30-01-2013, 04:26 PM
DEMOLITION OF BUILDING
[attachment=48964]
ABSTRACT
Demolition of a building means tearing down or falling down of a building with the help of equipments or explosives. This seminar report deals with how a demolition work is to be performed safely and also elaborates different steps involved before and during the execution of a demolition process. The various steps involved before the demolition process includes surveying, removal of hazardous materials, preparation of demolition plan, stability report and the precautionary safety measures to be taken. The main equipments used for these demolition activities are sledge hammer, excavators, bulldozers, wrecking balls etc. and main explosives used are dynamites and RDX. When explosive are used for the demolition, it is known as Implosion.
INTRODUCTION
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.
2. DEMOLITION
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:
1. Surveying
2. Removal of hazardous materials
3. Preparation of plan
4. Stability report
5. Safety measures
3.1 Surveying
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
It includes,
(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;
(6) Drainage conditions and possible problems on water pollution, flooding and erosion, especially on sloping sites and water receiving bodies;
(7) Shared facilities with adjoining building, including common staircases, party walls, and possible effect on it, such as self-enclosed walls to the adjoining buildings, during demolition;
(8) Hoarding and covered walkway requirements;
(9) Adjoining pedestrian and vehicular traffic conditions;
(10) Available headroom, clear spaces and distance of building from lot boundary which may affect the loading operation and transportation of building debris during demolition;
(11) The sensitivity of neighborhood with respect to noise, dust, vibration and traffic impact.
(12) Available site area to allow on-site sorting of building debris; and
(13) Street furniture such as fire hydrant, parking space/meters, street light, street sign and hawkers’ stalls which could be affected by the demolition project.
© Hazardous Materials
(1) Unless the Building Survey reviews that no obvious hazardous material is present in the building, the Authorized Person shall cause proper sampling and testing for the hazardous materials;
(2) In the case when hazardous materials e.g., asbestos containing materials, or petroleum, are present, they shall be removed and cleaned/disposed of according to the
statutory requirements administered by the Environmental Protection Department, Fire Services Department, Labour Department and any other Government Departments.
(3) In the case when the site has previously been used to store chemicals, and other dangerous goods, soil contamination assessment shall be required at pre-demolition stage and/or post-demolition stage; and
(4) In the case when the site has previously been used to store explosives, special procedures to ensure no explosives remain on site will be required.
B. Structural surveying
(a) Record Drawings
Prior to the Structural Survey, the existing record layout, structural framing plans and structural details shall be studied. The Registered Structural Engineer shall check the presence of unusual detailing that may cause abnormal structural behavior during demolition, e.g., upward anchor of tensile reinforcement in cantilevered structures. If existing record plans are available, these plans shall be used as reference and preferably be brought along with the Structural Survey.
(b) Survey Items
The Structural Survey shall cover the following:
(1) The structural materials used;
(2) The original structural system employed in the design;
(3) The method of construction;
(4) Any dilapidation and degree of deterioration on any structural elements;
(5) The structural conditions of adjoining structures and its shoring which may be affected by the proposed demolition work;
(6) The presence of continuous structures that may be truncated by the demolition;
(7) The structural system and structural conditions of basements, underground tanks or underground vaults;
(8) The presence of exposed bracing or possible presence of covered bracing;
(9) The nature of walls, whether it is block wall, reinforced concrete walls, load bearing walls or partition walls;
(10) Cantilevered structures such as canopies, balconies, or other forms of architectural features; and
(11) Any fixtures to the building such as signboard, sun-shading devices.
© Special Structures
The Structural Survey shall review the following:
(1) The correctness of structural information available;
(2) The presence of any unconventional structural elements which may require special attention and well-defined modification procedures;
(3) The possibilities of structural modification to enable efficient demolition traffic during demolition; and
(4) Any limitation on shoring and other temporary supports.
(d) Investigation and Testing
In the case when no structural details are available, the structural survey shall include on site measurement and retrieve any structural framing as much as practicable, performing tests and exposing some key structural elements to facilitate checking on existing structure. This will allow the development of procedures that ensure the stability of the building at all stages during demolition.
3.2 Removal of hazardous materials
If hazardous materials, such as asbestos containing materials, petroleum contamination and radioactive contamination, exist in the building, further investigation and removal of such hazardous material or contamination by specialist shall be referenced.
[attachment=48964]
ABSTRACT
Demolition of a building means tearing down or falling down of a building with the help of equipments or explosives. This seminar report deals with how a demolition work is to be performed safely and also elaborates different steps involved before and during the execution of a demolition process. The various steps involved before the demolition process includes surveying, removal of hazardous materials, preparation of demolition plan, stability report and the precautionary safety measures to be taken. The main equipments used for these demolition activities are sledge hammer, excavators, bulldozers, wrecking balls etc. and main explosives used are dynamites and RDX. When explosive are used for the demolition, it is known as Implosion.
INTRODUCTION
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.
2. DEMOLITION
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:
1. Surveying
2. Removal of hazardous materials
3. Preparation of plan
4. Stability report
5. Safety measures
3.1 Surveying
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
It includes,
(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;
(6) Drainage conditions and possible problems on water pollution, flooding and erosion, especially on sloping sites and water receiving bodies;
(7) Shared facilities with adjoining building, including common staircases, party walls, and possible effect on it, such as self-enclosed walls to the adjoining buildings, during demolition;
(8) Hoarding and covered walkway requirements;
(9) Adjoining pedestrian and vehicular traffic conditions;
(10) Available headroom, clear spaces and distance of building from lot boundary which may affect the loading operation and transportation of building debris during demolition;
(11) The sensitivity of neighborhood with respect to noise, dust, vibration and traffic impact.
(12) Available site area to allow on-site sorting of building debris; and
(13) Street furniture such as fire hydrant, parking space/meters, street light, street sign and hawkers’ stalls which could be affected by the demolition project.
© Hazardous Materials
(1) Unless the Building Survey reviews that no obvious hazardous material is present in the building, the Authorized Person shall cause proper sampling and testing for the hazardous materials;
(2) In the case when hazardous materials e.g., asbestos containing materials, or petroleum, are present, they shall be removed and cleaned/disposed of according to the
statutory requirements administered by the Environmental Protection Department, Fire Services Department, Labour Department and any other Government Departments.
(3) In the case when the site has previously been used to store chemicals, and other dangerous goods, soil contamination assessment shall be required at pre-demolition stage and/or post-demolition stage; and
(4) In the case when the site has previously been used to store explosives, special procedures to ensure no explosives remain on site will be required.
B. Structural surveying
(a) Record Drawings
Prior to the Structural Survey, the existing record layout, structural framing plans and structural details shall be studied. The Registered Structural Engineer shall check the presence of unusual detailing that may cause abnormal structural behavior during demolition, e.g., upward anchor of tensile reinforcement in cantilevered structures. If existing record plans are available, these plans shall be used as reference and preferably be brought along with the Structural Survey.
(b) Survey Items
The Structural Survey shall cover the following:
(1) The structural materials used;
(2) The original structural system employed in the design;
(3) The method of construction;
(4) Any dilapidation and degree of deterioration on any structural elements;
(5) The structural conditions of adjoining structures and its shoring which may be affected by the proposed demolition work;
(6) The presence of continuous structures that may be truncated by the demolition;
(7) The structural system and structural conditions of basements, underground tanks or underground vaults;
(8) The presence of exposed bracing or possible presence of covered bracing;
(9) The nature of walls, whether it is block wall, reinforced concrete walls, load bearing walls or partition walls;
(10) Cantilevered structures such as canopies, balconies, or other forms of architectural features; and
(11) Any fixtures to the building such as signboard, sun-shading devices.
© Special Structures
The Structural Survey shall review the following:
(1) The correctness of structural information available;
(2) The presence of any unconventional structural elements which may require special attention and well-defined modification procedures;
(3) The possibilities of structural modification to enable efficient demolition traffic during demolition; and
(4) Any limitation on shoring and other temporary supports.
(d) Investigation and Testing
In the case when no structural details are available, the structural survey shall include on site measurement and retrieve any structural framing as much as practicable, performing tests and exposing some key structural elements to facilitate checking on existing structure. This will allow the development of procedures that ensure the stability of the building at all stages during demolition.
3.2 Removal of hazardous materials
If hazardous materials, such as asbestos containing materials, petroleum contamination and radioactive contamination, exist in the building, further investigation and removal of such hazardous material or contamination by specialist shall be referenced.