I'm currently working on a single-cell box girder (balanced cantilever). The bridge is on a curve and comprises 10 spans. I've modelled the superstructure and piers together and defined the bearings as springs in the pier definition in the modeller. At the abutment the bridge sits on 2 bearings - free on the outer and fixed on inner side of the curve.At the pier the bridge sits on 2 bearings - free on the outer and longitudinally free (transversely fixed) on inner side of the curve.All bearings are free to rotate about all three axes
I've modelled the bearings as described, but I keep getting the negative pivot error. I've tried multiple iterations, including fixing all rotations at all piers, but I get the same error.
Does anybody know what I may be doing wrong here?
Hi Shijo, I'm presuming that you're using RM Bridge for the analysis, isn't it?
If you're using RM, Negative pivots is mostly due to restraint conditions at support bearings, not well connect nodes, or wrong elements activation. What I can suggest you is instead of using 0 for the release, use a very low value as 1 for example, and see if model runs. Look at bridge deformation shape to adjust the correct restraint conditions.
You can send me the *.tcl file for further investigation, if you wish: email@example.com
For more information about RM Bridge , please look at the below links:
Ana Carla Peres
Senior Technical Support Engineer
Answer Verified By: MarcosBeier
Thanks Ana, I was able to solve the issue