General requirements (walls seismic: ACI 318)
Maximum recommended axial force
As to impose the wall ductile behaviour axial force values are recommended to be kept low in the design of Special Reinforced Concrete Structural Walls resisting earthquake effects. The maximum axial force value in walls is recommended to be kept below the balanced point. Compression controlled walls should be avoided.
Limiting Height
Buildings in which Special Reinforced Concrete Structural walls compose the SFRS in any of the main directions should have their height limited. Where dual systems of SRCSW and Moment Frames resisting at least 25% of the total shear exist there are no height restrictions.
Vertical Segment Classification
Isolated vertical segments within a wall  wall with openings  can be classified as wall segments or wall piers. For Special Reinforced Structural Walls and depending on the classification of the segment the governing design provisions can be split into provisions for walls and provisions for wall piers.
Midzone Reinforcement
Vertical and horizontal bars in midzones of Special Reinforced Concrete Structural Walls are designed according to the requirements of the following sections.
Minimum number of reinforcement layers
The minimum number of reinforcement layers allowed to be used in a Special Reinforced Concrete Structural Wall is governed by the amount of inplane shear sustained by the wall
If the wall thickness b_{w} is greater than 250mm (10 in.) then at least two curtains of reinforcement are required.
If the wall thickness b_{w} is less than 250mm (10 in.) and the SFRS Type = Special Reinforced Concrete Structural Wall, then the minimum number of layers is dependent on the maximum shear force in the panel (ACI 31811); or the maximum shear force and wall geometry (ACI 31814). This is checked accordingly.
Additionally, reinforcement is required to be provided in both of the orthogonal directions in the wall plane  This requirement is automatically met as Tekla Structural Designer does not design walls with reinforcement in only one of the orthogonal directions in wall plane.
Minimum in plane reinforcement ratios
The minimum reinforcement ratio required in each of the orthogonal direction in the wall plane is dependent on the maximum panel factored shear force from analysis for seismic combinations and calculated as follows:
IF SFRS Type = Special Reinforced Concrete Structural Wall then the maximum factored shear force at the panel is checked:

If V_{u}  >  V_{u,lim} 
where  
V_{u}  =  Maximum factored shear force in the wall panel obtained from the analysis for seismic combinations.  
V_{u,lim}  =  Minimum factored shear force in the wall above which horizontal and vertical main reinforcement minimum ratios need to be checked.  
M_{nc,l,top}, M_{nc,r,top}  =  Nominal Moment Strength of the stack above converging on the same joint for the axial force value consistent with the minimum Nominal Moment Strength respectively for the left and right sway cases.  

Then a check for minimum reinforcement ratio in each orthogonal direction on the wall plane is performed as follows:

ρ_{l}  ≥  ρ_{min} 
ρ_{t}  ≥  ρ_{min}  
where  
ρ_{l}, ρ_{t}  =  Respectively the ratio of area of distributed vertical and horizontal reinforcement to gross concrete area perpendicular to each of those reinforcements.  
ρ_{min}  =  Minimum allowed ratio of reinforcement in the wall plane = 0.0025.  

Else if V_{u}  ≤  V_{u,lim} 

ρ_{l} and ρ_{t} are allowed to be taken as the wall design conventional values.
Depending on the overall dimensions of a wall the vertical reinforcement ratio, ρl in Special Reinforced Concrete Structural Walls is limited to be of the same value or larger than the horizontal reinforcement ratio, ρ_{t}
Endzone Reinforcement
Shear Strength
Minimum shear strength
The basic design requirement for shear reinforcement in a wall is to have the reduced shear strength higher or the same as the maximum factored shear force at the considered section resultant from earthquake combinations. Some level of overstrength is expected when designing to multiple load combinations.
IF SFRS Type = Special Reinforced Concrete Structural Wall then the following check for shear strength is performed:

ɸV_{n}  ≥  V_{u} 
where  
ɸ  =  Strength reduction factor. For purposes of checking the nominal shear strength = 0.6  
V_{n}  =  Maximum nominal shear strength at the considered panel.  
V_{u}  =  Maximum factored shear force in the wall panel obtained from the analysis for seismic combinations.  
