Two way slab shear and pattern loading

[ron9876]

Two questions--ACI 318-02 13.7.6.2 states that when using the equivalent frame method pattern loading is not required if live load is less than 3/4 of dead load and if it is variable. Does anyone see any problem with using this for a condo type of project. Second does anyone know of a program that calculates punching shear stress for the various conditions that you encounter in this type of project.

 

[swivel63]

we use RAM concept. but i don't like how they input wind moments.

 

[mrengineer]

In seminar notes I received fron Bijan Aalami, he mentions in an example that ACI does not require pattern loading for 2-way systems when LL/DL does not exceed .75, "as in most concrete floor systems for residential and office buildings". He therefore proceeds to NOT use pattern loading in the example, which uses 50 psf LL.

 

[structuralaggie]

Pattern loading at cantilevers can control. All live on the cant. and none on the back span. This leaves only DL to resist. It makes since that this probably won't control if LL is less than 75% of DL.