# Boundary Elements of Special Structural Walls.

Boundary Elements of Special Structural Wall requirements are met automatically

**International Design Codes**

* ACI 318-19 : *Boundary Elements of Special Structural Walls (v12)

* TSC 2018 : *Boundary Regions Reinforcement Detiling Conditions

**Notation in ACI 318-19**

**A _{s}**

**area of nonprestressed longitudinal tension reinforcement, in**

_{ }=^{2}

*gross area of concrete section, in*

**A**_{g }=^{2}

*cross-sectional area of a member measured to the outside edges of transverse reinforcement, in.*

**A**_{ch }=^{2}

*gross area of concrete section bounded by web thickness and length of section in the direction of shear force considered in the case of walls, and gross area of concrete section in the case of diaphrams. Gross area is total area of defined section minus area of any openings, in.*

**A**_{cv }=^{2}

*area of shear reinforcement within spacing s, in.*

**A**_{v }=^{2}

*width of compression face of member, in.*

**b**_{ }=*distance from extreme compression fiber to neutral axis, in.*

**c**_{ }=*specified compressive strength of concrete, psi*

**f**_{c}^{'}_{ }=

**√f**_{c}‘*square root of specified compressive strength of concrete, psi*

**=***specified yield strength for nonprestressed reinforcement, psi*

**f**_{y }=*specified yield strength of transverse reinforcement, psi*

**f**_{yt }=

**h****=**overall thickness, height, or depth of member, in.

**h**_{u}**=**laterally unsupported height at extreme compression fiber of wall or wall pier, in. equivalent to

*for compression members*

**l**_{u}

**h**_{w}**=**height of entire wall from base to top, or clear height of wall segment or wall pier considered, in.

**h**_{wcs }**=**height of entire structural wall above the critical section for flexural and axial loads, in.

**h**_{x }**=**maximum center-to-center spacing of longitudinal bars laterally supported by corners of crossties or hoop legs around the perimeter of a column or wall boundary element, in.

*length of clear span measured face-to-face of supports, in.*

**l**_{n}_{ }=*unsupported length of column or wall, in.*

**l**_{u}_{ }=

**l**_{w }**=**length of entire wall, or length of wall segment or wall pier considered in direction of shear force, in.

**M**_{u}**factored moment at section, in.-lb**

_{ }=*design shear force for load combinations including earthquake effects, lb*

**V**_{e }=*factored shear force at section, lb*

**V**_{u }=*= ratio of volume of spiral reinforcement to total volume of core confined by the spiral, measured out-to-out of spirals*

**ρ**_{s }

**δ**_{c }**=**wall displacement capacity at top of wall, in.

**δ**_{u}**=**design displacement, in.

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