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Moment Distribution Software? 1
- Thread starter Rednyx
- Start date
You are lucky that the Master of Internet Search is on this site ..go to this web site and enough the software which will full fill your needs of moment distribution for three type of loading systems , point , udl and trapezoidal.
- Thread starter
- #3
Is there a reason that you wish to find software that uses the moment distribution method? There is plenty of software out there. Most of it uses matrix methods however. Moment distribution is primarily a hand calculation method. What kinds of systems are you trying to analyze?
Dan
Dan
- Thread starter
- #5
Dear DAN .. being a student of BE i dont consider my self on any level to make comments on the difficulty level of Moment Distribution, i think its quite lengthy and chances of error in calc are high. But as u mentioned it as a hand held method, can u please send me the end moments of a 10 story-4 span frame with ordinary loading through Moment Distribution by hand. Ill add you up in the list of admired one .
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- #6
Dear Rednyx,
I stand with DAN.
Moment Distribution was always meant to be used for relatively simple hand calculations for analysis of 2-dimensional structures.
My experience with Moment Distribution dates back to 1954 or so when I, like you, was studying for my engineering degree. At that time I took the trouble of reading the original paper by Professor Hardy Cross, where he expounded his method for calculating bending moments in redundant frameworks by successive approximation.
Remember that at that time computers were not in general use outside research establishments, and that ALL structural design was done by hand methods. Your 10 story, 4 bay frame would have been nothing special (but it might have needed big paper and small writing). Almost certainly it would have been broken into substructures to facilitate the process.
Today it is difficult to imagine how the designers of any of the classic trussed arch bridges could have sorted them all out by hand, but they certainly did. I know that for the Sydney Harbour Bridge one young graduate was hired specifically for the purpose of calculating all of the 'secondary' stresses. And he would have had to work with no more than slide rule, log tables, pencil, paper and a personal care for accuracy.
But today, why would anyone in their right mind worry whether their software was based on moment distribution analysis or on direct solution of all the governing equations by other means, provided that the output could be shown to be valid?
Yes, there is real value in understanding how to analyse by Moment Distribution, since it may help you towards a better intuitive understanding of structural behaviour. But you won't get much of that understanding if all you do is to plug some input into someone else's program and read the answers. I strongly advise you to do the hard work and run several examples by hand (forgetting your 10 storey frame altogether). And then use the best current matrix based software that you can get your hands on for any substantial work.
I stand with DAN.
Moment Distribution was always meant to be used for relatively simple hand calculations for analysis of 2-dimensional structures.
My experience with Moment Distribution dates back to 1954 or so when I, like you, was studying for my engineering degree. At that time I took the trouble of reading the original paper by Professor Hardy Cross, where he expounded his method for calculating bending moments in redundant frameworks by successive approximation.
Remember that at that time computers were not in general use outside research establishments, and that ALL structural design was done by hand methods. Your 10 story, 4 bay frame would have been nothing special (but it might have needed big paper and small writing
). Almost certainly it would have been broken into substructures to facilitate the process.Today it is difficult to imagine how the designers of any of the classic trussed arch bridges could have sorted them all out by hand, but they certainly did. I know that for the Sydney Harbour Bridge one young graduate was hired specifically for the purpose of calculating all of the 'secondary' stresses. And he would have had to work with no more than slide rule, log tables, pencil, paper and a personal care for accuracy.
But today, why would anyone in their right mind worry whether their software was based on moment distribution analysis or on direct solution of all the governing equations by other means, provided that the output could be shown to be valid?
Yes, there is real value in understanding how to analyse by Moment Distribution, since it may help you towards a better intuitive understanding of structural behaviour. But you won't get much of that understanding if all you do is to plug some input into someone else's program and read the answers. I strongly advise you to do the hard work and run several examples by hand (forgetting your 10 storey frame altogether). And then use the best current matrix based software that you can get your hands on for any substantial work.
Hi Rednyx,
What Austim said above also makes good sense to me. Now... if you want the 10 story frame you mentioned with a hand moment distribution analysis of it... you probably won't get it unless you do it yourself. I've never attempted such a thing. Sounds like Austim "could" do it, but I don't think he wants to. I'm not sure why you would want it unless it is a school assignment for you ( in which case, you should try to do it yourself first ).
I do have a frame analysis package which I wrote a while back that will analyze your structure very easily. However, it uses a matrix method rather than moment distribution. It also uses a regular text file for the input rather than a fancy Windows driven user interface. It is ( in my opinion ) however, easier to use than most windows based programs. I'd be happy to send you a copy if you would like.
Dan
What Austim said above also makes good sense to me. Now... if you want the 10 story frame you mentioned with a hand moment distribution analysis of it... you probably won't get it unless you do it yourself. I've never attempted such a thing. Sounds like Austim "could" do it, but I don't think he wants to. I'm not sure why you would want it unless it is a school assignment for you ( in which case, you should try to do it yourself first ).
I do have a frame analysis package which I wrote a while back that will analyze your structure very easily. However, it uses a matrix method rather than moment distribution. It also uses a regular text file for the input rather than a fancy Windows driven user interface. It is ( in my opinion ) however, easier to use than most windows based programs. I'd be happy to send you a copy if you would like.
Dan
- Thread starter
- #8
Dear Austim n Dan,
I really appreciate your work in the specialised field and specially that of Austim. I do understand that without hard work done by myself i wont be able to understand the core logic behind. But through out my last acedmic Year we have been solving from Simple continous beams to two-dimentional 2-storied Sway frames by hand. I know how to break the frame and solve it. But now ,as we have been designing the whole buildings the no. stories are getting higher and the third dimension is in effect.Use of Moment dist. is the requirement. I have myself written Spread sheet of M Dist. But it has limits (3 spans, 2d). Now my main purpose is to Design a building.So i guess by analysing with the help of Computer, which is by every mean becomming essensiol nowadayz, i can save time and concentrate on whats more important for me now.
It would have been quite a hard work for you to Analyse whole of the structure by slide ruler. it would have been more difficult for those in the ancient Roman or Gothic age to Design the Colosseum, or for the Eqyption to do miracle with the Pyramids. But as the time passes humans are becomming more dependent on machines. We can only praise the hard work put on by living ppl like Austim, and those who have passed away dedicating their whole life with little resources. At the same time we should encourage the use of technology and make the most of it after all it has been invented because there was the need of it.
I really appreciate your concern, and understand whatever u suggested was for my betterment. If i have offended you by any of my comments, i opologise as this was not the intension.
I really appreciate your work in the specialised field and specially that of Austim. I do understand that without hard work done by myself i wont be able to understand the core logic behind. But through out my last acedmic Year we have been solving from Simple continous beams to two-dimentional 2-storied Sway frames by hand. I know how to break the frame and solve it. But now ,as we have been designing the whole buildings the no. stories are getting higher and the third dimension is in effect.Use of Moment dist. is the requirement. I have myself written Spread sheet of M Dist. But it has limits (3 spans, 2d). Now my main purpose is to Design a building.So i guess by analysing with the help of Computer, which is by every mean becomming essensiol nowadayz, i can save time and concentrate on whats more important for me now.
It would have been quite a hard work for you to Analyse whole of the structure by slide ruler. it would have been more difficult for those in the ancient Roman or Gothic age to Design the Colosseum, or for the Eqyption to do miracle with the Pyramids. But as the time passes humans are becomming more dependent on machines. We can only praise the hard work put on by living ppl like Austim, and those who have passed away dedicating their whole life with little resources. At the same time we should encourage the use of technology and make the most of it after all it has been invented because there was the need of it.
I really appreciate your concern, and understand whatever u suggested was for my betterment. If i have offended you by any of my comments, i opologise as this was not the intension.
Hi again, Rednyx
For my own part, no offense taken, no apology needed. But no, I do not now intend to resuscitate my fossilised moment distribution skills and have a go at your structure.
From what you have told us, it looks as if all you need now is some positive encouragement (and not some-one elses dubious software).
If you have sorted out a 3 span 2-D frame by spreadsheet, then you only need to work out how to add a second storey, then 4 span 10 storey is only more of the same. And don't worry about the 3-d aspect - moment distribution was never intended to cope with that. (MD was even stretched a bit if you had to calculate the sway effects in 2-D frames with sloping members).
Where you say that you have to design a 3-D structure, that shouldn't have to mean that you have to analyse 3-D frames.
Although it would be theoretically possible to account for the full 3-D distribution of bending moments throughout your full structure by Moment Distribution, the 'book-keeping' would be horrendous. If you were to maintain your interest long enough, you might be able to develop a spreadsheet with one page per frame, and model interconnecting members by links between pages. If you were to manage that, you would go close to the top of MY list of clever people! (But I would also put your final product near the top of my list of pointless achievements).
In my slide rule days, the only way of tackling your structure would have been to analyse each section through the building as an isolated 2-d frame, and ignore any moment transfer from one to the next via torsion in the interconnecting beams. Using moment distribution, I believe that would still be the only practical way to
progress. Even now I would be quite happy to use the same approach, but using a simple general 2-d frame anlysis program where I would have used Moment Distribution.
I hope that your existing spreadsheet allows for the effects of lateral sway. If not, then you have a bit more to sort out before progressing to the full 10 storey model.
Good luck with all this.
For my own part, no offense taken, no apology needed. But no, I do not now intend to resuscitate my fossilised moment distribution skills and have a go at your structure.
From what you have told us, it looks as if all you need now is some positive encouragement (and not some-one elses dubious software).
If you have sorted out a 3 span 2-D frame by spreadsheet, then you only need to work out how to add a second storey, then 4 span 10 storey is only more of the same. And don't worry about the 3-d aspect - moment distribution was never intended to cope with that. (MD was even stretched a bit if you had to calculate the sway effects in 2-D frames with sloping members).
Where you say that you have to design a 3-D structure, that shouldn't have to mean that you have to analyse 3-D frames.
Although it would be theoretically possible to account for the full 3-D distribution of bending moments throughout your full structure by Moment Distribution, the 'book-keeping' would be horrendous. If you were to maintain your interest long enough, you might be able to develop a spreadsheet with one page per frame, and model interconnecting members by links between pages. If you were to manage that, you would go close to the top of MY list of clever people! (But I would also put your final product near the top of my list of pointless achievements).
In my slide rule days, the only way of tackling your structure would have been to analyse each section through the building as an isolated 2-d frame, and ignore any moment transfer from one to the next via torsion in the interconnecting beams. Using moment distribution, I believe that would still be the only practical way to
progress. Even now I would be quite happy to use the same approach, but using a simple general 2-d frame anlysis program where I would have used Moment Distribution.
I hope that your existing spreadsheet allows for the effects of lateral sway. If not, then you have a bit more to sort out before progressing to the full 10 storey model.
Good luck with all this.
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- #10
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Moment Distribution is described in most structural analysis textbooks. You will also be taught it in your school classes ( or so I would hope ).
Dan
Dan
It seems that you (Rednyx) have'nt heard of "reduced frame" or "storey frame" methods. When you have a problem that's too big to do by hand, you simply break it into smaller pieces by doing one storey at a time as an approximation to the exact analysis. this is how the big buildings were done in the past, and you certainly should solve at least one problem using thsi method before using a computer program (which is what you would do in professional life)
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