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"Periodic Unloading " meaning ?

"Periodic Unloading " meaning ?

"Periodic Unloading " meaning ?

Dear all, please help me to understand the following:

What does " Periodic unloading " means? does it mean loading the structural system? or
removing the load from the structural system ?

here is the context

FROM A360-16, Determination of Load Rating by Testing, Page 16.1-235.
" Periodic unloading shall be considered once the service load level is attained and after the onset of inelastic structural behavior is identified to document the amount of permanent set and the magnitude of the inelastic deformations. Deformations of the structure, such as member deflections, shall be monitored at critical locations during the test, referenced to the initial position before loading. It shall be demonstrated, while maintaining maximum test load for one hour, that the deformation of the structure does not increase by more than 10% above that at the beginning of the holding period. It is permissible to repeat the sequence if necessary to demonstrate compliance."


RE: "Periodic Unloading " meaning ?

Dear all

After I read

"Periodic unloading, after the onset of inelastic behavior, will help the engineer of record determine when to terminate the test to avoid excessive permanent deformation or catastrophic failure." AISC 360-16 PAGE 16.1-551

I really think "Periodic unloading" referring to "process of adding load on structure for testing".However, My colleagues are saying that it means "process of removing the load from the structure after reaching the max test load". Non of us are native English speakers, Please help to conform.

Thx in advance

RE: "Periodic Unloading " meaning ?

This is how I interpret this section:
The entire test load needs to be periodically removed so permanent deformation can be measured and assessed. On page 16.1-551, the commentary states "Periodic unloading, after the onset of inelastic behavior, will help the engineer of record determine when to terminate the test to avoid excessive permanent deformation or catastrophic failure."

RE: "Periodic Unloading " meaning ?

Thanks a lot wannabeSE

I really appreciate your help, I just wanna understand the complete meaning.

1-I am confused about how I can terminate the test while removing the load ?!!!! I thought termination might happen if I am loading the structure, if I reach to critical situation (near to failure), I have to terminate the phase of adding load to the structure.

2-How during load removal I assess the deformation and make decision to terminate the test to avoid catastrophic failure?

Thx again

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