Article 4.3.4.6 Control * IMPORTANT EXPLANATION *

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Ismail Hakki Besler

Administrator
With the article 4.3.4.6 of the regulation, it is stipulated that the sum of the overturning moments caused by earthquake loads on the walls shall not be less than 75% of the total overturning moment occurring at the base due to earthquake loads for the whole building. The tipping moment calculated for the entire structure can be calculated equivalently or dynamically while applying this clause. There may be a difference of 10% between the two accounts. However, the most important situation here is the contribution of the walls to the total overturning moment of the building, especially in low-rise and flat structures, due to the normal force they take as they move away from the building centre. When the calculation is made as stated in the regulation, it becomes almost impossible to meet the 0.75 condition due to the axial forces of the curtains away from the center. In order to meet this condition, it is necessary to take the shear force contribution of the beams connected to this wall from the rigid direction. But the regulation does not say that you can do so. In order to provide this condition, it is necessary to add the Moments created by these normal forces (shear forces of the beams stuck in the wall) to the shear overturning moments. This is how ideCAD calculates the overturning moment of the tie-beam wall, which meets the degree of attachment requirement for shear walls. The regulation already calculates the overturning moment of the curtains with tie beams. However, it alone takes care of the overturning moment that occurs at the base of the walls in the walls where the beams that are not in the nature of tie beams are stuck. In Regulation 4.3.4.8 Mdev shall be calculated according to 4.5.3.7(d) or 4.5.3.8(c) for shear walls, and 4.5.4.3 for sheaths with tie beams (with spaces). If the total overturning moment M0 resulting from earthquake loads for the whole building is 4.7, 4.8.2 or 4.8.3, it will be obtained according to 4.7, 4.8.2 or 4.8.3. As such, ideCAD calculates correctly as the earthquake regulations say. In the attached project, almost all of which are curtain walls, the rollover control remains at 0.71 in the X direction. The reason is the normal forces of the curtains on the side to tip over. In the following project, 25x25 was chosen so that the columns do not contribute to the overturning of the system. In this system, the tipping moment rate is only 71%. The ratio will be even smaller when the columns are entered in reasonable sizes. When 50x50 columns are entered, Mdev/m0 decreases to 0.55. ideCAD Etabs comparison
 
Re: Important explanation about the control of Article 4.3.4.6 Everything came together due to the vague and incomplete statements in the regulation. According to what you wrote, it is almost impossible to solve a building as a hollow system or a mixed system. The structure turns into a tunnel form system.
 
Re: Important explanation about Article 4.3.4.6 Control There is no need to deal with complex projects to interpret the regulation. Almost all of the project I put the picture of is the curtain. In this structure, the ratio is 0.55 and this value gives this result both manually and with foreign origin programs. In this state of the regulation, when you create a group of curtains in the middle in the form of core proligon curtains, you come to the point where the regulation wants to be made and you easily meet the conditions. But for the mixed system, the 0.75 condition is mandatory.
 
Re: About Article 4.3.4.6 Control * IMPORTANT EXPLANATION * I tried to explain why the 75% requirement is not met in the moment of revolution investigation, with the simplest possible example. There are two simple projects. There are only two curtains in the system and there is a beam between them. In the first system, the beam can meet the 25/100, that is, the tie beam condition, whereas in the other system, the beam does not meet the 25/50 bond beam condition. In the example below, the tipping moment ratio is expected to be 100% in both projects by our users. The system on the left is Mdev/Mo 100% The system on the right is Mdev/Mo is 79% Because the earthquake code requires us to calculate the overturning moment in two different ways in both systems. In Regulation 4.3.4.8, Mdev shall be calculated according to 4.5.3.7(d) or 4.5.3.8(c) for walls without gaps, and according to 4.5.4.3 for shears with tie beams (with gaps). If the total overturning moment M0 resulting from earthquake loads for the whole building is M0, it will be obtained according to 4.7, 4.8.2 or 4.8.3. 25/100 beam system satisfies the 1/3 condition 1/3 system meets the rollover rate 100% 1/3 system fails the rollover rate 79%[/ b] As per the regulation, it is very difficult to meet the 75% requirement. Almost impossible.
 
It seems that the calculation method has changed with 10.05. While the project in my hand was Mdev/ M0= 0.95 in 10.03, I think the reason why the result is 0.06 now is the gradual basement. For example, if the 1st basement is 2500m2 (if 2000m2 is completely curtained, 500 m2 is just columns) and to the 2nd basement, this 500m2' (only the column consists of the walls, except for the walls where the level is formed) is given by the ide M0/Mdev= I understand that a value close to 0 will come out.
 
"Ismail Hakki Besler":1dpjkqkk" said:
Another simple example is just curtains used Mdev/Mo X direction 0.81 Y direction 0.52 X direction but it meets the 75% condition
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There is also a complete logic error here. When we consider the Y direction, the walls took 52%, but what happened to 48%? It is not possible to say the short edge effect of the walls in the X direction. Did the building grind the 48% tipping moment inside itself? In this system, the result should have been 100% in both directions. same as in alfas Total shear force = total shear to the walls + alphas to the columns = total shear force that the shear walls meet / Total shear force to the building In TBDY 2018, too, Total overturning moment = to the walls + Mdev/Mo to the columns = total sheared by the walls tipping moment / The building must have a total tipping moment, in this system there is no column and the result is 1. Keeping the mind
 
"siromar":3igm9q5i" said:
Considering the Y direction, 52% of the curtains were taken, but what happened to 48%? It is not possible to say the short-edge effect of the curtains in the X direction. Did the building grind the 48% tipping moment inside itself? [ /quote] This balance is as follows: Mo = MDev of columns + Mdev of walls + Normal forces of columns x distance to center of gravity + Normal forces of walls x distance to center of gravity Mo is not just the sum of shear and column overturning moments.
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We always use hollow floor tiles in Bodrum Bodrum. At this rate, it was understood that we would not be able to put a column in the building. We're going to have to create curtains entirely.
 
I don't know when there will be additional article on this subject, but in the next version of the Idea, under "General parameters" or in "analysis settings" "Consider the contribution of the shear forces caused by the earthquake at the ends of the beams stuck in the plane of the shear walls in the calculation of bending moments at the wall base" I think there should be an option. I think that it is of great importance for the user that ide puts such options where the regulation is unreasonable.
 
The article on this subject is very vague. In the article below, the regulation clearly says not to take these shear forces, except for curtains with tie beams that meet the 1/3 requirement. Clause 4.3.4.8 Mdev shall be calculated according to 4.5.3.7(d) or 4.5.3.8(c) for shear walls, and 4.5.4.3 for sheaths with tie beams (with spaces).
 
however, the 2nd basement of the project I sent in the attachments is gradual and the 2nd basement floor is not rigid. Therefore, I think that the fact that Mdev/Mo stays at 0.06 levels is due to the calculations of buildings with stepped basements. Because when I accept the 2nd basement as rigid, it comes to 0.5 levels of Mdev/Mo. The reason why Mdev/Mo decreased to 0.5 while alphas was 0.97 is due to not taking into account the contribution of shear forces from earthquakes at the ends of beams that are stuck in the plane of the shears mentioned by İsmail Bey.
 
Total shear force of floors = total shear force of walls + total shear force of columns Total overturning moment of floors = MDev of columns + Mdev of walls + Normal forces of columns x distance from center of gravity + of walls Normal forces x Distance from center of gravity Earthquake regulation only takes into account the part shown in red in curtains with tie beams that meet the 1/3 condition. It never takes into account the part shown in blue.
 
Since I do not have the program, I could not test it, but I would like to ask this. What I understand from the language of the regulation: Most rules prepared with orthogonal in mind... (0º and 90º ) Should components be considered in an element placed at an angle? (It should be taken according to me) When calculating the contribution of an element whose earthquake directions are defined as 0º and 90º in the program... to the floor shears or the floor overturning moment, for example, is the X and Y components of this element differentiated?
 
Yes, the code generally describes situations where all columns are rectangular, with all elements either in the exact X direction or the full Y direction. How to calculate intermediate angles or geometries such as polygon columns etc. is not clearly specified in most places. The current Mdev calculation in ideCAD is made by considering the global axes moments of the curtains. In other words, the components are taken into account. However, if the curtain is not in the earthquake direction related to a certain margin, the effects of that curtain are not included in the calculation of Mdev. In other words, the curtains standing vertically or close to vertical in the plan do not enter the total Mdev calculation in the X direction. By the same logic, horizontal or near-horizontal curtains do not enter the Y direction total Mdev calculation at all. P01 , P03, P05 and P06 enter Mdev account in both directions.
 
However, if the curtain is not in the earthquake direction related to a certain margin, the effects of that curtain are not included in the calculation of Mdev.
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Is there any concrete value regarding this boundary? how many degrees? or more accurately "If the X component is less than 20-30%, the element is considered in the Y direction" what is our limit?
 
30 degrees for now. In other words, in X direction control, if the angle of the press with the horizontal is less than or equal to 30 degrees, it is taken into account in the X direction, if it is greater, it is not taken into account. The same logic applies to the Y direction.
 
hello, the total overturning moment (Mo), which I understand from the regulation, is obtained by multiplying the shear force on each floor by the height from the base of that floor and then summing them up. Can we see it this way in the reports, just like in the alfas calculation, for each floor separately or is the program calculated this way? B.C
 
"inş.müh":1h2tf2qb" said:
hello, as I understand from the regulation, the total overturning moment (Mo) is obtained by multiplying the shear force on each floor by the height from the floor of that floor and then adding them together. It can be seen in reports like this in the alphas calculation. Can we calculate separately for each floor or is the program this way? 4B.7) and combines the mode contributions of these quantities according to 4B2.4 For example, the X direction for the nth mode More specifically, the modal layer shear force for each mode is obtained from the product of the following quantities: Vtxn = mtxn x SaR x Tn Vtxn = Base shear force modal effective mass x reduced design spectral acceleration x Vibration period Overturning moment for each mode is also k of the Vtxn value of each floor as shown in the formula It is obtained by multiplying and adding together the horse jeans. These values calculated for each mode are combined according to 4B2.4. As of v10.05 we give the combined values. These values calculated for each mode will be published in future versions.
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