Soil safety stress is negative how to design a foundation

[batuhann28522]

Re: How to design a foundation with negative soil safety stress

Analysis settings of the two projects you added are not the same. [ /i][/b] Soil class, Structural system behavior coefficients, etc. In addition, in the project named "KADİR AKGÜN STATİK.ide10", Earthquake Ground Motion Level DD4 was selected. For buildings with BKS=3, earthquake ground motion level was selected as DD2 and TBDY 2018 wizard was run accordingly. Comparison of two projects Analysis settings, load-bearing system and loads must be exactly the same. Note: The flooring type must be selected in the project, unidirectional gear flooring. Curtains Item 4.3.4.6 Does not meet the condition TotalMdev>0.75Mo. Curtains must be added to the system. Good work

Thank you for your reply and interest, but when I do the checks and enter the same analysis values, the results are not the same. I don't know if I drew your attention in the file named Project, but in a few columns equipment can help a lot are you ok?

 

[servany2]

Re: How to design a foundation with negative soil safety stress

The two projects you added Analysis settings are not the same. [/b] Soil class, Structural system behavior coefficients etc. In addition, in the project named "KADİR AKGÜN STATİK.ide10", Earthquake Ground Motion Level DD4 was selected. For buildings with BKS=3, select earthquake ground motion level DD2 and edit the TBDY 2018 wizard accordingly. Comparison of two projects Analysis settings, carrier system and loads must be exactly the same. Note: Floor type unidirectional gear flooring should be selected in the project. The curtains in the project do not meet the condition of Article 4.3.4.6 TotalMdev>0.75Mo. Curtains must be added to the system. Good work

Thank you for your reply and interest, but when I enter the same analysis values when I do the checks, the results are not the same. I don't know if I have caught your attention in the file named Project, but can you help a lot with reinforcement in a few columns.

I'm not on PC

 

[batuhann28522]

Re: What kind of foundation can I design when the soil safety stress is negative

I'm not on pc I got a pursantaj 0.03. I have that problem on my 3rd floor, although it appears normally on other floors, I can't fix the reinforcements on those 3 floors.

 

[servany2]

Re: What kind of foundation can you design a foundation if the soil safety stress is negative

I'm not on PC I couldn't look at the project

I got a max pursantaj 0.03. I have that problem on my 3 floors, although it appears normally on the other floors, I can't fix the fittings on those 3 floors. Thank you.

Levent, correct the mistakes he said, first add curtains to the system as far as I understand, you get the maximum pursanaj error or this value is already the maximum value in the program, this means that your columns are too hard, increase the sections, you can add curtains to these columns by removing them You also mentioned Ta and Tb values, if you examine the new regulation, the spectrum curve is formed dependent on many parameters. I hope you have your ground survey and coordinates in accordance with the 2018 regulation, by the way, the ground safety stress has been lifted, don't skip this part, good work.

 

[batuhann28522]

Re: The ground safety stress is negative, how can I design a foundation

I got a max pursantaj 0.03. I have that problem on 3 floors, although it is normal on other floors, I cannot fix the reinforcements on those 3 floors. I would be very happy if you could help me when you can look the same. Thank you.

Mr. Levent, correct the errors he said, first add curtains to the system as far as I understand, you get the maximum pursantaj error or this value is about 3% in the maximum value program, this means that your columns are having too much difficulty, increase the sections you will add to the curtains. You can overcome these columns by removing them and adding curtains in their places. Also, you mentioned Ta and Tb values, if you examine the new regulation, the spectrum curve is formed dependent on many parameters. I hope that you have the ground survey and coordinates in accordance with the 2018 regulation, by the way, the ground safety stress has been removed, do not skip this part, good work[/quote] When the floor safety stress is lifted, I don't understand it though?

 

[unver]

Re: How to design a foundation with negative soil safety stress Hello

I didn't understand when I said the ground safety stress was lifted, but ?

Soil bearing strength instead of ground safety stress in TBDY2018 This is approximately 2.5 times more than before. Soil bearing capacity will be entered into the program. Ünver ÖZCAN

 

[yavuz statik]

Re: How to design a foundation with negative soil safety stress WE USED FLOOR CARRYING POWER INSTEAD OF GROUND SAFETY. GROUND SAFETY* 2.5= GROUND BEARING POWER HAS BEEN BOUND BY HOW A CHANGE HAS BEEN MADE TO THE GROUND AND LOAD ACCOUNT IN THE DEPRM ACCOUNT.... ALİ YAVUZ

 

[yavuz statik]

Re: How can I design a foundation with a negative ground safety stress

Hi

I didn't understand that when I said the ground safety stress was lifted, but ?[/quote ] In TBDY2018, ground bearing force is used instead of ground safety stress. This is about 2.5 times more than before. Soil bearing capacity will be entered into the program. Ünver ÖZCAN

WE USE GROUND CARRYING POWER INSTEAD OF GROUND SAFETY. GROUND SAFETY* 2.5= GROUND BEARING POWER IS BEING HOW CHANGES WERE MADE TO THE GROUND AND LOAD ACCOUNT IN DEPRM ACCOUNT BASED ON THIS. IT IS NOT POSSIBLE TO DESIGN THE FOUNDATION WHEN ANALYSIS IS DONE. ALI YAVUZ

 

[servany2]

Re: How to design a foundation if the soil safety stress is negative In the past, the soil bearing strength was found and divided by the safety factor, the safety stress was found, now the soil bearing capacity is found and divided by 1.4 this is the only difference

 

[yavuz statik]

Re: How to design a foundation with negative soil safety stress We are now analyzing according to the value we entered as 20 t/m2 in the past, 50 t/m2 or more. we need to reduce our foundation sizes a lot

 

[servany2]

Re: How can we design a foundation if the soil safety stress is negative First of all, our soil bearing capacity has increased. We can use any type of foundation we want by providing security and security. You always made it, I made rafts.

 

[yavuz statik]

Re: How can we design a foundation with negative soil safety stress

First of all, our soil bearing capacity has increased. I don't think it's the right approach to choose the foundation type by looking at it, we can use any foundation type we want by providing economy and security. my teacher is not the answer to my question, I can't explain it and this problem bothers me a lot.

 

[MaFiAMaX]

Re: How to design a foundation with a negative soil safety stress Yavuz Bey, DBYBHY 2007 did not specify how to calculate the soil bearing capacity. As we saw in the soil mechanics lessons at school, soil bearing capacity was calculated with different formulas according to different theories. Then, the soil safety stress was calculated by dividing it by a value between 2 and 3 according to the foundation type and soil. In TBDY 2018, how to calculate the carrying capacity is shown with the formula. After calculating the characteristic bearing capacity, you will have calculated the bearing capacity by dividing the strength coefficient in the table 16.2 by the appropriate one. DBYBHY 2007 - Example: Let the soil bearing capacity be 50 t/m2. If 2.5 is used as the safety factor, the soil safety stress will be 50/2.5 = 20 t/m2. TBDY 2018 - Example: Let the characteristic bearing strength be calculated as 50 t/m2. If the strength coefficient is taken as 1.4 from table 16.2, the basic bearing capacity design strength will be 50/1.4 = 35.7 t/m2. Question: So why is the permissible load on the same floor 20 t/m2 in the past, why is it now 35.7 t/m2? Answer: Because the loads acting on the foundation are now increased by some coefficients and the reinforced concrete design of the foundation is made. In this case, since the stresses created by the foundation on the ground increase, it is desired to compare it with the calculated value. As a result; 1- Since the internal forces in the foundation have increased compared to the past, an increase in the foundation cross-sections can be expected. 2- Although the stresses under the foundation are increasing compared to the past, since the limit value has also been increased, a big change may not be expected in the soil's ability to meet the loads coming from the foundation.

 

[yavuz statik]

Re: How can I design a foundation with negative soil safety stress Sir, thank you very much, you explained it very well, why is the value of 20 t/m2 that I want to learn now from 50 t/m2 to 37.5 t/m2 here, what was the change in reinforced concrete? As a result of my research, it is given in the tbdy2018 chapter 4 and chapter 4A informative annex. D ( HOW MANY NUMBER OF DURABILITY) tbdy2018 is used. tbdy2018 table 4.1 D shapes the number of carrier system behavior R and bys D, and then you find fd from the formula fy(actual strength of the element) = fd(required strength) *d and continue your calculation accordingly. you reduce the load, so as a result, you take D= 2.5 AS A REINFORCED CONCRETE FRAME SYSTEMS WITH BYS =7 AND DUCTILITY LEVEL LIMITED, AND REDUCE THE ACTUAL STRENGTH BY 2.5 TIMES AND GET THE FLOOR BEARING STRENGTH ON THE FLOOR AND THE FLOOR BEARING STRENGTH ON THE FLOOR IS 1.4. . If 2.5 is used as the safety factor, the soil safety stress will be 50/2.5 = 20 t/m2. TBDY 2018 - Example: Let the characteristic bearing strength be calculated as 50 t/m2. If the strength coefficient is taken as 1.4 from table 16.2, the basic bearing capacity design strength will be 50/1.4 = 35.7 t/m2. 35.7 t/m2/2.5(D) 14.28 YOU WILL REDUCE THE LOAD BY 2.5 (DUE EXCESS OF STRENGTH) AND INCREASE THE GROUND VALUE Gs (according to the SAFETY NUMBER) BY A VALUE BETWEEN 2-5

 

[Ismail Hakki Besler]

Re: How to design a foundation with a negative soil safety stress Earthquake Regulation makes calculations by increasing the loads in the foundation calculation. As follows; Shear force Moments and Axial force for Columns in structures without basement Moments and Axial force with a coefficient of 0.6D For walls without a basement with a Moment D coefficient Normal force 0.6D shear force According to 7.6.6.3 Moment Normal force for columns in structures with basement and Moment Normal force and shear force for walls in structures with 0.6Top+Down Basement Moment Normal force and shear force for structures with 0.6 Top+Down Basement are increased by 0.6 Top Coefficients in cases where the critical perf height starts higher than the upper level of the foundation.[/b ] Roughly Down=3 Dalt=1.5, this increase is around 1.8 - 2 in buildings with basements, this increase is roughly in the new regulation. In response to this increase, the concept of increased bearing capacity came to replace the ground safety cost in the old regulation, which was an absurd use. Ground bearing strength is a value given to you in the ground report and is approximately 2.5-3 times the ground safety. Thus, when the loads increase about 2 times and the value you compare increases by three times, you actually make a serious economy in the foundations. Just as we have made a more realistic calculation of the transition from the calculation of safety stresses to the bearing capacity in the beam-column reinforced concrete calculation, this transition is realized for the foundation with this regulation. ideCAD makes the basic calculations and reports as described in the regulations section 4.10 and 16.8.3, which I have explained roughly here.

 

[yavuz statik]

Re: How to design a foundation with a negative soil safety stress IT IS NOT INCREASING, DIVIS IT BY THE NUMBER D, IT IS DECREASING, SECURITY

 

[Ismail Hakki Besler]

Re: How to design a foundation with negative soil safety stress

IT IS NOT INCREASING, IT IS DIVIDED BY THE NUMBER OF D, IT'S REQUEST SECURITY

Earthquake Regulation is basic In his calculation, he increases the loads with the D coefficients and calculates as follows. Please read the following pages carefully Especially the parts underlined in red Also, Mr. Mirza Check out the document added by

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[yavuz statik]

Re: How to design a foundation with a negative ground safety stress GOD BLESS MY HOCAM