Sliding resistance of a slab foundation for EQ seismic loads - Foundation mass 1

[KevinNZ]

When calculating sliding resistance of a slab foundation for EQ loads do we have to include the acceleration of the foundation itself?

For example if the pipe EQ load is 100KN, do we also add foundation mass*Xg?

Taking the extreme case of the structure being just a slab of concrete then only EQ load is from the mass of concrete. Now had something else to the slab the EQ load from the slab does not go away.

 

[BigInch]

Both. Take a free body diagram of the structure above any imaginary horizontal line. Shear load = M * A, where M is the mass of all elements above the line.

you must get smarter than the software you're using.