Berk Demir's Activities

Segmental tunnel lining

Nadeem Khan — Mon, 01 Jun 2020 12:15:46 GMT

communities.bentley.com/.../Plate-properties.pdf

Dear Sirs,

I am looking at the modelling of the segmental lining in Plaxis 2D. The dilemma I am facing is that should I use the reduced second moment of inertia (I effective) considering the number of segments (as proposed by Duddeck and Erdmann) or full stiffness without considering the joints.

Also, whilst considering reduced stiffness (with I effective), the plate thickness (d) also reduces in Plaxis plate properties. How this should be accommodated during the interpretation of results?

Many thanks.

Nadeem

Moment Concentration at corner of structure in plaxis 2D

Ahmad Rahmani — Tue, 20 Oct 2020 06:50:29 GMT

Hi
When i activate structure in my model (Stage Construction) I got moment concentration at corner point (90 deg)...it seems in reality it shouldn't be in this way.any one has any idea or solution

Modelling a raft foundation as plate and volume element in Plaxis 3D?

Abdirahman Yasin — Wed, 08 Jul 2020 19:34:26 GMT

Dear All,

Which approach is more accurate to model a raft foundation? Is it by using plate elements or volume elements?

Mesh Output File not Found

Berk Demir — Mon, 11 May 2020 15:33:46 GMT

Since there is no information on this error, I think it would be nice to keep it on the internet: "Meshing failed with the following error: Mesh output file not found" error is really bothering. The reason of this error is unknown to me, so the answer.

For my current tunnel model, the inclusion of bolts (emb. beam) seems to cause the problem.

Phi/C Reduction analysis with structure elements

Ahmad Rahmani — Sun, 15 Nov 2020 06:09:21 GMT

When performing safety analysis to check FOS of a anchored excavation (with diaphragm wall piles for example),via Pfi/C reduction method, if we check the force or moment in structure elements its considerably high and is far beyond capacity of structure.

anyone has any idea is it wrong or not?
should we introduce elasto-plastic structure element for safety analysis as a solution?

Importing 3DM file

Arpit Mathur — Thu, 25 Feb 2021 16:04:22 GMT

Can I import a geometry from Rhinos to Plaxis 3D. The format i received is 3DM.

Thanks

Diaphragm wall movement due to reduction of stiffness

Feng Ren — Wed, 17 Feb 2021 03:37:16 GMT

Hi,

I tried to model the long-term behavior of diaphragm movement by reducing its stiffness EI to 0.6EI for example. However, the results showed there is almost no change. The diaphragm wall in the model was a cantilever wall and modelled using plate elements. If I further reduce the long-term stiffness to 0.3EI, the model responds to the change and has larger movement. it seems that the model behaved unexpectedly. Can anyone please help with this?

More information can be provided if required.

Regards,

Feng

definition of pref

Baptiste LAROCHE — Tue, 02 Feb 2021 17:16:37 GMT

Hello,

in general geotechnics, p is the average stress (or octaedric stress) and p = (sigma 1 + sigma 2 + sigma 3) / 3

In the HSM model, can you confirm that pref is the average stress in the middle of the concerned layer ?

Thus pref = (sigma 1 + sigma 2 + sigma 3) / 3 ?

Thank you in advance.

Baptiste Laroche

Validation of oedometer test

Elena P. — Tue, 21 Apr 2020 12:06:06 GMT

Hello,

My problem concerns the validation of oedometer tests.
I run some incremental loading oedometer tests on medium stiff clays and simulated them in Plaxis using different soil models (SSC, hardening soil, MCC).
I followed the procedure explained at page 192 of the Material Models Manual and considered a point on the top.
The final compression curve (stress - void ratio) matches quite well with the laboratory curve, but the entire simulated curve is shifted downwards.
The first load step, when simulated in Plaxis, returns much higher deformation than the laboratory results.
Modifying the soil model or the stiffness values or the preconsolidation stress does not solve the problem.
Another publication shows the same offset of the compression curve (Asad, 2016, Prediction of One-Dimensional Compression Test using Finite Elements Model).

I wander why this happens.

Thanks

Simulating geotextile embedded collumns using embedded beam rows and drains in PLAXIS 2D

Kimberly Möller — Mon, 18 Jan 2021 11:58:32 GMT

Hi everyone,

at the moment I try to simulate an embankment founded on GEC (geotextile embedded collumns) and a bridge foundation. For that problem I used embedded beam rows acting as piles. As the material in the GECs is way more permeable than the clay layer I want to add drains to simulate the draining behavoir these GECs obtain.

Calculating the system without drains works. As soon as I try to add all the drains the calculation ends at some point (most likely in the beginning, Phase 2/3) saying the determinante is zero.
Some calculations I even stopped because P excess reached enormously high values (~800). Adding only some drains works as well (see picture below), but not adding all of them.

As the drains should improve the system I don't know what my mistake is. I would be really happy about every tip I can get. (clay is calulated as undraind and with SSC)

Best regrads

Kimberly

Convergence-Confinement method application in plaxis

Ahmad Rahmani — Tue, 12 Jan 2021 06:49:21 GMT

Hi
Im afraid if anyone could help me to use confinement convergence method in plaxis?

Im looking forward to find how to calculate beta value.

Output force in the axially loaded embedded beam row as a pile in plaxis 2D

Nitharshan — Wed, 06 Jan 2021 18:14:31 GMT

Hi all,

I designed a axially loaded pile system (total length = 10m) with properties shown and applied line load 100 kN/m.

The results are shown below.

i need some clarifications

01) Normally base resistance comes into action once skin friction dissipates but the results shows the base resistance, what is the reason?

02) Applied loading is 200 kN and slef-weight like 47.112 kN, which is get from the skin friction {(0.5x2.7x12.12x2) + (10-2.7)x12.12x2)} and base friction (24.71 x 2). but axial force showing different value, please explain how axial force output is calculated and shown?

Thanks,

How can I model a hinge between two beams?

Jeremy Kuelling — Wed, 06 Jan 2021 16:43:23 GMT

I want to model hinges at the end of a beam which is connected to several other beams. How can I do that in Plaxis 3D?

Thanks for your help!

Validation

Christian Olsen — Fri, 18 Dec 2020 09:26:55 GMT

Where are the previous files you could download to check and validate that plaxis worked on your PC. There where many different files in the past - but I can not find any now?

there where for example:

Validation-Bearing-capacity-of-strip-footing-3D-2016.00.p3dlog

Validation-Bi-axial-compression-test-with-Mohr-Coulomb-model-3D-2016.00.p3dlog

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Wed, 06 Jan 2021 03:30:59 GMT

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