Warning: Make sure you scan the downloaded attachment with updated antivirus tools before opening them. They may contain viruses. Use online scanners here and here to upload downloaded attachment to check for safety.
Posted: Mon Mar 28, 2022 11:18 am Post subject: Using "Fixed But" Support Instead Of Fixed Support in G+3 RC Building with Isolated Footing
Is it better option to provide "Fixed But" Support condition in Staad Pro model while designing a RC building structure (g+3) with soil condition of isolated footing?? Or I should go with fixed Support only?
Also it will be very helpful to be guided in how to use "Fixed But" support? Should I only release My and Mz?
And How to put sub-grade modulus in the value box beside.
Any guidance or advice will be very helpful
For Building columns on isolated footing :
Although column - footing joint is monolithic , the soil strata beneath footing needs to be seen , wether it allows slight rotation due to compatibility moment caused by gravity loading or not.
Rocky strata - No rotation of footing , Fully fixed support
Hard soil strata - some partial rotation is expected - Hence condition is in between fixed and hinged . Designer can judicially choose .
Medium and soft soils - Soil allows rotation of footing and a slight rotation ceases compatibility moment under gravity loading . Hence Hinged baSe can be taken.
However in case of Equilibrium moments caused by horizontal forces due to wind / EQ , the condition of joint is fully fixed.
Irony of input data is that for different load cases viz gravity and EQ separate set of support conditions can not be given in computer softwares and therefore fixed condition remains the only option left.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You cannot download files in this forum