# Theoretical Principles of Shear Wall Design#

Overview of the theoretical principles behind the tasks of Shear Wall Design.

## Simplified Compression and Tension Method#

The Simplified Compression and Tension Method (short: C & T Method) designs each boundary zone element of a wall for shear. There are two boundary zone elements A(Z+) and B(Z-) which always be located due to the local coordinate system as shown in the figure:

The critical section will always be designed with the option of reporting additional sections for each wall. The wall will be calculated for all load combinations and the stress resultants will be integrated along the height.

The C & T Method is based on a planar calculation. The resulting N_{Ed} and M_{yEd} around the strong
axis are representing the initial state. The forces N_{Ed} and M_{yEd} will be distributed as a couple of forces F_{a}
and F_{b} to each boundary zone element and the program iterates until the equilibrium
between the acting and resistant forces is reached.

There are several setting options to control the C & T Method:

Evaluate the boundary zone element length for each side

Provide an upper and lower length limit for each boundary zone element length

Provide a fixed boundary zone element length and evaluate required reinforcement

If no limitations are given, the maximum boundary zone element length will be half of the wall width and the minimum is starting with zero and increases the boundary zone element length in an iterative approach. Hereby, there is always considered a maximum ratio of reinforcement for compression and tension. The evaluation of the boundary zone element considers the maximum reinforcement ratio and if necessary the edge zone length will be increased. The program is finished when the boundary zone element is evaluated and a maximum utility degree is achieved.

## Required Shear Reinforcement#

The calculation of the shear reinforcement will consider the longitudinal reinforcement from the C & T Method and applies the rules according to EN 1992-1-1, Chapter 9.6.3. Hereby the lever arm is considered between the center of each boundary zone element.