How to apply cyclic load on shallow foundation in OpenSees?

[dasgovind]

A shallow foundation is modeled using BNWF model. but when a pulse time series(1 cycle/sec) is applied in vertical direction the displacement is constant after almost 1000 cycles. what can be done to find a plot between number of cycles versus settlement of shallow foundation????

[sb1966]

Hi,
Kindly check the duration of your applied pulse. Does your applied cyclic load continue beyond 1000 sec? If no, then it is natural to have more or less constant value, since BNWF has dampers attached.

[dasgovind]

Hello. Thanks for replying. I have applied a pulse of 100000 cycles "timeseries pulse 1 0 100000 -factor 70". Is there anything regarding Rayleigh damping. ? I have not applied any Rayleigh damping.

[sb1966]

dasgovind wrote:
> Hello. Thanks for replying. I have applied a pulse of 100000 cycles "timeseries pulse
> 1 0 100000 -factor 70". Is there anything regarding Rayleigh damping. ? I have not
> applied any Rayleigh damping.

Hi,
It seems you have not specified any period for the applied pulse. Kindly see the Command manual http://opensees.berkeley.edu/wiki/index ... TimeSeries. The command is:

timeSeries Pulse $tag $tStart $tEnd $period <-width $pulseWidth> <-shift $shift> <-factor $cFactor>

Here $period is the period of the pulse and is a mandatory argument of the Pulse timeseries command.

Hope this helps.