Curved ramp bridge Modelling

[Vincentzili]

Hi,
I am just wondering if I can draw a curved structure in the Seismostruct? How can I draw it if I can.

Thanks for helping me.

[huffte]

Well, you can certainly model a curved bridge in Seismostruct. As with most structural programs, it's mostly a matter of properly locating the substructures in plan, properly locating sufficient superstructure nodal locations such that straight elements between the nodes are a reasonable approximation to the curved shape, and applying the proper local rotation angles of the members to achieve the correct orientation of properties.

So, the geometry can take quite a bit of up front work in Excel or in a drawing program, but it should be easily accomplished with some diligence.

Best of luck Vincentzili.

[Vincentzili]

thank you very much !!!

[Vincentzili]

Huffte,
I have made my model. But another problem occurs.
After the software analyze for a while these came out:


Time= 3.01493, dt= 0.04500 (Iter: 2 => Converg)
Time= 3.05993, dt= 0.04500 (Iter: 2 => Converg)
Time= 3.05993, dt= (Iter: 1 => fbd_Ite)
Time= 3.06556, dt= 0.00562 (Iter: 2 => Converg)
Time= 3.07681, dt= 0.01125 (Iter: 1 => Converg)
Time= 3.07681, dt= (Iter: 1 => fbd_Ite)
Time= 3.07962, dt= 0.00281 (Iter: 2 => Converg)
Time= 3.07962, dt= (Iter: 0 => fbd_Ite)
Time= 3.07962, dt= (Iter: 0 => fbd_Ite)
Time= 3.07962, dt= (Iter: 0 => fbd_Ite)

And in my Performance Criteria log:
Otpt No: 61 Time= 2.7168, yield reached. Elm: colm2. Steel Strain = 0.00200863 - Sec(4)
Otpt No: 65 Time= 2.8799, crack reached. Elm: col2. Unc Conc Strain = -0.00390822 - Sec(0)
Otpt No: 65 Time= 2.8799, crack reached. Elm: col8. Unc Conc Strain = -0.00373064 - Sec(0)
Otpt No: 68 Time= 3.0149, yield reached. Elm: col4. Steel Strain = 0.00203593 - Sec(0)
Otpt No: 69 Time= 3.0599, crack reached. Elm: co3. Unc Conc Strain = -0.00357881 - Sec(0)
Otpt No: 69 Time= 3.0796, crack reached. Elm: col10. Unc Conc Strain = -3.8805E+022 - Sec(1)
Otpt No: 69 Time= 3.0796, crack reached. Elm: col10. Unc Conc Strain = -8.0005E+021 - Sec(2)
Otpt No: 69 Time= 3.0796, crack reached. Elm: col10. Unc Conc Strain = -1.4146E+022 - Sec(3)
Otpt No: 69 Time= 3.0796, crack reached. Elm: col10. Unc Conc Strain = -4.6987E+021 - Sec(4)
Otpt No: 69 Time= 3.0796, crack reached. Elm: col10. Unc Conc Strain = -1.1581E+023 - Sec(5)


I can't get it why it happens, and what can I do to solve it.

[huffte]

Vincentzili,

The messages regarding the various states of cracking and yielding as the solution progresses should be expected - I assume you have specified these criteria in the "Performance Criteria" tab of the pre-processor. So, unless I am missing something, these messages are valuable information to you as opposed to a problematic issue.

As for the "fbd_ite" message, I will first suggest a forum search on "fbd_ite" or "convergence" or "convergence difficulties. You will get several hits and this should provide some valuable guidance.

Secondly, a Help System search on "fbd_ite" will lead you quickly to additional insights into the meaning of this message.

Best of luck Vincentzili.