# Anchoring

The structural frame
The construction
The reinforcement I
The reinforcement II
Quantity/Cost estimation
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Slabs
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Appendix B
Appendix C
Appendix D
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Modelling slabs

Materials
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Introduction

## (a) Anchorage inside a strong boundary element

When the boundary element is strong enough and the horizontal rebars (distribution bars) get anchored inside the column’s core, a straight anchorage length can be used.

## (b) Anchorage inside a weak boundary column

When the boundary column is weak and its length is not enough to allow for a straight anchorage, it is mandatory to anchor the horizontal rebars by forming a hook at their ends.

## (c) Straight line anchorage inside the column core, when the boundary element is strong enough and one of its sides is flush with one side of the shear wall: (i) case:

In this case, the disadvantage lies in the need for bending, albeit slightly, the horizontal rebars in certain areas. In this case, the ‘S’-shaped reinforcement must restraint the horizontal rebars at the point where they intersect with the vertical ones.

## (c) Straight line anchorage inside the column core, when the boundary element is strong enough and one of its sides is flush with one side of the shear wall: (ii) case:

In this second case of a straight-line anchorage, the horizontal rebars do not have to be bent. This increases their cover thickness but since they mainly carry shear forces no serious problem arises. Moreover, the internal lever arm of the vertical rebars is diminished but only around 1cm so practically again, no problem appears.

## (d) Anchorage by encircling the boundary column and ending in a hook 1st case: adequate straight anchorage length:

No matter if the column is strong or weak, the horizontal rebars must end in a hook, which will be placed in the inside of the confined column. The anchorage can be achieved with a 90° hook placed inside the body of the boundary column.

## (d) Anchorage by encircling the boundary column and ending in a hook 2nd case: inadequate straight anchorage length:

When the column’s length is not large enough to provide an adequate straight anchorage length, hooks bend at 45° (135°) are being used. These are either completely prefabricated so as to have 45° bend in both edges, or they are assembled on site with horizontal rebars with ends bend in 45° and 90°. These shall be alternately placed along the wall height.

## (e) Rebar anchorage in continuous peripheral basement shear walls

In continuous basement shear walls the difficulty in placing the reinforcement is located in the column area. This difficulty may be overcome by placing there straight horizontal distribution starter bars. These bars would have a relatively small length, they would be subsequently tie lapped with the larger intermediate distribution rebars and then, they would both be tied together to the vertical ones.

## Reinforcement in continuous shear walls over ground levels

Usually, in the perimeter of the building, in the storeys above the ground, there is a seismic joint (30 to 100 mm), or a thermal insulation layer (30 to 50 mm), which are not required in the basement. However, their thickness can be used in the basement shear walls to secure the cover thickness and to enable the positioning of the distribution meshes outside the column reinforcement, as shown at the figure.