ETABS Tutorial 12: Choosing the Walls Flexural Stiffness (0.7Ig or 0.35Ig) Using the Rupture Modulus
In this video, you'll find:
0:00 ACI 318-14 Code Insights
A breakdown of ACI 318-14 code guidelines, explaining how to choose between cracked and uncracked cross-section properties for walls, all based on the modulus of rupture (MOR). If the tensile stresses of a wall exceed the modulus of rupture (MOR), a cracked cross-section property of the wall should be used.
1:48 Shell Stress Explanation with a Simple Wall Example
An example of a simple wall subjected to various loads (Dead loads, SIDL, and the RSA method) is used to closely examine the displayed shell stress results, with a focus on how ETABS handles stress calculations using both "Max" and "Min" options within load combinations.
8:52 Selection of Wall Stiffness in Our Case Study
In our case study, the wall stress results are displayed and directly compared to the modulus of rupture in ETABS software. The analysis shows that the uncracked section property is the appropriate choice for the walls.
11:57 Checking Wall Stresses in a Different Building Configuration
In this part, we closely examine wall stresses within a similar building having different structural configurations. Here, we observe locations where the wall's tensile stresses exceed the modulus of rupture. It's important to note that this building has torsional irregularities, which is the primary reason for getting higher tensile stresses.
You can access and download the Excel sheets by clicking on the link below:
drive.google.com/drive/folder...
Пікірлер: 21
Very nicely explained. I loved it!
Nice sharing of knowledge always worth watching your videos.
@Eng.tarekyoussef
10 ай бұрын
Glad to hear that
Nice explanation, regards from Guatemala.
@Eng.tarekyoussef
7 ай бұрын
Glad it was helpful!
Nice explanation
@Eng.tarekyoussef
3 ай бұрын
Thank you
At design of shear wall, after checking cracks on wall ,is be enough to change the modifier of the zone that exceeded the limit and continue the design or we should make shear wall safe from any cracks?
@Eng.tarekyoussef
Ай бұрын
In practical design, it is challenging to prevent all cracks in a shear wall. Minor cracks are often acceptable and expected due to the nature of concrete and the stresses it undergoes. When cracks exceed acceptable limits, one common approach is to adjust the stiffness modifier of the affected zone. This adjustment helps to account for the reduced stiffness of the cracked section and provides a more accurate representation of the wall's behavior. While these modifiers offer a practical solution, they may not always be entirely accurate, particularly in capturing highly nonlinear behavior. Performance-Based Design (PBD) allows for a detailed understanding of the nonlinear behavior of structural members. This includes evaluating the level of nonlinearity and determining whether the wall is performing safely despite cracking. Linear vs. Nonlinear Analysis: 1- Linear Analysis: In linear analysis, the material is assumed to remain within its elastic range. This assumption limits the ability to accurately assess cracking and nonlinear behavior. For regular buildings, linear analysis is typically sufficient, as it provides a reasonable approximation of the structure's response. However, it may not capture all aspects of cracking and nonlinearity. 2- Nonlinear Analysis: For irregular buildings or those expected to experience significant nonlinear behavior, nonlinear analysis is essential. This type of analysis captures the real response of the structure, including the effects of cracking and stiffness degradation. I hope I answer your question
NICE EXPLANATION COLUD YOU ILLUSTRATE WHY YOU USE WORKING COMBINATION HOWEVER IN CODE ( FACTORED MOMENT AND SHEAR ) WHICH MEAN ULTIMATE COMBINATION ?
@Eng.tarekyoussef
4 ай бұрын
In practice, it's essential to assess how buildings withstand different types of stress by examining all load combinations. In my tutorial, I'm specifically focusing on one particular load combination (0.9DL+EQ) as required by a research project I'm involved in.
@user-lh1uu7tc2x
20 күн бұрын
My question is what is the correct! Check stress due to working combination or ultimate combination And compary with moduls of rupture? @@Eng.tarekyoussef
@Eng.tarekyoussef
19 күн бұрын
@@user-lh1uu7tc2x You should use the factored load combinations (ultimate combinations). The load combination "0.9D + 1.0E " is part of the factored load combinations listed in Chapter 5, Table 5.3.1 of ACI 318-14 (it does not belong to the working load combinations! Please check the ACI code).
عندي سؤال بخصوص قيمة ss و s1 من الخرائط الزلزاليه مكتوب تحت الخريطه SS Risk-Targeted Maximum Considered Earthquake (MCER) ground motion parameter for 0.2 s spectral response acceleration (5% of critical damping), site class B. مثلا يوجد بالخريطة قيمة مكان المشروع ss = 16 كيف ادخل القيمه هي بالايتابز هل اضربها في g او اقسم على ١٠٠ او شوو ؟ وكمان بالنسبه ل s1 S1 Risk- Targeted Maximum Considered Earthquake (MCER) ground motion parameter for 1 s spectral response acceleration (5% of critical damping), site class B. ويعطيك العافيه
@Eng.tarekyoussef
10 ай бұрын
You need to compute "SD1" and "SDS" from "S1" and "SS". The "SDS" and "SD1" parameters are used to 1- Develop the Design Response Spectrum (Define" ==> "Function" ==> Choose "ASCE 7-10" ==> "Add new Function" ==> then you need to use "SS" and "S1"). kzread.info/dash/bejne/lniWxtemnrGWZ8o.htmlsi=2tVhs2XPUuSBUa2T kzread.info/dash/bejne/eJt3wdabkdSuf6Q.htmlsi=cB71LG-V6Ex1Pd3S 2- To calculate ELF Lateral Loads kzread.info/dash/bejne/fmiVvJJtg6uwk7Q.htmlsi=pL1sMMf4_-Zu-_69 Note that the acceleration parameters have the "g" unit. Then you should ensure that the "g" unit is included in the defined load case.
@LodyBasha
10 ай бұрын
Thank you tarek for your response and I know that I need to compute SDS and Sd1 from SS and S1 but my question when I defined seismic load pattern I need to input the value of S1 and SS from them map That I told you about in the previous comment. Do I need to divide the value of those value that I obtain from the map for example 16 do I need to divide it by 100 then multiply it by 9.81 (g) or not or just divide it by 100 ? Because in your case and your example you already have the value of SS & S1 Thank you
@Eng.tarekyoussef
10 ай бұрын
The acceleration values (SS & S1) in ASCE are expressed as a percentage of gravity (g). To convert this percentage to the standard unit of acceleration, you need to divide by 100 to remove the percentage sign. So, for example: 5% g = 5/100 * g = 0.05 * 9.81 m/s² ≈ 0.49 m/s² ETABS includes the "g" unit in the scaling factor when defining the load case, so you should indeed input the acceleration values from ASCE by dividing them by 100.
@LodyBasha
10 ай бұрын
This is what I found in etabs documentation ( S s is the mapped Risk-Targeted Maximum Considered Earthquake (MCER ) spectral acceleration for short periods as determined in ASCE 7-10 Section 11.4.1. A typical range of values for S s is 0 to 3. Note that the seismic maps show S s in % g with a typical range of 0% to 300%. The input in the programs is in g. Thus the map values should be divided by 100 when they are input. For example, if the map value is 125%g it should be input as 1.25g. S 1 is the mapped MCE spectral acceleration for a one second period as determined in ASCE 7-10 Section 11.4.1. A typical range of values for S 1 is 0 to 1. Note that the seismic maps show S 1 in %g with a typical range of 0% to 100%. The input in the programs is in g. Thus the map values should be divided by 100 when they are input. For example, if the map value is 100%g, it should be input as 1.0g. ) So what do you think ? when I took the value of SS from the map and then divided it by 100 then multiply it by g value 9.81 for example (16/100)*9.81 = 1.57 when I input this result in the 0.2 sec spectral acceleration ss in seismic load pattern definition, I got the seismic design category = D which is almost impossible in my country because I live in very low Hazard region So ? Only divide by 100 ? I am still somehow confused. 😅😊
@Eng.tarekyoussef
10 ай бұрын
@LodyBasha Absolutely, just divide by 100. And remember, when applying the scale factor in the load case, make sure it's in the "g" unit.
ياليت الشرح بالعربي
@Eng.tarekyoussef
4 ай бұрын
يمكنني مساعدتك إذا كان لديك أي سؤال؟