Table of Contents
What is the value of torsional constant?
The SI unit for torsion constant is m4….Rectangle.
| a/b | |
|---|---|
| 1.0 | 0.141 |
| 1.5 | 0.196 |
| 2.0 | 0.229 |
| 2.5 | 0.249 |
How do you release torsion in beam Etabs?
To release torsion in ETABS, select the beams/columns, go to Assign->Frame/Line-> End Releases and assign torsion in start node OR end node. Note that unlike STAAD, you cannot assign torsion release to both ends.
Why do we use property modifiers in Etabs?
During earthquake or dynamic load event the section of the concrete cracks and the concrete below the neutral axis or the One in tension region would be ineffective. This leads to decreased stiffness of the section. In order to account for this effect we would use property modifiers in etabs .
How is torsional constant calculated?
If the angle is in degrees, divide the value by 360 and multiply it by 2 * pi to convert it to radians. Divide the value from Step Two by the the shear modulus of the material. A table of shear modulus values for common materials is provided in the resources section. The resulting value is the torsion constant.
How is torsional stiffness calculated?
where I p = π D 4/32 is the polar moment of inertia of a circular cross section. Thus, the torque required for unit twist, i.e., T (θ) is called the torsional stiffness. The quantity is known as torsional rigidity and is represented …
What factors does torsional constant depend?
It depends on the material, cross sectional shape and the length of the shaft.
How is J torsional constant calculated?
For example, for rectangular cross-sections of sides a and b, the polar moment of inertia is J = ab(a2+b2)/12, while their torsional constant can be numerically calculated as J’ = ka3b (k value is tabulated, e.g., see https://en.wikipedia.org/wiki/Torsion_constant).
What is the torsional constant of a wire?
The torsional stiffness, or the torsion constant, κ, is defined as the amount of torque needed to rotate one end of a wire by 1 radian about the longitudinal axis of the wire with the other end being fixed.
What is torsion factor?
In the field of solid mechanics, torsion is the twisting of an object due to an applied torque. Torsion is expressed in either the pascal (Pa), an SI unit for newtons per square metre, or in pounds per square inch (psi) while torque is expressed in newton metres (N·m) or foot-pound force (ft·lbf).
What is the value of torsional modification factor?
The torsional modification factor modifies the Torsional Constant ( J) of a member. J is equal to the Polar Moment of Inertia for a circular section, however, it varies for other sections. E.g. for a rectangular section (with height (h)/width (b) = 2) its value is J = 0.229 (h) (b)^3.
What is the significance of torsional constant J 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
Is shear+torsion reinforcement required in ETABS?
Only minium torsion reinforcement is required in this case. In these cases you can run the analysis by reducing tosion stiffness of beam so that beam does not fail in shear+torsion in ETABS.
How do you factor out torsion in beam design?
There are none. You as an engineer will decide. If your beam for example can transfer the torsion to another beam then you may put a factor of 0.01 and completely neglect torsion. If you know that this beam has to be designed for torsion then don’t factor it down.