New Earthquake Regulation 2018 Retrofit

T

teknoadam

New Member
Dear idecad employees and users. I would like to share with you a question that stuck in my head. I want to benefit from your experience. Tbdy2018 says that you will design and evaluate existing buildings as SGDT in table 3.4. Only when I opened chapter 15, the design general rules say that you can subject existing structures to linear or non-linear performance analysis. What are your views on this subject? I felt a confusion. My second question is -- for example, I wanted to analyze a building according to şgdt. First of all, after making a linear analysis in such a way that the building will carry its own weight without earthquakes, after entering the existing reinforcements, I saved my project and made the necessary jacket or g. Wouldn't it make more sense if I switched to nonlinear analysis after I dropped my curtain? Thus, I have designed my existing building according to its strength, and I have made my analysis according to the shape change after throwing my reinforcement curtains
 
I bought that book for 1 month, Mr. Ismail, because of the things I wrote above in that book, I couldn't get out of it. Even prof. I asked Dr. Nuray the exact same thing. "Mr. Nuray says sgtd evaluation in table 3.4, but in section 15 he says you can do linear or nonlinear analysis" I said and he said "you will take nonlinear analysis from linear analysis". That's why I have a question mark in my mind that I should choose the analysis method as in the 2nd question I asked above.
 
I - If you are designing a new building, you can only calculate based on strength in the following structures: A) For BKS=2 and BKS=3, Hn<=70 m and 105 m height structures Houses, For workplaces, hotels, shopping centers, sports facilities, cinema-theatre-concert-class buildings, it is not necessary to calculate according to deformation in structures up to 70 m and 105 m high depending on DTS (Earthquake design class). B) For BKS=1 Hn<=42 m to 56 m height structures For hospitals, dispensaries, health centers, fire brigade buildings and facilities, schools, dormitory and dormitory class buildings, depending on DTS, in structures up to 42 m and 56 m high It is not necessary to calculate according to shape change. In structures other than these structures and in structures with BYS=1, it is obligatory to calculate according to strength together with deformation. II - Rules for previously constructed structures to be strengthened According to the 15th section of the Regulation: A) 15.5.3 Application limits of linear calculation methods This article explains the conditions under which linear performance analysis will be carried out. Linear performance analysis is a calculation method that also exists in the 2007 regulation. You do not need to make nonlinear calculations for structures that comply with these conditions. B) The application limits of nonlinear calculation methods are explained in detail in Article 5.6 of the Earthquake Code. It is obligatory to make non-linner calculations for the structures that do not comply with the conditions explained in 15.5.3.
 
Dear Teknoadam, I will write briefly because I am abroad and there is a time difference. If you want, I will write in more detail when I return to Turkey next week. According to Table 3.4, analysis according to SGDT is required for all current situation analysis and reinforcements. However, there is the possibility of linear analysis if the above-mentioned conditions are met in chapter 15. In this case, the analysis is performed again according to SGDT, but with linear analysis without non-linear analysis, plastic rotations and displaced rotations can be calculated from floor drifts and rotations as described in Annex A of Chapter 15. This is what Nuray Hodja means. From here, again, there are elongations on the outer surfaces of the reinforced concrete elements with geometry. The calculated elongations are controlled by the limit elongation values given in sections 5 and 15. In addition to these, interruptions are controlled again. However, linear calculation criteria are very open to interpretation. Because beam echoes are not possible to detect in an existing structure. This can lead to abuse or force nonlinear analysis directly.
 
thanks for the answer. Frankly, I did not fully understand what kind of path we will follow in analysis programs. For example, let's say we don't know the current equipment of the building. At first, we used to make earthquake-free analysis and equip the building to carry its own weight, then after meeting the need for new materials, namely reinforcement or jacket, we entered the normal building values and analyzed. now, in the new directive, it says şgdt in table3.4, and in chapter 15 it talks about the possibility of making linear. That's when I thought of this too. I first calculate my building with the linnet analysis method and place the necessary equipment. then the needed mantle and g. After I put my curtains in my model and show them as new elements, this time I choose my calculation method as nonlinear and see if my building performance target is met according to nonlinear. This is how I understood what my teacher nuray told me, I wonder if I understood it wrong.
 
Dear Teknoadam, No teacher can or will answer your question. The reason is that it is not correct to apply the method you explained to determine the reinforcement of the existing structure. First of all, it is necessary to determine the current situation analysis or the concrete, reinforcement, ground, load information of the structure to be strengthened. Unfortunately, it would not be a right move to design and equip an existing building like a new one. Existing equipment needs to be determined by methods such as stripping and x-rays and entered into the building one by one. Older buildings often have less reinforcement than regulations. Even in the 1975 regulation, the minimum column reinforcement ratio was 0.08. In 1998, this ratio increased to 0.01. However, in old buildings, we encounter reinforcements between 0.004 and 0.07. On the curtains, the situation is even worse. Designing a new building means discarding reinforcements according to current regulations. This will get you wrong in determining the performance of the building and therefore strengthening it. Not only the reinforcement ratio in the new regulation, but even the placement of the reinforcement affects the result. As a result, I cannot recommend you to detect existing structural reinforcement by analysis. If you have any questions about the future, I will be happy to answer them.
 
Thank you for your attention. I think I misunderstood something, I did it on the assumption as an example. In the old earthquake regulation, it is written in section 7, new dy and section 15 how many strips we will make from beams or columns and in how many of the remaining elements we will determine the reinforcements with the reinforcement scanning device. In the new direction, I think the number of cover stripping has been reduced a little bit. what I mean is that we can't always get complete data from the field. In the light of this limited data, we manually enter the equipment of our building. but we have to use the equipment provided by the program for the equipment that we cannot find in the field. For example, in support reinforcements, of course, we do not break or scan and detect each beam, for this we use the reinforcements provided by this program, and we do it in such a way that it can carry it under its own weight. Obviously this is how I know it's done. And what I really want to know is can I do linear analysis as preliminary design and then finish with nonlinear analysis. For example, in table 3.4, it says to make dgt as a preliminary design at dd2 earthquake level in table b. like saying then design with shgdt.
 
Mr. Technoadam, you are right about the beams. This is what I meant in my previous answer, when I said that it is not possible to detect the ECHO of the beams. For beams, it is not possible to detect reinforcement by stripping or x-ray from the lower middle region of the beam. It just gives an idea. What is generally done here is to accept the minimum reinforcement and increase the supports to carry the vertical load (if no vertical load-induced damage is detected on the beams). This is an option currently available in idestatic. I think this option will remain active in 9 versions because it is a useful application. However, I cannot say the same for columns and curtains. Detection is required. If something like a worst pre-inspection is being done, minimum reinforcement (minimum of time) can be taken. However, I do not find it right to discard the reinforcement by making a new design according to the 2007 regulation or the 2018 regulation. Makes it wrong.
 
Hello Mr. Suat, I saw this forum while I was searching for a topic related to the EKO account. In terms of the calculation logic of both TBDY 2018 and IdeCAD, I would like to ask at which point of the cross section the ECO calculation is made. EKO=Section moment / section moment capacity The section moment capacity is different for columns (because the axial force changes) at the top and bottom points. The calculated moment also varies along the section. Although there is no axial force for the beam, the ECHO value will be different at different points of the columns and beams (assuming we can detect the reinforcements) because the calculation moment in the section changes along the section and the span/support reinforcements are different. Logically, it can be called a critical section, but I think that in a situation where both moment and moment capacity change, it cannot be predicted which point will be critical. As a result, when performing ECO control in linear analysis, it seems that it is not very clear at which point the section should be calculated.
 
Hello there; I would like to answer your question about the eco account. Finite element solution is used in the program. When any column or beam is entered, they are defined as rod finite elements, and when slab or curtain is entered, shell finite elements are defined. Now let's talk about rod finite elements for ECO control. As you know, ECO is the Impact/Capacity ratio. For performance evaluation in TBDY, it is made according to the results of the joints at the ends of the elements. For this reason, when performing the performance analysis, the points where the joints can occur, that is, the two ends of the elements are taken into account. The most negative situation is shown in the reports by looking at the individual reinforcement conditions and the internal force conditions of the two ends where plastic hinges may occur. Different parts of the echo beams will take different values due to the different reinforcements and forces. However, all of these values are calculated according to all combinations and the design or performance is given according to that situation. In addition, due to the difference in upper and lower reinforcement in beams, capacity changes in different directions are also taken into account. This only applies to performance analysis. In the DGT approach, what you said above (span support reinforcement difference, normal force difference) should be taken into account for the whole section and is taken into account. Here the rod finite elements are segmented and split into stations. Reinforcement status and internal force status differ at each station, so control is carried out at all stations. In other words, if a column element has 7 stations, the internal forces and reinforcements at the 7 same points in this column are evaluated according to all combinations. Since the reinforcement situation at 7 points, the axial force and the biaxial bending situation differ, different results are calculated for each station and the design is made according to the most unfavorable situation. Best regards...
 
Thanks for your answer, it was enlightening enough. In other words, IdeCAD takes into account all the necessary combinations. In summary, for the performance calculation, at least 4 ECHOs in both directions (XY) at the bottom and at the top, and if it is calculated in the beams, again in both directions and in both directions, and 2 supports, a total of (at least) 2 directions x 2 Directions x 3 I understand as cross section = 12 ECO is calculated. I think the most critical ECO's should be taken into account in determining the average ECO values of vertical elements scaled by shear force and beams' average ECO values specified in the application limits of linear calculation method (15.5.3.1) of the regulation. Should we consider the largest of these 4 or 12 ECHOs calculated for each element, given that it is the most critical situation for any section to have an effect far above its capacity? Thanks
 
Hello there; When looking at the ECO values, it is necessary to take into account the earthquake in the relevant direction. For example, when considering the beams in the X direction, the ECO value should be calculated according to the effects of the G+0.3Q+Ex and G+0.3Q-Ex earthquakes. For beams in the other direction, earthquake effects in the other direction are taken into account. This is not the case for the columns, because they have a three-dimensional interaction curve and their capacities are subtracted according to the N-M2-M3 situation. In other words, there are 4 ECO values for G+0,3Q+Ex in the X direction, 2 for the shear force and 2 for the bending moment. These echo values are formed by considering the reinforcements in the relevant direction (such as the difference between the beams and the reinforcement). Since different ECO values will be obtained for each combination, all of these results are analyzed separately. To give another example, columns may have different shear strengths in different directions. (Due to differences such as slip area, number of stirrup arms...) Here, too, the relevant shear force and shear capacity in the relevant direction are taken into account. Best regards...
 
Hello, are the limit values specified in the cde clauses of article 15.5.3 also valid if the structure is formed after reinforcement is made? Something like this happened in the project I was working on.
 
"Abdullah Uzun":1z0z57il" said:
Hello, are the limit values specified in the cde clauses of article 15.5.3 also valid if the structure is formed after reinforcement is made. In other words, this check is done before or after the retrofit. If it provides, linear method can be used. If it does not, non-linear method is used. Sent from my SM-G973F using Tapatalk
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