How to Assign Moment release or Partial Fixity

In this video you will learn to release the degrees of freedom at either end of a frame section. In ETABS, there is no direct option to release a particular percentage of moments at the supports. This can be done by calculating the spring stiffness manually.
Watch the complete video, all the equations, calculation are shown in the video. In addition, a comparison in values is also explained that are generated by ETABS and calculated manually.
#ETABS #Partial_Release_Moments #Partial_Fixity #Assign_Moments

[@jamesz3316]

Una consulta Ingeniero, la rigez rotacional de una conexion metalica la tengo que agregar en los releases?

[@tolist-k1w]

Hello, how to define in Etabs that the bracing of my building is provided by concrete frames when we don't have reinforced concrete bracing wall? should i release moments at the start and end of columns or at the start and end of the beams ? the bracing is provided by free-standing reinforced concrete portal frames

[@vaibhavdhemre6282]

In case if we r analysing beam column frame structure, should we do same procedure for column too?

[@engineeringsolutions5143]

hi, when we have to release 70% of the moment , the formula (n/(1-n)) starts giving value great than 1 . This means the stiffness starts increasing . Could you please check and elaborate. TIA

[@virilnasutions.t.7054]

this.

[@User_39sankyu]

Thank you so much! Very good explanation

[@ThienNguyen-n4r]

Thanks for sharing. This is really helpful. But I'm wondering what if we want to reduce the moment 50%, by the reduction factor formula we have 50%/(1-50%) = 1. So it goes back to the normal stiffness, how do we deal with that?

[@mehmetgurer3729]

as u wrote, the reduction factor should be 1. there is no problem here. u can prepare a data and check the results.

[@neilbantugan]

How about beams connecting core wall and moment frame, fixed or pinned?

[@basmaamer9208]

Thanks for video.. I need this excel sheet please 🙏

[@Unknownguy51139]

Thats awesome

[@slimmy666]

Thanks Sir, but what is the proper percentage for a partial fixed connection? Is there any limitations? or it just needs to pass deformation and strength wise?

[@structguru2200]

Well generlly we don't assign partial release to any member. This is calculated by Etabs software through FEA by calculating the joint stiffness. We do assign total moment release incase of secondary beams.

[@slimmy666]

I am aware of that. But in case I needed a partial fixed connection is there a specific percentage that I should stick to?

[@TarikulIslam-tr8de]

Great.. Now my question is practical use of partial fixity on structure design. When we are allowed to reduce the moment partially (40%/70%) and what should be the code suggestions, or I can use this assumption whenever I need, definitely not. Like as in Staad pro, for secondary beams, we release partial moment (.99) to reduce the instability warnings). Please describe a little with practical use also. Great work, carry on.

[@structguru2200]

Moment releases are applied to simulate real world connection in structures. They are mostly applied for secondary beams because the moment in secondary beams is considered negligible and they are considered as pinned connection. The primary beam is supported on columns which provide fixed support. But in secondary beams, there is no such thing. There is rotation at the ends. These moments are countered by causing twisting in the primary beams to which they are supported. To avoid such effect, a shear connection is developed for secondary beams by releasing all the moments.

[@TarikulIslam-tr8de]

@@structguru2200 Thanks. I know the criteria that in 2ndary beam, we release all moments and place shear connection. I also know the theory for it. But the video you showed to release partial moment(not fully). So i asked for that's explanation in practical use and application. Thanks for the cooperation.

[@civilvimalpatel5831]

Thanks dear for considering my request

[@nakshsharma6661]

Please provide this excle sheet

[@positivevibes4265]

In case if i am modelling a balcony portion where should I release the moment? Please explain

[@mxmixi1242]

you have wrong value of modules of elasticity of concrete. should be 4700*(fc')^0.5

[@AbubakrESMusa]

I think the formula for calculating the reduction percentage is not acceptable. If one would like to reduce the moment by 50 %, then he will end up by a reduction factor equal to 1.0. Any reduction more than 50 % will result in a reduction factor more than 1.0 !!!