I asked a senior in our office about a reference for moment redistribution the other day and they gave me a book published by the PCA in 1960-something called "Continuity in Reinforced Concrete Frames", I haven't read the text but it seems to deal with moment distribution methods of structural analysis.
PCA still sells a pdf of this publication on their website for $9.00 US.
If you do a web search you might have better luck with "Hardy Cross moment distribution". Hardy Cross was the first to use this system for structural analysis (we Americans claim to be the first at everything).
The text is "Continuous Frames of Reinfoced Concrete" By Hardy Cross and Nelwin Dolbey Morgan. I have a copy on my desk in the easy to reach and grad section of A5 (approx 8" x 6") references.
He invented it, and was by all accounts an excellent teacher. The explanations are concise and clear. A word of caution: When he/they say "computer", they mean You (ie: the person doing the computation). The book predates all modern computers, including the Germans & earliest US efforts.
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
I agree, the moment distriution won't derive anything that you can't achieve by the direct stiffness method. But if you are going to utilise moment redistibution clauses set out in various codes then you need an understanding of the moment distribution method.
Hardy Cross is one of the pioneers of structural analysis as we know it today.
This looks like it explains EVERY step thouroughly. I've read several books and they skip steps and it just confuses me. I've never really understood this method or Hardy Cross. Hopefully this will help.
BTW - civeng80 - I am taking the SRT II Exam in a few weeks and I may have to use an approximate method like this.
Dunno where it came out of to be honest!! Have it years but yep think its either mine or one of my collegue's uni notes. I have a wealth of all that kind of stuff saved up over the years. Its not actaully that complictated.. and I think its important to appreciate the hand calc methods that can be used in lieu of computer analysis.
Useful exersise for someone next Saturday morning instead of messing with their measuring tape and worrying about torsion!!!(see thread 16th Sept)
If anyone here practices in a Seismic Zone, builds in reinforced concrete, and doesn't apply the Moment Distribution Method I can only ask why not???
IF you have an EQ force moment envelope (BMD) and also a gravity case (for my Code it is G + 0.6Q) BMD, hanging the gravity BMD from the seismic BMD is a quick and convenient superposition. From there you use the redistribution methods that asith alluded to, and acheive a much more economical frame.
Besides, why use a computer when you can employ a hand method that is easily as reliable and has fewer potential pitfalls (ie: Modelling error, computation error inside the black box, etc).
Regards,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
Well I don't know if the method is actually mentioned in many codes... It is, afterall, an analysis technique.
Redistribution is typically mentioned in concrete material codes, if only in terms of setting a maximum limit (in percentage) on how much redistribution a code committee have chosen to allow. This is normally 20 or 30%.
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
Haven't read most of the other ones mentioned, but I can tell you that the above text has conjugate beam, virtual work, moment dist., slope deflection, and it is all clear ENOUGH that no other book is needed for classical structural analysis techniques(all texts seem to skip some steps, unfortunately, including this one)
