# Effective Section Stiffness of Structural System Elements

**ICONS**

* d _{b} =* Diameter of longitudinal reinforcement (average in tensile) [m]

*column, beam, tie beam or curtain modeled according to the agglomerated plastic behavior*

**(EI)**Effective section stiffness of_{e}=**f**

_{y }*Average (expected) yield strength of reinforcing steel [MPa]*

**=****f**

_{ce }*Average (expected) compressive strength of concrete [MPa]*

**=****h**

*Section height [m]*

**=****L**

_{s }*Shear opening [m]*

**=****M**

_{y }*Effective yield moment [kNm]*

**=****ϕ**

_{y }*Curvature of yield [m*

**=**^{ -1}]

**θ**

_{y }*Flow Status to*

**=***the axis of rotation likelihood disposition*[rad]

**η**

*in the calculation of the first rotation Pour beams and columns, curtains received coefficient 0.5*

**=****TBDY Section 5.4.5. Effective Section Stiffness of Reinforced Concrete Bearing System Elements**

**5.4.5.1 -** Effective cross-section stiffness multipliers regarding in-plane and out-of-plane behavior of **linearly** modeled walls and slabs shall be taken from **Table 4.2** in **4.5.8** .

**5.4.5.2 -** Effective cross-section stiffness of columns, beams, tie beams and walls modeled according to the **piled** plastic behavior will be determined according to **Equation (5.2)** .

Here, M _{y} and θ _{y} show the average of the *effective yield moments* and *yield rotation* of the plastic hinges at the ends of the rod element . L _{s} is the shear gap (ratio of moment / shear force in cross section); It can be taken as approximately half the span in columns and beams, and half the distance from the base of each floor to the top of the curtain for curtains. **The** rotation of plastic hinge flow θ _{y in }**Equation (5.2) shall** be calculated by **Equation (5.3)** :

Here ϕ _{y} indicates the effective curvature flow in the plastic joint cross section. It will be taken η = 1 for beams and columns and η = 0.5 for walls. h is the section height. *Flow conditions for reinforcement stripping* rotation expressing last term containing D _{b} support (nodes or base A) Average diameter of the interlocking reinforcing steel, f _{ce} and f _{to} the concrete of the average (expected) shows the yield strength average of reinforcement compressive strength.