about hysteresis curve

liujinlong · Post by **liujinlong** » Mon Jun 25, 2007 7:19 pm

hi everyone, I have done the analysis of a cable-stayed bridge under ground motions, the input is earthquake accelerations by UniformExcitation Pattern, and got the m-υ hysteresis curve of the pier at the base, but the shape of the curve is not rational, it is like a 8 shape, I don’t know why?

Who can give me some advice. (the pier is a reinforced concrete model, and the section is defined by fiber quad section, and it have a prestressing force by the cable-stay)

silvia · Post by **silvia** » Mon Jun 25, 2007 8:47 pm

are you plotting reactions or element forces?
the reactions include inertias -- don't ask me why, and damping.
i'd plot the element forces, you should get better results.
however, isn't that what a prestressed section should behave?

liujinlong · Post by **liujinlong** » Mon Jun 25, 2007 10:54 pm

silvia wrote:are you plotting reactions or element forces?
the reactions include inertias -- don't ask me why, and damping.
i'd plot the element forces, you should get better results.
however, isn't that what a prestressed section should behave?

thanks silvia, i do plot the element force-deformation curve, and get the
moment-curvature hysteresis cure, and i found that with the smaller axial force i can get a better rusults, but if the axial force larger the rusluts will be bad. it have puzzled me for some time.

silvia · Post by **silvia** » Tue Jun 26, 2007 9:04 am

i think that is the behavior under such prestressing forces....
you should talk to someone there to discuss the behavior you expect.