When do we need to modifying the Stiffness

[ammer]

hello friends
I'm asking about the stiffness modifications in the idecad
when do we need to do this?
for the beams,column,and the slab
for example:
i have this cantilever beam,slab
Is it correct to do the stiffness modifications when we need to check the deflection?

 

[HakanŞahin]

Re: When do we need to modifying the Stiffness?

Hi Ammer,

You don't need to change stiffness of those you mentioned. Program finds beam-beam, beam-column connections automaticly and make them ready to analysis. You may see 6 end forces for each end of beam and columns, which is total 12.


Also, there is an option for torsion effect for beam-beam connection on Beam Parametres related to TS500. Make sure it's not checked as well to apply torsion effect on beam-beam connections.

 

[ammer]

Re: When do we need to modifying the Stiffness?

Hello Mr. Hakan
please tell
when we use the stiffness modification in the below image

 

[ammer]

Re: When do we need to modifying the Stiffness?

for my large cantilever beam slab
I find the amount of the long term deflection for the cantilever beam is a few
please check the attaches

 

[HakanŞahin]

Re: When do we need to modifying the Stiffness?

Height of cantilever beams in your project is 1.60 meter. Sudden deflection of B2 beam is 4.42 mm, long related deflection 8.19 mm and total deflection is 14.1 mm. I don't see problem on these values
TS500 gives reduction condition of moment of inertia of the beams related to left and right moments and program checks this condition and applies. If you don't want to consider TS500 conditions, you may change stiffness modification for vertical loads as amount of you wish to.

 

[ammer]

Re: When do we need to modifying the Stiffness?

hello Hakan
I'm satisfied to what did you said...
you are mean that the idecad takes consider the beam-beam or beam slab stiffness without enter them manually?
so, what are these factors which are based on TS code ?
thanks

 

[ammer]

Re: When do we need to modifying the Stiffness?

mr hakan really need your help :? :? :? :roll: :roll: :roll: :roll:

 

[HakanŞahin]

Re: When do we need to modifying the Stiffness?

Hi Ammer,

unfortunately there is no english version of TS500


Mmax=Maksimum moment along span
Mrc=2.5*fctd* Ic/y
Ic =moment of inertia of section
y= neutral axis of section

Along span of beam:

if Mmax<=Mcr moment, section not cracked-> uses inertia is full of section.
if Mmax>=Mrc moment of inertia is given as(section cracked -> uses effective moment of inertia Ief

Also new seicmic code(TBDY 2018) gives us reduce value of sections and program applies automaticly if we use seicmic code(TBDY 2018)

 

[ammer]

Re: When do we need to modifying the Stiffness?

Many thanks Mr hakan
I loved idecad
Regards