Motorspirit
Petroleum
Hi All
API 650 Appd E gives a table of response modification factors (for ASD methods) for use in calculating the spectral acceleration parameter.
These factors account for a combination of affects including ductility, damping, overstrenth and presumably to account for the fact that ASD method is used in design to App E as opposed to a Limit State Design.
Can anyone give any insight into what the individual factors are that make up these numbers? In particular what is the factor that accounts for ASD vrs Limit State.
Eg, take Rwi for a self anchored tank = 3.5
Is this made up by taking, say:
A ductility factor of 1.25
A damping factor of 1.5
An overstrenth of 1.25
and an ASD factor of 1.5
Therefore Rwi = 1.25 x1.5x 1.25 x 1.5 = 3.5
If anyone has any insight into how these figures were derived or where I could look to find out, that would be great.
The ASD - Limit state figure would be particularly useful as we often design anchor bolts to Limit State design, especially for concrete cone failure etc. It would be good to know how to factor down the API R figures to account for this (ie increase the spectral accelleration).
API 650 Appd E gives a table of response modification factors (for ASD methods) for use in calculating the spectral acceleration parameter.
These factors account for a combination of affects including ductility, damping, overstrenth and presumably to account for the fact that ASD method is used in design to App E as opposed to a Limit State Design.
Can anyone give any insight into what the individual factors are that make up these numbers? In particular what is the factor that accounts for ASD vrs Limit State.
Eg, take Rwi for a self anchored tank = 3.5
Is this made up by taking, say:
A ductility factor of 1.25
A damping factor of 1.5
An overstrenth of 1.25
and an ASD factor of 1.5
Therefore Rwi = 1.25 x1.5x 1.25 x 1.5 = 3.5
If anyone has any insight into how these figures were derived or where I could look to find out, that would be great.
The ASD - Limit state figure would be particularly useful as we often design anchor bolts to Limit State design, especially for concrete cone failure etc. It would be good to know how to factor down the API R figures to account for this (ie increase the spectral accelleration).
