What is torsional constant in Etabs?
The significance of Torsional Constant (J) is that when J is multiplied with Shear Modulus (G) it gives Torsional Rigidity. You will have to see books on Advanced Mechanics of Materials to get a more in depth knowledge on this. Coming to its value modification in ETABS, if J is kept as 1, the member will take all the.
What is m12 in Etabs?
Also in the figure is m12 which is the twisting moment that is included in the computation of the final bending moment to be used for design. The infinitesimal element (from CSI) Notice how Mxy is added to bending moments in a particular direction.
How is stiffness calculated?
Its stiffness is S = F/δ where F is the load and δ is the extension.
Why is the stiffness modifier for columns higher than beams?
The stiffness modifier value for column is higher than the beam since the columns will have higher axial compression than the beam. Hence, the extent of cracks would be lesser in the columns as compared to the beams. Hence, the stiffness modifier value for column is higher than the beams.
What are stiffness modifiers and why are they important?
These stiffness modifiers will result in a design in which you would under-estimate the demand in beams, and over-estimate in columns. The value of stiffness modifier for the wall depends on weather the wall is in tension, or not. If the edge of the wall is in tension, then the modifier is 0.35.
What are the stiffness modifiers in ETABS?
The concept of stiffness modifier is not related to Etabs. Stiffness modifiers are used to simulate the behaviour of structure in cracked stage. while there is nothing mentioned about stiffness modifiers in Indian standard, values mentioned in ACI 318 can be used. , 8 years of experience.
What is the stiffness modifier used in is 456?
The stiffness modifiers are used to take into account the cracking of RCC sections. IS 456:2000 does talk about stiffness of members in Clause 22.3. However, it does not provide the modifier values to be used. You can refer Code Section 10.11 of ACI 318 for stiffness modifier values suggest by ACI.