Deformation and Plastic Rotation Demand

The strain and plastic rotation demands are determined using the total displaced axis rotation θ_k obtained at the element end . Structure performance is determined as a result of unit strain and plastic rotation demands calculated by linear performance analysis in existing structures.

ICONS

h = Section height
L _p = Plastic hinge length
M _y = Effective yield moment
ϕ _y = Yield curvature
ϕ _t = Total curvature
θ _p = Plastic rotation demand
θ _y = Yield rotation
θ _k = Displaced axis rotation

15.5.4. Determination of Unit Shape Deformation and Plastic Rotation Demands

15.5.4.1 - The unit deformation and plastic rotation demands of the element sections shall be determined by using the total displaced axis rotation θ _k obtained at any element end as a result of the calculation made according to 4.7 or 4.8.2 . The definition of displaced axis rotations at the element ends is given in ANNEX 15A .

15.5.4.2 - total demand curve end section of the element φ _t , Eq. (15.2) wherein the bond will be calculated.

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In Eq. (15.2) , θ _{y is the} displaced axis yield rotation at the element end section , and ϕ _y is the flow curvature at the element end section. The definition of displaced axis yield rotations at the element ends is given in ANNEX 15A . L _{p is the} length of the plastic joint and shall be taken equal to half the cross-sectional dimension in the effective direction.

15.5.4.3 - Effective yield curvature ϕ _y and effective yield moment M _{y in} reinforced concrete systems will be calculated by moment curvature analysis.

15.5.4.4 - For confined or unconfined concrete and reinforcement steel models, if no other selection is made, ANNEX 5A can be used .

15.5.4.5 - plastic rotation lead section of element θ _p , Eq. (15A.2) shall be obtained from.