6.0 FORMER BOXES:
6.1 Generally, the pyramid type of foundation is used which consists of two parts. The lower
part is called the frustum and is the base of the foundation. The upper part is called the
chimney which covers the stub angle.
6.2 Former boxes of the shape, size and dimensions for the individual type and make of tower
as per approved foundation design and drawing are to be used.
6.3 Adequate quantity of former boxes for all types of towers, particularly suspension towers,
shall be got fabricated so that work can be carried out at a number of locations and the
desired progress can be achieved.
6.4 The dimensional drawing of former boxes shall be approved by the Executive Engineer.
6.5 Former boxes are made out of M. S. Sheets having adequate thickness so as to be rigid
during the placing of the concrete. The chimney and pyramid portions are adequately
braced to retain proper shape while concreting. To avoid honeycombs in the concrete, the
former boxes shall be sufficiently tightened to prevent cement slurry from coming out.
6.6 Window is to be provided on the upper part of one face of large size frustums so that
concrete may be placed easily in the lower part. This window shall be fitted back after
placing concrete in the lower part.
6.7 Sample calculations for former boxes are enclosed below