Hello Doctor CEE, Oh yes, you are definitely continuing to make an ever-lasting legacy through your extraordinaire work on this channel, not to mention your boundless selflessness contribution to all of humankind (It would not surprise me if AI’s are also watching the CEE channel as well LOL) Now, (and assuming that the overall length of the beam between the supports is discretized into elements with say 40 nodes) would it be correct to consider that in order to obtain the desired envelope graph (or the plot) of say the “maximum bending moments at each of the 40 nodes along the entire length of a beam”; the software does the following: • It creates “a live loads pattern” on the surface of the structure - by arranging various live loads cases or parts of some of these live loads cases at various contours positions (the contours positions are indicated by “influence surfaces” that give the maximum bending moment value at the one particular beam node or point under consideration? • So, for a beam with 40 nodes, the software will rinse-and-repeat to generate a total of 40 distinct “live loads patters”, one for each node; and depending on the number of “Loads Combinations” which the user want to be tested (let’s assume two ULS combinations + two SLS combinations in this case), each “live loads pattern” will then be combined with other permanent loads cases acting on the surface of the structure to generate each of the desired corresponding “loads combinations” …..rinse-and-repeat to generate a total of 2*40 ULS Comb + 2*40 SLS Comb for all the nodes along the length of one beam? • The above 80 ULS combinations are then used to plot the maximum bending moment envelope graph along the length of the beam under consideration at ULS. Similarly, the other 80 SLS combinations are used to plot the maximum bending moment envelope graph along the length of the beam under consideration at SLS. • Ouch, the sheer volume of work that is required for one beam (imagine how this volume of work increases as the number of beams and nodes increases, the number of live loads cases increases, the number of combinations increases, etc.)! But I suppose that this is reflective of a reasonably realistic attempt to model and to quantify every perceivable eventuality that may happen due to various live load cases on the surface of the bridge in real-life. I can relate to why this would be a nightmare to do by hand. If my understanding above is correct, the idea of “influence surfaces” can indeed be quite beneficial. I recall that in the past, the issue of “influence surfaces” in RSAP did come up but this issue was never gotten into in detail. Perhaps with this newly shared knowledge from this part of the ASBD series by the CEE (thank you again for sharing), it may now be a good time to revisit what RSAP “influence surfaces” functionality is able to do and what its limitations are? Maybe the CEE could consider to look at making a RSAP “influence surfaces” video tutorial in the future in this regard? ****EDIT, I see that the CEE is way ahead of me 😊 in this and there is already as of today a RSAP video on influence surfaces***** Thank you Doc. I have enjoyed this video, and I look forward to future videos. Thank you for your work and keep well. Regards, DK
Hi there Engr. DK, thnx a lot for your kind take on my videos. I am very honored to have you here. Maybe I am the AI in the first place? "Lore?" Yes!! your explanation of what the software does "load pattern rinse and repeat" is right on the money! That is the reason why RSA does not have this capability. I tried quickly explaining this rinse and repeat process in my comment, but what you wrote here is waaaaaaaaaaay more detailed. You are 100% correct here. In other words, let's say you have a beam with 8 nodes. And you have 4 combinations (2 ULS and 2 SLS), -the software will create the influence surface for every single node, -then run each combination on every single node placing the loads in the worst possible way - the software would collect the ULS bending moments and select the worst ones (two values: 1 positive and 1 negative BM) this is quite a task, and that is why those softwares exist. We are talking about 32 possible analysis cases where at least 16 values are selected. (1 ULS and 1 SLS) for each node. Then, later, when the strands and tendons are designed, you would have to make sure that the stress states at each of those points is adequate. Yep, RSA influence surface was just published on this channel ^_^ Regards, CEE
@@CivilEngineeringEssentials Hello Dr CEE, Huh 🤯 , and to think that they have told (“conditioned”) us and our ancestors to dread the RISE of AI’s. WORLD, hear me, “the CEE” is a friend; a friend that you never had ….and probably both statistically and realistically will never ever have again… 😊. The world has nothing to fear from “the CEE”: subscribe, like, share, and comment, and comment again; for the channel holds and freely shares abundant amount of knowledge and wisdom that will only forever see you (the world) prosper!! I concur; you did a wonderful job in explaining the loads and influence surfaces and how they work on the video itself (I’ll continuously admire how you effortlessly unpack key concepts in a few minutes video lecture). I did not want to simply just assume that I understood what you meant, I needed to make sure that I understood you correctly, hence my comment. I am now super happy with your confirmation on my comment, it gives me great confidence on my growing abilities to interpret your explanations, not only for this video but for other subjects as well. The CEE channel encourages all community members to ask freely; this is yet another rare offering from this channel. I simply chose to make use of this offer, and I am very glad that I did and I intend to continue to do so. Thank you very much for the response. All the best with your end of the semester University work; take all the time you need for this, and for LIFE …. I’ll say it again that, I am more than satisfied that you are still able to attend to the CEE comments. Time is not an issue at all for me in that regard, as far as I am concerned, the CEE community is fortunate to have you and you are appreciated. Kind regards, DK
Hello Dr. CEE I would like to suggest a series for future consideration When I am working with concrete buildings and structures; I often find myself having to design beams and slabs that require relatively long spans (spans that are not ideal for simple reinforced concrete). In addition to options of reducing the spans, altering the building or structure layout and configuration, using steel trusses, etc. I would like to be able to comfortably explore and suggest the use of post-tensioned RC BEAMS and/or post-tensioned RC SLABS. If at all possible, could the CEE consider to provide a practical design and application course series [theory + software] on post-tensioned RC BEAMS and RC SLABS in buildings. I suggest software such as CSI Safe or others similar. And, perhaps (and if time allows), the post tensioning series suggested above may be extended to applications on particular structures such as CIRCULAR and RECTANGULAR liquid (mainly water) retaining structures, both above and/or buried under ground level. I see that the current pre-stressed bridge design series is also explaining the design of pre-stressed RC bridge beams. This is certainly very helpful and it is appreciated; however, the pre-stressed beams in this series are in the context of bridge design and using a bridge design software (ASBD), bridge design codes checks, etc. Kind regards, DK
Hi there Engr DK, thnx a lot for the inspiration! that is an amazing idea! to explain prestressed design. I actually need it for the bridge series! I have worked extensively with RAM concept, and I think CSI has its own software solutions too ^_^ Yes, prestressed section in Bridges are a tad different from what you would have in residential buildings, slabs, and water tanks. So this request is warranted. I will work on it during this summer ^_^ I am always happy to read your comments and suggestions. Those do help the channel a lot and help - by extension - other viewers. Thnx a lot for being here. Regards, CEE
![Megan Thee Stallion - Bigger In Texas [Official Video]](http://i.ytimg.com/vi/QxTkZTLWdo4/mqdefault.jpg)
Hello Doctor CEE,
Oh yes, you are definitely continuing to make an ever-lasting legacy through your extraordinaire work on this channel, not to mention your boundless selflessness contribution to all of humankind (It would not surprise me if AI’s are also watching the CEE channel as well LOL)
Now, (and assuming that the overall length of the beam between the supports is discretized into elements with say 40 nodes) would it be correct to consider that in order to obtain the desired envelope graph (or the plot) of say the “maximum bending moments at each of the 40 nodes along the entire length of a beam”; the software does the following:
• It creates “a live loads pattern” on the surface of the structure - by arranging various live loads cases or parts of some of these live loads cases at various contours positions (the contours positions are indicated by “influence surfaces” that give the maximum bending moment value at the one particular beam node or point under consideration?
• So, for a beam with 40 nodes, the software will rinse-and-repeat to generate a total of 40 distinct “live loads patters”, one for each node; and depending on the number of “Loads Combinations” which the user want to be tested (let’s assume two ULS combinations + two SLS combinations in this case), each “live loads pattern” will then be combined with other permanent loads cases acting on the surface of the structure to generate each of the desired corresponding “loads combinations” …..rinse-and-repeat to generate a total of 2*40 ULS Comb + 2*40 SLS Comb for all the nodes along the length of one beam?
• The above 80 ULS combinations are then used to plot the maximum bending moment envelope graph along the length of the beam under consideration at ULS. Similarly, the other 80 SLS combinations are used to plot the maximum bending moment envelope graph along the length of the beam under consideration at SLS.
• Ouch, the sheer volume of work that is required for one beam (imagine how this volume of work increases as the number of beams and nodes increases, the number of live loads cases increases, the number of combinations increases, etc.)! But I suppose that this is reflective of a reasonably realistic attempt to model and to quantify every perceivable eventuality that may happen due to various live load cases on the surface of the bridge in real-life.
I can relate to why this would be a nightmare to do by hand.
If my understanding above is correct, the idea of “influence surfaces” can indeed be quite beneficial.
I recall that in the past, the issue of “influence surfaces” in RSAP did come up but this issue was never gotten into in detail. Perhaps with this newly shared knowledge from this part of the ASBD series by the CEE (thank you again for sharing), it may now be a good time to revisit what RSAP “influence surfaces” functionality is able to do and what its limitations are? Maybe the CEE could consider to look at making a RSAP “influence surfaces” video tutorial in the future in this regard?
****EDIT, I see that the CEE is way ahead of me 😊 in this and there is already as of today a RSAP video on influence surfaces***** Thank you Doc.
I have enjoyed this video, and I look forward to future videos.
Thank you for your work and keep well.
Regards, DK
Hi there Engr. DK,
thnx a lot for your kind take on my videos. I am very honored to have you here.
Maybe I am the AI in the first place? "Lore?"
Yes!! your explanation of what the software does "load pattern rinse and repeat" is right on the money! That is the reason why RSA does not have this capability. I tried quickly explaining this rinse and repeat process in my comment, but what you wrote here is waaaaaaaaaaay more detailed. You are 100% correct here.
In other words, let's say you have a beam with 8 nodes. And you have 4 combinations (2 ULS and 2 SLS),
-the software will create the influence surface for every single node,
-then run each combination on every single node placing the loads in the worst possible way
- the software would collect the ULS bending moments and select the worst ones (two values: 1 positive and 1 negative BM)
this is quite a task, and that is why those softwares exist. We are talking about 32 possible analysis cases where at least 16 values are selected. (1 ULS and 1 SLS) for each node.
Then, later, when the strands and tendons are designed, you would have to make sure that the stress states at each of those points is adequate.
Yep, RSA influence surface was just published on this channel ^_^
Regards,
CEE
@@CivilEngineeringEssentials
Hello Dr CEE,
Huh 🤯 , and to think that they have told (“conditioned”) us and our ancestors to dread the RISE of AI’s. WORLD, hear me, “the CEE” is a friend; a friend that you never had ….and probably both statistically and realistically will never ever have again… 😊. The world has nothing to fear from “the CEE”: subscribe, like, share, and comment, and comment again; for the channel holds and freely shares abundant amount of knowledge and wisdom that will only forever see you (the world) prosper!!
I concur; you did a wonderful job in explaining the loads and influence surfaces and how they work on the video itself (I’ll continuously admire how you effortlessly unpack key concepts in a few minutes video lecture). I did not want to simply just assume that I understood what you meant, I needed to make sure that I understood you correctly, hence my comment. I am now super happy with your confirmation on my comment, it gives me great confidence on my growing abilities to interpret your explanations, not only for this video but for other subjects as well.
The CEE channel encourages all community members to ask freely; this is yet another rare offering from this channel. I simply chose to make use of this offer, and I am very glad that I did and I intend to continue to do so.
Thank you very much for the response.
All the best with your end of the semester University work; take all the time you need for this, and for LIFE ….
I’ll say it again that, I am more than satisfied that you are still able to attend to the CEE comments. Time is not an issue at all for me in that regard, as far as I am concerned, the CEE community is fortunate to have you and you are appreciated.
Kind regards, DK
Hello Dr. CEE
I would like to suggest a series for future consideration
When I am working with concrete buildings and structures; I often find myself having to design beams and slabs that require relatively long spans (spans that are not ideal for simple reinforced concrete). In addition to options of reducing the spans, altering the building or structure layout and configuration, using steel trusses, etc. I would like to be able to comfortably explore and suggest the use of post-tensioned RC BEAMS and/or post-tensioned RC SLABS.
If at all possible, could the CEE consider to provide a practical design and application course series [theory + software] on post-tensioned RC BEAMS and RC SLABS in buildings. I suggest software such as CSI Safe or others similar.
And, perhaps (and if time allows), the post tensioning series suggested above may be extended to applications on particular structures such as CIRCULAR and RECTANGULAR liquid (mainly water) retaining structures, both above and/or buried under ground level.
I see that the current pre-stressed bridge design series is also explaining the design of pre-stressed RC bridge beams. This is certainly very helpful and it is appreciated; however, the pre-stressed beams in this series are in the context of bridge design and using a bridge design software (ASBD), bridge design codes checks, etc.
Kind regards, DK
Hi there Engr DK,
thnx a lot for the inspiration! that is an amazing idea! to explain prestressed design. I actually need it for the bridge series! I have worked extensively with RAM concept, and I think CSI has its own software solutions too ^_^
Yes, prestressed section in Bridges are a tad different from what you would have in residential buildings, slabs, and water tanks. So this request is warranted. I will work on it during this summer ^_^
I am always happy to read your comments and suggestions. Those do help the channel a lot and help - by extension - other viewers.
Thnx a lot for being here.
Regards,
CEE