Dear Sumant

we use 0.05 & 0.95 in columns & beams,

if you take 0.05 it means that for a 10 meter length beam, the hinge length will be created in 0.05*10=0.5 meter from the connection point,

sap2000 will automatically calculate the hing length,

for a braced frame it depends on the brace type,

Thanks Arash.

But that is the relative displacement at which centre of plastic hinge is located, as per my knowledge. I want to know the length of it.

i thick you can define any number of relative displacement in element (ex, 0.025:0.05:....:0.975), by doing this you have n location of probable plastic hinge in your element,

when your pushover analysis completed, you can check the force & etc of that n location and calculate the length of plastic hinge, you will get the length by status of hinge ( New Doc 33_2.jpg) the LS hinges will show the length of beam that the force in their location are greater than Fio-Fls.

or define some relative displacement close to each other in the length of beam which moment of beam in target displacement > ZFye of the section (New Doc 33_1.jpg )

you can easily get the force in your project step and apply it to the section in Abaqus, the exact location will be shown from stress diagram

They are point hinges. As such, they are a discrete point with x,y,z coordinates and, thus, the physical length in the model is zero. However, the typical hinges are developed based on ASCE41 procedures. Maybe a little digging in there will reveal the answer. However, I suspect there is no fixed assumed length for a specific hinge type since the hinges properties were experimentally derived, rather than being developed analytically (I think). Hope this helps.

In addition, plastic hinge length is difficult to measure in reality due to the spread of plastic deformations over non-uniform areas both through the depth of a member and with increasing plastic deformation. Could you clarify why the length is important? As others have recommended, the placement of hinges slightly away from the support is supposed to approximate the approximate hinge center of rotation, so you should adjust that value to attempt to capture plastic hinge length.

Thanks Cliff for your answer.

My interest in knowing the plastic hinge length, considered in auto hinge, is to know how the rotation is calculated using curvature and hinge length further resulting in plastic deflection L'* rotation.

Does the relative distance say 0.1L mean the length of plastic auto hinge is 2*0.1L ?

SAP2000 allows for direct input of hinge properties using moment-rotation. It also allows for moment-curvature inputs, however you have to define a hinge length (either relative or based on input units). Check how your hinge is defined and that should answer your question. I believe you do this through Define > Section Properties > Hinge Properties, and then you should have the properties of your auto-defined FEMA hinges there. If it's a moment-rotation hinge, you assume a discrete rotation equal to the rotation value computed in SAP2000. Note that the rotation is defined in multiple of yield rotation. Check the SAP manual, or online help, for calculation of this property as it may just assume the beam is adequately braced to develop full strength and, thus, base it on the elastic rotation when the section reaches FyZx, the plastic moment, or it may be "smarter" and consider other failure mechanisms.

Alternatively, SAP2000 also provides the ability to overwrite the scaling for moment and rotation. You may be able to get creative and define these values yourself to ensure you know exactly how the moment and rotation inputs are scaling in the model.