of steel. If it's a standard shape, you can reference EC3/AISC for the weight. You can check the supplier's brochure for metal panel system weight, they typically have those details.