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# ETABS - Science topic

Explore the latest questions and answers in ETABS, and find ETABS experts.

Questions related to ETABS

I need information about chord rotation . How to calculate it in etabs using time history analysis.

Hi, Can anyone give me a source where I can find detailed steps in modelling of negative stiffness isolator? Another question is, Can I use shape memory alloy as material of base isolators in ETABS? If so, what are the steps?

I have a pressing issue with my thesis, as I need to analyze numerous 3D moment frames, but I'm running short on time. Moreover, the buildings I'm studying are symmetrical and lack torsion or disarray complexities. I wonder if it's possible to model 2D frames with properties equivalent to those of the 3D frames, and still achieve accurate results. This would significantly save me time. I'm seeking assistance on how to perform this task in ETABS. Can anyone help me with this?

Hi

I was wondering how exactly are the pushover loads applied in FEA programs?

For instance, in SAP2000 you can apply the following load patterns

- user-defined
- modal
- accel

The first case is trivial but in modal and accleration load patterns, is th eload applied to all the elements? I.e. is it applied individually to each beam and column proportional to mass?

In MIDAS the available load patterns are similar. On their website on uniform acceleration they say the following:

*Uniform Acceleration**: The load is distributed relative to the inertia forces developed in the structure, which has been subject to a uniform acceleration. If the acceleration is uniform, the load pattern is determined proportionally to the mass at each story level.*

Since above they mention storey levels I wonder whether the programs try to lump the forces at individual floors.

Thanks

Dear all,

I am performing Time History(Linear) in ETABS using IS 1893-2016 along with static and Response Spectrum analysis. If the downloaded TH from PEER database is in the unit of G and I am using SI system of unit then what should be scale factor?

The scale factor to be again multiplied by Ig/2R or software will automatically calculate it?

Thanks

As part of the pounding analysis comprising a 5-story and a 3-story structure in ETABS, I have introduced gap elements between the buildings. I am currently evaluating which analysis method to employ - FNA or Direct Integration. Which of these methods would be more suitable for this scenario?

what steps should i ensure it is done correctly. do i apply it as a link or a spring

I want to overlay a processed image onto an elevation view of a ETABS model using openCV and ETABS API in c# !

I'm currently doing a nonlinear model in Perform3D and I need to calculate the mode shape. I create the structure first in ETABS and import it on Perform3D but I noticed that there's a difference in the modal mass participation ratio. Therefore, I know that the story response plot that I extracted in ETABS is different from the Perform3D.

Now I don't know where to extract that data. Can anyone help me with this? For research purposes only.

Thank you.

I am working on a 2D frame to study the response of Base isolated structure. I did modal analysis analytically in MATLAB and tried comparing with modal analysis output of ETABS. The modal time periods obtained is not same. I choose the stiffness of isolator to obtain time period of 2.2s which is closed to ETABS result of 2.4s while I am getting period of 3.4s from MATLAB.

It would be a great help if anyone can figure out the problem. Thank you

I am carrying out pushover analysis. I want to know if we design the elements using etabs and if we unlock the structure for giving nonlinear hinges will etabs consider designed area of reinforcement while assigning nonlinear hinges. or we need to give beam reinforcement overrides??

So far, ETABS doesn't open completely 8 out of 10 times. I have to close it using Task Manager. Upon debugging from the dialog box, it highlights the line 'EtabsObject.ApplicationStart' in yellow. The issue is that the same code opens the ETABS at other two times. With this uncertainty, I'm finding it difficult to continue programming. I'm attaching my VBA file.

I have modelled a structural wall in ETABS using shell elements. I need to obtain the moment and shear force from it. How can we extract it from ETABS?

Also, can anyone suggest any another method to model the structural walls in ETABS to get the results?

I've already calculated the blast pressure that will act on the building. However, I am not quite sure how can I apply this load to a building. Please, help me with this one. Thanks

I need to model about a dozen variations of a ten-story building using ETABS. I and my guide have decided to use ETABS OAPI for the purpose. Also, I'll be accessing it through Excel VBA. What would be a good way to learn it? I searched on web but there seem to be limited resources!

I am aware of checking this value for one member for one load combination, as shown in the attached figure. However, I am looking for ways to extract all these ratios in tabular form. Did anyone encounter this before?

I,m modelling the reinforcement concrete building in ETABS but i find the period very big in the first mode

In his name is the judge

I want to build some parametric structures. my objects is period of first mode, eccentricity and (frequency of torsional mode/frequency of transitional mode). So I decide to use NSGAII for make my parametric structure.

Inputs of optimization are transitional mass, rotational mass, length and width of structure and objects are period of first mode and (frequency of torsional mode/frequency of transitional mode) and in each one I assume eccentricity constant.

So I think there is a problem. I think there is a relation between rotational mass and transitional mass with respect to length and width of structure and eccentricity of mass.

If my guess is true I have to remove rotational mass from my inputs and use the relation instead.

So my big question is

Is there any formula to evaluate rotational mass based on dimension, eccentricity and transitional mass in rectangular plan?

wish you best

Take refuge in the right.

**Hello, Nonlinear analysis experts.**

I'm performing a static nonlinear pushover analysis of a RC shear wall as stated in the

**@Thomsen**and**@Wallace**example (**Thomsen, J. H., & Wallace, J. W. (2004). Displacement-based design of slender reinforced concrete structural walls—experimental verification. Journal of structural engineering. 130(4), 618-630.**).I used the

**ETABS**18.0.2 software to perform the analysis and construct the pushover curve. (the EDB file of the model is in the attachment field)I used the wide-column approach to simulate the shear wall and assigned

**6 fiber (auto) P-M-M hinges**to account the nonlinear behavior of the wall.More details about the shear wall are illustrated in the figure below.

Also, the material behavior was extracted using a plot digitizer tool and implemented on ETABS.

Further details about the materials are down below.

When I pushed the shear wall by a 141KN lateral force, it was expected to get a displacement of about 69.9mm, but the results were not as expected.

The last figure shows the comparison between the envelope of the experimental results and the resulted FE pushover curve.

Any suggestions?

I am doing non linear modeling of unreinforced masonry structure using equivalent frame modeling. when i assign moment rotation hinges at the top and bottom of masonry pier ETABS gives error assigning hinges requested calculated properties are not available for material or section type. how can get away from this error.

looking for your consideration on this please.

Hello, Anyone here with a recommended experimental research paper that conducts shake table testing of reinforced concrete. I am validating my results and in order to do that I need an actual building and simulate it in ETABS to verify that the ETABS are capable to depicts the displacement response through time when conducting Non-Linear Time History Analysis.

I have modelled a 16 storey RCC building in ETABS and performed non linear static analysis. But the analysis is found unfinished. I have reduced no. of storeys and increased number of null steps. But no use. Please help me to find out the reason?

I wanted to understand how these softwares are different in terms of the complexity of analyses and accuracy of results. I'm looking at performing Time History Analyses over a set of ground motion data and have observed slight differences in the results obtained using the mentioned software. I wish to know the reason behind this and why do we not hear about Drain 2Dx as often as SAP2000 or ETABS.

initially i decided to perform non linear time history analysis on SAP 2000 but my sir suggested me to create analyze and design the model in ETABS and then export to SAP 2000, but after creating the model we are unable to import it in SAP 2000 as we are getting errors so i have decided to perform non linear time history analysis in ETABS19, so please let me know is it possible?

I need to study the effects of tuning liquid damper on some building, so I search about the method of modeling TLDs on SAP2000 or etabs or RSA.

i am working on wall slab precast connection.

Anything related to seismic design or 3DCP, I would appreciate a lot. I know grasshoper, karamba, sap2000, etabs, autocad, revit, matlab and have experiencia in buildings. I am so sorry if this bother someone.

In ACI318-19 section R6.3.1 and its commentary, "member stiffness GJ should be reflected the degree of cracking and inelastic action that has occurred along each member before yielding".

On table 6.6.3.1.1(a) the value for I-cracked for each member is recommended. However, I cannot find any recommendation for cracked torsional stiffness.

I am analyzing the structure subjected to gravity, wind, and earthquake load according to ACI using ETABS, and I am struggling about this issue

Please explain what is the best practice for applying cracking stiffness modifiers for torsion in

beams (Torsional constant, J),

columns (Torsional constant, J),

walls (in-plane f12), and

slab sections (m12).

It would be really appreciated if supportive reasons are provided.

Thank you.

Hi everyone,

I am asking for your help, this is my problem:

I'm making a time history analysis in abaqus, I have defined material Rayleight damping as for etabs as for abaqus, but when comparing modal shapes I found out that although the two first modal shapes are similar, from the third one they change (because abaqus show an axial modal shape while etabs never shows it), then it takes me to different results when making a time history analysis and compare it to Etabs Results.

PD: I put a point mass in abaqus and etabs but still not sure if it is considered in the analysis.

I'm adding files for some of you to help me.

Thank you.

I'm working on behavior of base isolated frame in SAP2000.

For modeling Lead Rubber Bearings, we should use Link Element with nonlinear properties. One the properties we need is Effective Damping Coefficient. for example if the manufacturer of the device has been said that effective damping ratio is equal to 19%, i want to know how should i convert it to effective damping coefficient?

How to Control Punching Shear of Flat Plate without increasing Thickness and Providing Capital and Drop Panel?

I need help regarding ETABS 19 also. Any researcher here who can help me out?

I have understood the meaning of F11,F12, F22, V13, V23, M11, M22, etc but am still confused which one to use to check my shell forces. Please suggest some tutorial video if available

Sir,

I have performed time history analysis in ETABS. The size of the files after analysis is very large. I have extracted my results for my research paper.

Now, I want to store my data and free some space for other analyses.

How and where should store the analyzed file without losing the analysis results (without unlocking them)?

I am confused because if I copy the file it will unlock the model automatically.

Please help.

Thank you.

Should I use ETABS or Perform 3D for IDA analysis?

Does Perform 3D provide more functions for IDA?

I am modeling a steel braced frame in ETABS. I want to model the panel zone.

Please suggest how to do this.

Or share any document related to this.

Thanks.

In general, if we want to use the auto assign hinge in SAP2000 or ETABS, in the box shown in the second figure, what load combination or load case should be used for time history analysis?

Thanks

Dear all,

Am doing validation on a 3-D model of a 30 storey building on Etabs 2016 by a non-linear time history method with El Centro ground acceleration and the parameter that I used is nonlinear fluid viscous damper and lead rubber isolation after running the analysis fundamental period is ok but why storey displacement is so far different?

**Problem:**I want to model the glass fiber in concrete beam in ETABS 2019 but there is no option in ETABS 2019 about modeling of glass fiber for concrete beam.

How to Model GFRP in ETABS? The fiber reinforced polymers use ACI 440.1R-15 which is the most updated code I found. And there is no option in ETABS 2019

I would be happy to hear from you,

Thank you!

i am trying to simulate the flat slab with equivalent frame method with ETABS software to conduct the pushover analysis, for modeling the rigid torsional member I adjust the torsional constant modifier to a very high value (1+e15). am I correct? if not what is the suitable way to simulate the rigid torsional member?. Thanks in advance.

Hello Dear Researchers,

Should designers of earthquake-resistant buildings compare the period obtained by numerical analysis software (SAP, ETABS...), with the empirical period, and what is the relationship between these two periods, if any?

Thank you for explaining this to us.

Best regards.

Hello

Recently I have heard that just SAP should be used for dynamic analysis of building and the results of ETABS are not valid for nonlinear dynamic analysis. I have done nonlinear dynamic analysis with Etabs software. Are the results acceptable?

Is there any evidence for this?

Thanks in advanced

how the shear force or bending moment diagrams are helpful for us for the design of structures in etabs? by just looking at these diagrams what do we get?

Which is better in your opinion ETABS - SAP2000 - SAFE

For analysis and design Steel and Concrete structure

I am performing nonlinear pushover analysis of RC building structure by auto hinges in ETABS and during analysis it shows, 'maximum number of total steps reached, subsequent results will not be available.'

How to resolve this issue. ?

What should be the value of target displacement to be used in the software?

hello all

I have to define a correctly nonlinear property for steel. what I must do for filing out the parts that I show in the picture?

hello everyone,
i'm trying to model a 3D one story buiding with mass IIrregularity, the model has 4 elastic columns and rigid diaphragm. the model has no beam, so i used rigid diaphragm to equal dof of top nodes of columns. i use a model from a reasercher's article, he note that the modal frequences of first three mode is 1.16 , 1.96 , 2.37 HZ respectively. i builded the model in etabs and can verify my model with 0.33% error, but i couldn't verify model in opensees. i trying almost everythings to verify it but Unfortunately all my work was unsuccsesfull. in my reaserch i found that mass moment of inertia is principle parameter in model with mass IIrregularity, so i try figure out how modal analysis run in etabs and opensees and what difference between them. i found that etabs centeralized all masses in center of mass and then make mass matrix with 3 parameters like that
[mass in x direction 0 0
0 mass in y direction 0
0 0 mass moment of inertia about hight axis ]
but i wondering opensees generate mass matix for each node(also we can use center of mass for assigne mass) and also mass matrix for 6 dof model with 3 limited dofs (dofs limited in z direction and rotation about x ,y axis) is 6*6, so i'm confused to understad how opensees derrive mass matix and calculate modal frequences. i try both assigning mass to nodes and center of mass. in first condition i assigned mass moment of inertia like that
mass n "mass in x direction" "mass in y direction" 0. 0. 0. "mass moment of inertia about height axis"
etabs calculate mass moment of inertia with multiple each mass of nodes by distance of node from center of mass then sum these valus and attain mass moment of inertia abuot height axis. also we can use another formula for it. i try all patterns i found but i can't verify my model because i can't understand how opensees run modal analysis and make eigen values. for best understanding i upload my model in opensees and etabs.
I'm so thankful if you can help me.
with best regard

Asslam-o-alaikum everyone,

The time for a building comes out to be 0.79 sec in ETABS, 0.822 sec in Perform 3d Software and by manual calculation it comes out to be 0.922 sec for the 1st mode using the modal mass of the building using the equation of simple harmonic motion. Why there is difference and are these values in acceptable range?

Thank you

Among all the softwares for analysis and design. Which is best for design of ribbed slabs and also raft foundations. I tried etabs but failed to get the results

Hello dears

Do I have to adjust the non-linear specifications of the steel property in ETABS manually? how can I do it correctly?

thanks

Dear all

I have a 2D steel frame that is subjected to nonlinear time history analysis.

7 acceleration records have been selected from the PEER and scaled to normal (1g) and then used for the analysis.

But unfortunately, no significant yielding has occurred in the frame's plastic hinges.

I am thinking that the PGA of my scaled record must not be sufficient to enforce hinges to yield.

A friend says that I have to multiply another g (=9.81) in my function.

Would you please teach me what is the right way?

HI,

can anyone explain me how to get modal mass coefficient and modal participation factor as per ATC 40 from SAP 2000?

I am analyzing an existing steel structure with viscous dampers. However, when I performed a FNA analysis, the period of my first mode is excessively large, it's not realistic. Clearly, I have some error in modelling, but I can't pinpoint em out.

I have attached the modal period with their corresponding participating mass ratio.

I want to assign panel zones in my model. I am confused about how to assign it properly. I do not how to fill the P/Py for columns. Do I need to assign individually for each joint?

Please help.

Hello everyone,

I have imported the structure into perform 3d from etabs version 19 and assign the nonlinear properties at material or cross section level. When i tried to run the analysis, it says that structure is poorly conditioned or unstable but in the Etabs the structure looks fine and it is already designed building. Can anybody tell me how to solve this issue?

This is the response spectrum that I have defined. I have chosen zone III f . and then I want to go for pushover analysis and see the pushover curve.. and see the Vy value generated for Zone III that I have chosen.

Now here Spectrum Source = Defined function (RS IS, that I have defined, ) But what to put at SF (m/sec2) ?? The value that is being displayed is by default. But what I have to put ?? I have to put something right ?? Please help.

Aslam-o-alaikum,

Hello everyone, i don't know why my monotonic pushover curve is not reaching the target displacement without any warning errors (but it reaches by enhancing tolerance) and why my different cases of cyclic pushover curve (with even enhanced tolerance) terminate without any prior error messages in ETABS? I am so fed up with it. Any help would be appreciated.

Thank you in advance.

Hi guys. Just a question.

I am modelling my columns and beams in section designer. I noticed that in SAP2000, Mander's ( confined) can be modified inside Section designer including the ties spacing which can affect the stress-strain curve of the concrete.

But in ETABS, as I model the columns in section designer, I noticed that I cannot modify ttie spacing. Also, I dont know if nonlinear properties of concrete are already incorporated in the model automatically.

thoughts?

Good day Sir/Ma'am, anyone here knows how to extract data from structural analysis software specifically from ETABS to MS Excel. Thank you and God bless!

Why Moment Resisting Frame Drift is more than Shear Wall Frame Drift, if they are in the same Seismic zone and the same quantity of material?

- Analyzing two Models ( Moment Resisting Frame and Shear Wall Frame) by Etabs.
- The same property and the same quantity of materials.
- Analyzing both Models in the same Seismic Zones.
- Both Models are the same geometry, the same height and Floors.

My question is:

Why Base Shear and Drift in Model of Moment resisting frame provided more than in Shear Wall Frame?

I have to do push over analysis on a 10 storey composite frame consisting of WPB steel embedded composite column. Since automatic hinge application is available only for steel and concrete members in Etabs. The only option is to apply a user defined hinge to the composite column. But while giving user defined hinges the input parameters while defining hinge should be consistent with my composite section. It would be helpful if anyone has idea on user defined hinges. I have attached the error message shown by Etabs.

I created Fiber P-M-M hinge where I pasted the fiber layout generated by section designer. I assigned it at the support of my column. However, I came accross this error once I run the program. It says it cannot generate fiber hinge data. Any ideas?

I tried the same procedure in ETABS but the analysis commenced.

While running non-linear analysis in ETABS I am getting the following error.

* * * W A R N I N G * * *

THE P-M-M INTERACTION SURFACE IS NOT CONVEX,

HINGE PROPERTY: C3H2,

RELATIVE ERROR = 0.010275, THE SURFACE WAS ABLE TO BE ADJUSTED

Can anyone of you who have faced a similar problem can share the reason or solution to fix this error?

I want to nonlinear static analysis according to FEMA 440. But in etabs the only option available for the plastic hinge is by using ASCE 41-17 code.

Please let me know how to assign the hinge according to FEMA 440

Please compare various common programs, e.g., ETABS, TEKLA, etc. as well as the new generation of parametric ones, e.g., Karamba, Kangaroo, etc.

Please reply by referring to valid scientific papers.

According to the FEMA356 and ASCE41-17 (3.3.3.2), we have to push the structure 150 percent greater than the target displacement!

In this case, controlling the performance level of plastic hinge seems uneconomical. Why do the CODES refer to this paragraph at all?

I have performed a nonlinear static analysis in etabs for a steel braced frame. The pushover curve is linear and the model has shown any yielding. But the analysis has stopped before reaching the target displacement. I do not know why?

Please suggest what to do. Why the analysis is stopping if there is no plastic hinge formed before reaching the target displacement?

Can ETABS design a non-prismatic concrete section?

I have been trying to make non-prismatic beam design in ETABS, but every time I try to run the concrete design module, an error shows.

I would really appreciate any tips or suggestions

Thank you very much in advance

I want to perform wind analysis in ETABS for 30+ storey building and i am in confusion for what type of analysis should i prefer for exact answer?

I mean Linear analysis or Non linear analysis for Wind analysis?

Linear and Non linear analysis is used for earthquake but can we use it for Wind analysis?

I have wind Tunnel Test data available with me.

In your opinion which is the best software to analyse a 3D frame:

(a) STAAD

(b) ETABS

(c) ABAQUS

What are the merits of your answer?

I have been looking for information on the mathematical model used in ETABS Ultimate to compute the properties of the rotational spring assigned to Panel Zones of steel frames. I found one reference manual issued in 2016 that says: "Mathematically, panel zone deformation is modeled using springs attached to rigid bodies geometrically the size of the panel zone." However, the manual does not explicitly say if the Scissor Model or the Krawinkler Model is used in the software.

Does anybody know what model ETABS uses? If you have supporting material, please share it!

Thank you,

Rafaela