Construction technology ii report


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Construction technology ii report

  1. 1. SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN BACHELOR OF QUANTITY SURVEYING (HONOURS) QSB1524 – Construction Technology II Scaffolding August Semester 2013 Construction Technology II Report Submission Date: 6thDecember 2013 Name StudentID Yam Yih Hwan 0305861 Low Rong Tzuoo 0304924 Janice Kong Yin Ying 0308798 Harvey Yap Zhu Guang 0309325 Wong Ha Shiong 0309640 Construction Technology II - Report 1
  2. 2. Table of Content Page Cover Page 1 Table of Content 2 Introduction 3 Objective 4 Methodology of Scaffolding 5-7 Safety Precautions 8 - 11 Material Used in Scaffolding 12 - 14 Suitability of Usage 15 - 18 Conclusion 19 References 20 - 21 Construction Technology II - Report 2
  3. 3. Introduction On 26thSeptember 2013, along with my group mates, we went for a site visit in a construction site located at SS16, Subang Jaya. It is somewhere nearby the Subang Jaya Komuter Station. In this project, the main contractor is KP Synergies Berhad – Transgrid Ventures Sdn. Bhd. (Consortium), and the sub-contractor is Bintang Puspa. Once the construction work is done, it will be passed over to TNB, even the contractors/employees are restricted to enter the land, unless with permission. The size of the land is roughly around 5 acres, 20234.3m2, and a combination of two lots. It was then merged together for the construction of the TNB building. The purpose of the land is to build the Subang Jaya Tower Center (Live Station), also known as ―Pencawang Masuk Utama‖. It is a 2 years contract, estimated to complete on 20th October 2014 including the engineering, construction & commissioning works. For your information, the total amount spend is RM 130 million, and RM 17 million only on the construction and civil structure. Once the building is completed, it will be around 5m high all the way to the roof of the tower. Firstly, they clear off the site in order to make platforms for the piling machine to enter the site. Piling must be done in flat ground. Then, they excavate vary from the size of the loading, particular pile group thickness. Excavation level is depending on the size of the pile cap, the depth/width/length of the pile cap = volume (m3). The higher the loadings, it requires bigger size pile caps & deep excavation. As for smaller loadings, it only requires smaller size pile caps &swallow excavation. Pile is around 300mm2 deep into the ground, using reinforced pre-cast concrete piles 45mm thick. Moreover, total numbers of 5 transformers is placed under the building with the depth of 1.5m. On the left side, it contains three 240 MVA (megavolt) transformers. And on the right side, it contains two 90 MVA (megavolt) transformers. Each one of the transformer contains of 87 thousand liters of transformer oil. Furthermore, returning walls are built at the sides of the lower ground; it is required to raise up the platform for the construction of walls, and then backfill it. This project is a conventional construction; it does not use any system formwork or any special plan off construction metrology. The only precast unit used is precast piles, because it is cheaper as compared to in-situ casting. Construction Technology II - Report 3
  4. 4. Objective  To help us get a more understanding on the basics of construction process while paying a visit to the site.  Let us experience the actual working environment as a Quantity Surveyor on site dealing with uncertain circumstances such as the weather condition and the risks that may take place on the site.  Let us aware of the importance of personal safety on site, and the safety precautions that we need to take in order to avoid accidents from happening. For instance, we are required to wear safety helmet on site.  Increase our knowledge on the basic construction process by observing the building team and gathering information on the actual practice that carried on the site.  Explore and identify various types of building materials and type of technology used in construction while constructing a building. Construction Technology II - Report 4
  5. 5. Methodology of Scaffolding Scaffolding is a structure or framework that is temporarily used to support loads of humans and materials during a construction process. It is also used to ease the accessibility of a person going from one floor to another and provides a safe working space at an elevated height. Scaffolding system normally uses metal tubes or metal pipes to connect with each other and it can also be from other materials besides metal. For example, bamboo, that is widely used in Asia. Scaffolding is normally used when the working level is 1.5 m above the ground. Structural elements of scaffolding The basic elements of a scaffold are the three components such as: standards, ledgers and transoms. The standards, also known as uprights, are the vertical long pipe or tube that transfers the loading mass of the structure to the ground where they rest on a square base plate for the spreading of the load. There is a shank in the centre of the base plate to hold the tube and sometimes it is pinned to a sole board. In between each standard, the component that runs horizontally is called ledger. It adds further support and weight distribution to the whole structure. There is also a component called transom, which are placed upon the ledgers at right angles. Main transoms are placed next to the standards and they hold the standards in place to provide support for boards. Whereas intermediate transoms are placed in between the main transoms to lend additional board support. Besides standards, ledgers and transoms, there are a few other supportive elements that are also used to reinforce the fundamental scaffolding. One of it is the braces. There are many different types of braces such as the cross braces, façade braces, and additional couplers. It can be used in different combinations to support the structure in several ways. Cross braces are braces that run diagonally between ledgers and it is attach securely to standards to increase a structure’s overall rigidity. However, they can also secure themselves to ledgers, in which case they are simply called ledger braces. In order to prevent the structure from swaying, façade braces are attached on the face of the scaffold. It runs the length of the face of the structure and securely attaching at every level. Construction Technology II - Report 5
  6. 6. Methodology of Scaffolding Furthermore, couplers help in connecting structural elements, and come in several variants. A right-angle coupler is used to connect a ledger or transom to a standard. A putlog or single-coupler should be used if a transom supports a board and must be connected to a ledger. A swivel coupler is recommended for any other angle of connection between scaffold piping. The width, length, and height of each scaffold element depend on the need of the building, but there are several required measurements for each basic component. Generally, the width of a scaffold is determined by the width of the scaffolding boards. The height between ledgers, which is also known as the lift height, is usually between 2 to 2.7 m. The placement of transom depends on the board thickness. If the board is 38 mm thick, the transoms should be 1.2 meters apart, at the most. A 50 mm thick board requires that transoms be not more than 2.6 meters apart. In addition to the basic structural elements of a scaffold, there are a few different kinds of ties to secure a scaffold to the adjoining building. As a general rule, ties are attached at every 4 meters on alternating lift levels. However, depending on the kind of scaffold, the patterns and types of ties used can also varies. For example, ties can be used to secure a scaffold to a building by entering a building’s open window. A box ties are used to help in securing a scaffold by attaching to a building’s external features, such as strong pillars. Firstly, a level surface that is stable should be used to erect the, and if it is not, the contractor will have to stabilize it and make sure that it is adequate to support the scaffolds. Appropriate measures need to be taken if the scaffolding is to be erected in a public place as the safety of bystanders is incredibly important. For example, the work can be scheduled to proceed during quiet periods (usually at night), which less people are likely to be in proximity to the structure or roads can be closed through council permission. An important reminder is that scaffolding should never be erected near power lines as this can be extremely dangerous and result in fatalities. Construction Technology II - Report 6
  7. 7. Methodology of Scaffolding Construction Technology II - Report 7
  8. 8. Safety Precautions Scaffolding can also be a dangerous place to work if it is not properly installed or used. Your live might be at risk and also the people beneath might face fatal injuries if knocked by falling objects from high level. A scaffold must always be erected plumb. This is because it will be more stable for the workers while working on it. An OSHA-defined qualified person should have knowledge about the bracing, load and safety code requirements for each and every job site. A ―competent person‖ described by the COSHA should inspect all the elements of the scaffolding to make sure in is in good condition before it is being used. 1. Ensure each and every worker is well trained. As stated in the safety regulations code, workers are required to be trained in the design structure and operation of scaffolding. The training should cover important safety work practices such as how to safely get on and off the scaffold (using an access ladder, not the scaffold frame; unless it is specially designed to be climbed and both hands are free to grab the rungs). Besides that, it should also cover comprehensive fall protection training specific to the type of scaffolding, dismantling and erecting procedures for those who will be involved. 2. Take time for the preparation work. Before using scaffolding, we must make sure that the base is level, adjusted and sound no matter how long it takes. The legs of the scaffolding must be plumb and all braces in place. Next, make sure that the locking devices and ties are secured, cross members are levelled and the planks, decks and guardrails are installed and secure. Last but not least, check the location for ground conditions, such as slopes, and stay clear away from hazards such as overhead wires. Construction Technology II - Report 8
  9. 9. Safety Precautions 3. Understand the load capacity. Failure to consider the loads to which the scaffold may be subjected is one of the top things that go wrong at the design stage. The scaffold must be strong enough and capable of holding the desired weight, otherwise it could collapse. Do not try to fit as many workers as you can on the platform just to speed up the construction process. Do not overload it with equipment and materials that it is not supposed to and we are not supposed to rest anything near the guardrails as they might just fall off. 4. Ensure the scaffold is properly secured. The scaffold must be properly braced or tied to the building. It could be blown over if it isn’t well secured. According to the Construction Safety Association of Manitoba, ―Bracing must be properly secured in place; otherwise scaffold movement may dislodge an end, reducing the stability of the scaffold. There is several braces retention or locking systems found on scaffolds. These devices must operate freely for ease of assembling and dismantling, and also lock securely to prevent a brace from dislodging. Nails and other miscellaneous odds and ends should not be used in place of proper retention parts supplied by the manufacturer.‖ 5. Use guardrails. The design of the scaffold must incorporate guardrails on at least the three sides facing away from the building if the scaffold is more than 10 feet above ground. There should be a top rail, mid rail and bottom rail (toe board). If you must remove any guardrails while hoisting materials, replace them promptly. Wear fall protection at all times, ex: Safety harness. People tend to neglect the importance of guardrails as it might be an additional cost implied to the project. Construction Technology II - Report 9
  10. 10. Safety Precautions 6. Inspect and maintain. Scaffolding must be routinely inspected by the supervisor or by a competent person — ideally a professional engineer or a person designated in writing by a professional engineer. In the case of a suspended platform, inspect and test all components including welds, stirrups, connecting pins, connecting plates, trusses, beams and working surface. Check whether the lumber is of good quality and if any pieces get broken or damaged, replace them right away. Frames, braces and other components must be inspected for damage, bends and excessive rust or wear. Also check motors, platforms or wire ropes for damage from chemicals or corrosive material. 7. Use appropriate PPE (Personal Protective Equipment). This includes non-slip protective footwear, head protection and fall protection as required, in the form of a safety harness tied off to a solid structure, such as the building or on the scaffolding. Ontario’s construction safety regulations indicate that the harness can be tied off to the suspended platform or scaffold only ―if all or part of the platform or scaffold has more than one independent means of support and the platform or scaffold is so designed, constructed and maintained that the failure of one means of support will not cause the collapse of all or part of the platform or scaffold.’ 8. Good housekeeping. There isn’t much room on a scaffold, so it’s important to store tools and materials in an orderly fashion. Keep the platform free of obstructions. Place debris and waste material in a container or remove it from the platform immediately. Construction Technology II - Report 10
  11. 11. Safety Precautions 9. Keep your balance. A scaffold and its platform must be perfectly level (CSA standard says it mustn’t deviate from the vertical by more than 12 millimeters per three meters of height) to minimize the risk of workers losing balance and falling off. Particularly on swing stages, there must be an adequately weighted counterweight. Pay attention when working on a scaffold. Any sudden movements, or reaching too far from the platform, can cause a loss of balance. Construction Technology II - Report 11
  12. 12. Materials Used in Scaffolding A scaffold, properly designed, erected and maintained will provide both a means of access and working place which is as safe as those found in existing structures and on permanent structures. Basically the materials used in scaffolding are tubes, couplers and boards. Tubes can be steel or aluminium, although composite scaffolding uses filament wound tubes of glass fibre in a nylon or polyester matrix. They are either in 'black' or galvanized. The tubes come in a variety of lengths and a standard diameter of 48.3 mm. One basic 24 pounds per unit a scaffold of many sizes and heights could be assembled easily by a couple of labourers without the nuts or bolts. The main difference between the two types of tubes is the lighter weight of aluminium tubes, a greater flexibility and lower strength. Tubes are generally bought in 6.3 m lengths and can be cut down to certain typical sizes. On the other hand, boards offer a safety working surface for scaffold users. They are qualified wood and come in three thicknesses which are 38mm (usual), 50mm and 63mm. The standard width is 225mm and the maximum length is 3.9m. The board ends are protected either by metal plates called hoop irons or sometimes nail plates. (Google Book, n.d.) The requirement of timber scaffold board is BS 2482. Steel, laminated boards or aluminium decking can also be used. In addition to the boards for the working platform, there are sole boards which are placed beneath the scaffolding if the surface is soft. Construction Technology II - Report 12
  13. 13. Materials Used in Scaffolding Besides that, couplers are the fittings which hold the tubes together. The most common are called scaffold couplers. There are many types of couplers of scaffolding and the three basic types are right-angle couplers, putlog couplers and swivel couplers. The coupler used at construction in Malaysia is Swivel coupler because Swivel coupler are highly flexible, have exceptional performance, rotates in all directions and it has international standard. The function of the coupler is to connect horizontal and vertical tubes together. Only right angle couplers and swivel couplers can be used to fix tube in a 'load-bearing connection'. Single couplers are not load-bearing couplers and have no load-bearing capacity. Other types of common scaffolding components include base plates, ladders, ropes, anchor ties, and reveal ties, gin wheels, sheeting, and many more. All elements in the scaffolding that are made from metal can be painted. However, elements that are made of wood should not be painted as this could hide defects. Many scaffolds measure tubes and boards in imperial units, with tubes from 21 ft. down and boards from 13 ft. down, despite the metric measurements given. Construction Technology II - Report 13
  14. 14. Materials Used in Scaffolding The construction site that we have visited is the Tenaga Nasional Berhad (TNB), located atSelangor. The construction site uses steel scaffolding, swivel couplers and a piece of wood placed on the scaffolding. We think the platform used in the construction is very dangerous compared to the other countries. Basically in Malaysia, they are using the same type of platform, a piece of wood, the reason why they used that type of platform is to lower the cost but it increases the safety risks of the users on the scaffolding. In an international scope, like Hong Kong, bamboo scaffolding is commonly used, with nylon straps tied into knots as couplers. In India, bamboo or other wooden scaffolding is also commonly used, with poles being pounded together using ropes made from coconut hair known as coir. (Unknown, Construction Technology II - Report 14
  15. 15. n.d.) Suitability of Usage There are many different types of scaffoldings that are used in the construction industry today. Each of them can also serve different purposes such as bricklaying, plastering, or demolition. When deciding which types of scaffoldings should be used, the design, shape and location of the building or structure should be considered. The most suitable or adaptable scaffolding should be selected. Generally, there are 3 basic types of scaffoldings that are supported, suspended, and aerial lifts. The supported scaffolding is the most widely used scaffolding. It is set on the ground and can be stacked up to very high altitudes. As the taller and wider the scaffolding gets, its stability also increases. Workers can reach the upper platform by using the ladders at the side, or in modern scaffoldings, through the stairs. There is also a similar type of supported scaffolding, but with wheels installed at the bottom to allow movement and flexibility. However this type of scaffolding is less safe than the common supported scaffolding as the stability is lower and it has a limited height. Construction Technology II - Report 15
  16. 16. Suitability of Usage The suspended scaffolding however, is very different from the supported scaffolding. It is suspended above the ground with special ropes which can support its required weight. It allows workers to be able to do their job more conveniently due to its flexibility to move around the building to the sides. It is much easier to install compared to the supported scaffolding but it has higher risks. It cannot be placed too high on a building or structure as it can be dangerous. There is also a cantilever type where there are no ropes to hold the scaffolding but instead is supported with beams connected to the building or structure. Construction Technology II - Report 16
  17. 17. Suitability of Usage Aerial lifts are rarely used. They are considered to be vehicle-mounted aerial devices. They are used only when some levels or location are harder to reach. Workers can ride on it and be lifted up to the desired level or location. Since scaffoldings are so widely used, the wide variety of scaffoldings can be brought down to specific types. This means that they have different characteristics and serve different purposes. Birdcage scaffold is mainly used for carrying out ceiling works. It is normally constructed inside the building from corners to corners to internal ceiling works. Tower scaffold is very similar to mobile scaffolds. Mobile scaffolds have rollers attached to them for movement. Tower scaffold has the same qualities but with additions of bracers that are attached to the ground at the corners for better stability. Construction Technology II - Report 17
  18. 18. Suitability of Usage Tube and coupler scaffold is a system that can have a connection of two tubes to be placed at any position and is usually used on structures with unusual design, shape or function. The diameter and strength of the components when using this type of scaffolding should be considered. Tube and coupler scaffold can be of metal, however, it is important not to mix aluminium and steel tubes in one scaffold. Frame scaffolds are often minor scaffolds and similar to the supported scaffoldings but with the use of prefabricated frames, braces, and accessories. It does not require a licensed scaffolder to construct or dismantle. It is commonly used for bricklaying, plastering, and painting. Hung scaffold is similar to the suspended scaffoldings. However, it does not have special ropes to hold it, instead, it is an independent scaffold that hangs from another structure which prevents its ability to move around the building vertically or to the sides. Construction Technology II - Report 18
  19. 19. Conclusion After the site visit, we had gained experiences from the actual work environment on site. We found that working on site is definitely not an easy job as the weather is usually hot. Even after a few hours of site visit, we are so tired and exhausted. As a professional Quantity Surveyor, sometime we haveto go on site to check out stuffs on our own. So, we have no choice but to adapt such circumstances. Construction Technology II - Report 19
  20. 20. References 1. WorkCover NSW (2011). Erecting, altering and dismantling scaffolding. Retrieved on December 2nd, 2013 from ering_dismantling_scaffold_part2_2826.pdf 2. Morra,M. (2011). 10 scaffold safety essentials. Retrieved on December 2nd, 2013 from 3. Google Book. (n.d.).Popular Mechanics (1954 February).Retrieved on November 30th, 2013, from ular+Mechanics&hl=en&sa=X&ei=sJAKTnTDMqRgQenq_mzAg&redir_esc=y#v=onepage&q&f=true 4. Unknown. (n.d.). Guidelines on the Design and Construction of Bamboo Scaffolds. Retrieved on November 30th, 2013, from 5. Safe Work Australia. (n.d.). Scaffolds and Scaffolding Work. Retrieved on December 4th, 2013 from 6. Home Improvement Ideas, Tips and Guide. (2012). Different Types of Scaffolding and Their Uses.Retrieved on December 4th, 2013 from Construction Technology II - Report 20
  21. 21. References 7. The University of Tennessee Office of Environmental Health & Safety. (n.d.). Scaffolding. Retrieved on December 4th, 2013 from 8. Princeton University. (n.d.). Scaffolds and Aerial Lifts Requirements. Retrieved on December 4th, 2013 from Construction Technology II - Report 21