What should the ideCAD user who insists on rigid analysis do?

[engineer_yildiz]

What should an Idecad user who insists on rigid analysis do? Dear İsmail Hakkı Beşler, Thank you for your reply and comments. I just invite you to think a little more positively. No need to lock threads. Our aim is not to try to upset or offend anyone. I'd appreciate it if you didn't lock the threads. I want to tell you very clearly. We wanted İdecad users to solve the projects they presented with "semi-rigid" analysis with your guidance. But this situation disturbed some idecad users. They insist on making a "rigid" solution. What I want to ask you: What are your guiding instructions to users who persistently want to solve RIGID with the İdecad program? For example: In the rib flooring system, the tooth directions are parallel to the short direction, the balance equations may not be satisfied at the following points, they should or should not, etc. Thank you and have nice work

 

[Ismail Hakki Besler]

Re: What should Idecad user, who insists on rigid analysis, do The rigid diaphragm solution of the IdeCAD Program also works correctly in rib systems. The program warns the user in an unstable situation that it cannot solve and gives the message that the system cannot be resolved. Every project where the analysis is completed is solved correctly. Guide other program users as you would. If you want a semi-rigid solution in rib and cassette systems, you are forcing it. But if they bring the elastic diaphragm (semi-rigid diaphragm) dissolved, that's okay. If you insist on semi-rigid solutions, you are out of regulation, that is, outside the law. The program's own option comes to the users as semi-rigid. Our recommendation is always to guide the elastic diaphragm. Suggest elastic diaphragm solution to all mehndi, no matter what program they use.

 

[Ismail Hakki Besler]

Re: What should Idecad user who insists on rigid analysis do Let you solve a 4 m by 6 m, four columns, four beams, single layer, 7 cm plate thickness ribbed system with another local program and share it here. Write the column direction and dimensions of the system you entered, the beam dimensions, the floor covering and live loads, the wall loads, the floor height, the concrete and reinforcement class, the floor group. Take the ribs in the short direction once, this is a solution, then the ribs in the long direction. Let us solve the system you have defined with etabs, our children. And let them solve it with ideCAD. Then let me interpret the results for you. Let us know the moment value of 1.4g + 1.6g for both long and short beams and write it under this heading. Solve the same system once semi-rigidly with this domestic program. Let's examine the rigid solution and semi-rigid solution results of Etabsin ideCAD and other domestic programs. Rigid solution results will be close in all three programs. Semi-rigid solutions of the same system will also be close to each other in three programs. However, the results of rigid and semi-rigid solutions will differ.

 

[engineer_yildiz]

Re: What should Idecad user who insists on rigid analysis do If a program says "Semi-Rigid behavior gives a MORE ACCURATE result than Rigid behavior" in the User's manual, theory booklet or official forum site, then of course choose a solution that gives more accurate results. should be preferred. The situation is no longer a preference status and becomes a compelling factor. It will be much closer to the current legislation, Science and Art rules. This is true not only for idecad, but also for all programs. The difference of Idecadin from the others is that they are more transparent. It is to inform more users. Program users should use the Forum environment very actively in order to increase their knowledge and use the program more accurately. While making this correspondence with you, we do not think negatively about you, on the contrary, how we can write the questions more accurately so that there is no misunderstanding. We aim to ask questions, we do not intend to question. We can have different ideas (right, more correct, partially correct, wrong, more wrong ideas) on technical issues. The important thing is that you teach with tolerance and we can learn as well. Thank you for your enthusiasm. Best regards

 

[engineer_yildiz]

Re: What should Idecad user who insists on rigid analysis do Dear İsmail, There are valuable articles of our brother Ahmet ÇELİKKOLLU on the Internet. What is your opinion? Rigid diaphragm--semi-rigid diaphragm While idealizing the structural system, it is important to take the diaphragms (floor) rigid or semi-rigid. Taking the diaphragms to be rigid reduces the system period considerably, while the acceptance of a semi-rigid diaphragm causes the periods to be large. This directly affects the magnitude of the earthquake forces in the structure. As can be seen from the spectrum curve as the building period gets larger, the earthquake forces in the structure decrease. As the period gets smaller, the system becomes rigid and the earthquake forces increase. If you accept a rigid diaphragm, the earthquake forces that will occur in the structure will increase. If you accept a semi-rigid diaphragm, the earthquake forces in your structure will be relatively low. It means that the forces will occur. Rather than accepting, it is necessary to accept what the situation is. In the case of semi-rigid diaphragm acceptance, even beam support reinforcements may be reduced by almost half. Because there are less earthquake forces. Therefore, less reinforcement is required. Fully rigid diaphragm In the acceptance, especially the support reinforcements are too much compared to the semi-rigid diaphragm. As it is understood from these articles, the assumptions of full-rigid or semi-rigid diaphragm should not be made unconsciously, the system should be based on whatever it is. It is not possible to always accept a semi-rigid diaphragm just because I use less reinforcement. it is not true. When our earthquake regulation is examined, the phrase "floors that operate as a rigid diaphragm" is constantly mentioned. In other words, the regulation seems to have directed us to it relatively. What we need to decide is in which situation we should accept semi-rigid and in which situation fully rigid. Fully rigid refers to the following. If the slab is fully rigid, the slab moves planarly at the moment of horizontal load without bending and twisting and transfers the horizontal load to other carriers. If the slab is not fully rigid, the slab may bend relatively at the moment of horizontal load, and the force transfer is not fully realized. The prominent element at this stage is In case of horizontal load, the slab bends and bends. That is, in thick slabs, full rigid diaphragm is required. If there are A2 and A3 irregularities, which are considered slab failures, in these cases, semi-rigid diaphragm can be accepted for the relevant places. Besides, in non-beamed slabs, since the slabs are not surrounded by beams, they can easily change shape. Semi-rigid diaphragm can also be accepted in non-beamed floor systems. Besides, in hollow floor systems, the direction parallel to the hollow beams is fully rigid. Because hollow beams provide too much rigidity. However, there is a floor thickness of 5-7 cm perpendicular to the hollow beam beams and a semi-rigid diaphragm can be accepted. Acceptance of fully rigid diaphragm and semi-rigid diaphragm should be made consciously. Semi-rigid diaphragm is not accepted only because the reinforcement is low and the sections that do not save are saved. Or, when you call the software company, they say that the system will be solved by accepting a semi-rigid diaphragm, so it is not accepted as semi-rigid. The engineer decides on this. .If you look at the essence of the job, this is a calculation job. RIGIDITY cannot be divided into TWO AS FULL OR HALF. It is more realistic to use certain ratios in systems most of the time. Let's be careful in choosing a fully rigid diaphragm and semi-rigid diaphragm. Let's not forget that the slab thickness calculation in TS is prepared with fully rigid work in mind. However, if a slab with a thickness lower than the Ts value is to be made, stiffness reduction can be considered (classical slab). As some said, software was not developed in the past, so semi-rigid diaphragms were not developed. The rigid acceptance could not be made. The talk that can be done now does not show the truth. It could be done in semi-rigid, as well as fully rigid, in the past. The important thing is to make the acceptance the way the system will work. That's why I wrote this article... Ahmet ÇELİKKOLLU

 

[Ismail Hakki Besler]

Re: What should Idecad user who insists on rigid analysis do The following items have been copied and pasted from the 2017 earthquake regulations. I know that the 2017 earthquake regulation is an advanced earthquake regulation. I followed its development closely and contributed. In the following cases, a semi-rigid diaphragm (elastic diaphragm) solution must be made. According to the article 3.7.2.2 In buildings where A2 and A3 type irregularities exist, the floor slabs are located within their planes by the vertical carrier system. Two-dimensional sheet (membrane) will be modeled with finite elements to show that it can be transferred safely between Semi-rigid diaphragm (elastic diaphragm) According to 4.5.6.2 According to 3.7.2.2, reinforced concrete slabs in buildings where there are A2 and A3 type irregularities and/or slabs are not intended to function as rigid diaphragms, to include degrees of freedom regarding in-plane displacements The two-dimensional sheet (membrane) will be modeled with finite elements. In this case, three degrees of freedom will be considered at each node. If desired, shell finite elements with six degrees of freedom at each node can also be used, including degrees of freedom for out-of-plane displacements. Semi-rigid diaphragm (elastic diaphragm) 4.5.7.1 As specified in 3A.6.4, all or most of the inertial forces occurring in the upper floors, which are involved in the transition from normal floors to very rigid basement floors, are suddenly removed from the basement It is essential to provide sufficient in-plane rigidity and strength in the floors of transition floors, which have to transfer to the perimeter walls of the floors. According to 4.5.7.2 According to 7.2.2., regardless of the presence of A2 and A3 type irregularities, the floors of the transitional floors will be modeled according to 4.5.6.2 by taking sufficient floor thicknesses. (ie it will be modeled with shell elements) semi-rigid diaphragm According to 7.11.3 In-plane axial and shear stresses in the floors of buildings with and without beams shall be calculated by assuming an elastic diaphragm. (Elastic diaphragm means semi-rigid diaphragm. ) According to article 7.11.4 In buildings with beamed slabs where there are A2 and A3 irregularities where it is necessary to show that the earthquake loads are transferred from the floors to the vertical bearing elements safely, the conditions given in article 7.11.3 will be met for the floors. (Refers to the semi-rigid diaphragm solution. .) Let's come to my thoughts; This regulation is a very accurate regulation that does not leave the engineer in hesitation, and defines very clearly in which cases a semi-rigid diaphragm (elastic diaphragm) should be used. With the semi-rigid diaphragm, the solution gives more sensitive, more accurate and economical results. IdeCAD users can use it with confidence. Semi-rigid diaphragm analysis takes longer and requires more memory than rigid diaphragm analysis.

 

[siromar]

Re: What should the ideCAD user who insists on rigid analysis do Good work The shallowest view in elastic and rigid solution is the logic -Period increases, earthquake load decreases-. Do we stay on the safe side with rigid acceptance just because that's the case, of course not. Unfortunately, this approach also exists in the superstructure interactive solution. The general opinion is that the period increases there, the earthquake load decreases, so we stay on the safe side with the assumption of rigid foundation. Although hundreds of articles have been written on it and the result is always "the necessity and realism of the superstructure interactive solution", unfortunately, with this wrong logic, in the article 16C.1.2 of Tdy 2016, it is recommended that the ground-structure interaction can be neglected on superficial foundations. If we look at the superstructure interactive (ide fixed bed coefficient and allows pseudo-coupled method) - rigid acceptance logic with the same elastic - rigid laying logic, that is, the period lengthens, the earthquake load decreases, and the shallow view... . b) The ground changes the earthquake motion and transmits it to the structures, and this effect can sometimes be in the form of amplification. In addition, if the periods of the structure and the ground coincide, the superstructure is exposed to great stresses due to the resonance that will occur in the structure. c) The ground changes the earthquake motion and transmits it to the structures, and this effect can sometimes be in the form of amplification. In addition, if the periods of the structure and the ground coincide, the superstructure is exposed to great stresses due to the resonance that will occur in the structure. d) Sudden movement of the ground creates inertial forces (inertial forces) in the structure. e) Soil properties change the period and mode shapes of the building. f) In the event that the vertical component of the earthquake affects the structure, we ignore situations such as the structure may move upwards by separating from the ground. In the conclusion part of my doctoral thesis, which I compared 24 models on different floors as rigid foundation - fixed bearing coefficient and variable bearing coefficient, it was seen that the rigid foundation was not on the safe side. Likewise, the assumption of staying on the safe side in a rigid flooring system is definitely wrong. It is up to us Engineers to prefer realistic modeling and realistic analysis.

 

[engineer_yildiz]

Re: What should ideCAD user who insists on rigid analysis do Dear Ömer Özer and all friends who want to help, It is said that the semi-rigid situation is very clearly stated in the new earthquake regulation, which is expected to be issued. Relevant articles of the new regulation are referenced. I am reviewing the regulation as a whole, but it talks about solving semi-rigid slabs where 1) floors with irregularity A2 and A3 and 2) floors in transitional floors and 3) floors are not intended to function as a rigid diaphragm. We can detect the case with A2 and A3 irregularity. We can also detect the transition floor slabs. Well, when I was looking for an answer to the question of "how do we determine the situations where the floors are not foreseen to work as a rigid diaphragm": The new regulation is for the rigid solution: "In regular buildings where there are no A2 and A3 type irregularities and significant in-plane deformations are expected to occur, reinforced concrete floors rigid can be modeled as aperture". In a nutshell:For semi-rigid "Situations where floors are not intended to function as rigid diaphragms" For rigid " regular buildings in plan" where significant deformations are not expected to occur. This means that the slab must not be rigid so that I can determine the semi-rigid behavior with straight logic. The main question I asked myself at that time was "A2 and A3 irregularity and in cases where there is no transition floor slab, which slab types do not work as a rigid diaphragm? How do we determine that it does not work?[/ color]" Is the structure rigid, based on FEMA, be it New Zealand or Malaysia? Or is it semi-rigid? is behaving. It carries out studies that can help engineers regarding this situation. What are you thinking? Thank you and have nice work.

 

[Ismail Hakki Besler]

Re: What should the ideCAD user who insists on rigid analysis do There are two types of statements in the regulation, the first is "will be done", "modelled", "calculated", "provided". Another expression is "can be made" or "modelled". The article 4.5.6.4 you mentioned is a conditional permission article. The situations where you will use the "semi-rigid model" are very clearly given in the imperative mode as "will be done" or "modelled". You can use a Rigid diaphragm model if you conditionally show the Engineer a permit (permitted) "no significant deformation" with the 4.5.6.4 you mentioned. Based on this point, if you solve "semi-rigid" in this case, you will not use this permission and make your calculation with a more realistic method.

 

[engineer_yildiz]

Re: What should the ideCAD user who insists on rigid analysis do General Question: Which types of floors work as rigid or semi-rigid? Reduced Question: In the case of irregularities A2 and A3 and no transitional floor slab; which flooring types work as semi-rigid diaphragms? How do we determine whether it works or not?"

 

[siromar]

Re: What should ideCAD user who insists on rigid analysis do

General Question: Which types of slabs work as rigid or semi-rigid? Reduced Question: A2 and A3 irregularity and transition layer In cases where there is no flooring, which flooring types work as a semi-rigid diaphragm? How do we determine whether it works or not?"

Hello We discussed this issue with Mr. Ismail in the forum before. You can find. Slabs do not work as rigid or semi-rigid. In the literature, there is the term slab rigidity - "rigid diaphragm" if the slab stiffness is much more rigid than the system rigidity, "semi-rigid diaphragm" if the slab stiffness is close to the system rigidity, and "flexible diaphragm" if the slab stiffness is much lower than the system stiffness. The naming of the analysis method in the program should not be confused with the naming in the literature. With the semi-rigid analysis method, you accept that the slabs can displace under their own plane. Any flooring system can be solved with semi-rigid assumption. But not every flooring system should be solved with rigid acceptance. If there is A2-A3 irregularity, it must be solved semi-rigidly. The assumption of semi-rigid slab without rib cassette beams will give more accurate results and should definitely be preferred. My personal preference is always the elastic method. It can be used in two acceptances in plate system and regular structures. I also use semi-rigid in this case. If we make a similarity. In Z1 and Z2, the superstructure interactive solution and rigid foundation acceptance give close results. In Z3 and Z4, however, superstructure interaction is required because foundation displacements can cause serious problems. We can also make another analogy in bar modeling and acceptance modeling in vertical carriers. According to a vertical carrier regulation 40/279, we accept it as a column and it is introduced to the system as a bar element. However, modeling a carrier of this size as a shell will give more accurate results. However, if this size was 30X30, close results could be obtained in rod and shell. Good work Sent via iPhone using Tapatalk

 

[engineer_yildiz]

Re: What should ideCAD user who insists on rigid analysis do Hello, Thank you for your comments. Your comment: "Dslabs do not operate rigidly or semi-rigidly. Slab stiffness - much more rigid than the system rigidity "rigid diaphragm" in the literature "semi-rigid diaphragm" if the floor stiffness is close to the system rigidity "semi-rigid diaphragm" If the floor stiffness is much lower than the system rigidity diaphragm " " So how can we determine the stiffness of the system and the stiffness of the slab? Is there a formulation (You seem to be talking in an intermediate form) Your comment: "Every flooring system can be solved with semi-rigid assumption. But not every flooring system should be solved with rigid assumption. " [color=# FF0000]Would we be more correct to solve a structure that is likely to behave rigidly by solving it semi-rigid? or what would we do?[/color] Your comment: The assumption of semi-rigid slab without rib cassette beams will give more accurate results. Well, on what basis can we say that it gives more accurate results? WE CAN TALK ABOUT THE FOLLOWING TOPICS UNDER ANOTHER TITLE.[/ b] Your comment: If we make a similarity. In Z1 and Z2, the superstructure interactive solution and rigid foundation acceptance give close results. In Z3 and Z4, however, superstructure interaction is required because foundation displacements can cause serious problems. So when you say that foundation displacements cause problems, is it because of the slump values they determined according to the formulation they used in the soil survey report / due to different settlements? Or is it because the formulations used in the references in the ground survey reports are not considered as superstructure interactive?) (Isn't it necessary to specify this situation in the ground survey reports so that the superstructure can be solved interactively?) Your comment: We can make another similarity in bar modeling and acceptance modeling in vertical carriers. According to a vertical carrier regulation 40/279, we accept it as a column and it is introduced to the system as a bar element. However, modeling a carrier of this size as a shell will give more accurate results. However, if this size was 30X30, close results could be obtained in rod and shell. When you say it gives close results, is our reference here a stick model? (Are we doing some kind of Calibration) Shell model solution What should be the optimum preference of the finite element mesh sizes (mesh) in Shell solutions for the closeness of the Rod and Shell results? (The mesh range is a separate detail anyway) Does a 40/279 vertical carrier act like a curtain? Or does it contribute to Alfa s? Thank you for your valuable comments and I wish you a good work.

 

[Ismail Hakki Besler]

Re: What should the ideCAD user who insists on rigid analysis do There are some restrictions in the literature and regulations, especially in steel structures, so that the floor diaphragms can be modeled with "rigid diaphragm acceptance". There is also this verification in ideCAD. You can do these checks and calculate with rigid diaphragm acceptance. This verification was added to the program in versions 5 and earlier, when ideCAD did not yet have the ability to calculate with a semi-rigid diaphragm.

 

[engineer_yildiz]

Re: What should ideCAD user who insists on rigid analysis do

There are some calculations in the literature and regulations, especially in steel structures, for modeling floor diaphragms with rigid diaphragms. There is this check. You can do these checks and calculate with the acceptance of a rigid diaphragm. This check was added to the program in versions 5 and earlier, when ideCAD did not have the calculation opportunity with semi-rigid diaphragm yet.

Hello Mr. Ismail, Do we have a chance to access the information you mentioned? (Is there any explanation and example in the Theoretical principles or user manual of İdecad 5 and previous versions?) I would be glad if you could help.

 

[YasinTezel]

Re: What should ideCAD user who insists on rigid analysis do Hello, the control that Mr. İsmail is talking about is the A2 - A3 report. With this report, a warning is given when the Moment/Strength moment in the slab section investigated for the critical section you will determine in the project is less than the tensile strength of the concrete. The amount of As given as a result of the calculation can be placed above and below the slab section. According to the results of the A2 A3 irregularity report, if additional reinforcement is found in critical slabs, it is concluded that the slab rigidity is not sufficient, and it is appropriate to analyze with the "Semi-rigid diaphragm" option in such structures. In addition, you can always find a solution with a semi-rigid diaphragm, without the need for any such inspection. For example, in the attached project, we received two separate reports by making the thickness of the D7 slab 8 cm and 12 cm. Plan view D7 Floor 8cm thick A2 - A3 control report D7 Floor 12cm thick A2 - A3 control report Result of the A2 - A3 control report When the floor thickness is 8 cm, it can be concluded that the structure cannot behave in accordance with the fully rigid diaphragm assumption, and a solution can be made with the "Semi-rigid diaphragm" model. . In the plan mentioned in Articles A2 and A3 of the Earthquake Code, there are local floor gaps that make it difficult to transfer the earthquake loads to the vertical structural system elements, Both the dimensions of the protruding parts in two perpendicular directions in the building floor plans are more than 20% of the total plan dimensions of that floor of the building in the same directions. in case it is larger (Figure 2.3). A semi-rigid diaphragm solution is required.

 

[engineer_yildiz]

Re: What should ideCAD user who insists on rigid analysis do Thank you Mr. Yasin for your help. The A2 and A3 irregularity control you mentioned is also available in these versions. İsmail Bey talked about 5 and previous versions. İsmail Bey is talking about something different. I wish you good work.

 

[Ismail Hakki Besler]

Re: What should ideCAD user who insists on rigid analysis do

There are some calculations in the literature and regulations, especially in steel structures, for modeling floor diaphragms with rigid diaphragms. There is this check. You can do these checks and calculate with the assumption of a rigid diaphragm. This check was added to the program in versions 5 and earlier, when ideCAD did not yet have the option to calculate with a semi-rigid diaphragm.

[color=#FF0000 ]You DON'T READ or UNDERSTAND WHAT YOU READ.[/color] "ideCAD also has this verification" and I said "It was added to the program in versions 5 and before" I asked Yasin to prepare it Yasin Tezel is in charge of ideYAPI AŞ Technical Service.

 

[engineer_yildiz]

Re: What should ideCAD user who insists on rigid analysis do Everyone's writing is valuable and I read it. We try to understand what we read. I try not to be offensive while making sentences. If the sentences made in the communication have started to be offensive, either the subject has started to disturb one of the parties or it is due to the lack of self-criticism. Is it your attempt to be offensive, Mr. Ismail, so that we do not ask you any questions?

 

[Ismail Hakki Besler]

Re: What should ideCAD user who insists on rigid analysis do There is no offensive expression in any of my sentences. I told you the situation, either that or that. The size and position of ideYAPI AŞ today is known by everyone that I, as the owner of the company, value the users and my ability to self-criticize. But you can be sure that I will take into account what you say and make even more self-criticism.

There are some calculations in the literature and regulations for modeling floor diaphragms with rigid diaphragms, especially in steel structures. There is also this verification in ideCAD. You can do these verifications and calculate with rigid diaphragm acceptance. ideCAD was added to the program in versions 5 and before, in versions where it did not have the ability to calculate with a semi-rigid diaphragm.

I wrote you

Yasin, thank you for your help. The A2 and A3 irregularity control you mentioned is also available in these versions. İsmail Bey talked about 5 and previous versions. İsmail Bey is talking about something different. I wish you good work.

you wrote. Did you read my post? "Yes" or "No" If your answer is "Yes" Got it? Thanks good work. Definitely keep writing. Ask a question, comment. But let me decide for myself what to say and how to act. More than 6000 Civil Engineers follow this forum. They decide whether I'm being offensive or not preventing you from asking questions.

 

[engineer_yildiz]

Re: What should ideCAD user who insists on rigid analysis do

[color=# FF0000]You do not read or understand what I wrote.[/color]

We will continue to ask in a polite and tolerant manner and expect answers in the same manner.