Combo of load effects, E, on silo foundation

[CTW]

I'm designing a mat foundation to support (2) 60 ft tall by 12 ft dia silos, and I need some help in clarifying the seismic load on the silo support columns. Each silo is supported by four columns. According to ASCE 7, (for nonbuilding structures) the combination of load effects, E, shall be considered. So each leg will have an effect from the combination of Dead, Live, and Seismic.

Is this force "E" in addition to the compressive force produced by seismic overturning, or do I just use the largest of the two? Any advice is greatly appreciated.