alternate imposed displacement, and tStart for Linear TimeSeries (in OpenSeesPy)

[Euge]

I'm a newby, and I'm trying to modelize a frame (with OpenSeesPy), in order to replicate the results from an experiment at the laboratory. There, loads where applicated as imposed displacement at top edges, alternatively, pushing at the left from left to right and, at the end of the displacement, at the right, from right to left:
→ (t) (1) ------------------ (2) ← (t)

If I have understood the way to go, I should generate several linear timeSeries, applying a imposed motion (and a ground motion) at nodes (1) and (2).
But optional value "-tStart" seems not to work [ timeSeries('Linear', tag, '-factor', factor=1.0, '-tStart', tStart=0.0)]. When I run

Code: Select all

ops.timeSeries('Linear', 2, '-factor',   -5, '-tStart', 1)

I have an error → WARNING invalid factor in LinearSeries with tag: 0
The questions are:
1.- does anybody have a suggestion to modelize alternative imposed displacement?
2.- How can I introduce a linear timeseries, acting at a starting time?

Thank in advance

[mhscott]

You can use the Path time series to specify different points on the load path