Hijratullah Niazi's Communities Activities

Shear velocity Vs

Hijratullah Niazi — Sat, 13 Mar 2021 16:32:33 GMT

Hi,

Any one has idea how to plot or find out shear velocity of the soil?

I want to make sure input Shear Modulus G0 ref gives same Vs output.

Is it possible to plot Shear velocity? In other words, how can we make sure that input Shear Modulus gives correct Shear Velocity for the soil?

Shear force Node to Node Anchor

Hijratullah Niazi — Mon, 29 Mar 2021 11:16:12 GMT

Hi,

Any one know if it is possible to plot shear force from Node to Node Anchor?

In this case, node to node acts like a column, however, I do not see option to plot shear force for this type of member. If I modell this as plate, then it is not correct based on my assumption.

Another solution?

Material property and result

Hijratullah Niazi — Thu, 11 Mar 2021 06:40:48 GMT

Hi,

After several attempt I came to conclusion, in order to choose the material property correctly, a benchmark can be run to check if input material property is correct.

In this case, soil height is 15m, , gamma material is 20 kN/m3, Vs=200 m/s

G should be 82000 kN/m2 and this will give following:

					PSA tid
gamma =	20000	N/m3		T =	0,30	s
g =	9,81	m/s2		f =	3,33	Hz
				Vs =	200,00	m/s
Vs =	2038,73598	m/s

G =	82000	kN/m2	From Plaxis
Vs =	200,551739	m/s2

This means, a quick check if material has Vs=200m/s, the PSA ouput graph should show peak value at 0,3s.

I am not very sure if this is the way to check material input. Even I used this method, PSA peak was not even close to 0,3s.

Any one can share their ideas how to check properly material input in Plaxis?

Maximum Shear force, Base Shear Force

Hijratullah Niazi — Mon, 08 Mar 2021 20:34:17 GMT

Hi,

Forces during dynamic time will not be constant and it varies.

Any one has idea how to find maximum shear force of the columns/walls during dynamic time?

I am looking for Base Shear Force which is described in EC8 (4.3.3.2.2). By using same response specter in Plaxis and EC8, same mass, etc, following shear forces are very small in comparison to EC8.

Any idea how to make sure/output shear base?

Thank you!

Manual-boundary conditions

Hijratullah Niazi — Fri, 05 Mar 2021 14:44:43 GMT

Hi,

I want to compare Plaxis's boundary conditions with manual calculation according to the Kramer.

Some one has done this before and summary should like lik this.

This is based on several points observation and this is plotted in Excel. Any one knows which manual is this method described?

verification of boundaries

Hijratullah Niazi — Tue, 09 Mar 2021 07:13:22 GMT

Hi,

Has any one attempt to verify boundary conditions with analytical method described by Kramer?

I want to check how much damping boundary conditions gives to the soil.

How to do that?

Boundary conditions and deformation

Hijratullah Niazi — Tue, 02 Mar 2021 06:46:23 GMT

Hi,

I can see similar question is asked, but my model behaves bit different than what I was expecting.

Deformation is very small and does not seem right.

Boundary conditions are as suggested by Plaxis, I assume everything in this model is correct, but the deformation is not ok, the whole soil moves side to side.

PSA output

Hijratullah Niazi — Sat, 27 Feb 2021 12:03:50 GMT

Hi,

Any one can share why output PSA from Plaxis decreases from input PSA.

Soil will scale the time series and PSA on the top of the ground when you apply dynamic multiplizer at the bottom of the ground. I experience that output PSA decreases dramatic and it is not even close to input.

In my opinion, there should be something wrong in my model.

Bottom of the soil is rock, and soil is clay.

Input dynamic multipliser

Output PSA on the surface

Any one has solution to this?

Ask A Question II

Mon, 08 Mar 2021 20:34:18 GMT

Ask 10 questions in a forum.

Material properties

Hijratullah Niazi — Fri, 26 Feb 2021 11:57:13 GMT

Hi,

Anybody know if it is possible to out put material properties in Excel

Calculation time

Hijratullah Niazi — Mon, 01 Mar 2021 20:52:22 GMT

Hi,

I am running 2D dynamic analysis, I have used same setting as Tutorial 14. I have additionally, made some changes in boundaries and other settings, not quiet sure what causes that a very simple modell just soil takes some hours. Dynamics phase settings looks like picture below.

Even after four hours, analysis was still not finished for such a small modell.

Any one has suggestions regarding time steps, interval and other settings to decrease calculation time?

Thank you

PSA

Hijratullah Niazi — Thu, 25 Feb 2021 10:27:32 GMT

Hi,

Any idea why PSA from top of the soil in Plaxis do not match with input time series?

PSA for ground type and height of 15m soil on the bedrock, should give around 0,8. Plaxis shows result of 0,5 on top of soil, which means at the bottom it is even lower.

Any idea how to PSA varies from bottom of soil to the top?

How it varies because of soil own frequency, and so on?

There is a way to manually calculate how much this will differ?

Another thing regarding acceleration, this will be scaled on the top of the soil because of soil depth and its own frequency. Ide how to calculate this manually?

Contact info at Bentley

Hijratullah Niazi — Thu, 18 Feb 2021 11:05:53 GMT

Hello,

I want to write my master thesis, topic is, seismic loads on a concrete frame/structure, and compare results with EC8.
Any idea whom I should contact at Bently?

Calibrating Plaxis with DeepSoil

Hijratullah Niazi — Thu, 25 Feb 2021 21:22:02 GMT

Hi,

Highly appreciate if someone can share possible solution.

I am trying to calibrate Plaxis with DeepSoil. DeepSoil gives higher PSA at the surface.

Plaxis gives lower PSA at the surface

I suspect that material input in Plaxis do not correspond with DeepSoil.

One thing in particular I am not sure, is G/Gmax in Deep Soil.

Material used in Plaxis is HS small

I assume G0ref in Plaxis is G max in Deep Soil

G= E'/1-2v = 20000/2(1+0,2) = 8333,3 kN/m2

G/Gmax = 8333,3/180000=0,046

Inserting this small G/Gmax, DeepSoil will give way higher PSA.

Any one has idea what is the correct G/Gmax or how to calculate this from material input in Plaxis?

Thank you

Error code :113

Hijratullah Niazi — Thu, 11 Feb 2021 20:40:42 GMT

Hi,

Any one has idea, what can be error with Error code:113?

I did not find in manual, what this error means.