Sum of value above

Hello, I am trying to create a value for the sum above to then plot in an overall graph of capacity vs increments.so capacity vs Ts.idx (100mm) increments. 

Increment

Ts.idx 0 would be 0 

Ts.idx 0.1 would be 0.08+0=0.08

Ts.idx 0.2 would be 0.321+0.08+0=0.401 

etc and so on.

so, the value of Ts.idx and everything above it

Then I can see quiet easily and what total length would be needed to resist the ULS load in a good visual output.