trapze load?

[moshtagh]

Hi every body
I have problem, that there wasn’t any where (OpenSees Command Language Manual & example).
I have some load that have Trapezium shape time series. Its mean that the load have linear value (for example increase from 0N to 10 N) from time 0 to 2 second ( with Linear Time Series) , and it heve constant value for 5 seconds from time 2 to 7 second (with Constant Time Series) and suddenly the load should be decrease to 0 from time 7 to 9. How I can wrote the time series that the Openess knows , what am I doing.
In an other word how can I apply Trapezium load on the structure
Please help me
The shape of the Trapezium load:


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