Point load on multiple spans

[nathmechy]

Hi everyone,

I'm currently updating an old excel spreadsheet and it makes reference to a bending moment calculation for multiple spans using what looks to be an approximation with K-value coefficients.
Has anyone come across a reference or similar method to these diagrams?

 

[robyengIT]

have a look here

 

[Celt83]

the method looks to be influence lines.

AISC Similar tables for bridges:

https://www.aisc.org/globalassets/a...-reactions-for-continuous-highway-bridges.pdf

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering