6. DEMOLITION OF SPECIAL STRUCTURES
6.7 Pylons and masts
If using hand demolition, a pylon or mast should be dismantled in the reverse order to that in which it was erected. If another method is used, such as demolition by wire rope pulling, planning including the provision of adequate clear space will be required.
6.8 Precast concrete panels
If a structure is composed of a series of reinforced precast concrete panels, an inspection of the fixings to the rest of the structural elements, jointing between elements, and the lifting points or fittings should be undertaken to establish their nature and condition before any demolition of the structure begins.
Where possible, the panels should be removed by a crane in the reverse sequence to that used for their erection. Wherever panels act as bracing, for example along a wall, sufficient temporary bracing should be provided to the structure, to maintain its stability during and after removal of the panels.
The original lifting points or fittings should not be reused to lift and / or support a panel during its removal if they have deteriorated and corroded.
Before removing any individual panel, it should be fully supported, both vertically and horizontally, above its centre of mass, so as to prevent any sudden rotational movement during its detachment from the supporting structure.
For further guidance on precast concrete elements, refer to the Code of Practice: Tilt-up and Precast Concrete Elements in Building Construction [ under revision ].
6.9 Façade retention
The retention of façades should be planned and documented before demolition work commences. The demolition method( s) used should take into account the limits imposed by the planned façade retention.
Use guarding, hoarding and / or exclusion zones to protect persons against the risk of being struck by falling debris and materials.
The façade or footings may need to be repaired and temporary support for the façade may need to be installed before demolition work commences. Temporary support may also need to be installed in stages during the demolition work, depending on the support design and other external factors such as wind.
Supervision by a competent person( for example, structural engineer) during various stages of the demolition work may be necessary in order to monitor any façade movement or cracking. The structure should be inspected after any unusual incidents such as heavy rain or wind, an earth tremor or accidental impact on the façade or its supports.
CODE OF PRACTICE | DEMOLITION WORK 35