Problem

How can we combine multiple damages from different SACS analyses? 

Solution

You can combine multiple fatigue analyses by generating fatigue damage files. I'm using Sample 07 and Sample 08 in the SACS Project directory for this example.

On the first fatigue analysis (Sample 07), select the "Output fatigue damage file" option in column 76 on the FTOPT2 line in the fatigue input (ftginp) file. 

A fatigue damage (ftgdmg) file should be generated after running the fatigue analysis:

On the second analysis (Sample 08), select the "input fatigue damage file" option in column 76 on the FTOPT2 line in the fatigue input (ftginp) file.

In the Analysis Generator, select "Edit Fatigue Option". Select the "Import Damage File to Accumulate Damage" to activate the Fatigue Damage Input file input as per next snapshot.

You may then enter the first fatigue damage file as additional input for your second fatigue analysis.

When you run this analysis, the fatigue damage from the first analysis will be added to the second.

If you have more than two fatigue analyses, you can instead select the "input and output fatigue damage file" option to perform both of the above operations.

PRECAUTIONS:

The damage files can only be combined when the geometries are identical, including the same nodes/beams, etc. Otherwise, SACS will return an Error - Input Damage File Incompatible.
User need to add the damages manually by extracting the results from SACS. 

 

How about combining fatigue damage for pile driving phase?

If you want to combine fatigue damage for pile driving phase, you could try generating one of these files from the pile driving analysis and then use it as fatigue damage input. Alternatively, you can identify the critical joints for fatigue across both analyses and manually combine the damage using Excel as the damage values can be combined linearly.