resolution beams on three spans, four supports, two swings

[fsts]

Good evening,

I was citing myself with the resolution (calculating the moment and cut diagram) of a beam continues on three spans, four supports and two swings, through the method of the elastic line.

in the photo more details on the structure.
I thought I'd take off the two swings with equivalent forces, but I can't find the value of the elastic line just for the swinging part, in the passage where we have to match the rotation to the right and left of the unknown moments.

could someone indicate how to proceed, without using software but with manual calculation?

friendliness

 

[fsts]

I apologize for grammatical errors here and there in the previous message (equalgliare, the title, I thought instead of "I thought I'd replace" the two bounces etc.).

I thought we could change the post after publication; I hope this does not prejudge your answer.

Thank you.

 

[antonio_sc]

hello, don't worry..capita all a grammatical error every once in a while (we're not the bran) ^_^
I've been praying for a long time that I haven't touched the subject..comanywhere. .
returning to the core of the matter:
- if you like to simplify your life note that the structure is symmetrical with distributed load symmetrically and therefore the reactions are symmetrical with respect to the half-work plane (in a nutshell you know that ra=rd and rb=rc), then you have two other equations (that to add to the balance equations to solve the system). theoretically you can do, going to simplify the structure as in this example (i.e. consider only half):

I'm not sure but so, on two feet, I think inserting a bipender in your case is not essential and you would not have added information (as you only look for reactions to the supports). .

if you want to complicate your life (or the structure is not symmetric) and then you want to proceed as indicated by yourself:
a) the contribution due to the term q*l is null (the reaction if it catches all the left support)
(b) the contribution to rotation due to the term (q*l^2) /2 the revenues from the attached image (you are interested in the fia and you must replace m with the value in question).eye that to get fi2 per second member you must consider the contribution to the rotation given by:
-load on the stretch l3
-More
-moment mcs (in turn function of the value of the loads acting on the right section of the structure)
I don't understand why you didn't think to replace the two central supports with vertical forces and focus on the moments....

for the rest I give good that the calculations you made are correct, however the method (as far as I remember), should be this.

a tip: even if studies for an exam always check with some software if the values are accurate (check the procedure)

 

[fsts]

thanks antonio_sc for support and clear explanation.

I don't understand why you didn't think to replace the two central supports with vertical forces and focus on the moments...

Yes I had thought (the structure was also resolved with ftool)However, for the resolution of continuous beams on several supports we must use (for a course in university) this process of moments.

if you want to complicate your life (or the structure is not symmetric) and then you want to proceed as indicated by yourself:
a) the contribution due to the term q*l is null (the reaction if it catches all the left support)
(b) the contribution to rotation due to the term (q*l^2) /2 the revenues from the attached image (you are interested in the fia and you must replace m with the value in question).

eye that to get fi2 per second member you must consider the contribution to the rotation given by:
-load on the stretch l3
-More
-moment mcs (in turn function of the value of the loads acting on the right section of the structure)

exact, but I can't find the two values for the structure loaded, in point a, with a moment and for the structure loaded with the only ql reaction.