Below is a brief method statement that is for the demolition of existing covered walkway. Existing structure shall be removed completely, which is a cantilevered structure supported by steel elements and covered with roof tiles.
Below is list of equipment for demolition works:
- Skip Tank
- Oxygen Acetylene cutting torch
- Electric Concrete breaker
- Mini- excavator
Preparatory Requirements Before the Demolition Work
All demolition works shall comply with applicable Code of Practice for Demolition. Also the demolition of structure shall be carried out in accordance with the provisions set out in the Workplace Safety and Health regulations.
All underground and above ground services at the site and around the site perimeter shall be detected and a services plan will be produced, i.e. Electricity; Water; Gas; Telecommunication; Drainage etc.
Pre construction Survey shall be carried out including the proposed demolition site and the vicinity and a report shall be prepared. The report will be signed by neighbors and shall be submitted to consultants.
Relevant utility companies and relevant agencies shall be consulted prior to demolition of the structure if the corresponding services are going to be affected.
All the services within the area of demolition shall be terminated or capped off and the last manhole/inspection chamber shall be sealed.
The partition wall or external wall shall be protected against infiltration and water seepage when it is exposed to the weather. Proper plastering method shall be carried out for this purpose.
Proper covering such as gutter, flashing, canvas, etc. shall be provided at roof level to prevent water seeping into neighboring units.
The demolition plan shall ensure that during the course of demolition, no existing utilities in the vicinity of the demolition sites are affected by the demolition operation.
Safety Measures During Demolition Activity
Risk assessment shall be carried out to identify hazards associated with the demolition process, assess such hazards and take reasonably practicable steps to eliminate or control the risks arising from those hazards.
Workers shall possess valid work permit, SOC and in proper attire.
Necessary Personal Protective Equipment PPE shall be provided to workers prior to the start of demolition work.
Safety belts with associated safety harness and lifeline to be provided for the workers, whenever required.
The perimeter of demolition site shall be hoarded up firmly with proper sealing. Sufficient covering shall be provided to prevent dust and debris flying away to neighborhoods/properties.
Sufficient Temporary Warning Signboards, Safety Barriers and Protective Hoarding shall be provided and shall be maintained throughout the period of operation.
Generally, there shall not be any site works during foul weather conditions.
Procedure of Demolition
Top down method shall be implemented for the demolition.
Super structure and roof dismantling shall be carried out stage by stage without affecting the structural stability.
Roof shall be dismantled at first. The removal order shall be for roof tiles and other roof partitions then battens and finally rafters to follow.
Then the structural elements shall be dismantled. The dismantling area shall be identified and be checked on the discontinuity of structural system prior to dismantle.
In the case when structural stability of beams is affected, the affected beams shall be propped prior to loss of support or restraint. Propping shall be provided until the confirmation of structural stability.
The demolition order for the super structure shall be secondary beams, main beams and finally columns.
Plasma cutting shall be used if necessary to disconnect welded joints.
Once superstructure is removed, floor demolition shall be started.
Floor slab shall be demolished by gradually breaking away from the edge of slab.
The reinforcement shall be remained and be cut off after the concrete is broken away.
As the final process of the demolition, substructure shall be removed. First the stumps then footings shall be hacked away. If required, an excavator shall be provided to remove the footing.
Any holes/pits found shall be immediately backfilled with a suitable materials.
Environmental Aspects During Demolition Activity
Noise controlling shall be carried out in accordance to Code of Practice for Noise Control on Construction and Demolition Sites.
Noise monitoring equipment unit shall be provided according to National Environment Agency regulations.
The noise monitoring equipment unit is installed as shown in the approved site plan.
Vibration monitoring shall be installed on site as shown in the site plan.
Method of demolition shall minimize noise emission as well as vibration generation.
To minimize the dust impact, the structure shall be watered before demolition.
Water shall be continuously sprayed during any crushing operation.
Nettings/coverings shall be provided to minimize further dust spreading.
Dust mitigation measures shall be adopted to minimize dust emissions.
Burning of waste shall not be allowed.
All debris generated shall be kept at a designated area and be removed at the end of the day to the skip tank.
Proper housekeeping shall be maintained throughout the whole demolition operation.
Contractor shall be concerned about the neighborhood cleanliness and shall take immediate remedial actions if the neighborhoods are affected by the demolition activity.