Question:

Why does COMPRESS apply a factor 0.6 to the weight W when calculating anchor bolt loads and required thicknesses of shells based on longitudinal stress?

From Base Ring report:

From Cylindrical Shell report:

Answer:

The factor 0.6 is applied for ASCE 7 load combinations that include wind or seismic loads.

By default, COMPRESS will consider load combinations 7 and 8 of ASCE 7-05 (etc), paragraph 2.4. These load combinations are specified with reduced dead load in combination with full wind and seismic bending moments.

COMPRESS allows the designer to override these load combinations:

• select the Action menu
• select Set Mode Options command
• select the Calculation tab on the Set Mode Options dialog
• "check" option labeled "Do Not Consider ASCE Load Combinations 7 and 8"
• Click "OK". See below: