Seismosoft | Earthquake Engineering Solutions

I'm analysing USCS Full-Scale Blind Prediction Contest Bridge Pier

under Dynamic Time History Analysis. For Capturing its stiffness

degradation behavior, I've added Takeda link element at the bottom.

I've calibrated the link element by performing static pushover

Analysis and converting the Capacity Curve to a bilinear curve.

The static pushover Analysis model can be seen here

https://drive.google.com/folderview?id= ... sp=sharing


Fy for the link =600.17 kN , other calibrating parameters can be

seen in the model.


I'm not getting any force in the Link Element (though yielding

seems to be taking place from performance Criteria Check)

Please check my model. Direction of interest for analysis is X-axis.

https://drive.google.com/folderview?id= ... sp=sharing

(I'm confused regarding which node to restrain. Both the coincident structural nodes or only one and which one ? Also which node to apply the time history ? Also does it make any difference if i change the order of first two initially coincident nodes of the link element?)

Dear adeelfaisal,

You should restrain just the one of the nodes and apply the loads to the restrained one. The second node of the link element(without any restraints) will be the first node of the column element. The only difference in changing the order of the initially coincident nodes of the link element lies in the link's local axes.

Hi adeelfaisal. As z.gronti points out, the second node of the link element needs to be the first node of the column element. In your model in question, this may be accomplished by simply changing the first node for the column from '1' to '1bis'. There are other ways to get the same effect, but this is the most straightforward.

As modeled, the first node of your column was restrained and the link was simply along for the ride with no response. The above-mentioned change will capture the link behavior you seek. I encourage you to sketch out your model and try to understand why this is true.

Best of luck adeelfaisal.

Thank you very much Z.Gronti for your response. This has solved my problem.

Thank you Huffte. I appreciate your suggestion. I changed the first node of my column to 1_bis and as you had said, i got the behavior i was seeking. Thanks again Huffte.

I am analyzing a RC circular concrete column for static time history analysis. For the stiffness degradation I used Takeda Link element for the static time history analysis.
I am getting base shear and displacement, but not getting force in the Link element.
As per the previous discussion on forum, I restrain the first node and unrestained the second node, then not I was not getting any force. After that I restrain the second node, the base shear and displacement is good, but no force in the link element.
Anybody, could please check the mode.
https://docs.google.com/file/d/0B3tbcUu ... pIZDA/edit

https://drive.google.com/open?id=0B3tbc ... authuser=0
Thanks
Anant

Are you applying the load to the restrained end and is the second node of the link the first node of your column? I tried to download your model but access was denied.

quote:Originally posted by anantparghi

I am analyzing a RC circular concrete column for static time history analysis. For the stiffness degradation I used Takeda Link element for the static time history analysis.
I am getting base shear and displacement, but not getting force in the Link element.
As per the previous discussion on forum, I restrain the first node and unrestained the second node, then not I was not getting any force. After that I restrain the second node, the base shear and displacement is good, but no force in the link element.
Anybody, could please check the mode.
https://docs.google.com/file/d/0B3tbcUu ... pIZDA/edit

https://drive.google.com/open?id=0B3tbc ... authuser=0
Thanks
Anant

Hi Adeel,
Thank you very much for your reply. I am running static time history analysis.I restrained the second node of the link which is the first node of column. The first node of the link was restrained only y+rx+rz. The load I applied to the top of the column with axial mass, and lateral cyclic load.


quote:Originally posted by adeelfaisal

Are you applying the load to the restrained end and is the second node of the link the first node of your column? I tried to download your model but access was denied.

quote:Originally posted by anantparghi

I am analyzing a RC circular concrete column for static time history analysis. For the stiffness degradation I used Takeda Link element for the static time history analysis.
I am getting base shear and displacement, but not getting force in the Link element.
As per the previous discussion on forum, I restrain the first node and unrestained the second node, then not I was not getting any force. After that I restrain the second node, the base shear and displacement is good, but no force in the link element.
Anybody, could please check the mode.
https://docs.google.com/file/d/0B3tbcUu ... pIZDA/edit

https://drive.google.com/open?id=0B3tbc ... authuser=0
Thanks
Anant

Dear Anantparghi
I've checked your model.I'm not very sure about why link is not

behaving in the expected way but i would suggest you to check if

you have correctly calibrated the link element. Fy =500 kN for the

Takeda Link is the default value used by the program. You need to

find out the actual parameters for your column by performing

static pushover analysis for your column to get the capacity curve

for your column and converting the capacity curve to idealized

bilinear curve.

Best of Luck-- Anant

quote:Originally posted by anantparghi

Hi Adeel,
Thank you very much for your reply. I am running static time history analysis.I restrained the second node of the link which is the first node of column. The first node of the link was restrained only y+rx+rz. The load I applied to the top of the column with axial mass, and lateral cyclic load.


quote:Originally posted by adeelfaisal

Are you applying the load to the restrained end and is the second node of the link the first node of your column? I tried to download your model but access was denied.

quote:Originally posted by anantparghi

I am analyzing a RC circular concrete column for static time history analysis. For the stiffness degradation I used Takeda Link element for the static time history analysis.
I am getting base shear and displacement, but not getting force in the Link element.
As per the previous discussion on forum, I restrain the first node and unrestained the second node, then not I was not getting any force. After that I restrain the second node, the base shear and displacement is good, but no force in the link element.
Anybody, could please check the mode.
https://docs.google.com/file/d/0B3tbcUu ... pIZDA/edit

https://drive.google.com/open?id=0B3tbc ... authuser=0
Thanks
Anant

I've obtained Hysteresis Plot using Takeda Link.

I've to find stiffness degradation resulted from Dynamic Time History

Load. How can i find the stiffness degradation from the hysteresis

plot. I guess that the slope of the final loading branch should be

considered as the degraded stiffness and compared with the initial

stiffness, Sy. Is it the right approach ? Comment plz

Seismostruct model https://drive.google.com/folderview?id= ... sp=sharing

Excel Sheet containing the plot https://drive.google.com/file/d/0B1zFr_ ... sp=sharing