Bs bab 4


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Bs bab 4

  1. 1. DEMOLITION WORKS General Objective C3001 / UNIT 4 / 1 : To understand demolition works in a safe and economical manner Specific Objectives : At the end of this unit you should be able to: • understand demolition processes. • explain demolition methods. • describe safety precautions taken in demolition of building. • recognize machineries used in demolition.
  2. 2. DEMOLITION WORKS 4.0 C3001 / UNIT 4 / 2 INTRODUCTION DO YOU KNOW? With the increased number of fatal accidents caused by demolition of high rise buildings, safety in demolition works becomes a great concern to both the Government and the public. The reasons leading to such horrible accidents are many, of which the lack of planning and supervision are the major ones. Following the issuance of various practice notes to Authorized Persons, Registered Structural Engineers and Contractors, regarding the safety measures for demolition works for the protection of the Public, the Building Department has recently prepared a draft of the Code of Practice for Demolition of Building.
  3. 3. DEMOLITION WORKS C3001 / UNIT 4 / 3 It is intended to be followed by specialist demolition contractors for the demolition of various building works in Malaysia, aiming at minimizing the risks of injury to persons and damage to properties, the risks of endangering the health and safety of site personnel and damage to the environment in the vicinity. The Code sets out the guidelines for demolition of the buildings from roof level to ground level and the demolition of basement, underground tanks, as well ascertain common civil engineering structures, but not major civil engineering works such as underpinning, excavation, highway bridges, dams and nuclear reactors. General guidelines are also given for the design of temporary works and checking of temporary structures. The code covers common methods typically used in the demolition of buildings in Malaysia, but exhaustive guidelines for all methods are not given. The code does not intend to discourage any other demolition methods, which may be used subject to approval. The content of the unit includes the following topics: • Demolition Processes • Demolition Methods • Machinery used in demolition
  4. 4. Based on the Oxford Fajar dictionary demolition means to “ pull to or knock down a building ”, and another meaning for demolition is a “ highly skilled and dangerous activity in terms of damage to life and property”. 4.1 Rina , what is the meaning of “Demolition” ? Demolition Tariffs And Reasons For Demolition C3001 / UNIT 4 / 4 DEMOLITION WORKS
  5. 5. DEMOLITION WORKS C3001 / UNIT 4 / 5 Does anybody know the causes of demolition? ?????? No…sir 4.2 Causes Of Demolition It’s ok, let me tell you about the causes of demolition, the example are: Commercials Aesthetic Human health Human safety Building new buildings Renovation Structure problems Environment ( near slopes ) Population density Adjacent buildings Traffic
  6. 6. DEMOLITION WORKS C3001 / UNIT 4 / 6 Let us list together the demolition processes Demolition Processes 1. Before demolition a. identify site locations, special site restrictions and impact of special buildings b. identify buildings/structures to be demolished c. verify dimensions of site and building d. identify hoardings requirements e. verify building construction, types of materials f. verify existing fixtures g. verify the building use h. verify utilities location i. prepare demolition schedule j. test and remove hazardous materials
  7. 7. DEMOLITION WORKS C3001 / UNIT 4 / 7 k. identify the safety measures for protection of the public l. arrange for debris handling m. prepare demolition plan n. prepare stability report with calculations o. apply consent (also submit supervision plan, names and details of Technically Competent Persons. 2. During demolition a. install site precautionary measures b. remove hazardous materials c. inform site personnel the specifics and precautionary measures d. establish emergency access e. establish line of communication to supervisor f. progress work in accordance with method statements approved. g. remove debris to avoid accumulation h. control dust emission i. adequate supervision j. protect party walls k. ensure workers follow safety procedures l. ensure machines and equipment are well maintained. m. provide security n. schedule regular inspection and maintenance of scaffolding.
  8. 8. DEMOLITION WORKS C3001 / UNIT 4 / 8 3. After demolition a. clear debris and level site b. secure boundaries c. protect all excavations d. for sloping site and/or site with retaining wall i. seal ground surface ii. provide surface drainage iii. provide demolition plan to the foundation contractor for maintaining the supports. Let’s answer the questions in the next activity to test our knowledge.
  9. 9. DEMOLITION WORKS C3001 / UNIT 4 / 9 State whether the following questions are True or False. 1. Commercials, aesthetic, human health, human safety, build new building are the example of the causes of demolition. 2. Demolition processes have 3 situations; it is before, during and after. 3. Demolition means to “ pull to or knock down a building ”, and another meaning for demolition is a “ highly skilled and dangerous activity in terms of damage to life and property”.
  10. 10. DEMOLITION WORKS C3001 / UNIT 4 / 10
  11. 11. DEMOLITION WORKS C3001 / UNIT 4 / 11 1. 2. True 3. 4.2 True True Types And Ways Of Demolition In many circumstances, buildings and structures should be demolished in the reverse order to their erection; although where partial demolition is involved a more careful evaluation of the nature of the effects of the demolition is necessary. Normally, the demolition contractor is able to adopt a method of work which:-
  12. 12. DEMOLITION WORKS  C3001 / UNIT 4 / 12 gradually reduces the height of the building; or arranges the deliberate controlled collapse of the building or structure so that work can be completed at ground level. The choice of demolition technique will depend on the nature of the building or structure and its environment. Risks to the public, operatives involved in the demolition process and adjacent structures and buildings should be considered. Demolition techniques may be categorized as:• Piecemeal demolition, using hand-held tools or machines, to reduce the height of the building or structure gradually; • Deliberate controlled collapse, demolition to be completed at ground level. 4.2.1 Manual Demolition of buildings or structure by hand-held tools such as electric or pneumatic breakers, sometimes as a preliminary to using other methods, should be carried out, where practicable, in the reverse order to the original construction sequence. Lifting appliances may be necessary to hold larger structural members during cutting and for lowering severed structural members and other debris. Chutes may be used to
  13. 13. DEMOLITION WORKS C3001 / UNIT 4 / 13 discharge debris into a vehicle or hopper. Foundations would normally be grubbed up by excavation machines. Figure 4.1 demolition by hand 4.2.2 Machinery’s Components Simple roof structures supported on wall plates should normally be demolished to the level of wall plates by hand, but if this may involve unsafe working, then demolition totally by machine may be appropriate.
  14. 14. DEMOLITION WORKS C3001 / UNIT 4 / 14 Where a building that is to be demolished by machine is attached to another structure, the two properties should be separated by the use of hand methods before the main demolition process begins. When any part of a building is being demolished by a balling machine, pusher arm or similar equipment, only the machine operator and banks man should be allowed close to the working area. The cabs of all machines should be strong enough to protect the operator against the fall of debris. In particular, the windscreen and roof light should be of shatterproof material and guarded by a grille of steel bars or a substantial mesh. Figure 4.2 Demolition by machinery’s components Balling machine Balling machines generally comprise a drag-line type crawler chassis fitted with a lattice crane jib. The demolition ball, with a steel anti-spin device, is suspended from the lifting rope and swung by the drag rope.
  15. 15. DEMOLITION WORKS C3001 / UNIT 4 / 15 Balling should only be carried out by skilled operatives under the control of experienced supervisors using well maintained machines adequate for the proposed duty and standing on a firm, level base. The manufacturer should be consulted before a machine is used for balling to establish any restrictions on the type or length of jib or the weight of the ball. Balling operations subject cranes to dynamic stresses and wear, and the ball chosen should have the minimum weight necessary for effective use. In many cases, demolition balls of quite light weight will be adequate. Floors should be demolished by dropping the ball on the highest remaining floor and allowing the debris to fall inside the building. The debris should be removed regularly to prevent excessive weight accumulating on the lower floors. Walls or columns can be demolished either by swinging the ball in line with the stationary jib, using the drag rope, or by slewing the jib. The ball should not swing by derricking the jib.
  16. 16. DEMOLITION WORKS C3001 / UNIT 4 / 16 Figure 4.3 Demolition ball Figure 4.4 Demolition ball
  17. 17. DEMOLITION WORKS C3001 / UNIT 4 / 17 Figure 4.5 Ball crane Figure 4.6 Ball crane Figure 4.7 Ball crane
  18. 18. DEMOLITION WORKS C3001 / UNIT 4 / 18 Hydraulic pusher arm Articulated, hydraulically-powered pusher-arm machines are normally mounted on a tracked or wheeled chassis, and have a toothed plate or hook for applying for applying a horizontal force to a wall. The machine should stand on a firm level base and apply force by a controlled movement of the pusher arm. Figure 4.8 Figure 4.9 Mini Hydraulic Breaker Hydraulic Breaker Figure 4.10 Hydraulic Mobile crane ( 20 T - 200 T )
  19. 19. DEMOLITION WORKS C3001 / UNIT 4 / 19 Long arm excavator Figure 4.11 Long Arm Excavator Figure 4.12 Long Arm Excavator
  20. 20. DEMOLITION WORKS C3001 / UNIT 4 / 20 Dynamite If explosives are to be used for demolition, the planning and execution, include pre-weakening, should be under the control of a person competent in these techniques. For large demolition, the competent person is likely to be an experienced explosive engineer; for smaller work, a shot-firer may be sufficient. When the use of explosives is contemplated, it is usual to employ a technique that will ensure the total demolition of the whole building by staging a controlled collapse. The explosive charges are set and fired in a sequence that will weaken the structure in such a way that the building collapses in upon itself. Although we tend to think of explosives as devices producing spectacular bomblike explosions, the use of non-explosive "explosives" is now at an advanced stage. These non-explosive techniques are essentially expanding charges that achieve the same results as explosives but without the noise and initial devastating blast. “Did you understand all the information in this unit? If you have difficulties go through the notes again. Now let us answer the question in the next activity”.
  21. 21. DEMOLITION WORKS C3001 / UNIT 4 / 21 Complete the sentences below by providing the correct answers. 1. Demolition means………………….. 2. Demolition techniques may be categorized as ……………… 3. Manual and Machinery components are ……………………… 4. List the machinery’s components. Write your answers in the space below. a) …………………………. b) …………………………. c) ………………………….. d) ………………………….. 5. Who should be allowed close to the working area?
  22. 22. DEMOLITION WORKS C3001 / UNIT 4 / 22 1. Based on the Oxford Fajar dictionary Demolition means to “pull or knock down a building”, and another meaning for demolition is a “highly skilled and dangerous activity in terms of damage to life and property”. 2. Demolition techniques may be categorized as:Piecemeal demolition, using hand-held tools or machines, to reduce the height of the building or structure gradually; • • Deliberate controlled collapse, completed at ground level. demolition to be
  23. 23. DEMOLITION WORKS 3. Manual and machinery components are ways of demolition 4. a) balling machine b) hydraulic pusher arm long arm excavator dynamite 5. The machine operator and banks man should be allowed closed to the working area C3001 / UNIT 4 / 23
  24. 24. DEMOLITION WORKS C3001 / UNIT 4 / 24 Answer the following questions: 1. Give FIVE of the most important safety precautions which must be taken into account before starting a demolition project to prevent your actions from undermining the structural integrity of the building? 2. Give THREE proper attire and tools needed to ensure a safe environment in a demolition project? 3. Give FIVE steps that need to be taken to ensure the homeowner’s safety. 4. Explain how to schedule the best time to start a demolition project. 5. List three examples of Machinery’s Components.
  25. 25. DEMOLITION WORKS C3001 / UNIT 4 / 25 ANSWER NO. 1 • Always know exactly what it is you're about to remove. Before you move or remove anything, always check to see what's behind it, below it and what it might support. • Never assume that a structural member you're about to remove doesn't support anything • When removing framing that is near electrical wiring, shut off the electricity, even if you're not removing the wiring. Do the same for any plumbing or gas lines. A single nick with a saw blade or a drill can cause disastrous results. • When removing electrical wiring, turn off the circuit breaker or remove the fuse controlling the circuit you're working on, and then post a note on the electrical panel warning others not to turn it back on. • Never attempt to work on a gas or water line without first making certain it has been shut off. Also, do not assume that a shutoff valve works - after closing the valve, test the line to be absolutely sure it's off.
  26. 26. DEMOLITION WORKS C3001 / UNIT 4 / 26 ANSWER NO. 2 • Use only the proper tool that is designed for a particular task - don't improvise. If you are prying up a board, use a heavy pry, not a big screwdriver. On the other hand, use a screwdriver to remove a screw; don't yank it out with a pry bar. • If you don't have the proper tool for the job, don't proceed until you are able to buy or rent one. If you need a jack to lift a heavy beam, get one - don't try to rig up a couple of 2 X 4 as a lever. If scaffolding is required to work safely at a given height, get some and take the time to set it up correctly - balancing a 2 X 12 on a couple of ladders is an invitation for disaster. • Wear the appropriate clothings. Demolition work requires long pants, a heavy shirt, and solid shoes - allowing your crew to work in shorts and tennis hoes can net you a serious fine. Wear gloves, and always wear eye protection. If anyone is working above you, or if there is any potential for falling objects, make hard hats mandatory.
  27. 27. DEMOLITION WORKS C3001 / UNIT 4 / 27 ANSWER NO. 3 • Secure all tools at lunchtime, at the end of the day, and during absence from the job site, cords need to be unplugged and sharp tools placed in a safe and secure enclosure. Remember that children are fascinated with construction sites, and this curiosity can lead to serious injuries. • Motorized equipment needs to be securely locked and the keys placed in a safe locked area. • Take down ladders at the end of the day. This includes covering holes in the floor and placing temporary barricades over window and door openings. • If you cannot cover or otherwise close off an area - such as an open trench that is still in use - ring the area with caution tape and place lighted barricades at regular intervals as a warning. • Cover holes and other danger spots.
  28. 28. DEMOLITION WORKS C3001 / UNIT 4 / 28 ANSWER NO. 4 • In most cases, demolition work is best left until the last possible moment in order to help avoid weather and security problems. The addition should be completely framed, roofed, and enclosed with siding, and exterior windows and doors should be installed, before the walls connecting the addition with the existing house should be removed. • Try to work in stages as much as possible, again doing only as much demolition work as necessary for a particular phase of the construction. You may, for example, need to remove a small section of siding at the base of the wall in order to align the new foundation with the old one, or perhaps take down some drywall to line up the new ceiling joints. • Even if it's all coming down eventually, it's best to remove only what you need to accomplish the task you are working on at the moment. ANSWER NO. 5 • Long arm excavator • Hydraulic pusher arm • Balling machine