We know every structure is designed for a life period. The existence of the structure after the service life period is very dangerous to its occupants and surrounding buildings .The building act usually contains provisions that enable local authorities to control demolition works for the protection of public safety and to ensure adjoining premises and the site are made good on completion of the demolition. A notice of conditions is issued that require certain works to be undertaken to achieve these aims. Where demolition of a building takes place, the owner must inform the council. Greenhouses, conservatories, prefabricated garages and sheds do not require permission to be demolished. Usually if the building to be demolished has a volume of less than 1750 cubic feet (49.56 cubic meters), then permission is not required to knock it down.
Demolition is the process of tearing down or falling down of a building after its life period with the help of some equipments or any other method. When explosives are used for this then the demolition process are called as an implosion. Every civil engineering structure is designed for a life period. After that the existence of a structure is very dangerous. So removal of such structures with proper safety measures has got great importance. There are different steps involved before and during the time of a demolition activity. They are described as follows.
3. Steps before Demolition
The different steps before the execution of a demolition process are:
2. Removal of hazardous materials
3. Preparation of plan
4. Stability report
5. Safety measures
Surveying means study of different parameters of the structure and its surroundings. There are two types of surveying are mainly conducted. They are
A. Building surveying
B. Structural surveying
A. Building surveying
(a) Record Drawings
Prior to the Building Survey, the existing record plan, including layout plan showing adjoining properties, pedestrian walkway, roads and street, etc. shall be retrieved.
(b) Survey Items
The Building Survey shall cover the following:
(1) The construction materials;
(2) The existing use and, if possible, the past uses of the building prior to demolition;
(3) The presence of wastewater, hazardous materials, matters arising from toxic chemicals, flammable or explosive and radioactive materials, etc. and possible presence of materials which can contribute to air pollution and soil contamination;
(4) Potential dangerous areas, e.g., abnormal layouts, presence of enclosed voids, and non- ventilated light wells which may trap obnoxious gas at the bottom;
(5) Adjoining properties and site conditions, such as the existence of slope and retaining wall, wall supporting ground, illegal structures, bridges, underground railway and its above ground structures, including entrances, vent shafts, distribution substations, traction substations, plant rooms, overhead railway structures, surface track sections, overhead cables or guy wires, and other utility Service connections;