Module 5: Pre-Cast and Prefabricated Construction Planning, Analysis, and Design PDF

MODULE 5: PRE-CAST AND Weather conditions can impact the PREFABRICATED CONSTRUCTION production and delivery schedules Coordination between trades and PLANNING, ANALYSIS, AND DESIGN...

MODULE 5: PRE-CAST AND Weather conditions can impact the PREFABRICATED CONSTRUCTION production and delivery schedules Coordination between trades and PLANNING, ANALYSIS, AND DESIGN contractors is crucial Precast Construction: Quality control during manufacturing, transportation, and Precast construction transforms installation is essential concrete into a group of shapes and sizes by pouring it into reusable molds. CONSIDERATIONS ON PLANNING, INSTALLATION PROCESSES Prefabrication Construction I. Precast Installations: involves Prefabricated construction involves assembling prefabricated concrete assembling pre-made components at the elements on-site. construction site rather than pouring concrete into molds at a factory. a) Sequencing of Construction and Installation Procedure. Products of Precast/Prefabrication b) Technique for Offering Temporary Construction: Assistance 1. Column c) Installation Tolerances 2. Wall Panels d) Handling and Rigging 3. Double tees, single tees Requirements 4. Inverted tees II. Waterproofing: it is essential to prevent 5. Hollow cores water infiltration, which can lead to 6. Spandrels structural damage, mold growth, and other 7. Rectangular Beams problems. 8. Stairs a. External joints must be sealed with Advantages of Precast Concrete baker rods and sealants after being Increased durability and strength of filled with grout. structures III. Mechanical, Electrical, and Plumbing Lower carbon emissions and better Fittings: resource allocation High level of standardization and a) Mechanical, electrical, and mass - production, leading to cost plumbing fittings shall be kept on or savings. concealed as per the requirements Provides better quality control and b) Before casting, the conduits and assurance of safety, resulting in electrical boxes must be installed higher precision and consistency in and fixed in the molds. construction. c) Provision of National Building Code Enables faster construction times for firefighting systems. reducing overall project duration. IV. Fire Rating: Precast concrete must be Disadvantages of Precast Concrete designed for fire resistance in accordance with prescribed standards and Transportation can be a challenge requirements of the structure being for precast concrete components constructed. due to their size and weight. Proper handling and installation of V. Finishes: considerations for the precast and prefabricated finishings of the construction elements are components is crucial summarized by:  a) Precast concrete can be produced d) Prefabricated designs must in a variety of shapes, colors, consider explosions, ensuring textures, and finishes localized damage doesn't spread b) Rebating, Grooving, Surface and overall stability is maintained. Coatings, Cement-based renders, MATERIALS, MOULDS, AND MODULAR oxide coloring, and other surface COORDINATION AND treatments are required STANDARDIZATION CONSIDERATIONS ON ANALYSIS AND DESIGN PRECAST AND PRESTRESSED CONCRETE: MATERIALS I. Consultants and the Precast Method: CONCRETE: Modern concrete is a. Type of Building produced with a combination of cement, b. Scale of the Project fine aggregate, coarse aggregate, water, c. Site Location and Local mineral admixtures, and chemical Conditions admixtures. d. Economy A. Cement II. Architectural Considerations: Type I Portland cement is a a. Planning general-purpose cement that can b. Massing be used for any application that c. Surface does not require the special d. Architectural Precast properties of other types of cement. Cladding Type II Portland cement is used to e. Waterproofing protect against moderate sulfate attack. III. Structural Considerations: Type III Portland cement provides a) Advantages and Constraints high strength at an early age and is b) Integrated Design Concept ideal for achieving high-release c) Distribution of Precast Design strength. This cement is widely Responsibility used in precast and prestressed concrete plants. IV. Economical and Ecological Type IV Portland cement is used to Considerations: reduce heat of hydration and is a) Increase in Costs useful in mass concrete structures. b) Reduction in Cost Type V Portland cement is used in c) Ecology concrete that is subjected to severe sulfate attack, such as those found V. Risk and Health Assessment in in some soils. Design Considerations B. Aggregates a) Each component must be designed with the proper end conditions and Concrete's major constituents are stresses in consideration at fine and coarse aggregates, which account different phases of construction for approximately threequarters of its b) When designing, appropriate safety volume. They have a significant impact on measures must be implemented the performance of both fresh and c) Every load bearing component at hardened concrete. the building's corners needs to be Aggregate-influenced properties of restrained fresh concrete include workability, pumpability, air content, and finishing MOULDS characteristics. Type of formwork used to shape C. Water concrete or other materials into definite shape and designs. Water used to mix concrete must be clean and free of oil, salt, acid, alkali, sugar, Difference between precast and site vegetable oil, and other harmful cast moulds substances. Water that is known to be Two popular methods of using potable may be used without further concrete as a construction material is by testing. If there is any doubt, water must using precast concrete and cast-in place meet ASTM C94 (AASHTO T26) concrete. Precast concrete is often standards. manufactured in a factory or offsite, and GROUT, MORTAR, AND DRYPACK then transported to the job site where it is assembled or installed. In contrast, cast in When water, sand, and a place concrete is poured and shaped on cementitious material are combined site all into a permanent structure. without coarse aggregate, the resulting mixture is known as grout, mortar, or Types of Moulds drypack, depending on its consistency. 1. Plywood Moulds They are sometimes used solely for fire or corrosion protection or cosmetic treatment, Plywood's availability, cost, and while others are used to transfer loads versatility make it a popular choice for across horizontal and vertical joints. formwork. Made from plywood panels, moulds for various concrete constructions A. Non-Shrink Grouts Shrinkage can be such as slabs, columns, and beams are reduced, or more accurately compensated simply fabricated. It is especially easy to for, by using commercially available non- cut and put together correctly, and it works shrink, high strength pre-mixed grout. particularly well on flat surfaces B. Epoxy Grouts The physical properties 2. Steel Moulds of epoxy compounds vary greatly. Also, epoxy grouts behave very differently than Steel molds are known for their sand-cement grouts. dependability and strength, which can handle heavy loads of concrete. When STRUCTURAL STEEL: Prefabricated repeated use is required in large-scale buildings are constructed using steel frame components construction projects, it is commonly used. Steel shuttering is very customizable and A. Bearing Pads can be fashioned into intricate shapes and patterns. Bearing pads are used to distribute concentrated loads and reactions across 3. Plastic Moulds the bearing area while allowing for limited Plastic formwork is more durable, horizontal and rotational movements to relieve stress. lighter, and easier to handle than timber. It is very useful for shaping concrete into B. Structural Bolts / Anchor Bolts curved or unusual shapes. In addition to being reusable and clean, plastic formwork Bolts to connect precast concrete is resistant to corrosion components are usually installed in standard, oversized, or slotted holes. 4. Rubber Moulds PROS AND CONS OF DIFFERENT MOULDS Naturally, one of the biggest benefits of rubber for precast moulds is its 1. Plywood Moulds flexibility. Other, harder materials, in Pros comparison, are more rigid – not giving the same desired effect. Rubber moulds can Versatile and widely available. usually be cast in different shore Smooth surface finish for concrete. hardness’s, meaning they’re tailored to the Reusable if maintained properly. specific needs of you and your projects. It also decreases the risk of damaging your Cons units when you remove the mould, as Susceptible to moisture damage. rubber is so flexible. May require more frequent 5. Aluminum Moulds maintenance. Aluminum moulds is easy to use 2. Steel Moulds and lightweight. It is widely employed in the Pros development of residential and commercial structures with repeating layouts. Highly durable and can withstand Aluminum formwork is now known for its heavy loads. precision and effectiveness, and it is Reusable for many construction reasonably simple to modify for varying cycles. dimensions Provides excellent concrete finish. 6. Fabric Moulds Cons Concrete is shaped using fabric Expensive upfront cost. formwork, which is made of elastic, Heavy and requires machinery for tension-resistant fabric that is frequently handling. supported by a frame or other structural elements. It is applied to concrete structures to produce original and striking 3. Plastic Moulds forms. Unusual, free-form patterns are allowed by the fabric moulds Pros 7. Permanent Insulated Moulds Lightweight and easy to handle. The benefits of insulation and Resistant to moisture and formwork are combined in permanent chemicals. insulated molds. In applications like Quick assembly and disassembly. erecting insulated concrete walls or Cons building envelopes, where both structural support and insulation are required, it is Not as durable as steel or widely utilized. Once installed, it becomes aluminum. an integral part of the building's structure. Limited to smaller to medium-sized projects. 4. Rubber Moulds Pros Flexible and easy to use. Provides detailed textures. Lightweight and durable. Cons 7. Finishing Can be expensive. Modular Coordination Prone to wear and tear. Modular Coordination (BCA Buildability Requires careful handling. Series) 5. Aluminum Moulds developed by the Building And Pros Construction Authority (BCA) in March 2000 provides great insight Lightweight and easy to handle. and details to this specific process Precise and consistent results. that revolutionized the construction Reusable for multiple projects. industry. Cons This was initially developed as a conceptual tool immediately after Initial cost is higher compared to the start of the process of some alternatives. prefabrication in the construction business within the developed 6. Fabric Moulds countries. Pros It provides an effective design tool, providing modern principles and Flexibility in design and shape. guidelines, balancing flexibility in Suitable for artistic and architectural planning with freedom architectural applications. to select construction methods. Cons Key Advantages: Limited to specific decorative or (a) Increased coordination and artistic projects. collaboration in a construction May not provide the same structural environment. strength as traditional (b) Shorter design time, exploiting standard formwork. details and dimensioned alignment. 7. Permanent Insulated Moulds (c) Greater benefits from increased adoption of Computer-Aided Design and Pros Drafting (CADD). Combines formwork and insulation (d) Lower costs for fabrication and in one. installation. Ideal for energy-efficient buildings. (e) Minimizes the use of on-site cutting and Cons trimming and thus reduces waste of May have higher upfront costs. materials, time and labor. Limited to projects where energy (f) Additional support for fabrication. efficiency is a priority. TERMS AND DEFINITIONS Processes Involving Moulds 1.1 Coordination 1. Planning and Design 2. Mould Fabrication 1.1.1 Dimensional Coordination - 3. Mould Placement a range of related applications are applied 4. Concrete Pouring to the sizing of buildings af campers the 5. Curing buildings along with components and 6. Mould Removal assemblies incorporating them.  1.1.2 Modular Coordination - (b.) Axial Reference Dimensional coordination through basic It coordinates the position of a module, multiple modules, sub module and a modular reference system component by letting the two axis coincide in a modular coordinating grid 1.2 Modules (c.) Interaxial Reference 1.2.1 Module - a dimension used as a basis for dimensional coordination. Also coordinates the position and dimension of a component through a 1.2.2 Basic Module (M) - a module known reference of 100mm. (d.) Flush Reference 1.2.3 Multi-Module - a module which is an agreed multiple of 100mm. Determines the position of a component by arranging the component so 1.2.4 Planning Module - a multi- that one side is flushed onto a modular module chosen for a planning grid. coordinating grid and/or plane 1.2.5 Sub-Module - a module Components and Finishes which is an agreed subdivision of 100mm. Structural Components Modular reference systems means the (a.) Columns three dimensional system of orthogonal space coordinates of the positions and The recommended dimensions for sizes of components, elements, and columns are multiples of 1M with 0.5M as installation can be connected to the second preference. There is also the references to points, lines, or planes. possibility of using columns of different sizes PLANNING APPROACHES (b.) Beams Face Planning The beam width has less To position components and implications. Beams should be of elements of construction in relation to the recommended depth in increments of grid. Then it also shows you how different 0.5M. components are connected to each other. Pairs of parallel lines are represented. (c.) Floor Slabs Axial Planning The depth of floor slabs will be in submodular increments of 0.5M (50mm) or Often the positions of major 0.25M (25mm) components are determined by axial planning, for instance column and cross (d.) Walls walls. This plan grid lines will be along the center of the components The planning grid chosen will determine how many walls will be. If the Positioning of Components and Space walls are not modular, recommendations (a) Boundary Reference are submodular increments of 0.5M and 0.25M. Determines the position of a (e.) Stairs building’s component through the use of two parallel modular coordinating grids as The coordinating spaces will be seen in the figure wide enough on plan to contain the two flights and as much space in between as could eventually be achieved. Architectural Components Importance of Modular Standardization (a.) Doors is a critical method in modern construction that entails standardizing Width: Multiples of 1M. Height: building components to facilitate assembly Multiples of 1M. The second preference for and customisation. This strategy allows doors is 0.5M. The measurements include builders to achieve shorter construction the door frames. timelines, higher quality, lower prices, more (b.) Windows flexibility, and better sustainability. Modular standardization allows for the design of Width: Multiples of 1M. Height: accurate and efficient building systems, Multiples of 1M. The second preference for reducing waste and interruption while windows is 0.5M. The measurements increasing advantages include the frames. JOINTS IN PRE-CAST & PREFAB Finishes CONSTRUCTION AND CURING (a.) Ceiling Finishes TECHNIQUES If the building is designed on JOINTS AND CONNECTIONS Modular Coordination, then the space is Joints and Connections in a Structure also modular. The standard grid used is 6M x 6M. Joints and Connections are critical elements in a structural system as they are (b.) Wall and Floor Finishes responsible for holding together various The dimensions are the parameter structural members and for ensuring the of interest with thickness of the materials stability of the structure. being the main concern determined by the What is a Joint? suppliers. The finishes must be allowed within the column, wall and floor zones. A joint is the gap between adjoining elements in a structure where action of Importance of Modular Coordination forces such as tension, compression, and It is an important part of modern shear occur. It provides physical separation construction since it promotes compatibility between the precast elements so that there and efficiency among various building will be spaces between the components of components. By standardizing dimensions the structure. Joints may be horizontal, and relationships, it allows for faster vertical, and inclined. construction, less waste, and higher What is a Connection? quality. Connection is a location where two Modular Standardization or more structural elements meet. It is a design and construction consists of the interfaces and parts of method that involves standardizing the different components that are joined. proportions and interactions among Connections are designed to withstand the various building components. This forces or moments that the structural standardization enables the use of elements will experience. interchangeable, prefabricated modules Purpose of Joints and Connections that may be joined in numerous ways to generate diverse building structures. To transmit forces between structural components To provide overall stability To provide strength to the structure  To prevent from external leakages are projecting at the end of the column To resist unpredictable loads due to passing into sleeves that are then filled with fire, impact, and explosion grout. Requirement for Connection of Joints Wall Panel to Foundation Connection 1. Strength – The connection must be The purpose of this connection is to able to resist the forces that it will tie the load-bearing walls to the foundation. be subjected to throughout its Beam to Column Connection lifetime. 2. Ductility – It is the ability of the This connection creates a moment connection to experience large resistant connection between the beams deformations without failing. and columns at the corner of frames. 3. Change in volume – Changes in volume due to creep, shrinkage, It can be performed through either and temperature reduction induces dry or wet connections. tensile stress in the precast Column to Column Connection components which must be resisted by the connection. The main function of this type of 4. Durability – Connections that have connection is to keep the panels from exposed sections must be bowing and to transfer the vertical shear periodically inspected and force between panels. maintained. This type of connection involves the 5. Fire resistance – Connections that use of splice connection and anchor bolts have been exposed to fire may weakened so it must be protected CURING by concrete or grout and enclosed Curing is the process to control or sprayed with fire resistance moisture loss during hydration of cement. materials. Hydration takes time – days, or even weeks CLASSIFICATION OF JOINTS rather than hours. To achieve its potential strength and durability, curing needs to be Joints may be classified depending done for an ideal period. on the method of connection that was used on the precast members. Purpose of Curing Dry Joint It prevents or replenishes the loss of moisture from the concrete Dry joints are accomplished by It maintains a favorable placing two members through the use of temperature for hydration to occur welding or fastening. for a definite period. Wet Joint Considerations for selecting a curing Wet joints are accomplished by method casting with cement and concreting and The type of construction such as grouting material. those involving large horizontal TYPES OF CONNECTIONS surface areas as in roads, floors, and airfields, or, those involving Column to Foundation Connection formed concrete in walls, columns, The foundation connection can be beams, cantilevers, and arches, etc done through a base plate connected to the column or through the reinforcing bars that  The place of construction, whether formwork is removed) is covering the indoors and damp situations (as surface with straw, burlap, hessian or jute inside a building) or outdoor soaked in water. These are kept moist for The weather conditions where the entire period of curing. Fabrics are concrete is being laid in cold particularly useful on vertical surfaces climates or in dry and hot weather since they help distribute water evenly over the surface and even where not in contact TYPES OF CURING METHODS with it, will prevent the surface evaporation Water Addition Method from within the concrete and supply the additional water required for hydration This method keeps the surface of the concrete moist by ponding, d. Immersion spraying/sprinkling, fogging, misting, wet This method is commonly used in burlap, and other water absorbent the laboratory for curing concrete test materials specimen The precast concrete items are a. Spraying or Fogging normally immersed in curing tanks for a certain duration. Pavement slabs, roof slab This method is ideally suited for etc. are covered under water by making almost all types of construction in most small ponds. Immersion in water is conditions. Vertical reclining walls, particularly important when the concrete plastered surfaces, concrete columns, etc. has a low water-cement ratio. are cured by spraying water. It involves spraying water with the help of house pipes Water Retention Method by Curing connected to the main water supply lines. Compounds (Membrane Method) b. Ponding This method requires less water than other methods, and falls under the Ponding is a method of thermal category of ‘moist curing’. A layer of curing where sand dykes are set up around impermeable compound coats the the perimeter of the surface area, and concrete surface, thereby sealing in the water is pooled within the perimeter to water while effectively avoiding retain moisture over the surface. This evaporation. The thick film of chemical effectively regulates its temperature, but compound starts peeling off after some may be challenging to carry out during time (2-4 weeks) leaving behind the chilly weather conditions. properly cured concrete. These can maintain up to 80% of the humidity in a In this method, pavement slabs, batch of concrete for a week. It is seen roof slabs, etc., are kept under water by membrane curing for 28 days gives making small ponds. Small ponds, not equivalent strength to two weeks of moist more than 5 cm deep, are made over the curing. surface by raising temporary barriers. Water-based membrane curing is a more c. Wet covering environmentally friendly option, consisting Wet moisture soaked burlaps of water-soluble polymers or resins. It's placed on concrete surfaces also aid in the applied directly to wet concrete and is easy prevention of moisture evaporation, and to apply and clean up. However, it may act as surface protectants. This technique require multiple applications in hot, dry is most effective when used alongside climates and can be susceptible to rain or polyethylene covers. wind. Another method, suitable for flat, Oil-based membrane curing is made columnar, and vertical surfaces (after the from petroleum-based products like asphalt or bitumen and is applied after the MODULE 6: PRE-CAST AND concrete has reached initial set. It provides PREFABRICATED CONSTRUCTION a stronger barrier against moisture loss and HANDLING, TRANSPORTATION, AND is more resistant to environmental factors. ERECTION TECHNIQUES However, it contains VOCs, requires more careful application, and is generally more A Handling Techniques expensive than water-based options. A systematic approach is required Temperature Control Method when lifting and offloading precast and prefabricated structures to guarantee The development of the strength of safety, effectiveness, and correct execution concrete is a function of not only time but of the procedure. also of temperature. When concrete is subjected to a higher temperature, it Lifting and Offloading accelerates the hydration process which results in faster development of strength Lifting is the process of utilizing specialized equipment, like cranes or a. Steam curing at ordinary temperature hoists, to raise precast and prefabricated components from their transport position to These methods can best be used in a specified height or location. precast concrete work. In steam curing the temperature of steam should be restricted The subsequent process is called to a maximum of 75°C as in the absence of offloading, and it involves carefully proper humidity (about 90%) the concrete lowering the raised components onto the may dry too soon. In case of hot water ground or another support structure. curing, temperature may be raised to any limit, at 100°C. Equipment b. Steam curing at high temperature The equipment used for lifting and offloading precast structures often includes Unlike ordinary steam curing, this tower cranes, telescopic cranes, side curing is carried out in a closed chamber. boom or crawler cranes, tool carriers, The super-heated steam at high EOT cranes, and forklifts, with specific temperature and high pressure is applied to lifting devices such as web slings, wire the concrete. This process is also called ropes, chains, D-shackle, Hooks, ‘autoclaving. Chains and Spreader bar that are securely attached to the structures. c. Electrical Curing B. Transportation Techniques Electrical curing is a method of accelerating the curing process of concrete Route Planning by passing an alternating current through it. This technique is particularly effective in A comprehensive route planning is extremely cold climates where traditional necessary, wherein variables like weight curing methods may be hindered by low limitations, road conditions, and potential temperatures. This method can also be obstructions are evaluated. economically viable in ordinary climatic Equipment conditions. Heavy-duty vehicles and specialized lifting equipment are required in transporting precast and prefabricated structures. The size and weight of large products typically require the use of specialized vehicles, such as heavy-duty trailers or flatbed trucks, minimizes the possibility of movement by equipped with secure loading systems that aligning and stabilizing the precast utilize straps and chains to prevent elements during the curing process. movement during transport. Forklifts and Furthermore, correctly grouted cranes can be utilized to load and unload connections can strengthen the precast and prefabricated components component's load-bearing capability and safely. increase its durability. C. Erection Techniques III. CASE STUDIES IN PRE- FABRICATING TECHNOLOGY FOR LOW Site Preparation COST AND MASS HOUSING SCHEMES This includes foundation A. Some Applications of Prefabricated assessment wherein the existing Technology foundation is inspected to guarantee that it has been appropriately prepared and Education Facilities cured. Since the foundation must sustain Healthcare Facilities the weight and structure of the precast Shelter Facilities pieces, it must be well-prepared. Housing/Residential Lifting Equipment Other Structures Building walkways, bridges, In construction projects where and modular road precast components are utilized, cranes infrastructure components play a vital part in lifting and moving large are all included in this. precast and prefabricated materials. It is crucial to select cranes with suitable lifting B. Challenges for using Prefabricated and reaching capacities. Technology Alignment and Positioning Perception and Acceptance o It might be difficult to gain Accurate alignment and installation acceptance for modular of precast and prefabricated elements building approaches and to requires the use of tools like plumb bobs overcome typical and laser levels. Considering misalignment construction attitudes. can cause issues during construction, Design Limitations accurate alignment is critical for o While modular building maintaining structural integrity as well as offers flexibility, there may the correct position between components. be restrictions in Connection Methods architectural design compared to traditional Sealants are applied to the joints construction methods. separating precast parts to form a weather- tight seal to prevent water penetration and C. Local Studies maintain the component's structural Modular construction is an integrity. Moreover, sealants are useful in affordable option as it eliminates material enabling movement carried on by thermal waste and labor expenses due to the contraction and expansion. regulated environment of a manufacturing Grouts are applied to the gaps or setting. Modular construction resulted in voids between precast components. It considerable cost reductions for a low- makes it possible to distribute loads income housing project in Davao City. between the components more evenly, When compared to traditional methods, the enhancing its stability. Additionally, it regulated production process in a factory environment eliminated material waste, V. FABRICATION AND ERECTION OF leading to a 15% reduction in overall STEEL STRUCTURAL ELEMENTS building costs. Structural Steel D. International Studies Structural steel refers to steel products that Case Study 1: Prefabrication in the are used primarily in the construction Singapore Construction Industry industry. Structural steel is fabricated in Case Study 2: Prefabricated many different shapes, including beams, Construction for Mass Housing In plates and channels. Mumbai How is Structural Steel Fabricated? IV. CASE STUDIES IN PRE-CAST Structural steel fabrication is the TECHNOLOGY FOR LOW COST AND process of constructing or reconstructing MASS HOUSING SCHEMES metal structures with steel. This fabrication A. Local Studies process basically consists of cutting, bending, and assembling the fabricated Case Study 1: Deca Homes Precast steel. Building System for Mass Housing A. Steel Fabrication Process Location: Philippines 1. Design Preparation Case Study 2: Aboitizland Continues Innovation Push with Stronger And More Design preparation is the Sustainable Homes Using Precast Panel foundation of structural steel fabrication. It Technology involves collaboration between structural engineers, architects, and draftsmen to Location: San Juan, Batangas develop precise shop drawings and project Case Study 3: Megawide Builds Precast specifications. These drawings specify Portfolio Via Phirst Park’s Batulao dimensions, material grades (such as ASTM A36 or A992), welding requirements, Project Location: Nasugbu, Batangas and connection types. B. International Studies Bill of Materials (BOM): Lists the Case Study 1: Cidco Mass Housing type, quantity, and dimensions of Project Using Precast Technique materials needed. Bill of Operations (BOO): Location: Taloja, India Provides a detailed sequence of fabrication tasks and workflows. Case Study 2: India's First Mass Housing Project Built Entirely by The 3d Modular Advanced Building Information Precast Concrete Construction System Modeling (BIM) tools may also be used to generate 3D models, ensuring the design Location: Ranchi, India is efficient, error-free, and clash-free with Case Study 3: Precast Lightweight Wall other structural elements And Roof Panels For Mass Housing 2. Material Acquisition Location: India Once the BOM is finalized, the Case Study 4: Adaptable Housing of procurement team orders raw steel from Precast Panel System In Malaysia suppliers or manufacturers. The material can come in various forms—steel beams, Location: Malaysia plates, tubes, pipes, angles, or bars— depending on project needs.  Standard Length vs. Custom Cut: Press Braking: Forms sharp Some steel may arrive in standard bends in steel plates. lengths (typically 6 or 12 meters) Welding is essential for joining and will require on-site cutting, components. The welding method chosen while other materials may be pre- depends on material type and design cut to the required sizes before specifications: delivery. Material Inspection: Upon Manual Metal Arc (MMA) delivery, the steel undergoes initial Welding: Suitable for heavy-duty inspections to verify compliance structural welding. with the project specifications and Metal Active Gas (MAG) Welding: material certifications (e.g., Ideal for precision welding and chemical composition and automated systems. mechanical properties). Submerged Arc Welding (SAW): 3. Steel Cutting and Drilling Used for thicker materials to create highquality welds with minimal In this step, raw steel is cut and defects. drilled to precise dimensions based on the design specifications. Several cutting 5. Quality Control and Testing techniques are used depending on the Quality checks at multiple stages material thickness, shape, and precision ensure the steel meets the required requirements: tolerances and safety standards. Key Circular Saw Machines: Suitable inspections include: for straight cuts on beams and bars. Visual Inspection: Checks for surface Laser Cutting Machines: High defects, weld continuity, and proper precision, especially for thin plates finishes. and intricate designs. Waterjet Machines: Use high- Dimensional Inspection: Verifies that pressure water mixed with components are fabricated to the correct abrasives for heatfree cutting, size and angle. preventing material distortion. Non-Destructive Testing (NDT): Plasma Cutting Machines: Techniques such as: Commonly used for thicker steel plates due to its speed and Ultrasonic Testing (UT): Detects efficiency internal defects like voids or cracks. Magnetic Particle Inspection 4. Bending and Welding (MPI): Identifies surface and After cutting and drilling, some steel nearsurface flaws. components need to be bent or curved into Radiographic Testing (RT): Uses specific shapes. X-rays to assess weld integrity. Bending Methods: Quality control ensures the steel complies with international standards (e.g., AWS Section Bending: Used for beams D1.1 for welding, ASTM for material and channels. properties). Roll Bending: Gradually bends steel plates into cylindrical forms. 6. Surface Treatment and Finishing Tube Bending: Shapes pipes and To protect the steel from environmental tubes for applications like handrails. corrosion, it undergoes surface preparation and finishing:  Sandblasting: Removes rust, during this phase to ensure long-term scale, and contaminants to create a safety and durability. clean surface for coatings. B. Steel Fabrication Equipment Priming and Painting: A primer coat is applied followed by layers of A variety of equipment is necessary epoxybased or zinc-rich paints. for cutting, shaping, welding, and Some projects may require assembling steel components during the galvanizing, which involves dipping fabrication process. the steel in molten zinc for superior corrosion resistance. Cutting Equipment Intumescent Coatings: Applied for Plasma Cutting Machines fire protection, expanding under Oxy Fuel Cutting Machines high temperatures to provide Laser Cutting Machines insulation. 3-Axis Mills (CNC Machining) 7. Delivery, Assembly, and Installation Water Jet Cutting Machines Once fabrication is complete, the Machining and Drilling Equipment steel components are packaged and Drill Press delivered to the construction site. Proper Milling Machines handling and transportation are critical to avoid damage during transit Forming Equipment Assembly Methods: At the site, steel parts Press Brake are assembled through: Rolling Machine Bolting: Common for fast, CNC V-Grooving adjustable connections. Machine Material Processing Riveting: Less common but still Equipment used for specific industrial applications. Overhead Crane Welding: Permanent connections Stackers and Forklifts where bolting is insufficient. Conveyor Heavy machinery like mobile or tower Finishing Equipment cranes is used to lift and position steel Deburring Tools elements into place. The erection process follows a planned sequence to ensure Painting Equipment stability, starting with key load-bearing Grinders and Sanders members (columns and beams) before Welding Equipment secondary components (purlins, bracings). MIG Welder 8. Post-Installation Inspections and TIG Welder Commissioning C. Steel Erection After installation, the structure undergoes final inspections to confirm that Steel erection is the process of it aligns with design requirements and local constructing big structures including building codes. Load tests may also be buildings, bridges, and other buildings performed to verify the steel assembly’s using steel beams, columns, and trusses performance under expected loads. Any as the structural framework. defects or alignment issues are corrected Steel Erection Process 10.Modifying steel components through welding or cutting using oxyacetylene 1. Preparation welding equipment. Site Preparation D. Steel Erection Hazards Pre-construction Planning Safety Planning “Effect of Safety and Environmental Variables on Task Durations in Steel 2. Erection Erection” (Irizarry, Simonsen, & Abraham) Foundation Preparation lists the major identified hazards involved in the steel erection process: Structural Steel Delivery Assembly of Steel Components Materials – carrying heavy tools and Installation of Secondary Steel handling heavy suspended loads 3. Post-installation Check Tools – using tools needed for connections exposes workers to falling object hazards Load Testing Inspection and Maintenance Design – working with structural elements that have irregular shapes and unstable Tasks involved in the Steel Erection loads when rigging Process Process – walking on narrow and irregular 1. Setting up hoisting equipment to raise surfaces, to the other side to make workers and position structural steel connections, and to the center of element components. for unhooking; moving at high elevations; 2. Installing girders, columns, and other and interacting with moving equipment structural steel parts to create the Causes of Steel Erection Accidents framework of the structure. Data from OSHA show that steel 3. Attaching steel members to cable hoists erection accidents leading to fatalities are using cable, rope, or chain. often due to the following factors: 4. Adjusting the position of steel members Premature crane disconnections using hoisting mechanisms. before the piece was secured 5. Placing components accurately using Workers landing or placing a load crowbars, turnbuckles, hand tools, and on unsecured or unabridged joists jacks. Workers getting hit by objects while walking or working under a load 6. Aligning rivet holes in steel parts by Workers being struck by objects driving drift pins or wrench handles. while landing a load or making a 7. Ensuring the horizontal and vertical connection, by a tool slipping, or by alignment of steel parts using a level and a piece of decking being blown off a plumb bob. pile when fall protection is neither provided nor used 8. Safely catching and inserting hot rivets Failure to use available fall into appropriate holes using tongs. protection systems even though the 9. Temporarily securing aligned steel parts worker was wearing a safety with bolts before permanent riveting, harness welding, or bolting. Stepping onto or working on unsecured decking that slipped out of place when fall protection was neither provided nor used  Workers not being tied off while at MODULE 7: TUNNELING TECHNOLOGY the workstation INTRODUCTION TO MECHANIZED Walking or standing on the TUNNELING beam/joist where fall protection wasn’t provided or used, resulting in DEFINITION AND MAINTENANCE slips, trips, and falls Flying metal splinters; working with Mechanized tunneling involves a chisel and hammer; and constructing tunnels with specialized conducting sharpening, cutting, or machines that handle excavation, ground support, and material transport all at once. welding works without using Personal Protective Equipment This method, particularly through (PPE), resulting in eye injury Tunnel Boring Machines (TBMs), has Lifting and moving heavy loads, become the preferred choice for modern causing back and spinal column infrastructure projects due to its efficiency, injury speed, and safety. Touching live electrical wires or working with portable power tools A Tunnel Boring Machine (TBM) which may lead to electrocution is an advanced system designed to Exposure to high noise levels excavate circular tunnels through different geological materials, ranging from hard How to Improve Steel Erection Safety rock to loose sand. As the ILO recommends, the WHAT IS INSIDE OF A TBM? preventive measures that steel erection companies must consider implementing CUTTER HEAD include: It is located at the front of the TBM and is the primary cutting tool that makes Ensuring that employees are using contact with the tunnel face. It rotates and ladders in good working order and is equipped with various cutting tools, appropriately placed to prevent including disc cutters and scrapers, which slipping; break through soil or rock. The cutter head Requiring the use of PPE that is is designed to grind away the material in suited for the type of work; front of the TBM and create the tunnel. Training employees on safe techniques for raising and lowering CONVEYOR BELT loads; The conveyor belt system is Doing regular maintenance and responsible for transporting the excavated routine checks on portable power material (called "spoil") from the tunnel tools and equipment; face, where the cutter head operates, to the Providing employees with work rear of the TBM and out of the tunnel. clothes that are apt for conditions of the workplace WORKING PLATFORM Evaluating the safety of scaffolding components before work starts; The working platform is the area and inside the TBM where operators and workers control and monitor the machine's Enforcing the necessary medical, operation. An access area to regulate key technical, and administrative operational tasks and safety checks are procedures for preventing injuries carried out to ensure smooth tunneling caused by hand-arm vibrations. operations. TYPES OF TUNNEL BORING MACHINE Machines (TBMs) create circular tunnels (TBM) with little disturbance to the surface, which is vital in busy urban environments. EARTH PRESSURE BALANCE (EPB) Sewers: Mechanized tunneling is The Earth Pressure Balance commonly employed for both the (EPB) TBM is a tunneling method that uses installation and repair of sewer lines. Big excavated material to support the tunnel tunnel boring machines (TBMs) can drill face during excavation. This material is through different types of soil, allowing for plasticized to make it transportable and is the construction of deep sewer systems then moved into the machine via a screw without the need for major surface digging. conveyor, or "cochlea," which maintains pressure balance and prevents ground Roads: Using mechanized tunneling in collapse. EPB TBMs are commonly used in road construction offers several soft ground conditions like clay, silt, and advantages, particularly for building gravel, where groundwater pressure is less underpasses and bypass tunnels that help than 7 bars. ease congestion and enhance traffic movement in cities. SLURRY SHIELD TBM UTILITY TUNNELS Slurry Shield TBMs are designed for tunneling in areas with high Utility tunnels functions in setting up groundwater content or unstable soils, and servicing important utilities like water, such as sands and gravels, and are gas, electricity, and telecommunications. particularly effective in granular soils with Using mechanized tunneling is an effective high water pressure where face stability is way to construct these tunnels below city critical. The machine operates by filling the streets while minimizing disturbances to cutter head with pressurized slurry, what's happening above ground. applying hydrostatic pressure to the CHALLENGES AND CONSIDERATIONS excavation face to prevent collapse and ensure smooth tunneling. GROUND CONDITIONS AND MACHINE SELECTION HARD ROCK TBM The ground conditions play a crucial role in Hard Rock TBMs are designed mechanized tunneling and heavily impact specifically for tunneling through hard rock the choice of Tunnel Boring Machine formations. They use disc cutters mounted (TBM). Geological factors such as soil type on the cutter head to apply high pressure (clay, silt, sand, gravel, or bedrock) and to the rock face, creating stress fractures groundwater levels dictate which type of that cause the rock to chip away. The TBM is most appropriate. For instance: excavated rock, or muck, is then transferred through openings in the cutter Soft Ground: In soft ground conditions, a head to a belt conveyor system, which Slurry Shield or Earth Pressure Balance moves the material out of the tunnel (EPB) TBM may be the best option. These through multiple conveyors. machines handle the pressure from surrounding soil and fluids, preventing APPLICATIONS OF MECHANIZED TUNNELING cave-ins and controlling groundwater inflow. Subways: The advent of mechanized Hard Rock: For tunneling through hard tunneling has transformed how subway rock, a Hard Rock TBM is typically used. systems are built, enabling quicker, safer, Equipped with rotating discs and heavy- and more efficient digging beneath duty cutters, these machines can efficiently crowded city landscapes. Tunnel Boring break through dense material while which can be susceptible to interference maintaining stability. from ground conditions or external factors. Mixed Ground Conditions: When dealing Calibration: To maintain accuracy, with varied geological conditions, more alignment systems require frequent adaptable TBM is required—one that can calibration. Factors such as ground shifts handle both soft and hard ground features. or water pressure can impact TBM These machines may combine elements of performance and necessitate adjustments. both TBM types. Data Management: The large volume of MAINTENANCE OF TBMs data generated by alignment systems can be overwhelming, requiring effective Regular maintenance of Tunnel Boring programming and data management to Machines is important for keeping efficiently interpret and act on real-time tunneling operations running smoothly and information prolonging the machine's lifespan. HOW TO EXTEND TBMs LIFE? Accessibility: Since TBMs work deep underground, reaching certain components PROPER CUTTERHEAD DESIGN for repairs can be difficult. Proper planning Maximizing TBM life relies on the is needed to ensure easy access to critical mechanical and electrical systems. proper design of the cutterhead and cutters, focusing on high-strength Scheduled Maintenance: TBMs require materials, wear protection, and cutter periodic inspections and maintenance after spacing. The cutterhead should allow for specific operational hours or distances easy inspection and replacement of cutters tunneled. Important parts like the cutter and must be structurally strong, especially head, gears, and hydraulic systems need with back-loading designs. Strengthening regular checks and servicing to avoid occurs through welding and stress testing malfunctions. during manufacturing, while deflector plates protect the cutters from loose rock. Emergency Repairs: Unexpected Properly sized muck buckets and durable, equipment failures can cause serious replaceable bucket lips ensure efficient delays. A strong maintenance strategy, with muck removal and reduce wear. spare parts readily available and skilled technicians on-site, is vital for reducing OPT FOR RUGGED, LARGER downtime due to unforeseen issues. DIAMETER DISC DIAMETERS ALIGNMENT AND GUIDANCE SYSTEMS Larger disc cutters, like 19-inch or 20-inch, are preferred over smaller ones Geometric Precision: TBMs need to due to their greater load capacity and wear follow exact alignment to ensure the tunnel volume. High-quality, clean steel is meets design specifications for both essential for fatigue resistance, and metal horizontal and vertical positioning. to-metal face seals are standard for Deviations from the planned path can lead preventing material ingress and to expensive corrections and structural withstanding high temperatures during problems. Real- hard rock excavation. Time Monitoring: Modern guidance DRY SUMP LUBRICATION systems use technologies like laser systems or gyroscopes to continuously Dry sump lubrication helps keep the track the TBM’s position and trajectory. main bearing cavity clean by continuously These systems rely on advanced sensors, filtering and recycling oil, extending bearing life. Additionally, it allows for monitoring the oil to detect signs of wear or distress, suggest a circular design would be superior enabling preventive maintenance before to Brunel's rectangular design failures occur. In 1864, Peter W. Barlow applied for a MINIMIZE DOWNTIME WITH design patent that had a circular cross- CONTINUOUS CONVEYORS section. A smooth muck flow is essential, Greathead was the first to ever use a with continuous conveyors preferred over cylindrical tunnelling shield, which he did in locomotives and muck cars for efficiency, the course of the construction of the Tower especially in longer tunnels. Conveyors Subway under the River Thames in central must have robust transfer points to reduce London in 1869. The Greathead shield was wear, and maintenance systems like muck 7 feet 3 inches (2.21 m) in diameter. scrapers and flashings are vital to keep the Similarly, Alfred Ely Beach opened his belt clean and prevent spillage. tunnel to the public on March 1, 1870 DAILY MAINTENANCE Greathead also used one in the construction of the City and South Regular maintenance, tailored to London Railway (today part of London tunnel length and geological conditions, is Underground's Northern line) in 1884 essential for TBMs, with more detailed inspections needed for longer operations. His shield was also used in the driving of Daily cutter inspections, fluid checks, and the 12 foot 1+3 ⁄4 inches (3.702 m) monitoring of all major systems through diameter running tunnels for the Waterloo logs are crucial for effective maintenance. & City Railway which opened in 1898. INTRODUCTION TO SHIELD WHY SHIELD TUNNELING? TUNNELING Shield tunnelling method is an A tunnelling shield is a protective underground excavation method in which structure used during the excavation of a shield machine with a metal shell is used large, human-made tunnels. When to excavate ground and install lining excavating through ground that is soft, supports under the protection of the metal liquid, or otherwise unstable, there is a shell. potential health and safety hazard to The shield tunnelling method is generally workers and the project itself from falling suitable for tunnel construction in weak materials or a cave-in. A tunnelling shield formations. can be used as a temporary support structure. It is usually in place for the short- SHIELD TUNNELING A term from when the tunnel section is GROUNDBREAKING TECHNIQUE excavated until it can be lined with a permanent support structure. At its core, shield tunneling employs a protective shield to excavate tunnels while designed by Marc Isambard Brunel simultaneously supporting the surrounding soil. The first successful rectangular tunnelling shield was developed by Marc Isambard OPEN SHIELD Brunel and patented by him and Lord Cochrane in January 1818. Open shield type TBM refers to those providing lateral support only. They THE TRIUMPHS OF SHIELD can be further classified into single shield TUNNELING and double shield. Its straightforward methodology makes it a popular choice for In 1840, Alfred Ely Beach, editor of various infrastructure projects, though it Scientific American journal, was the first to comes with challenges related to surface COMPACTION SOIL STABILIZATION disruption and stability. TECHNIUE CLOSED SHIELD Uses mechanical means for expulsion of air voids within the soil mass Closed shield type TBM refers to resulting in soil that can bear load those providing lateral support and frontal subsequently without further immediate support. compression. Dynamic compaction is one COMPRESSED AIR SHIELD of the major types of soil stabilization; in this procedure, a heavyweight is dropped Compressed air TBM is suitable for repeatedly onto the ground at regular cohesive soils under water table (e.g. intervals to quite literally pound out ground with low permeability with no major deformities and ensure a uniformly packed discontinuities). surface. Vibratory Vibro compaction is EARTH PRESSURE BALANCE (EPB) another technique that works on similar principles, though it relies on vibration Particularly effective in soft, rather than deformation through kinetic unstable soils; they maintain equilibrium force to achieve its goals between the earth pressure and the tunnel pressure, using a mixture of soil and foam FROM SUBWAYS TO SEWAGE to stabilize the excavation and prevent SYSTEMS: HOW INNOVATIVE collapses. TUNNELING TECHNIQUES SHAPE MODERN CITIES HARD ROCK SHIELD To date, the Novaliches-Balara Hard rock shields are built to tackle Aqueduct 4 Project is the largest water challenging geological conditions, where supply infrastructure project in Metro the soil consists of solid rock. Manila. MIXED-MODE SHIELD Lagusnilad built in the 1960s is considered a shield tunnel and is Mixshield is a terminology constructed using a tunnel boring machine introduced by German manufacturer (TBM). Herrenknecht for what is essentially a Slurry TBM that uses an air bubble to CHALLENGES IN SHIELD TUNNELING control and support pressure at the face. Mixshields are not meant to go from high High initial cost pressure soft ground to significant rocky Complexity of operation conditions with great efficiency, hence the Limited ground conditions name “Mixshield” is somewhat of a Waste generation misnomer. Risk of water ingress Logistical challenges MECHANICAL SOIL STABILIZATION Displacement of soils TECHNIQUE Limited flexibility The oldest types of soil stabilization MICROTUNNELING are mechanical in nature. Mechanical solutions involve physically changing the Microtunneling is one of the most property of the soil somehow, to affect its rapidly expanding techniques in the gradation, solidity, and other tunneling industry, providing innovative characteristics. solutions for constructing small diameter utility tunnels.  Based on Gerald Bauer (2021), which enhances efficiency and reduces microtunneling is a trenchless construction construction time. technique that allows for the installation of 5. Technology Utilization: Microtunneling tunnels with diameters ranging from 20 to 160 inches. employs advanced technologies, such as laser guidance systems and real-time TYPES OF MICROTUNNELING monitoring, to ensure precision and minimize the risk of misalignment. 1. Slurry Micro Tunneling - is a trenchless Traditional methods may not utilize such excavation method that employs a slurry sophisticated technologies, potentially mixture to support the tunnel face during leading to greater inaccuracies during the the boring process. construction process. 2. Auger Boring- involves using a rotating MICROTUNNELING EQUIPMENT AND auger to excavate soil and create a tunnel. TECHNOLOGY This method is suitable for shorter distances and smaller diameters, making it 1. Microtunnel Boring Machine (MTBM) - ideal for projects that require quick The MTBM is the primary equipment used installation without extensive excavation. in microtunneling. It features a cutting head that excavates soil and rock while DIFFERENCES FROM TRADITIONAL simultaneously creating a tunnel. TUNNELING METHODS 2. Pipe Jacking System - This system is 1. Excavation Technique: Traditional used to push pipes into the tunnel as tunneling often involves open-cut methods excavation progresses. It ensures that the that require significant excavation and pipes are installed behind the MTBM, surface disruption, whereas microtunneling maintaining the alignment and integrity of utilizes a small, specialized boring machine the tunnel. that operates underground, limiting the need for surface excavation. 3. Control Room - The control room serves as the operational hub for the 2. Diameter and Depth: Traditional microtunneling project. It houses tunnels can vary widely in size and are monitoring equipment that tracks the often used for larger applications, while performance of the MTBM and other microtunneling focuses on smaller systems in real time. diameters and shallower depths, making it ideal for utility installations in urban 4. Guidance System - A key component environments. for ensuring precision, the guidance system helps maintain the correct 3. Surface Impact: Traditional tunneling alignment and depth of the tunnel. It uses techniques can lead to substantial surface sensors and software to provide feedback disruption, including the removal of roads, to the operators, allowing for real-time sidewalks, and vegetation. On the other adjustments and minimizing the risk of hand, microtunneling is designed to misalignment. minimize surface impact, preserving existing infrastructure and reducing 5. Automated Spoil Removal System - disruption to traffic and local communities. This system efficiently handles the removal of excavated material (spoil) from the site. 4. Installation Process: In traditional It transports the spoil away from the MTBM, tunneling, the process typically involves allowing for continuous operation without separate excavation and pipe installation interruptions. phases. However, microtunneling integrates these steps, allowing for simultaneous excavation and installation, ADVANTAGES OF MICROTUNNELING INSTRUMENTATION AND MONITORING TECHNIQUES Minimal Surface Disruption Precision and Accuracy Automated Total Stations and Laser Improved Safety Scanning: These techniques are used for Versatility high-precision deformation monitoring. ATS provides real-time data on the DISADVANTAGES OF alignment and convergence within the MICROTUNNELING tunnel post-blast, which is crucial for any corrective actions if deviations occur. Higher Initial Costs Limited Diameter Seismic Monitoring Systems: These Technical Complexity detect and analyze the vibrations induced Soil Limitations by blasts, allowing for the adjustment of explosive charges to minimize disruptive DRILL & BLAST TUNNELING METHOD tremors and assess the stability of the Drill and Blast (D&B) tunneling is a surrounding rock mass in real time. construction technique critical for Embedded Sensor Technology: Sensors excavating through solid rock and other such as strain gauges and piezometers are resilient materials. This method is embedded into the tunnel lining and especially pertinent in geologically surrounding rock. challenging conditions, such as hard rock formations and areas with complex PIR PANJAL RAILWAY TUNNEL geological structures. The Pir Panjal Railway Tunnel, It involves a systematic process of situated in the Pir Panjal Mountains of boring and explosive demolition. The Jammu & Kashmir, India, is a major methodology includes two primary phases: component of the 202 km Udhampur – drilling, where holes are meticulously Srinagar – Baramulla rail link project driven drilled into the rock using advanced by Northern Railways. machinery tailored to the specific rock's KOLKATA METRO PROJECT hardness and composition; followed by blasting, where these holes are filled with The Kolkata Metro project, covering explosives and detonated in a controlled UG-1 and UG-2 packages, presented a manner. challenging underground construction environment due to the dense urban setting GEOLOGICAL SUITABILITY AND of Kolkata. ADAPTATION TUNNEL BORING MACHINE METHOD 1. Rock Fragmentation Mechanics: The process begins with an in-depth geo- The Tunnel Boring Machine (TBM) mechanical analysis of the rock formation, method, also known as a “worm”, is a where factors such as rock strength, popular technique used for excavating fracture toughness, and existing stress tunnels in a variety of geological conditions. fields are evaluated. It’s a large cylindrical machine that can excavate through various types of soil and 2. Blast Design Parameters: Simulation rock by using a rotating cutter head with software is used to model blast outcomes disc cutters, which can excavate the tunnel using various explosive types and charge face while simultaneously installing the arrangements. tunnel lining. TYPES OF TUNNEL BORING MACHINE COMPONENTS AND SEQUENCE OF EXECUTION IN NATM 1. SLURRY PRESSURE BALANCE (SPB) - the basic principle of this TBM is to Surveying maintain the face pressure during the Drilling, Loading, and Blasting excavation phase by filling the working Defuming chamber, located behind the cutter head, Scaling with slurry Shotcreting 2. EARTH PRESSURE BALANCE (EPB) - Mucking This is a mechanized tunnelling method in Rock Anchoring/Bolting which spoil is admitted into the tunnel Wire Mesh with Shotcreting (2nd boring machine (TBM) via a screw Stage) conveyor arrangement which allows the Steel Rib Support (For Class IV and pressure at the face of the TBM to remain V) balanced without the use of slurry. CUT & COVER METHOD 3. HARD ROCK TBM - This method In a cut and cover tunnel, the involves the use of a Tunnelling machine structure is built inside an excavation and with a shield and cutter head suitable for covered over with backfill material when hard rock. construction of the structure is complete. NEW AUSTRIAN TUNNELING METHOD Cut and cover construction is used when the tunnel profile is shallow and the The New Austrian Tunneling excavation from the surface is possible, method (NATM) was developed between economical, and acceptable. 1957 and 1965 in Austria. It was given its name in Salzburg in 1962 to distinguish it BOTTOM-UP CONSTRUCTION from old Austrian tunnelling approach. The In the conventional “bottom-up” main idea is to use the geological stress of construction, a trench is excavated from the surrounding rock mass to stabilize the the surface within which the tunnel is tunnel itself. constructed and then the trench is SEVEN FEATURES ON WHICH NATM IS backfilled and the surface restored BASED: afterward. Mobilization of Rock Strength Shotcrete Protection TOP-DOWN CONSTRUCTION Accurate Measurements Flexible Support With top-down construction, the Closing of Invert tunnel walls are constructed first, usually Contractual Arrangements using slurry walls, although secant pile Rock Mass Classification walls are also used. Thin Shotcrete Layer CLAY KICKING METHOD AL ZOJILA TUNNEL PROJECT This method is used for strong The Zojila Tunnel Project in Jammu clayey soil conditions. This is an old and Kashmir, Asia's longest bi-directional method and used for small works like tunnel at 14.2 kilometers, aims to ensure sewage pipes installations etc. In this year-round connectivity between Srinagar method, a hole is excavated into the and Leh. ground and after some depth tunnel is excavated which is done by the clay kicker which lies on a plank at 45 degree angle. An excavating tool is provided under clay temporary support structure to prevent the kicker foot. The excavated using that tool is surrounding soil from becoming unstable. collected by other workers. BOX JACKING METHOD Zonnebeke Tunnel Box jacking method is similar to This tunnel was part of the pipe jacking, but in this case instead of extensive network of underground pipes, specially made boxes are driven into passages built by British tunneling the soil. A cutting head is provided at the companies in the Zonnebeke sector, front side of the box. Excavated matter is designed to facilitate troop movement and collected within the box. supply transport while minimizing exposure PIPE JACKING METHOD to enemy fire. The clay-kicking technique was particularly well-suited for the clay-rich Pipe jacking method is used to geology of Flanders, allowing for efficient construct tunnels under existing structures and effective tunneling. like roadways, railways etc. In this method, specially made pipes are driven into SHAFT METHOD underground using hydraulic jacks. In this method tunnel is constructed Maximum size of 3.2-meter diameter is at greater depth from the ground surface. allowed for tunnels. Pipe jacking is a non- The shaft is built up to the depth where disruptive method of installing utility tunnel is required. Tunnel shafts are tunnels and conduits by thrusting pipes vertical passages that connect the ground through the ground as controlled surface to the tunnel roof. excavation is undertaken at the face TYPES OF SHAFTS UNDERWATER TUNNEL CONSTRUCTION METHOD 1. Inclined Shafts - These shafts are used when the shaft depth is less. The An underwater tunnel is a structure excavation of such shafts proceeds in the that is built underwater to make a way upward direction through it.Underwater tunnels are built using tunneling shield, tunnel boring 2. Vertical Shafts -This type of tunnel shaft machines, immersed tubes. They are dug is usually easier and more economical to deep into the earth or sit on the ocean or excavate when compared to the inclined river floor. The tunnels are usually buried shaft. beneath stone to prevent collapse. 3. Circular Shafts - These shafts are Underwater tunnels are used as an usually circular and are lined with pre- alternate means of transportation. stressed steel liner plates or concrete. INTRODUCTION TO TUNNELING SHIELD TUNNELING METHOD HAZARDS It is an underground excavation COMMON HAZARDS method in which a shield machine with a 1. Ground Stability metal shell is used to excavate ground and 2. Water Ingress install lining supports under the protection 3. Air Quality Issues of the metal shell. 4. Fire and Explosion The shield tunneling method is a 5. Human Factors technique used to construct tunnels without excavating trenches. This method involves the use of a shield, which is a protective metal cylinder. The shield acts as a IMPORTANCE OF SAFETY permanent hearing damage, making ear PROTOCOLS protection essential. a) Worker Protection SAFETY GLOVES b) Operation Efficiency Provide extra protection against c) Regulatory Compliance electrical hazards, cuts, abrasions, and d) Crisis Management impacts, ideal for handling heavy or sharp e) Environmental Protection objects in construction zones. EQUIPMENT AND INSTRUMENTS USED FACE SHIELDS Total stations ensure accurate alignment Face shields offer full-face of the tunnel path by measuring angles and protection from flying debris, sparks, or distances, allowing for precise tunneling direction. chemicals during cutting, welding, or grinding operations in tunnels. They Laser scanners and LiDAR create complement hard hats and safety glasses detailed three-dimensional maps of the for comprehensive facial protection. tunnel environment, capturing accurate FOOT PROTECTION geometries and surfaces. Safety boots with steel toes can Other devices like incl