Using Multiple EI values in Beam Construction

[MatthewMansfield]

Hello all

I wanted to ask about beams.

I have the following structure:-

My question is that given this structure is composed of 2 x different EI values (the first 4m being EI and the last 8m being 2EI) then what would the purpose of using 2 different EI materials on a beam?

I can only think of the fact that over the 2EI length the deflections and moments need to be reduced but are there any other reasons?

Secondly how can this type of beam be constructed? off the top of my head I would assume that 2 members of EI are either welded or bolted together?

Any ideas or web sites you can direct me to?

 

[Lomarandil]

One example that happens commonly is a steel bridge girder with cover plates. (Or nowadays, they're just directly fabricated with variable size flanges). Use the steel where it's needed, save money elsewhere.

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just call me Lo.