staged construction analysis with additional load

[jwoong]

Hello,
I attached my simple truss analysis input.
In the first stage, I applied -1000 downward, and I got reaction 500 at both supports. It is OK.
In the second stage, I also applied -1000 downward, and I got reaction 2000 at both supports.
It is double of the correct reaction 1000.
Please let me know how to modify the input to get correct answer.

# Applied load
pattern Plain 1 Linear { load 1 0 -1000 0 0 0 0 }

# Analysis generation
constraints Plain
numberer Plain
system ProfileSPD
integrator LoadControl 1.0
algorithm Linear
analysis Static

analyze 1
puts "##### STAGE 1 - finished #####";

pattern Plain 2 Linear { load 1 0 -1000 0 0 0 0 }

analyze 1
puts "##### STAGE 2 - finished #####";

[mhscott]

Your time series are linear, so the load increases every time you analyze and advance to a new step.

[xinyue]

You ended up with a psedo time =2.0 for both loads applied. To correct this, you should make the first load constant and reset time to zero before applying the second load so that the second analysis will start from time 0. Hope this helps!

[fmk]

i.e. end of file should look like the following with the loadConst added:

analyze 1
puts "##### STAGE 1 - finished #####";

loadConst -time 0.0

pattern Plain 2 Linear { load 1 0 -1000 0 0 0 0 }

analyze 1
puts "##### STAGE 2 - finished #####";