Torsion analysis and overturning moment (Enercalc & RISA)

[afk2000]

Hi Guys,

1- On Enercalc or Retain Pro, which one of these following numbers should be used for torsion design of a grade beam that holds a retaining wall above it?
Overturning Moment or Resisting Moment?

2- Base on that number above how can obtain the area of steel to design the number of ties on that Grade Beam? ( I am using RISA 3D to design the Grade Beams)

Thanks in Advance for your future comments

 

[civilperson]

The overturning moment is the maximum moment that will be experienced by the structure for the load case under consideration. The structure is usually designed per foot of length with every foot in static equilibrium. The only torsion experienced would be if a transfer of moments from a section of the wall is to be resisted at another section away from the location of the loading, sach as a missing section of footing requiring the footing on either side to provide the necessary resistance. Torsion would be experienced along the wall until the footing existed again.

 

[afk2000]

Thanks for your respond,

so basically I don't have any torsion in my situation because the whole ret. wall is sitting continuously on the beam, (support to support) am I right?

but if overturning moment is the maximum moment how come the resisting moment is always greater than that?

last question, because I am using the grade beam as a footing for that retaining wall, what else do I need to consider in order to design the beam (except the vertical load)

Thanks,