Wish List

[Anonymous]

Hi Rafal and Arthur

To design of a RC Beam,  the supports should be set by the user

It could be helpful if the program sets automatically the supports for the following conditions

Supported Nodes

Columns

without further assignment or check, those elements can be considered as supports. (except : if tension in the column exists)

for Beams 

can ARSA use the deformations at the intersections in order to determine which support which?

so that the user doesn't have to determine whether the beam can be considered as a support for another beam.

Because this can lead to wrong reinforcement distribution.

Thanks a lot in advance

Best Regards

Marcelo

[Artur.Kosakowski]

To design of a RC Beam,  the supports should be set by the user

It could be helpful if the program sets automatically the supports for the following conditions

Supported Nodes

Columns

without further assignment or check, those elements can be considered as supports. (except : if tension in the column exists)

By default they are considered as supports.

for Beams 

can ARSA use the deformations at the intersections in order to determine which support which?

so that the user doesn't have to determine whether the beam can be considered as a support for another beam.

Because this can lead to wrong reinforcement distribution.

I'm not sure how the deformation could be used for such detection? In case of the intersections of two beams the value of displacement in this point will be the same for both of them. What is done is the detection of  all adjoining beams as possible supports but by default only beams of the same and larger heights are treated as the supports (unless you mark other as supports too).

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[Anonymous]

Dear Arthur

Yes the displacement for the intersection must be the same by compatibility definition, but the angle could be different for the beams (only for symmetrical geometry and load will be equal).

If try to imagine the local rotation of the beams :

1 The supporting beam will have always the smaller rotation value

(for Ex. in a symmetrical geometry but not symmetrical load one beam will have rotation angle =0 in the middle, and this beam has to support the another beam, the load flow will show that behavior.

2 A internal control can be done be checking the Q values too.

[Artur.Kosakowski]

1 The supporting beam will have always the smaller rotation value

I'm afraid that this may not always be true.

[Anonymous]

This is exactly what I mean

If Ry>Rx there must be Reactions in the nodes 3 and 5 from the load applied on the beam 1 (from node 1-2)

Then the shorter Beam2 “carries” Beam1

When the relation changes (Rx>Ry) Beam 1 will support Beam 2 

We are lead to think that the Beam with the mayor Iy will support the smaller, but this is not totally correct

I will attach a file with 4 little examples

Best Regards 

Marcelo

[Artur.Kosakowski]

Perhaps I'm entirely miss the point but mind that design of reinforcement is based on actual internal forces distribution (diagrams) calculated for a particular beam during the static analysis of the whole model rather than based on a separate static analysis for a single beam with declared locations of supports. If so what supports what is already 'taken care' of 'inside the stiffness matrix'. The definition of supports while you make the import to the design module is more for arrangement of stirrups than amount of main rebars.

BTW: The solution you proposed would be at this stage difficult to introduce anyway. The reason is that this would require comparing of angles of rotations of intersecting bars in an arbitrary locations along them. First of all this kind of result is currently not available as the output. In addition bars at intersection can be continuous or divided and to make things more complicated you may have compatible nodes defined there. Currently the defaults are as you correctly noticed based on sizes of the sections which in my opinion is in most situations correct.

[Anonymous]

Dear Artur

Yes you are wright, it is too complicated to decide which carries which

But is will be better if internally we can have the posibility to recover the rotation of the intersection and use to improve our performance.

The RC modul gives different longitudinal reinforcement arrangement, cutting the lower reinforcement if the other beam is declared as a support, even if it is declared mistakenly.

Please take a look to the file and the .png file

Best Regards

Marcelo

[Artur.Kosakowski · Accepted solution]

I understand the situation yet the final decision on what should be treated as a support is currently left in hands of a user who can check the rotations of the nodes in doubtful situations. At this moment the development of the functionality is not planned and has to wait for the implementation of the possibility of accessing the bar rotation output which has already been added to the wish list. Thank you for all your remarks.