Two Span Continuous Beam Analysis

[MrEngineerUS]

Is there a reference for the design moments and shears resulting from 1) A distributed load and 2) Two equal concentrated loads (moving) on a two span continuous beam? The spans for my case are equal.

I did some searching around and haven't found anything. This seems so basic I just thought there'd be a simple envelope diagram with coefficients or something to find the moment and shear envelopes.

Cheers!

 

[MrEngineerUS]

I suppose all I'd be looking for is the concentrated moving loads case. The uniform load case is readily available.

 

[JAE]

I've got a book by AISC from 1959 that has tables for 2, 3 and 4 spans with AASHTO truck loads on it.
But not with just two concentrated loads.


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[Lomarandil]

The NDS Beam Design Formulas design aid has a figure for a single concentrated load on any point of a two equal span continuous beam (Fig #28). That might be enough to get you started.

 

[mike20793]

You will need to generate influence lines for shear and moment for the moving load case. There are some tables from AASHTO available for typical continuous bridge types, just as JAE mentioned.

 

[mike20793]

The influence lines will tell you how to apply the load and the resulting moments and shears.

 

[msquared48]

I believe the 1963 California Bridge Design Manual has a very helpful table for this loading in the back.

Mike McCann, PE, SE (WA)

 

[rb1957]

google "three moment equation"

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[mike20793]

Charts and tables are nice but is it really that difficult to generate influence lines? It can be done in 10 minutes or less on programs similar to STAAD or RISA 3D (when I was in bridge design in school we used RISA 2D). If you have Virtis/Opis, it will generate them for you.