4.7.3.1 - 4.7.3.2 - 4.7.3.4 about period values

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etriye

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The existence of the construction period in article 4.7.3.1 of the regulation, and the limitation in articles 4.7.3.2 and 4.7.3.4. Are the modal analysis values in the account outputs controlled according to the formulas given in the regulation articles? I could not find it, I would be glad if you inform me about it.
 
Re: 4.7.3.1 4.7.3.2 About 4.7.3.4 period values Section 4.7 of the regulation describes the calculation according to the equivalent earthquake load method. It says in 4.7.3.1 unless a more precise calculation is made for Tp. ideCAD makes exact calculations for Tp. In 4.7.3.3, on the other hand, it gives a much simpler formula for low-rise buildings and says you can use this formula if you want, for Tp. Therefore, when calculating the equivalent earthquake, you find the Tp value as a result of the dynamic analysis. Since ideCAD calculates according to the mod combination method (section 4.8), the items you wrote are also not valid. LD
 
Re: 4.7.3.1 4.7.3.2 About 4.7.3.4 period values There are two main headings related to earthquake calculation in TBDY; Section 4.7 is the Equivalent Seismic Load Method and Section 4.8 is Modal Calculation Methods. The equivalent seismic load method is based on finding the equivalent seismic loads acting on each floor (ie mass) using the building's natural vibration period, storey masses and indirectly horizontal translational stiffnesses. In order to find the numerical values of these equivalent forces, the period of the structure must be known. The period of the structure is also found using Equation 4.26 in Section 4.7.3.1. Modal Calculation Methods ideCAD uses "Mode Combination Method" (or Response Spectrum method) in Earthquake Calculations. Details of this method are given in TBDY Annex 4B.
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. The period calculation (for X and Y directions) used in the equivalent earthquake load actually corresponds to the 1st and 2nd modes of the structure calculated using the mode combination method. The formula in Section 4.7.3.1 is also obtained by finding the 1st vibration mode in the mode coupling method. However, this may not always give accurate results. For this reason, the earthquake code has brought certain restrictions on the use of the equivalent earthquake load method. Because different internal forces can be seen in structures under the influence of higher modes. For example, the "additional equivalent earthquake load" value described in Section 4.7.2.2 is actually an approximation of the effect of higher modes. To summarize, the period calculation used in TBDY Section 4.7.3.1 is made only when the equivalent earthquake load method is used. Best regards...
 
Since we have enlarged the modal analysis results according to the equivalent base shear force (item4.8.4), these periods are actually used indirectly in the modal analysis, in a way. In this respect, it is important to calculate the equivalent earthquake load correctly. even if the modal analysis is performed, which must comply with the specified conditions. While analyzing with American programs other than idecad, you can calculate this TPA value itself, and you can write it manually. When it calculates itself, you can see that value and check its accuracy. I don't know what this situation is in idecad.
 
You registered to the forum at 10:39 today and wrote this message at 10:44. We look forward to your suggestions and contributions to the forum with curiosity and impatience. By the way, if you are not a user, you can download the demo program and make your determinations on purpose, without any apology, as you wrote in your next messages what is the situation in ideCAD .
 
"Muhendis30":2mdes84j" said:
Since we have enlarged the modal analysis results according to the equivalent base shear force (item4.8.4), these periods are actually used indirectly in the modal analysis, in a way. It is important in this respect that the equivalent earthquake load is calculated correctly. compliance with the specified conditions Even if the necessary modal analysis is made. When analyzing with American programs other than idecad, you can calculate this Tpa value itself and you can write it by hand. When it calculates it itself, you can see that value and check its accuracy. I don't know what this situation is in idecad.
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TBDY when modal analysis is applied Magnification of Reduced Internal Forces and Displacements according to Equivalent base shear force is done in the program according to Section 4.8.4. You can see the amplification factor given in Equation 4.31 in the dynamic analysis report in ideCAD v10. The design forces of all elements are enlarged with this dynamic amplification factor.
 
"oguzcan":3f367ycx" said:
"Muhendis30":3f367ycx" said:
Since we enlarged the modal analysis results according to the equivalent base shear force (item4.8.4), these periods are actually used indirectly in the modal analysis, in a way. In this respect, it is important to calculate the equivalent earthquake load correctly. even if the modal analysis is performed, which must comply with the specified conditions. While analyzing with American programs other than idecad, you can calculate this TPA value itself, and you can write it manually. When it calculates itself, you can see that value and check its accuracy. I don't know what this situation is in idecad.
Click to expand...
When modal analysis is applied, according to TBDY Section 4.8.4, magnification of Reduced Internal Forces and Displacements according to Equivalent base shear force is done in the program. You can see the magnification coefficient given in Equation 4.31 in the dynamic analysis report in ideCAD v10. The design forces of all elements are increased by this dynamic amplification factor.
Click to expand...
actually what I meant was that Tpa is also effective in modal analysis indirectly. since we consider the period limitation when calculating the equivalent earthquake load. I used versions up to 8.62, I already know that it increases, I said I don't know if idecad allows writing the limit status of the new regulation 10
 
Hello there; I would like to make one more clarification for TBDY Equation 4.26. In Article 4.7.3, unless a more precise calculation is made, the natural dominant vibration period of the building will be calculated by Equation 4.26. Here, what is meant by a more precise calculation is the period calculation found by dynamic analysis. The period calculation Tpa in TBDY Section 4.7.3.4 is only an empirical relation applied without making detailed calculations based on the height of the building. When the conditions in Section 4.7.3.4 are met, the natural vibration period of the building can be accepted as this empirical equation. However, in ideCAD v10, the period and the earthquake calculation related to it are made with the mode combination method, which is one of the dynamic analysis methods that are calculated precisely and the period is calculated according to this method. Best regards...
 
Thanks for your answers, it is once again revealed that the articles of the regulation should be written a little more clearly and clearly. It would make even more sense if he stated that when he said a more precise calculation (modal analysis -ztaa )
 
One of the most clearly written articles of the regulation is article 4.7.3.2; In this article, he clearly states Equivalent.(4.26). The limitation is only valid for the approximate calculated period according to clause 4.7.3.2. ideCAD makes the earthquake calculation as written in the regulation and prints the necessary information.
 
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