Hey, any chance you can make a video on the method that diveds the element in to 12 parts(or any number), and then calculate each segment moment of inertia, and then calculates the deflection using numeric integration of the curvature at each point ?
Would an RCC wall such as an ICF wall have any load, deflection or shear effect on an RCC beam if the wall was equal to the effectiive length of the beam once the wall was fully cured?
Sorry I just graduated heard a case where there is about 3 cm deflection on beam that is floor slab ones they said 1/360 rule saves it but what about creep and more loads like walls because it's now there is just topping concrete! Thanks for the video subscribed
Sorry I wasn't clear - the specified limit would also apply to beams supporting the floor. Beams supporting roofs will often times have different (typically more lenient) limits.
Hello sir, I'm modelling a reinforced concrete beam using solid65 and link180 element, For link180 element I'm defining BISO property with yield strength of 500 MPA and running the solution. I'm getting results but when i change the yield strength to 415Mpa the results value remains the same as that of 500mpa, I have cleared the previously generated results and tried to solve the model but still its not working. Overall i think the BISO property is not working at all Can you please help me out 😊
What are the stress and strain in the link180 elements? If it is less than yielding (415 MPa) then the bilinear yielding behavior will obviously do nothing - the material is still elastic. Otherwise, it’s impossible for me to say what is going on here.
There is no such provision in ACI. The (n-1)As' comes from mechanics. Normally a transformed area would be n*As, where n = Es/Ec, and this is valid for the tension steel. However, the compression steel is displacing an area of uncracked concrete which is also carrying compression, so we use (n-1) to reflect this.
Deflection limits like L/360 work for any kind of unit, no need to convert. If length L is in inches, then the resulting limit will be inches. If the length L is in millimeters, than the resulting limit will be in millimeters.
Great explanation, I’m just working on a continuous beam (5 spans) and I’m wondering if the process is the same? Do I need to calculate this effective moment of inertia at each span, or each section? How would you do it? I want to get a deflection diagram of the whole beam
The ACI 318-19 code has a few things to say about multiple spans. ACI 435 committee design guides will have more information on this topic. Code Section 24.2.3.6 permits us to average the effective moment of inertia (I_e) taken from the critical positive and negative moment regions. Section 24.2.3.7 also permits us to use I_e computed only at midspan for continuous spans. Take your pick. Either way, these seem to imply that you could compute I_e for each span and then compute a deflection. Keep in mind that the purpose of these code sections is largely for control of maximum deflections, not always exact calculation of a deflected shape. Personally, I'd just use the midspan value if it is less than the value at the supports rather than taking an average. The other approach that I like is suggested by Bischoff (2007): take a weighted average of the flexibilities. For example, using something like I_span = 1 / (0.70*(1/I_mid) + 0.15*(1/I_end1) + 0.15*(1/I_end2)), where I_span would be the overall effective moment of inertia of the span, and I_mid, I_end1, and I_end2 are the effective moments of inertia calculated at midspan and the two ends, respectively. Of course, you are always permitted to do a more rigorous analysis, and that might be preferable if you want a really accurate profile of the deflections along the entire length of the beam. You may compute the effective moment of inertia at each section, and then find the curvature = M/(E*I) along the entire length. Finding the displacement would then require you to integrate the curvature twice (or have some software do it for you).
Hey,
any chance you can make a video on the method that diveds the element in to 12 parts(or any number), and then calculate each segment moment of inertia, and then calculates the deflection using numeric integration of the curvature at each point ?
Would an RCC wall such as an ICF wall have any load, deflection or shear effect on an RCC beam if the wall was equal to the effectiive length of the beam once the wall was fully cured?
Great Explanation.. highly appreciated your work .Thanks Dr. Brock
You are welcome!
Great explanation! Thank you for the video!
hello sir i am a researcher from india can i get videos of seismic analysis of RC building by RSA in ANSYS
Sorry I just graduated heard a case where there is about 3 cm deflection on beam that is floor slab ones they said 1/360 rule saves it but what about creep and more loads like walls because it's now there is just topping concrete! Thanks for the video subscribed
Hello Sir? If these limits are for floors, then how can we use it for beams. Your kind guidance is required please.
Sorry I wasn't clear - the specified limit would also apply to beams supporting the floor. Beams supporting roofs will often times have different (typically more lenient) limits.
Good explanation , thanks
Glad you liked it!
Hello sir, I'm modelling a reinforced concrete beam using solid65 and link180 element,
For link180 element I'm defining BISO property with yield strength of 500 MPA and running the solution.
I'm getting results but when i change the yield strength to 415Mpa the results value remains the same as that of 500mpa,
I have cleared the previously generated results and tried to solve the model but still its not working.
Overall i think the BISO property is not working at all
Can you please help me out 😊
What are the stress and strain in the link180 elements? If it is less than yielding (415 MPa) then the bilinear yielding behavior will obviously do nothing - the material is still elastic. Otherwise, it’s impossible for me to say what is going on here.
Where is the provision in ACI that state that the transformed section of compression steel is equal to (n-1)A's ?
There is no such provision in ACI. The (n-1)As' comes from mechanics. Normally a transformed area would be n*As, where n = Es/Ec, and this is valid for the tension steel. However, the compression steel is displacing an area of uncracked concrete which is also carrying compression, so we use (n-1) to reflect this.
I am from India , superb
Great video! may I ask; is the deflection limitation also applicable in S.I. units? or do we need to convert mm to inches?
Deflection limits like L/360 work for any kind of unit, no need to convert. If length L is in inches, then the resulting limit will be inches. If the length L is in millimeters, than the resulting limit will be in millimeters.
@@StructuresProfH thank you for the clarification sir, your help is much appreciated :)
Great explanation
Great Explanation
Thank you
Great explanation, I’m just working on a continuous beam (5 spans) and I’m wondering if the process is the same? Do I need to calculate this effective moment of inertia at each span, or each section? How would you do it? I want to get a deflection diagram of the whole beam
The ACI 318-19 code has a few things to say about multiple spans. ACI 435 committee design guides will have more information on this topic.
Code Section 24.2.3.6 permits us to average the effective moment of inertia (I_e) taken from the critical positive and negative moment regions. Section 24.2.3.7 also permits us to use I_e computed only at midspan for continuous spans. Take your pick. Either way, these seem to imply that you could compute I_e for each span and then compute a deflection. Keep in mind that the purpose of these code sections is largely for control of maximum deflections, not always exact calculation of a deflected shape.
Personally, I'd just use the midspan value if it is less than the value at the supports rather than taking an average. The other approach that I like is suggested by Bischoff (2007): take a weighted average of the flexibilities. For example, using something like I_span = 1 / (0.70*(1/I_mid) + 0.15*(1/I_end1) + 0.15*(1/I_end2)), where I_span would be the overall effective moment of inertia of the span, and I_mid, I_end1, and I_end2 are the effective moments of inertia calculated at midspan and the two ends, respectively.
Of course, you are always permitted to do a more rigorous analysis, and that might be preferable if you want a really accurate profile of the deflections along the entire length of the beam. You may compute the effective moment of inertia at each section, and then find the curvature = M/(E*I) along the entire length. Finding the displacement would then require you to integrate the curvature twice (or have some software do it for you).
@@StructuresProfH thank you so much for your answer. This was very helpful. Keep doing those great videos
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