General

Shear walls are vertical elements that apart from their ability to bear vertical loads, they also limit the horizontal deformations of the structural frame. The term “shear wall” refers to any vertical element with a length to thickness ratio of 4 or more.
In order for a shear wall to behave in the required way, it must have two columns embedded inside its ends (boundary elements).
In case the shear wall does not dispose of clearly defined, normal columns at its ends, two hidden columns are formed using appropriate reinforcement at the edges of the wall’s mass. Their width is equal to the shear wall’s thickness and their length must be at least equal to one and a half times the wall’s thickness (≥ 1.5b).

The cracks that open due to the applied seismic forces in one direction, will close when the direction changes. This will continue to happen for the entire duration of the earthquake.

The boundary elements, either normal or hidden, are reinforced according to the rules that apply to columns.
The wall body is reinforced by two parallel grates one at each face that are held together using ‘S’-shaped transverse bars. The vertical grate rebars must have a diameter at least equal to Ø10, while the horizontal rebars should be at least Ø8 .The ‘S’ shaped reinforcement must be greater or equal to 4Φ8/m².

‘S’-shaped bars provide anti-buckling restraint to the longitudinal reinforcement. Moreover, it ensures that the vertical and the horizontal rebars will continue to work together even after a possible concrete spalling, in case of an intense earthquake event.
The ‘S’-shaped link is formed with one closed corner at an angle equal to 180°, or 135° and the other corner bent at an angle equal to 90°. This is necessary for its trouble-free placement. However, after its positioning the second corner must be also bent at an angle at least equal to 135°.

‘S’-shaped bars provide anti-buckling restraint to the longitudinal reinforcement. Moreover, it ensures that the vertical and the horizontal rebars will continue to work together even after a possible concrete spalling, in case of an intense earthquake event.
The ‘S’-shaped link is formed with one closed corner at an angle equal to 180°, or 135° and the other corner bent at an angle equal to 90°. This is necessary for its trouble-free placement. However, after its positioning the second corner must be also bent at an angle at least equal to 135°.