SAP 2000 - Science topic

The suitable distance to get blast is 50 m

It is likely that auto hinge option is not compatible with the type of column you are using. The auto hinge option may be designed for a different type of column or for a column with different properties (e.g. stiffness). It is possible that the column is too flexible for the auto hinge option and so it is automatically switched to being force controlled instead.

If you still have problem with modeling link elements in SAP2000 you can read CSI manual or if you have not found your answer you can send me an email to prove it for you.

The presence of plastic hinges in a structure can significantly affect its modal periods, which are the natural frequencies at which the structure tends to vibrate. In a linear analysis, the modal periods are determined solely by the stiffness and mass distribution of the structure, and the presence of plastic hinges is not taken into account.

However, in a nonlinear analysis that accounts for the formation of plastic hinges, the stiffness of the structure changes as the hinges form and develop. This change in stiffness can affect the natural frequencies of the structure, and therefore its modal periods.

The formation of plastic hinges typically results in a softening of the structure, which can lead to a decrease in modal periods. This means that the structure tends to vibrate more rapidly at lower frequencies than it would if the hinges were not present.

In addition, the location and extent of the plastic hinges can also affect the modal periods. For example, if the hinges are concentrated in certain areas of the structure, such as at the ends of beams or columns, the resulting change in stiffness may affect the natural frequencies of those specific modes more than others.

Therefore, when modelling a structure that is expected to undergo significant plastic deformation, it is important to use a nonlinear analysis that can capture the formation of plastic hinges and their effect on the modal periods.

If you are running a Pushover Analysis (or TH), select the push load case (or TH) for the calculation of V. Once you run the analysis, the hinge properties will be automatically updated according to the calculated value of "V". Re-run the analysis again by allowing update of the hinge properties until there is no significant difference between two successive analysis results. Alternatively, you can update the Automatic Hinge properties from "Assign > Update All Generated Hinge Properties".

Yes. You may check this using the option Design - selecting IS Code 456:2000-View all members passed

Check out Bispec software which does exactly what you're looking for:

Hi Woongchan,

Yes, it is possible!

However, you need to convert the acceleration records into displacement records using SAP or any other seismic software. Then you define load pattern for each loading record and assign a unital displacement load on that node using the defined load pattern. Finally, define time history load case for using load pattern not acceleration. You may check Appendix B in my thesis on how to conduct multi-support excitation time history analysis using SAP2000.

Best,

Bashar

Mao Cristian Pinto Cruz here is watch and learn tutorial by CSI about buckling factors and how to obtain the buckling load. You can find it at the following link:

I've responded to a similar question there:

BR.

Here they present a cost depending on the core material. Consider inflation and that's it.

Guerrero, H. et al.(2017) ‘Evaluation of the economic benefits of using Buckling-Restrained Braces in hospital structures located in very soft soils’, Engineering Structures, 136, pp. 406–419. doi: 10.1016/j.engstruct.2017.01.038.

Yes, you can model using SAP2000. The equations for simulation of loading on the tank walls depends on the type of tank rectangular/circular and their dimensions. Based on the seismic loading on the tank foundation, the loading on the walls vary along the height of the tank. The loading should be applied using FE simulation on the water tank walls. If you want to know equations, they are available different methods. Equations for ACI method is one of the popular method. If you want to know detailed literature, you please write to me.

Is there any software which can model the flood loads on a bridge?

Dear Chirag Hingad,

Yes, it is ease to perform non linear time history analysis for G+15 RCC building in ETABS 19.

IF incase, you are looking for importing model to SAP or ETABS - use the following links. Check the version's of your current software.

https://wiki.csiamerica.com/pages/viewpage.action?pageId=15074050

Thank you.

Dear Mr. Thierno Ly,

Of course it is good to read papers of other researchers to learn more about dynamic analysis of structures. Together with that I suggest you a very simple way to check your own analysis. It is comparison of the values of vibrations' periods.

Please tell me which structure (number of floors, height, dimensions in plan) are you modeling and analyzing and give me the obtained by you values for the vibrations' periods. Then, based on my extensive experience, I can with some accuracy tell you whether your analysis is good or not.

Best regards,

Doctor of Sciences (Engineering), Professor

Academician of the Saint-Petersburg Arctic Academy of Sciences

Academician of the Athens Institute for Education and Research

President of the Armenian Association for Earthquake Engineering

Vice-President of the International Association of CIS Countries on Base Isolation

Member of the American Association for Science and Technology

Foreign member of the Research Center of Seismic Resistant Structures of the Institute of Industrial Science, University of Tokyo

Eminent Expert of the Committee of Eminent Experts in International Research Base of Seismic Mitigation and Isolation of Gansu Province in China

Founder of the "Save the Yerevan Schools From Earthquakes" foundation

Director of the "Melkumyan Seismic Technologies" LLC

+374 (91) 94-54-02

You can download the trial version and read user manual to practice the software.There are various online platforms offering a shirt term course for beginners like CAD Academy

That's an unusual design

That is a good question.

Dear Soshal deulkar

ATC or FEMA standards are the codes you are looking for. However, I strongly recommend reading the following article:

Dear fatima fadel ,

I will recommend you to go for PLAXIS-2D for the required calculation s.However, the accuracy of computed displacements and distribution of shear and moment along the pile length essentially depends on the subsoil characterization and properly transferring it to the numerical model.

It is also important that you are able to verify the program ouputs with the already available standard methods in litetatue

Hi

Modal analysis outputs can be found in the SM toolbox 6.0.4 instructions in the following sections:

74.29. ModalLoadParticipationRatios

74.30. ModalParticipatingMassRatios

74.31. ModalParticipationFactors

74.32. ModalPeriod

74.33. ModeShape

Best regards

have a look at the video, hope it will be useful to you

Pushover Analysis Using SAP2000

Dear Saurav JYOTI Dutta

did you compare these results with other FE software ?

Hello,

Could you describe your question in more detail?

You can get in touch with me through my e-mail:

Best regards

Kay Guanlao Go through steps

1. Model your section using section designer

2.In Define > Define fibre layout > choose the number of fibres that you need based on your section > Check the box calculate moment-curvature using the fibres > click ok > then a pop up window comes with all the fibre data generated.

3. Ctrl+A to select the data of all the fibres ( remember the number of fibres) and ctrl+c to copy the data.

4. Go to define hinges - fibre-P-M2-M3 hinge

and follow the images as attached.

The images are named in the sequence, I didn't have a proper writing tool

hope it will help everyone.

Dear Omoniyi Moses Tope

The negative eigenvalues represent buckling modes and refer to the reversed direction of loads. have you considered changing the load's directions?

i have a model with shear wall. how can define and apply the blast load on the structure in etabs 2018. kindly help me out

Feel free to get in touch with me for more explanation.

Hi Mehmet FATİH Arat

Please try the following

Assign > Frame > Hinge Overwrites

From here you can choose a steeper degradation rather than the 10% of elastic stiffness, which is assigned automatically by SAP2000.

I hope everything works for you

You may be able to do that with link elements.

SAP OR ETAB has a provision to check soft storey possibilities. You must check this and ensure that frame has strong column and week beams to ensure hinges in beams.

In your case bottom storey failure is leading to collapse of structure.

1. Seismic codes suggest simplified force-deformation models in order to estimate the inelastic behavior both in monotonic and cyclic loading. The monotonic F-δ curve is considered as the envelope and the skeleton curve of F-δ loops under cyclic loading. The real inelastic behavior under cyclic loading depends on the material and the dynamic loading, e.g. reinforced concrete under seismic loading. So, stiffness and strength deterioration should be considered under cyclic loading in the concentrated plasticity modeling technique.

2. Uncertainties about deformation capacity are high beyond the point C of the F-δ curve. Even in the Collapse Prevention performance level (before point C), the ultimate deformations shows significant dispersion in experimental cyclic tests (e.g. reinforced concrete). Consequently, appropriate acceptance criteria for different performance levels and for different materials can be found in seismic codes (ASCE 41-13, FEMA, Eurocode, EN 1998-3, etc) or in other technical literature using model safety factors to scale down the proposed mean values to mean plus standard deviation ones.

I also tried the static nonlinear analysis of MI-RC frames using Etabs & SAP 2000.

1. In Etabs I modelled the masonry wall but it is not taking wall hinges. How to overcome this?

2. In SAP I modelled the infill but I didn't get an option of infill hinge creation.

I created material nonlinearity for beam-column easily by providing hinges. But how to create masonry wall nonlinearity in both the softwares?

Requesting to suggest any related materials and inputs.

Regards

K.S.S Keshav

Divya Brahmavrathan, as I can see in the image there is you have defined the function, so for that first of all, you need to define the response spectrum (RS) from the define menu in SAP2000. Now, there is two IS 1893 codes available in the drop-down list. I suggest you just go with IS 1893:2016 and now again run the Pushover analysis and go to ATC-40 and modified the function. where select your predefined RS and then there is SF, which is known as a Scale factor, in other words, the multiplier for your RS. you should multiply only g=9.81 value in it and also assure that what spectra are you defined before is it elastic or inelastic. If you are willing to do the fragility analysis in that case you should go with elastic RS. it means the R-factor should be taken like 1.

I hope this video will help you a lot.

Hi Ravi

I would recommend to start checking the frequency band over which you perform the SMSIM simulation. This kind of short period trough could be due to high-pass filtering - or absence of HF computation - at frequencies around 5-20 Hz. Have a look at the Fourier spectra of your SMSIM acceleration time series and compare it with the expected typical shape (log-log scale).

Do you have similar troughs whatever the site conditions ? What is the "kappa" value you consider ?

Hoping it will help, all the best

pm

Dear Rakan Alalwan

you should draw a point as TMD then connect it to a node in the structure using two-point link. The value of mass is assigned to the point directly. Also, the damping coefficient and stiffness of TMD should be defined in the properties of the link.

Dear Sumair

I think you should define and assign a member section manually and do not use the librarian sections. Also, check the compatibility of the materials in the define section menu and assigning tab.

You should check your hinge properties and locations.

This picture tells me that the bridge is modeled with linear force-deformation relation. In order to obtain pushover curve, nonlinear deformations have to occur and the nonlinear behavior depends to hinge deformations.

Good luck.

Hello,

It should be possible you add automatic hinges to your piers. Check it before any changes to your model.

and for details you can use CSI DETAILS

Please take a look at this link

Dear Omoniyi Moses Tope

Please take a look at this link

https://hosting.umons.ac.be/html/mecara/Theses/YunXinWu_phd.pdf

Hi Saptadwipa Jha

You can get the base shear from Display> Base Reaction and for the displacement, click the joint that u want to move then, from Display > Joint displacement and then you can plot for pushover curve for force-controlled pushover analysis.

Dear Aakash

first, check the increments and then use Advanced SapFire Options.

we did a similar research but in abaqus. The following is our paper:

As described in the CSI Analysis Reference Manual

The Fiber PMM hinge is more “natural” than the Isotropic or Parametric PMM hinges described above, since it automatically ac counts for interaction, changing moment-rotation curve, and plastic axial strain. However, it is also more computationally intensive, requiring more computer storage and execution time. You may have to experiment with the number of fibers needed to get an optimum balance be tween ac cu racy and computational efficiency.

yes u can analyse it in staad pro.

For compatibility torsion we can ignore the torsional moment (Mx- torsional moment in STAAD).

For equilibrium torsion we need to design the structure for equivalent moment and shear as per codal provision.

EQUILIBRIUM TORSION AND COMPATIBILITY TORSION

MOMENT:

The longitudinal flexural tension reinforcement shall be determined to

resist an equivalent bending moment Me1 as given below:

Me1 = Mu + Mt

where Mu = bending moment at the cross-section, and

Mt = (Tu/1.7) {1 + (D/b)}

where Tu = torsional moment,

D = overall depth of the beam, and

b = breadth of the beam.

SHEAR:

The equivalent shear, a function of the actual shear and torsional

moment is determined from the following impirical relation:

Ve = Vu + 1.6(Tu/b)

where Ve = equivalent shear,

Vu = actual shear,

Tu = actual torsional moment,

b = breadth of beam.

Note:

STAAD notations…

Mx - torsion

Mz and My major and miner axis moments.

Thank you Rafael Salehin.

I agree with you, but if we compare Push over analysis with nonlinear Time history analysis in terms of the max. ductility and the point at which the structure is no longer is available to withstand any load, Pushover curve will drop at that point defining the max. capacity of the structure.

While in nonlinear time history analysis, the program will continue calculating forces and displacements beyond that point, and it will not stop analysis unless it reaches the last second defined in the record.

In case someone needs, here is a small program to convert PEER data file to .txt file: https://github.com/pham-hung/PEER-to-ASCII

I think that with link element in SAP2000 you can easily model shear springs. in SAP2000 you must first define your shear spring in define menu and after that you can use a 2node link/support element from draw menu to draw your spring in your project, for more info you can go to document of SAP2000 and find CSIREFERENCE.

Thank you all for response. I conducted progressive analysis with sap 2000 by removing column. What failure criteria can be set in analysis since fracture or crack propagation can't be initiated with SAP2000?

Thank you so much Denniis Miller

Athanasios Bakalis

Hi Saptadwipa,

I would say create all the relevant load combinations (SAP also creates code based combination automatically) and create an envelop of them. DCR values should be picked from this envelope case.

No, PMM ratio and DCR are different things. PMM is just the interaction and is more to deal with the capacity of your beam-column element. DCR is simply demand/capacity. And yes, the results will be different for non-linear static and dynamic analysis.

Hope this helps,

Cheers,

Shivang

Thankyou

I used "Area Spring" for defining gap where foundation is modeled by shell element. It is easy and you must select the shell, then in Assign menu select "Area Spring" and then select the "Compression Only" in that menu. furthermore you need to make all combination load nonlinear.

I think area springs are correct. In general, you should allow the foundation to uplift (or gapping between soil and foundation) when you're modeling soil and foundation interface. this means that you should utilize elements that have no tension resistance.

Good question

After you have completed the structural analysis in SAP2000, go to results and select 'plot functions' and select the joints and elements that you are interested in. You can now plot force and displacement for your selected list of nodes and elements. SAP2000 will display the plot.

Alternatively, if you wish to plot in MS-Excel, go to results and select " tabular output ". Now, copy force and displacement data from the SAP tables into MS-Excel.

Hi Ankit Goyal , you may input the rotational ground motion as a rotational acceleration load in SAP2000. To do this, first define a time history function based on the ground motion data you have. Next, define a load case for the acceleration load. Select "Time History" under the load case type. Under "Loads Applied", select "Accel" load type and the rotational degree of freedom under "Load Name". Use your defined function for the rotational acceleration. You may refer to the following websites for more information:

Following..

SAP2000 allows for direct input of hinge properties using moment-rotation. It also allows for moment-curvature inputs, however you have to define a hinge length (either relative or based on input units). Check how your hinge is defined and that should answer your question. I believe you do this through Define > Section Properties > Hinge Properties, and then you should have the properties of your auto-defined FEMA hinges there. If it's a moment-rotation hinge, you assume a discrete rotation equal to the rotation value computed in SAP2000. Note that the rotation is defined in multiple of yield rotation. Check the SAP manual, or online help, for calculation of this property as it may just assume the beam is adequately braced to develop full strength and, thus, base it on the elastic rotation when the section reaches FyZx, the plastic moment, or it may be "smarter" and consider other failure mechanisms.

Alternatively, SAP2000 also provides the ability to overwrite the scaling for moment and rotation. You may be able to get creative and define these values yourself to ensure you know exactly how the moment and rotation inputs are scaling in the model.

it could be TH gives larger displacements than Response Spectrum Analysis

In general, SAP2000 can be used for modeling of masonry, but it has a lot of shortcomings and you have to be aware of them (local axes definition, how to handle orthotropic materials, automeshing, etc.). It is a bit clumsy to model solid elements.

As Muhammed suggested, it is more commendably to do such analysis ina finite element software, such as ABAQUS, ANSYS, ADINA, TNO DIANA, etc. Personally, I'm very fond of TNO DIANA to model solutions for masonry elements/structures, since it has lots of useful elements, material models and analysis tools.

Good luck!

Respected Machach Laila, I understand that your doing Pushover analysis for concrete gravity dam by using SAP 2000 software. In this it is necessary to define the plastic hinges. A “plastic hinge” is rarely a “true hinge”, it is a theoretical implementation of a concept to verify weaknesses in a design and to eliminate the most complex issues that can fail a gravity dam.

Kindly go through following references as need. http://www.iitk.ac.in/nicee/wcee/article/13_1823.pdf

https://www.scoop.it/t/civil-engineering-5

https://www.civilax.com/sap2000-tutorials-training-videos-manuals-and-model-files-38-gb/

https://www.researchgate.net/publication/268051954_Pushover_analysis_of_reinforced_concrete_frame_structure_using_SAP_2000

Regards,

Brahma Chari J Kanneganti - KL University.

Go to Define - Section Properties - Link Properties.

Cheers!

Hinge formation is expected at column first, since it is more vulnerable to lateral loading.

attached file depicts pushover analysis of a corroded structure. You can see, hinges are formed only in column. Also, In some papers, I found, beams are considered as elastic element.

Hope this helps.