Negative Moment - Rules of Thumb?

[zaxen]

I am trying to come up with a criteria for qualitatively selecting regions of highest "negative moments" in continuous beams. The parameters are of course w and ln. ACI lets you use formulae that are generically wl² / something.

I am looking for rules of thumbs like when two supports are closer together, negative moment should be lower than if there was one support? or the longer the clear span(s) the higher (or lower?) the negative moment.

Any input would be appreciated. Thanks

 

[JedClampett]

Why are you looking for this? The reason that rules of thumb are pretty restricted, is that they're heavily dependent on the assumptions (equal spans, evenly distributed loads, etc.). So messing around with the assumptions is likely to give you inaccurate results. And trying to keep them conservative is a guessing game.
To figure out moments for unequal spans (I'm assuming that's what you're after), involves moment distribution or some other indeterminate analysis. If you have a lot of experience you might get pretty close with your own personal tools or estimates. But that takes a lot of experience.