This document discusses formwork and scaffolding used in construction. It describes the key requirements of good formwork including being strong enough to hold concrete, rigid without deformation, tight to prevent leaks, and providing a smooth surface. Various materials for formwork are discussed, including timber, plywood, steel and aluminum. Different types of formwork are also described, such as timber formwork, steel formwork, climbing formwork and movable formwork. Scaffolding is introduced as a temporary structure used to support workers and materials at elevated heights during construction.
Formwork is a mold used to shape and support concrete structures until the concrete gains sufficient strength. It is commonly made from steel or timber. Formwork must be strong enough to support its own weight as well as any loads placed on the concrete. Proper formwork design, fabrication, erection, and dismantling according to industry standards helps ensure quality concrete structures. Formwork is used for walls, columns, slabs, beams, stairs and other concrete elements.
Formwork is used to create structures out of concrete that is poured into molds. It can be made from materials like steel, wood, aluminum, or prefabricated forms. Construction of formwork takes up 20-25% of total structure costs and involves supporting structures and molds. Proper formwork is designed to be easily removable, economical, leakproof, durable, rigid, provide smooth surfaces, be strong, and have adequate supports. Common types include conventional timber formwork, engineered prefabricated formwork, and modern systems like flying forms. Materials used include steel, plywood, plastic, and aluminum. Proper bracing and construction is needed to avoid failures from improper stripping, inadequate bracing, vibration
Form work_Advanced Construction Technology (Semester-6), Civil EngineeringA Makwana
The form work is a temporary ancillary construction used as a mould for the structure, in which concrete is placed and in which it hardens and matures.
Cost of form work- 20 to 25 % of the cost of structure in building work
1) Formwork is a temporary structure used to hold wet concrete in desired shape until it hardens. It is made of timber, plywood or steel sheets.
2) Shuttering is a temporary platform constructed using wooden or steel materials that supports the formwork during concrete pouring.
3) Scaffolding provides access to work areas and supports formwork and shuttering using materials like bamboo, wood or steel pipes.
This document summarizes key concepts related to building construction formwork, scaffolding, and shoring. It defines formwork as artificial supports provided below and around concrete work, noting that formwork can be made of steel or wood. Factors that affect the cost of formwork include material, erection, removal, and labor costs. Formwork is needed for foundations, walls, columns, slabs, beams, and stairs. Scaffolding provides a temporary work platform at different building levels, and can be single, double, ladder, cantilever, suspended, or steel/tubular. Shoring provides temporary support to unsafe structures and can be horizontal, vertical, or inclined. Sketches of column formwork, double
This document discusses formwork, which is a mould used to contain and shape concrete until it hardens. Formwork is commonly made from timber or steel. It must be strong enough to support the weight of wet concrete and other loads without excessive deflection. Proper formwork design considers containment, strength, water tightness, accuracy, ease of handling, finish quality, and cost. The document describes formwork requirements and objectives, as well as details for common structural elements like walls, columns, beams, slabs, stairs, and removal procedures.
Beam and collunm less framwork fo huge construction of multistrey buildings with high strenght and econamy. Best suited for countries lkies India and helpful to achive the goal of gov of India to provide homes to all the citizens .
This document discusses formwork, which is a temporary mold used to shape wet concrete until it hardens. It describes the key requirements of good formwork materials, including strength, water resistance, and smooth surfaces. The major types of formwork materials are then outlined - timber, steel, plastic, and aluminum. Advantages and disadvantages of each type are provided. Uses of formwork include columns, beams, slabs, and walls. Factors that influence formwork costs and safety precautions are also summarized.
Formwork is a mold used to shape and support concrete structures until the concrete gains sufficient strength. It is commonly made from steel or timber. Formwork must be strong enough to support its own weight as well as any loads placed on the concrete. Proper formwork design, fabrication, erection, and dismantling according to industry standards helps ensure quality concrete structures. Formwork is used for walls, columns, slabs, beams, stairs and other concrete elements.
Formwork is used to create structures out of concrete that is poured into molds. It can be made from materials like steel, wood, aluminum, or prefabricated forms. Construction of formwork takes up 20-25% of total structure costs and involves supporting structures and molds. Proper formwork is designed to be easily removable, economical, leakproof, durable, rigid, provide smooth surfaces, be strong, and have adequate supports. Common types include conventional timber formwork, engineered prefabricated formwork, and modern systems like flying forms. Materials used include steel, plywood, plastic, and aluminum. Proper bracing and construction is needed to avoid failures from improper stripping, inadequate bracing, vibration
Form work_Advanced Construction Technology (Semester-6), Civil EngineeringA Makwana
The form work is a temporary ancillary construction used as a mould for the structure, in which concrete is placed and in which it hardens and matures.
Cost of form work- 20 to 25 % of the cost of structure in building work
1) Formwork is a temporary structure used to hold wet concrete in desired shape until it hardens. It is made of timber, plywood or steel sheets.
2) Shuttering is a temporary platform constructed using wooden or steel materials that supports the formwork during concrete pouring.
3) Scaffolding provides access to work areas and supports formwork and shuttering using materials like bamboo, wood or steel pipes.
This document summarizes key concepts related to building construction formwork, scaffolding, and shoring. It defines formwork as artificial supports provided below and around concrete work, noting that formwork can be made of steel or wood. Factors that affect the cost of formwork include material, erection, removal, and labor costs. Formwork is needed for foundations, walls, columns, slabs, beams, and stairs. Scaffolding provides a temporary work platform at different building levels, and can be single, double, ladder, cantilever, suspended, or steel/tubular. Shoring provides temporary support to unsafe structures and can be horizontal, vertical, or inclined. Sketches of column formwork, double
This document discusses formwork, which is a mould used to contain and shape concrete until it hardens. Formwork is commonly made from timber or steel. It must be strong enough to support the weight of wet concrete and other loads without excessive deflection. Proper formwork design considers containment, strength, water tightness, accuracy, ease of handling, finish quality, and cost. The document describes formwork requirements and objectives, as well as details for common structural elements like walls, columns, beams, slabs, stairs, and removal procedures.
Beam and collunm less framwork fo huge construction of multistrey buildings with high strenght and econamy. Best suited for countries lkies India and helpful to achive the goal of gov of India to provide homes to all the citizens .
This document discusses formwork, which is a temporary mold used to shape wet concrete until it hardens. It describes the key requirements of good formwork materials, including strength, water resistance, and smooth surfaces. The major types of formwork materials are then outlined - timber, steel, plastic, and aluminum. Advantages and disadvantages of each type are provided. Uses of formwork include columns, beams, slabs, and walls. Factors that influence formwork costs and safety precautions are also summarized.
Formwork is a temporary structure used to support wet concrete until it cures and can support itself. There are different types of formwork materials including timber, steel, and glass reinforced plastic. Proper formwork design and construction helps ensure safety, cost-effectiveness and quality of the finished concrete surface. Common causes of formwork failure include inadequate bracing, vibration, unstable soil or improper stripping. Safety precautions like secure fixing and inspections are important to prevent accidents. Permanent formwork is part of the permanent structure and remains in place for the life of the building, offering advantages like reduced construction time and costs.
This document provides an overview of formwork and its types. Formwork is a temporary mold used to hold fresh concrete in shape until it hardens. It can be made from materials like steel, timber, plywood, aluminum, and plastic. There are different categories of formwork including conventional formwork built on-site, modern prefabricated forms for speed and efficiency, and engineered forms with a metal frame and covering. Common types include steel, timber, plywood, and aluminum forms. Formwork must be strong, rigid, prevent concrete leakage, and allow removal without damage to the concrete. It is an important but costly part of concrete construction.
Construction Technology III (Group Assignment) - Semester 3Yee Len Wan
The document discusses various formwork systems used in construction projects. It provides details on steel formwork systems including their manufacturing and assembly process. Some advantages of steel formwork are that they are reusable, durable and provide uniform size and surface. Rail climbing systems and panelized slab formwork were used in the Setia City Residences and Equatorial Plaza Hotel projects respectively to enable fast and efficient construction. Tunnel forms were used to construct the high rise Paramount at Buckhead project. In conclusion, the suitability of formwork systems depends on the project scope and requirements.
formwork centering and scaffolding by khalid shaikh khalid
This document discusses different types of scaffolding and formwork used in construction. It outlines four major types of scaffolding - brick-layer scaffolding, mason's scaffolding, needle scaffolding, and steel scaffolding. It also discusses different materials used for formwork like timber, plywood, steel, and aluminum and their advantages. Centering is defined as the part of formwork that supports horizontal surfaces like beam bottoms and slabs.
All you need to know about Construction FormworkAnkit Singhai
Formwork is temporary structure used to support and contain wet concrete until it hardens. It molds the concrete into the desired shape and controls its position. Formwork materials include lumber, plywood, steel, and plastics. Proper formwork design can significantly reduce construction costs. Formwork accounts for a large portion of the total cost of a concrete structure.
This document provides information about slab formwork, including the types of materials used and the steps for placing formwork. It discusses common materials like timber, steel, plywood, aluminum, and plastic. Timber is described as light weight and economical but other materials like steel and plywood provide better finishes and reusability. The document outlines 11 steps for placing slab formwork, from setting the level marks to applying a shutter oil to prevent concrete sticking. It emphasizes safety, rigidity, and leak-proof joints in the formwork design.
Formwork is temporary mould used to contain and shape wet concrete until it hardens. It is usually made of wood like plywood and timber. Proper formwork is strong, rigid, leak-proof and allows concrete to be easily placed and compacted. It must be inspected before each pour to ensure it will not deflect or collapse under the weight of wet concrete. Release agents are applied to formwork surfaces to ensure concrete does not stick when forms are removed.
Covers basic definition of formwork, material used, qualities of good formwork, cleaning and treatment, and stripping time for formwork. Intended for undergraduate students of civil engineering.
This document defines formwork and its requirements, categories, types of materials used, and construction process. Formwork is a temporary mold into which concrete is poured and shaped. It must be strong enough to support the weight of wet concrete and loads. There are traditional, engineered, and modern modular types. Common materials are timber, steel, plastic, and aluminum. Proper construction and removal of formwork is important for quality, safety, and economy of concrete structures.
This industrial training report summarizes the student's training at Simplex Infrastructures Ltd. It provides details of two residential construction projects - Godrej Prakriti Housing Complex III and describes the structures being built. Quality control procedures are outlined including material testing and ensuring specifications are met. Formwork designs, reinforcement details, and estimating quantities are discussed. Plant and machinery used on-site are listed. The report aims to impart the student's practical and theoretical engineering skills.
Formwork Presentation for Construction TechnologyI'mMiss Lily
1. Formwork refers to the temporary structure used to support wet concrete until it is cured and can support itself. Common materials used include wood, steel, aluminum, plastic and plywood.
2. A good formwork must be water tight, strong, and reusable while also considering factors like quality, safety, and economy. It must be able to withstand loads, retain its shape, and be removed without damaging the concrete.
3. Different types of formworks are used for columns, beams, slabs, and other structural elements. Column formwork typically consists of side and end planks joined by yokes and bolts. Beam formworks use thick timber or plywood and are supported by props.
This document discusses different types of formwork and foundations used in construction. It describes conventional formwork made from timber and plywood on site, and engineered prefabricated formwork with metal frames. Reusable and permanently insulated formworks are also discussed. The document also outlines beams, columns, and slabs, and the different materials used for forming concrete foundations, including plywood, timber, steel, and aluminum.
Building Construction 8. formworks and scaffoldingsHamdija Velagic
This document provides information about formwork, scaffolding, shoring, and underpinning. It defines each construction technique and describes the typical components and uses. Formwork supports wet concrete until it cures and is used for foundations, walls, columns, slabs, beams, and stairs. Scaffolding provides temporary work platforms at different heights using standards, ledgers, and boards. Shoring supports unsafe structures using horizontal, vertical, or inclined bracing. Underpinning strengthens foundations by installing supports beneath them.
Formwork is a temporary mold used to contain and shape wet concrete until it is cured, and gain sufficient strength to support its own weight. It is commonly made from timber or steel. Formwork must balance requirements like containment, strength, resistance to leakage, accuracy, ease of handling, finish, access for concrete, and economy. It is designed according to factors like the loads it will support, type of structure being built, and materials used. Formwork goes through stages of assembly, concrete placement, and stripping. Proper design, construction, and maintenance of formwork is important to produce high quality, safe concrete structures economically.
This document provides information on masonry, specifically brick masonry. It discusses the manufacturing process of bricks, including definitions of key terminology used. The document outlines the four important qualities to consider when choosing bricks: the molding process, color from the firing process, size, and type/grade as specified by standards. It describes common brick molding processes of molded, extruded, and their differences. The firing process and how it affects brick color is also summarized. Key terminology used in brick masonry is defined.
This document provides information on formwork used in concrete construction. It defines formwork and lists its common materials as steel and wood. It describes the major objectives in formwork as quality, safety, and economy. It discusses the various types of formwork including temporary and permanent structures. It also provides details on formwork for different structural elements like walls, columns, slabs, beams, stairs, and chimneys. Finally, it covers topics like requirements, loads, design, and maintenance of formwork.
This Presentation Covers the knowledge of concrete which we are having as of now and how we are thinking about Concrete. Advanacment of concrete Technology.
Applications of advance Concreting practices like smary dynamic concrete. This knowledge was gained from the famours RMC producers.
Formwork is used to support wet concrete until it cures and can support itself. It must be strong yet allow concrete to be placed accurately to shape. Common materials include timber, plywood, steel, aluminum and plastics. Proper formwork design considers strength, containment, leakage prevention, finish quality, and economics. Specialized formwork like climbing, sliding, and tunnel forms improve efficiency for structures like walls, columns, and buildings. Proper formwork selection and construction is essential for quality, safety, and cost-effectiveness in concrete projects.
Formwork is a temporary structure used to support wet concrete until it cures and can support itself. There are different types of formwork materials including timber, steel, and glass reinforced plastic. Proper formwork design and construction helps ensure safety, cost-effectiveness and quality of the finished concrete surface. Common causes of formwork failure include inadequate bracing, vibration, unstable soil or improper stripping. Safety precautions like secure fixing and inspections are important to prevent accidents. Permanent formwork is part of the permanent structure and remains in place for the life of the building, offering advantages like reduced construction time and costs.
This document provides an overview of formwork and its types. Formwork is a temporary mold used to hold fresh concrete in shape until it hardens. It can be made from materials like steel, timber, plywood, aluminum, and plastic. There are different categories of formwork including conventional formwork built on-site, modern prefabricated forms for speed and efficiency, and engineered forms with a metal frame and covering. Common types include steel, timber, plywood, and aluminum forms. Formwork must be strong, rigid, prevent concrete leakage, and allow removal without damage to the concrete. It is an important but costly part of concrete construction.
Construction Technology III (Group Assignment) - Semester 3Yee Len Wan
The document discusses various formwork systems used in construction projects. It provides details on steel formwork systems including their manufacturing and assembly process. Some advantages of steel formwork are that they are reusable, durable and provide uniform size and surface. Rail climbing systems and panelized slab formwork were used in the Setia City Residences and Equatorial Plaza Hotel projects respectively to enable fast and efficient construction. Tunnel forms were used to construct the high rise Paramount at Buckhead project. In conclusion, the suitability of formwork systems depends on the project scope and requirements.
formwork centering and scaffolding by khalid shaikh khalid
This document discusses different types of scaffolding and formwork used in construction. It outlines four major types of scaffolding - brick-layer scaffolding, mason's scaffolding, needle scaffolding, and steel scaffolding. It also discusses different materials used for formwork like timber, plywood, steel, and aluminum and their advantages. Centering is defined as the part of formwork that supports horizontal surfaces like beam bottoms and slabs.
All you need to know about Construction FormworkAnkit Singhai
Formwork is temporary structure used to support and contain wet concrete until it hardens. It molds the concrete into the desired shape and controls its position. Formwork materials include lumber, plywood, steel, and plastics. Proper formwork design can significantly reduce construction costs. Formwork accounts for a large portion of the total cost of a concrete structure.
This document provides information about slab formwork, including the types of materials used and the steps for placing formwork. It discusses common materials like timber, steel, plywood, aluminum, and plastic. Timber is described as light weight and economical but other materials like steel and plywood provide better finishes and reusability. The document outlines 11 steps for placing slab formwork, from setting the level marks to applying a shutter oil to prevent concrete sticking. It emphasizes safety, rigidity, and leak-proof joints in the formwork design.
Formwork is temporary mould used to contain and shape wet concrete until it hardens. It is usually made of wood like plywood and timber. Proper formwork is strong, rigid, leak-proof and allows concrete to be easily placed and compacted. It must be inspected before each pour to ensure it will not deflect or collapse under the weight of wet concrete. Release agents are applied to formwork surfaces to ensure concrete does not stick when forms are removed.
Covers basic definition of formwork, material used, qualities of good formwork, cleaning and treatment, and stripping time for formwork. Intended for undergraduate students of civil engineering.
This document defines formwork and its requirements, categories, types of materials used, and construction process. Formwork is a temporary mold into which concrete is poured and shaped. It must be strong enough to support the weight of wet concrete and loads. There are traditional, engineered, and modern modular types. Common materials are timber, steel, plastic, and aluminum. Proper construction and removal of formwork is important for quality, safety, and economy of concrete structures.
This industrial training report summarizes the student's training at Simplex Infrastructures Ltd. It provides details of two residential construction projects - Godrej Prakriti Housing Complex III and describes the structures being built. Quality control procedures are outlined including material testing and ensuring specifications are met. Formwork designs, reinforcement details, and estimating quantities are discussed. Plant and machinery used on-site are listed. The report aims to impart the student's practical and theoretical engineering skills.
Formwork Presentation for Construction TechnologyI'mMiss Lily
1. Formwork refers to the temporary structure used to support wet concrete until it is cured and can support itself. Common materials used include wood, steel, aluminum, plastic and plywood.
2. A good formwork must be water tight, strong, and reusable while also considering factors like quality, safety, and economy. It must be able to withstand loads, retain its shape, and be removed without damaging the concrete.
3. Different types of formworks are used for columns, beams, slabs, and other structural elements. Column formwork typically consists of side and end planks joined by yokes and bolts. Beam formworks use thick timber or plywood and are supported by props.
This document discusses different types of formwork and foundations used in construction. It describes conventional formwork made from timber and plywood on site, and engineered prefabricated formwork with metal frames. Reusable and permanently insulated formworks are also discussed. The document also outlines beams, columns, and slabs, and the different materials used for forming concrete foundations, including plywood, timber, steel, and aluminum.
Building Construction 8. formworks and scaffoldingsHamdija Velagic
This document provides information about formwork, scaffolding, shoring, and underpinning. It defines each construction technique and describes the typical components and uses. Formwork supports wet concrete until it cures and is used for foundations, walls, columns, slabs, beams, and stairs. Scaffolding provides temporary work platforms at different heights using standards, ledgers, and boards. Shoring supports unsafe structures using horizontal, vertical, or inclined bracing. Underpinning strengthens foundations by installing supports beneath them.
Formwork is a temporary mold used to contain and shape wet concrete until it is cured, and gain sufficient strength to support its own weight. It is commonly made from timber or steel. Formwork must balance requirements like containment, strength, resistance to leakage, accuracy, ease of handling, finish, access for concrete, and economy. It is designed according to factors like the loads it will support, type of structure being built, and materials used. Formwork goes through stages of assembly, concrete placement, and stripping. Proper design, construction, and maintenance of formwork is important to produce high quality, safe concrete structures economically.
This document provides information on masonry, specifically brick masonry. It discusses the manufacturing process of bricks, including definitions of key terminology used. The document outlines the four important qualities to consider when choosing bricks: the molding process, color from the firing process, size, and type/grade as specified by standards. It describes common brick molding processes of molded, extruded, and their differences. The firing process and how it affects brick color is also summarized. Key terminology used in brick masonry is defined.
This document provides information on formwork used in concrete construction. It defines formwork and lists its common materials as steel and wood. It describes the major objectives in formwork as quality, safety, and economy. It discusses the various types of formwork including temporary and permanent structures. It also provides details on formwork for different structural elements like walls, columns, slabs, beams, stairs, and chimneys. Finally, it covers topics like requirements, loads, design, and maintenance of formwork.
This Presentation Covers the knowledge of concrete which we are having as of now and how we are thinking about Concrete. Advanacment of concrete Technology.
Applications of advance Concreting practices like smary dynamic concrete. This knowledge was gained from the famours RMC producers.
Formwork is used to support wet concrete until it cures and can support itself. It must be strong yet allow concrete to be placed accurately to shape. Common materials include timber, plywood, steel, aluminum and plastics. Proper formwork design considers strength, containment, leakage prevention, finish quality, and economics. Specialized formwork like climbing, sliding, and tunnel forms improve efficiency for structures like walls, columns, and buildings. Proper formwork selection and construction is essential for quality, safety, and cost-effectiveness in concrete projects.
The document provides information about formwork systems used in building and construction. It discusses different types of formwork materials like sawn timber, plywood, steel, aluminum, glass fiber reinforced plastic, rubber and plastic. It explains formwork components for walls, columns, slabs and beams. It also covers formwork inspection, erection, concreting procedures and factors affecting removal of formwork. Falsework is described as the temporary structure used to support formwork until the permanent structure can support itself.
IRJET- Analytical Study of High Volume Fly Ash Concrete Bubble Deck SlabIRJET Journal
This document analyzes bubble deck slabs made with high-volume fly ash concrete (HVFA) and plastic balls to reduce weight. Four slab models were analyzed: one without balls, one with 16 evenly distributed balls, one with alternating horizontal rows of 8 balls, and one with alternating diagonal rows of 8 balls. Finite element analysis was conducted in ANSYS Workbench. Results showed the load capacity was comparable to traditional slabs, with up to a 10.6% reduction for some ball arrangements. Stresses and deformations increased with ball inclusion but were still within acceptable ranges. The study demonstrated bubble deck slabs can achieve strength comparable to reinforced concrete slabs while reducing weight and cement usage.
1. The document discusses various types of special concretes including lightweight concrete, foam concrete, self-compacting concrete, vacuum concrete, fibre reinforced concrete, ferrocement, ready mix concrete, slurry infiltrated fibre concrete (SIFCON), and shotcrete.
2. Lightweight concrete uses lightweight aggregates like shale, clay, or slate to reduce density while maintaining strength. Foam concrete is made by injecting air or gas into the mix to create a cellular structure.
3. Self-compacting concrete can be placed without vibration due to its fluidity. Vacuum concrete has water removed using vacuum mats to increase strength.
- Foundry engineering involves making castings through the molding process using patterns. It is an ancient practice dating back 5000 years.
- The casting process has five main stages: pattern making, molding and core making, melting and casting, fettling, and testing and inspection.
- Foundries can be classified by type (jobbing, production, etc.) or materials produced (ferrous, non-ferrous). Patterns come in various types like split patterns, gated patterns, and are made from materials like wood, metal, plastic to suit different production needs.
This document provides an overview of concrete structures and design methods for reinforced concrete. It discusses sustainable construction topics like whether concrete is a green material. The key points are:
1) Concrete is made from abundant local resources like water, aggregate and cement and can incorporate waste materials, making it environmentally friendly.
2) There are two main design methods - using moment diagrams or strut and tie models - and incorporating fly ash and minimizing corrosion can improve sustainability.
3) While concrete has benefits, reinforced concrete must crack to work and rebar corrosion is a durability issue, whereas prestressed concrete prevents cracking.
Concrete is the most widely used construction material due to its durability, affordability, and ability to be cast into any shape. A proper concrete mix design targets compressive strength, workability, durability, and quality control. The key aspects of mix proportioning include selecting aggregates based on properties like composition and size, using an optimized gradation, and determining the right water-cement ratio to achieve the desired strength and minimize waste. Chemical admixtures can be added to improve properties like freeze-thaw resistance or to accelerate or retard setting times for different construction needs.
This document discusses formwork, which is used as a mold for pouring concrete. It begins by introducing formwork and its importance, comprising 20-25% of total construction costs. Requirements for formwork include strength, rigidity, tight joints, and removability. Common materials are timber, plywood, steel, and aluminum. Timber is most common but can warp or shrink. Stripping is the process of removing formwork. Indian standards specify shape retention and tolerances. The document then describes various types of formwork in more detail, including their characteristics and uses.
Flexural Behaviour of Reinforced Concrete Beams Rehabilitated With Ferro-ceme...IRJET Journal
This document discusses using ferrocement laminates to rehabilitate and strengthen reinforced concrete beams. Ferrocement is a versatile material formed from cement mortar reinforced with a closely spaced wire mesh. It has a higher tensile strength and better cracking resistance than concrete. The study aims to increase the strength of existing beams and extend their lifespan by applying ferrocement laminates containing fly ash and silica fume as partial replacements for cement. Experimental flexural tests were conducted on beam specimens reinforced with different layers of chicken wire mesh and mixtures containing various replacement proportions. The results were analyzed to evaluate the flexural behavior and load carrying capacity of the rehabilitated beams.
A presentation with exhaustive information about the general idea of formwork, the various types, the newest introductions and a comparative study between the conventional and modern-day formwork.
It also includes the study of causes of failure of formwork and the safety measures to be taken for preventing failure.
Modern construction formworks:-
1. Aluminium formwork
2. Precast system
3.Modular formwork
4.Tunnel formwork
5.Fiberglass shuttering
Description of each formwork with their advantages and disadvantages
This document discusses the materials and design considerations for plain and reinforced concrete structures according to the National Building Code of India. It outlines the types of cement, aggregates, water, admixtures, and reinforcement that can be used. It also covers mix design and proportioning, durability requirements, and factors to consider when selecting reinforced concrete as a construction material such as its economy, suitability for structural and architectural functions, low maintenance needs, availability of materials, rigidity, and fire resistance.
Aluminium Formwork Vs Conventional Formworkchaitanyakrsk
This technical paper covers the information about formwork introduction, types of formworks and mainly about the comparing aluminium formwork with conventional formwork. Data compiled from various prominent resources and from the experience gained over the years.
This document outlines the advantages of using post-tensioning in building structures. Post-tensioning allows for longer spans, reduced floor thickness, increased floor area, faster construction speeds, and reduced material usage. It discusses common post-tensioning systems used in building floors and specialized structural elements. Post-tensioning provides more flexible and economical building structures compared to other methods.
This document discusses various low-cost and sustainable construction materials that can be used for cost-efficient construction. It covers materials like earth/mud, compressed earth blocks, ferrocement, cement and concrete substitutes, wood/timber substitutes, interlocking blocks, bamboo, and prefabricated construction. Traditional materials like mud are inexpensive but not durable, while stabilized materials like compressed earth blocks provide improved strength and water resistance at low cost. Ferrocement and prefabricated construction allow for fast, inexpensive assembly. Using materials that are locally available and have low embodied energy, like bamboo, earth, and wood substitutes, supports sustainable construction.
The Utilization of Coal Pond Ash and Rice Husk Ash as a Supplementary Cementi...IRJET Journal
This document reviews research on using coal pond ash and rice husk ash as supplementary cementitious materials in concrete. It finds that:
1) Studies have shown that partially replacing cement with coal pond ash or rice husk ash in concrete mixtures can improve strength and durability while reducing costs and environmental impacts compared to traditional concrete.
2) Concrete mixtures containing rice husk ash up to a 30% replacement level of cement exhibited increased strength and corrosion resistance along with decreased permeability.
3) The combination of ordinary Portland cement with rice husk ash and fly ash was found to enhance mortar strength even at low replacement levels, as well as improve resistance to corrosion.
4) Using a mixture of 22.
Effect of Admixture on Properties of ConcreteIRJET Journal
This document discusses the effect of admixtures on the properties of concrete. It begins by defining concrete and its main components of cement, water, aggregates, and sometimes admixtures. It then discusses different types of admixtures including their physical and chemical functions. The document also examines how admixtures can be used to increase properties like strength and decrease weaknesses in concrete like brittleness. Finally, it analyzes how admixtures like silica fume can improve properties of lightweight concrete by increasing its strength.
Practical eLearning Makeovers for EveryoneBianca Woods
Welcome to Practical eLearning Makeovers for Everyone. In this presentation, we’ll take a look at a bunch of easy-to-use visual design tips and tricks. And we’ll do this by using them to spruce up some eLearning screens that are in dire need of a new look.
Explore the essential graphic design tools and software that can elevate your creative projects. Discover industry favorites and innovative solutions for stunning design results.
Storytelling For The Web: Integrate Storytelling in your Design ProcessChiara Aliotta
In this slides I explain how I have used storytelling techniques to elevate websites and brands and create memorable user experiences. You can discover practical tips as I showcase the elements of good storytelling and its applied to some examples of diverse brands/projects..
Architectural and constructions management experience since 2003 including 18 years located in UAE.
Coordinate and oversee all technical activities relating to architectural and construction projects,
including directing the design team, reviewing drafts and computer models, and approving design
changes.
Organize and typically develop, and review building plans, ensuring that a project meets all safety and
environmental standards.
Prepare feasibility studies, construction contracts, and tender documents with specifications and
tender analyses.
Consulting with clients, work on formulating equipment and labor cost estimates, ensuring a project
meets environmental, safety, structural, zoning, and aesthetic standards.
Monitoring the progress of a project to assess whether or not it is in compliance with building plans
and project deadlines.
Attention to detail, exceptional time management, and strong problem-solving and communication
skills are required for this role.
Revolutionizing the Digital Landscape: Web Development Companies in Indiaamrsoftec1
Discover unparalleled creativity and technical prowess with India's leading web development companies. From custom solutions to e-commerce platforms, harness the expertise of skilled developers at competitive prices. Transform your digital presence, enhance the user experience, and propel your business to new heights with innovative solutions tailored to your needs, all from the heart of India's tech industry.
Visual Style and Aesthetics: Basics of Visual Design
Visual Design for Enterprise Applications
Range of Visual Styles.
Mobile Interfaces:
Challenges and Opportunities of Mobile Design
Approach to Mobile Design
Patterns
Connect Conference 2022: Passive House - Economic and Environmental Solution...TE Studio
Passive House: The Economic and Environmental Solution for Sustainable Real Estate. Lecture by Tim Eian of TE Studio Passive House Design in November 2022 in Minneapolis.
- The Built Environment
- Let's imagine the perfect building
- The Passive House standard
- Why Passive House targets
- Clean Energy Plans?!
- How does Passive House compare and fit in?
- The business case for Passive House real estate
- Tools to quantify the value of Passive House
- What can I do?
- Resources
ARENA - Young adults in the workplace (Knight Moves).pdfKnight Moves
Presentations of Bavo Raeymaekers (Project lead youth unemployment at the City of Antwerp), Suzan Martens (Service designer at Knight Moves) and Adriaan De Keersmaeker (Community manager at Talk to C)
during the 'Arena • Young adults in the workplace' conference hosted by Knight Moves.
Technoblade The Legacy of a Minecraft Legend.Techno Merch
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1. UNIT 16 FORMWORK AND SCAFFOLDING
Structure
16.1 Introduction
Objectives
16.2 Formwork
16.2.1 Requirements of Good Formwork
16.2.2 Economy in Formwork
16.2.3 Materials
16.3 Typesof Formwork
16.3.1 Timber Formwork
16.3.2 Steel Formwork
16.3.3 Climbing Formwork
16.3.4 Moving Formwork
16.3.5 PermeablePormwork
16.3.6 Permanent Prestressed Concrete Formwork
16.4 Removal and Maintenanceof Formwork
16.5 Scaffolding
16.5.1 Types of Scaffolding
16.5.2 Double Scaffolding
16.5.3 Steel Scaffolding andCentering
16.5.4 U-Frame Scaffolding
16.6 Summary
16.7 Key Words
16.8 Answers to SAQs
16.1 INTRODUCTION
In previous unit you studied aboutPiles and Caissonsand their constructionmethods etc.
In this unit, you will studyFormwork and Scaffolding.
The term ''Formwork indicatesa temporary structureerected toreceive wet concreteand
to hold it in place, till it is sufficientlyhard and strong to be self-supportingwithout any
deformation. The other synonymousterms used are: shutteringandcentering. The
1 formworkcanbe of different materials and different types depending upon the type of
I structureandsiterequirements, economy,safetyand qualityrequired in the ftnishedwork.
The "Scaffolding" is a temporary structure which isused in building constructionto
supportplatformsforworkers,structural materialsand constructionequipmentrequired
I
during constructionat elevatedheights. The scaffoldingis useful in building construction,
maintenance,demolitionand repair works.
Objectives
At the end of this unit, you shouldbe able to :
i
* distinguishbetween 'Formwork' and Scaffoldmg,
i * describedifferentmaterialsused informwork and scaffolding,
1 * describeessentialrequirementsof formworkand scaffolding,and
* understand functioningof different types of formwork and scaffolding.
16.2 FORMWORK
'Ibe economicaldesign and constructionof formwork is of great importanceas the cost of
formworkis a large proportion of the total cost of the structureand is most difficult part to
estimate. The appearanceof finished structure and the speed with which the work can be
executedalsodepend mainly on the efficient constructionof formwork.
2. Chstmctirn~efludq~~ea Jthough the formwork is a temporary structure,which shouldbe readily dismantableand
lovable, it is designedto withstand the likelypressures and loads coming on the member
during concreting.Poor formwork design and performanceleavesbehind permanent scars
on the structure and has led to failuresin concreteconstruction. Some of the common
deficienciesnoticed are lack of allowance in designfor loadingslike wind,equipment,
temporary material storage,inadequateanchorageagainstuplift, insufficientslenderness
ratioof compressionmembers, impact of constructionequipmentand leakingjoints etc.
Let us now first examine the requirements for a good formwork.
16.2.1 Requirements of Good Formwork
a) It should be carefully designed,so as tobe strong enough to resist the pressure
of freshconcrete and the super-imposed loads due to men, materials and
equipmentetc.
b) It shouldbe rigid enough to retain its original shapewithoutundue deformation
which isnonnally restricted to 1/300th of spaninnormalcases.
c) It should be tight enoughso as not to allow cement and other materials to leak
through thejoints.
d) The formwork shouldnot warp, bulge, bend or sink and should remaintrue to
.the designedsize.
e) The inner surfaceof the formwork shouldbe smooth so as to givepleasing
appearance to the finishedsurface.The inner surfaceis also applied with
mould oil to facilitate its removal.
16.2.2 Economy in Formwork
A formwork systemis economical only when it fulfils all the tasks on hand with a few
versatilecomponents.You are aware that total cost of concrete construction includesthe
cost of the formwork. However, sometimes the cost of formwork,which actually does not
formpart of the finishedconcretestructure,may exceedthe cost of concrete itself.
Therefore, we should make all'efforts to rninimise the cost of formwork while keeping the
safety aspects in view. Formwork costmainly constitutesthe cost of materials and labour
required for fabrication,erectionand removal of forms.These costs can be minimised by
keeping some good points in mind which will lead to economy in formwork.These good
points, steps or measures are now givenbelow :
a) Avoid use of irregular shapes of forms.
b) The formwork should be fabricatedinto modular sizes and in sufficient
numbers so as to allow re-use.
c) - The structurecomponentsof the building shouldbe so dimensioned and
designed,so as to permituse of commerciallyavailableforms in the market.
d) The working drawings of the formwork shouldbe properly prepared and
checkedbefore fabricating the same.
e) The various components of the formworkshouldbe prefabricated on the
ground,using power equipment. This will reduce labour costs and delays and
holdups in the work. Also, the labour can work more efficientlyon the ground
than on the scaffoldingat an elevated level.
f) The formwork design shouldbe balanced design so as to provide adequateand
not excessivestrengthand rigidity.
g) Where possible, adopt assembly line methods in fabricatingformwork to
increasethe efficiencyof the labourers.
h) In timber formwork,where possible, use doubleheaded nails to facilitate their
removal.
i) Constructionjoints shouldbejudiciously incorporatedto reduce the quantityof
forms required in one operationthus enabling re-use.
j) When mechanical vibrators are used, bolts mustbe employed insteadof wire
ties or nails to ensure safety.
k) The formwork shouldbe handled and stackedcarefully.It shouldbe oiled and
cleaned after each use to prolong its usage life.
3. 16.2.3 Materials F O ~ ~ W O ~ ~
aod Scaffolding
The selectionof materials to be used forfabrication of formwork is governedby job
requirementsand economy.The most commonly used materials are timber, plywood, steel
and aluminium.When the formwork is to be used for small works and that too a few times,
then timber proves to be more economical than steel or aluminium.However,if the
formworkis required to be reused several times likein a multistoreyedbuilding, then the
use of steelor aluminiumis preferred.In case of steel,though the initial cost is very high,
but it proves to be economical when it is used repetitively in large works. Also the erection
and removal of steel formwork are simple and present a better appearanceon removal.
Particularlyin case of structureslikeround columns, carved surfaces,monolithicsewers,
tunnels and sirniliar structure, the use of formworkshould be made as a matter of
expediency.
However, in Indian conditions,timber is still used quitecommonly in smallerworks. This
is due to the fact that it is easily worked and that its use to a degree is traditional. Timber
should preferablybe softwoodusually pine, fir or sprucewhich has been partially
seasoned. Very dry timber will absorbmoisture from wet concrete or atmosphereand
swell,while green timber will shrink. Hardwoodis not normally used as it is expensive,
heavy and difficultto work and nail.When appearanceof finishedcomete isof littleorno
importme,cleansawntimbermay be used,but inview of greatereaseof fitting,the use ofplaned
timber will oftenprove to be ecormmicalboth in time andlabour.
Sizes of forms alsoplay an important role and are linked to the material used for formwork.
The sizes should be based on the criteria givenbelow :
a) If forms are prefabricatedinto panels or sections, it is desirable to fabricate
them in sizes as big as the concretemembers or the sizeswhich the adopted
method of handling will permit. This helps in reducing the labour and time
costs in erection and removal of forms.
b) If the formwork is to be handled manually,then the weight of a singlepanel
should not exceed 35kgs per person.
c) If the forms are to be handled by mechanized method i.e. power equipment,
cranes etc. then the size of formwork is limited by the length of timber
available,the dimensionsof concrete structureand the capacity of the
handling/hoisting equipment. However,timber has been graduallyreplaced by
plywood and today a durable plastic coated material is available to the user. As
timber is becoming expensiveand rare day by day, the need for steel to replace
timber has increased. Aluminium offers a good mediumfor light structural
formwork.In the production of architecturalconcrete,formwork needs special
attention and offersspecialchallenges.For domes,inflatableformsover which
concreteis sprayed is anove) techniquewith an innovativeapproachand with the
range of materials availabletoday, developmentof other forms is a distinct
possibility.
16.3 TYPES OF FORMWORK
There are several types of formwork which are used in construction.Over the years some
special forms like slipform,climbing form and permeable formworkhave alsobeen
developedand are being used. We will now discuss differenttypes of formwork,starting
with the most common i.e. Timber Formwork.
16.3.1 Timber Formwork
Thesizesof timbercommonlyusedforvariouspartsof formworkaregiveninTable 16.1.
Let us now examinea few timber formwork details.
a) Formwork For Columns
Formwork details for a rectangular or square column is given in Figure 16.1.
You may note someimportant features :
i) Columnbox consists of two ends and two sides.
ii) Theheight of each panel is equal to the storeyheight minus the slabthickness
and the floor sheeting.
4. iii) The width betweentwo oppositepanels is kept equql to the actual dimensionof
the columnplus twice the thickness of sheeting.
iv) Yokes are equally spacedon both sides and ends. They project atboth endsby
about 25 cm.
v) A hole is usually provided at the bottom of formwork to remove debrisetc.
before placing the concrete. This cleanouthole is covered before starting the
concreting.
vi) The formcomponentsof column are required to be designed to resist high
pressures which result becauseof continuous fillinglpouringof concrete.
Table 16.1 :Dimensionof CommonlyUsed Formwork Parts
Si.No. Part of Fonnwork Timber Thicknessorsize
1) Sheeting 2.5 to 5 cm
2) Beam and column sides 2.5 to 5 cm
3) Beam bottoms 5 cm
4) Joists 5 cm x 10cm to 7.5 cm x 22.5 cm
5) Ledgers 5 cm x 10cm to 7.5 x 22.5 cm
6) Posts 7.5cmx10cmto15cmx15cm
7) Column Yokes 5 cmx 10cmto 10cmx 10cm.
8) Steeds andWailings 5cmx10cmto15cmx15cm
Sheeting forming
PLAN column sides
ISOMETRIC VIEW
Figure 1
6
.
1 :Formwork forCol-
b) Fonnwork for RCC Beam and Slab Construction
The details of formwork for this arrangementare shown ia Figure 16.2.
5. Rpre1
6
.
2 :Wooden Fonnworkfor MonolithicRC.C. Beam Pnd SlabFloor
The importantfeaturesof this formworkare as follow :
a) The formworkfor slab is generally supportedby means of wooden centering
on the floorbelow.
b) The formworkshouldbe strongenough to support the weight of conterete and
the additional load of approximately 30% to cater for construction loads like
labour, equipment and storageof materials, etc.
c) The formwork forslabmaybe of steel forms while theother components are
wooden.
d) Desired slope shouldbe given in the floorforms itself.
e) Generally, the beam formwork is fabricatedon the ground level and then
hoistedk d placed in position with the slab formworkabove it.
f) Openingsshouldbe provided in the mainbeam formworkto receive the
formwork for secondarybeams.
16.3.2 Steel Formwork
Steel fonnsare manufacturedasproprietaryarticlesby severd firms. While constructional
details vary with the manufacturer,somedetailsare common in them. The forms may
comprisestandard flator curved panel units or be made for a specificpurpose. Generally
speaking,flatpanels maybe adopted to a wide range of usage and the manufacturers
normally supplyaccessories to enable such adaptationsto be made conveniently.
The panel units arenormally made up of steel sheetsreinforced with angle sectionsand are
clipped togetherby keys and wedges or some such similar device to formpanels.
Horizontaland vertical stiffeningis provided by bearers of angle sectionwhich are clipped
to the made up panels (See Figure 16.3).
Rpre1
6
.
3:Sted Fonns
6. cadmeti- T a q a This method of assembly ensuresrigidity and an accurate face. Flat panels are made in a
variety of sizesbut a common size is 60 cm x 60 cm with a range of narrower sections for
use as closures.
The advantagesof steel forms in comparisonwith timber are :
a) They can be easily and rapidly assembledby unskilled labour.
b) They have a long life even with minimumreasonable maintenance.They may
be used upto about 50 times before repair becomesnecessary whereas timber
formworkcannot normally be re-used more than four or five times.
c) May be adapted to a wide variety of usage without alteration.
d) Are non-absorbent.
e) No shrinkageor distortiondue to change in moisturecontent. The main
disadvantagein comparisonwith timber is that initial cost is comparatively
high but this is partly offset by reduced labour charges for assembly. Also
where forms are repeatedly used their cost is less then that of timber forms.
There are severalproprietary steel forms availablein the market. We will describebriefly a
fewjust to illustrate, and this may not be construed as a recommendation and is only for
illustrationandinformation.
I) P -form shuttering
In this type ohhuttering pressed steelsections are used to protect the edges of
plywood shutteringwhich alwaysdeteriorates from the edges. Thus this system
has all the advantagesof plywood shuttering as well as normal steel wall -
form shuttehng as one can use all the accessories of steel shutteringwith P -
form shuttering.
11) Steel Forms
Steelforms for Reinforcedbeam and slab construction. A typical steel
formworkcombinedwith plywood for a reinforcedconcrete slab is shownin
Figure 16.4.
1. 16 mm Thick Ply 2. Steel Truss Called Acrow Spans
3. Floor Fom- 4. 7 5 x 7.5 cm Teakwood Runner
5. Beam Clamp 6. Bracing 7. Steel Adjustable Prop,
Figup 16.4 :Centeringfor Reinforced ConcreteSlabs
In the above figure it can be seen that floor formslslab forms are placed on
Acrow spans (steel truss) for reinforcedconcrete slab construction.,The
adjustablebeam clamp holds timber, plywood or steelfirmly and thus prevents
bulging. This formwork is supportedon adjustable steelprops or telescopic
props.
7. 111) GridDecking System
This system is designed for flat slab beams and slab, waffle and trough floor
construction (SeeFigure 16.5).
figure165:Grid Decking System
The dropheads with their seatingsin raised position are erectedon adjustable
jacks or verticals.Deck beams are securedon the drop head settings.
Floorforms or plywood over infile beams at required spacingare placed
between deck beams andjacks are adjusted to get the required level. The deck
beams drop through 80m
r
n height after strikingdropheads alongwithremoval
of formwork and thus leaving supportto slabs,undisturbed.
IV) WallformSystemof Formwork
The Wallformsystemof formwork with soldiers, walers and clips is a self
supporting system It is availablefor concretingwalls in pour heights such as
1.25 m, 2.5 m, 5 m or more for buildings, water tanks, basement walls etc. One
such system is shown in Figure 16.6.
figure1
6
.
6 :Wdform Clhnbii Steel Shuttering
8. This wallformsystem is either for one sided shuttering or both sided shuttering
with loop anchors or wall ties, embedded in concrete for anchorage.
Another systemhas a basic elementcalled H-16 beam which is I - shaped
plywoodtimber beam. It is versatile,sturdy and handy, dimensionallystable,
uniform in size and possess uniform high strength. For walls, H-16 beams are
combinedwith steel waiers to produce a light weight panel which can be easily
assembledas required. This enables full size plywood sheets to be used as
sheathingwithout the necessityof cutting them into smaller panels. This
minimises the number of sheathingjoints and helps in achieving good quality
concretesurface. The Figure 16.7givenbelow will give you some idea of
differentparts of this system.
I. Plywood 2. H-16 Beam 3. Steel Walers 4. Adjustable Props
Figure16.7 :Wall Formwork
V) Tubular Steel Formwork
This formwork is well illustratedin the Figure 16.8.
The exampleshown above is formwork for barrel shell-roofs. This formwork
consistsof tubular steelfittings and is extensively used for sheet-roof
constructionin developed countries.In this formwork steel sheet is provided at
the top continuingin valley beams to receive the concrete. Adjustablejack
bolts and props are provided to obtain varying heights of shell roofs as well as
of ribs and valley beams.
Curve H.S.Tcc
Steel tube5cm
Figure 16.8 :TubularSteel Formwork for BarrelShell-roofs
9. 16.3.3 ClimbingFormwork
Climbingforms are used for tall structures and consistessentially of a narrow band of
formworkencircling the structures,which is raised as work proceeds.They may be made
up on siteor be specially manufactured.Various proprietary forms are availablein the
I market.
!i a) In most cases of climbingformwork, the height of concrete lift is restricted between 30
j cms to 100cms but certain types allow for continuouspouring in order to produce a
joint free structure.In the latter case the formwork is carried in a yoke suppoded and
t raisedbyjacks resting on rods embedded and left in concreteor on posts erectedon
both sidesof the walls (SeeFigure 16.9).Slipformwork is a good example of climbing
i
formwork.
Figure 16.9 :ClimbingFormwork
b) Steelforms are particularly suitablefor this type of formwork.Two simple
arrangementsof climbing formworkusing steel formsfor thick walls are shown in
Figure 16.10.
Horizontal
liners
Vertical
liners
Wintirs
First set-up
I60 or 120cn lift)
2nd l i f t
First set-up
( 60 or 120cnlif
Win tie Iwp
cut off after
strappmp
Second subsequent d + p
l60cn l i f t s )
3rd l i f t
1
...',.
:
.
. .., .
,
. cmcrete after
' : .
Second and subsquent d-p
( 60 cn l i t ts
Figure16.10 :Climbing Formwork of Steel Forms for Thick Walls
10. C O D S ~ I - I I ~ ~ ~ O I I
Techniques C) A sophisticated type of climbing formwork is shown in Figure 16.11.
This incorporatesa working platform and is fitted with optional accessories like
push-pull struts for aligningthe formwork assembly. It also has rolling mechanism for
side shifting of the formwork assembly to provide working space to fix reinforcement
and other inserts in narrow and deep wall construction. The slip form and anothertype
of climbing formwork are shown in Figures 16.11 and 16.12.
water 2,Sm long. 8Nos.
for 2.5 m height of
Figure~l
6.11 :Climbing Formwork
Form panels, straightor curved, are fitted to sturdy
yokes with working platform,suspended walkways
and safety railingsHydraulicjacks mountedon yoke
beams climb on solidjack rods. The slipform is
available fortapered structuresalso.
Figure 16.12:Slipform
d) Automatic climbing formwork,which is another type of climbing formwork is also.
called self climbing formwork as it does not need any crane for the climbingoperation.
This systemhas certain special featureswhich are enumeratedbelow :
i) This systemhas automaticclimberswhich automaticallyhoist up the formwork
step by step.
ii) Formwork for tall structuresis solved conveniently and crane costs are cut
down and work is speeded up.
iii) The entire work can be performed during the normal day shift and thus costly
night and week-end shiftscan be dispensed with.
iv) Since it provides stationary platform and formwork,it rationalisesreinforcing
and pouring operations.
v) The formworkis designed for safeguardsagainst strong winds and other
eventualities.
vi) The need for scaffoldingis eliminated.
vii) It enables easy and speedy cleaning of form shutters.
viii) Since working space available is sufficient,it also allows better supervision
and qualitycontrol.
ix) Concretingupto 1.5 metre per day is possible.It also allows adjustments for
slope and precision alignments.
Thus, the use of this systemis bound to lower the constructioncosts and result in
higher productivity.In this formwork system the need for slulled labour is less as the
need to make, fix and remove scaffolding is rninimised, which reduces expenses.
A automaticclimbing formwork for constructionof cooling tower is shown in Figure
16.13.The formworkcan be seenat the top of the cooling tower.
11. Figure 16.14 :TravellingFormwork
16.3.5 Permeable Formwork
The Japanesehave pioneered and perfected the systemof permeable formworkfor
verticaUinclined surfacesto improve the durabilityof concrete. The formwork is first
prepared in the conventional manner. The sheetingof formwork can be of plywood or steel.
Now a series of holes are drilled in a grid pattern to facilitatedraining of water and
Figure 16.13 :Automatic ClimbingFormworkfor Cooling Towers
16.3.4 Moving Formwork
Where long lengths of concrete work of constant cross-section have to be constructed,
moving or travellingformwork maybe used with advantage.In such cases a complete
section of formwork is fabricated and assembled and is carriedon some suitableform of
travelling carriage running on railway lines or other suitabletracks.A typical example is
shown in Figure 16.14.
12. T d n i q u a expellingof air when the concreteis placed and vibrate$. Generally the hole diameter is 3
mm and their spacingis 100rnmcentreto centre. Next, a Coven fabric is fixed to the inside
face of the sheathingof the formwork,such thatno water remains trapped in the interstices
between the fabric and the sheathing.For fixing to plywood, staplers may be used while for
steel, glue or adhesiveis used. The concrete mix used with permeableformworkgerferally
has watercement ratios in the range of 0.4 to 0.6. The permeable formworkis designed fm
all pressures as applicabletonormal formwork.
When the concrete is placed in the formwork,high pore water pressure formsin the
concrete in proportion to its depth. But the use of permeableformwork,allowsdissipation
of this pressure by drainingoff water. As a result,pore water in the concretevaries form
high pressure in the core of the concreteto a low pressure at the face of the formwork. This
movement and drainageof water improves the quality of the concretefor a depth of about
150mm from the face of the permeable formwork. The lowered water -cement ratio
results in reduction of permeability of concrete and improvementof surface qualityof
concrete.
16.3.6 Permanent Prestressed Concrete Formwork
Permanent forms are formswhich are left in place, that may or may not become an integral
part of the structuralframework. These forms maybe of rigid type like metal deck,precast
concrete,brick, ferrocement, wood, plastics and some types of fibre board. The flexible
types could be likereinforced waterrepellentcorrugatedpaper or wire mesh with
waterproof paper backing.
Reinforcedconcrete,fibrousconcrete and wood wool concretehave alsobeenreportedto
be used aspermanent formworkto cast structuralmembers such as slabs and beam.
Prestressedconcretecan alsobe used in casting as it offers distinct advantageslikehigher
strengthto weight ratio over plains or reinforced concrete.The use of pennanent formwork
would alsoresult in large savingsin timber or steel forms and also results in savings in
constructiontime.
SibQ 1
a j '~Vhntarc !hc advantages of steel Soi~lis
over tinlbcr forms ?
b) Wri:c a short ~lotc:
on the economy m fo~~~iwork.
L: W:nal nlatcriais are conmionly used in tomiwork'!
di %hat are the constituentsof cost of formnwork?
16.4 REMOVAL AND MAINTENANCEOF FORMWORK
Formwork shouldbe strippedor removed with care so as not to damage the concrete.
Wedges shouldbe slackenedgraduallyto avoid suddenimpositionof loads on the structure.
The strippingtime for different members has been laid down in 13:456-1978which gives
generalguidelinesabout the time of removal of formwork,where ordinaryportland.cement
is used. It statesthat "Forms shallnot be struckuntil the concretehas reached a strength at
least twice the stressto which the concretemay be subjectedat the time of removal of
13. formwork. The strength referred to shallbe that of concreteusing the same cementand F O ~ W O & and Scaffolding
aggregateswith the sameproportions and cured under conditionsof temperature and
moisture similar to those existingon the work. Where possible the formwork shallbe left
longer as it would assist the curing."
It furtherlays down that "In normal circumstances and where ordinary portland cement is
used, formsmay generallybe removed after the expiry of the followingperiods :
a) Walls, columnsand vertical faces 24 to 48 hours as may be
of all structuralmembers decidedby the engineer-in-charge
b) Slabs (propsleftunder) 3 days
c) Beam soffits(props leftunder) 7 days
d) Removal of props under slabs :
1) Spanning upto 4.5 m 7 days
2) Spanningover 4.5 m 14 days
e) Removal of props under beams
and arches :
1) Spanningupto 6 m 14 days
2) Spanningover 6 m 21 days
For other cements,the stripping time recommendedfor ordinaryportland cement may be
suitably modified."
It alsofurther lays down that 'The number of props left under, their sizes and disposition
shallbe such as to be able to safelyc;l-ry the full dead load of the slab,beam or arch as the
casemay be with any live load likely lo occur during curing or further construction."
You may alsoobservefollowinggeneralpoints during stripping
a) Any prising that is necessary, should be done against formwork and not the
concrete.
b) As formworkis stripped,it should be cleaned and properly stacked.
c) All smallparts such as wedges and bolts etc. shouldbe storedimmediately in
separatecontainers.Such a practice reduces loss of material.
d) Steelforms shouldbe greased immediately aftercleaning and before stacking.
Let us now examine another important temporary structure called "Scaffolding".
16.5 SCAFFOLDING
The "Scaffolding" is a temporary structure which is employed in building construction
operationsto supportplatforms for workmen, materials and equipments. Scaffoldingmay
be erected eitheron one or both sidesof the walls. The height of the scaffolding canbe
adjusted as the work progresses.
The Figure 16.15 shows anordinaryscaffolding.Different parts of the scaffolding are
labelledto enable you to identify them.
The variousparts of a scaffoldiilgaregenerally secured by means of rope-lashings, bolts,
etc.
16.5.1 Types of Scaffolding
The different types of scaffoldings which are generallyused :
a) SingleScaffolding
b) Double Scaffolding
c) Ladder Scaffolding
d) CantileverScaffolding
e) SuspendedScaffolding
f) SteelScaffolding and Centering
g) TrestleScaffolding
14. VERTICAL SECT1ON
Figure 16.15 :Scaffoldingand its Various Parts
We will examineonly two of these, i.e. Double Scaffoldingand Stee1Scaffolding.
16.5.2 Double Scaffolding
This Scaffoldingis called Mason's Scaffoldingand is shown in Figure 16.16.
This scaffoldingis strongerthan singlescaffoldingand'does not require to be secured into
the wall and hence no holes are to be ma& in the wall. The first row of standardsare kept
15cm from wall face and the other at 1.2to 1.5maway from the face of the wall. The
putlogs are supportedat both the endson ledgers.
SECTIONAL ELEVATION
Figure 16.16 :Detailsof Double or Mason's Scatiolding with Raking Shore
16.5.3 Steel Scaffoldingand Centering
Details of tubular steel scaffoldingused as centeringfor slabandbeam constructionis
shown in Figure 16.17.
15. W t o m boards at
- - +Jp~qf'"
supports or
(1 braces fl
SECTIONAL ELEVATION
Figure16.17 :Details &TabularSteel ScaffoldingUsed m Centeringfor Slaband Beam Corntruetion
You would have noticed that the constructional details of steel scaffolding are similar to
that of wooden scaffoldingexcept that wooden members arereplacedby steel tubes,plates and
angles and they arejoined by special couplings and screws. The diameter of steel tubes
generally used varies from40 to 60 mm with sheet metal thickness of about 5 m
r
n
Steel Scaffoldinghas several advantages over ordinary timber scaffoldingnamely :
It is suitablefor any height.
Though its initial cost is high, but it is economical in the long run.
Its erection and dismantlingis rapid.
It is strong and durable and has longer life.
Ithas better fie-resisting qualities and higher salvagevalue.
It can be converted into moving form unit by the use of wheels.
16.5.4 U-FrameScaffolding
It consists of right welded frame of two verticals and two horizontals. The various frames
are interconnected by scissor cross braces through plug welded on frames and are locked in
position by spring clips. This imparts very good rigidity and it can be erected even by
unskilled labour.It is ideal for heavy stiuctures,high slabs,bridge girders etc. It is shown
in the Figure 16.18.
Figure 1618 :U-FrameScaffolding
16. cOmtru& Techniques
16.6 SUMMARY
The appearance of the finished structureand the speed with which it can be completed are
greatly dependentupon the efficientconstructionand type of fonns employed. Several
material liketimber,plywood, steeland aluminium are being used in formwork. Several
types of formwork are now available which are efficient, safe and simple to use. In large
and tall structures, moving and travelling formworks are being increasinglyused. A major
technological advancement is the development of slipfonning techniqueand automatic
climbingformwork. Among the recent advancementsare the permeable formwork and
permanent formworks.The questionuppermost in the mind of an engineeris as to whether
a revolutionary change in formwork can be done to evolve a formworkwhich fonns an
integral part of the concreteand adds to its durability.
Steelscaffoldingis becoming most popular, particularly the tubular steel scaffolding
becauseof their light weight, long life and ease of erection. New forms of standardised
steel scaffoldinghave made the task very easy and they help in speedingup the work
without sacrificing safety.
Activity
A largenumber of commercially manufactured formwork and scaffoldingsystems are
now available in India. Compile a data sheetcomprising all details about these systems
for ready reference.
16.7 KEY WORDS
Formwork : Temporary structureto receive wet concrete and hold it in place.
Scaffolding : Temporary structureto supportplatform forworkers, materialsand
equipments.
Stripping : Removal of formwork afteruse.
16.8 ANSWERS TO SAQs
SAQ 1
a) The advantages are :
i) They can be easily and rapidly assembled by unskilled labour.
ii) They have a longlife evenwith minimum reasonable maintenance.
iii) They can be reused upto 50 times or so before repair becomes necessary.
iv) May be adapted to a wide variety of usage without alteration
v) Are non-absorbent.
vi) No shrinkgeor distortion due to change in moisture content.
b) See Section 16.2.2for details of the answer.
c) The commonly used materials are timber, plywood,boards, steel, aluminium
and plastic coated sheets.
d) The constituentsof cost of formwork are :
i) Cost of materials,
ii) Costof labour required for fabrication,
iii) Costof erection and removal of forms, and
iv) Cost of maintenance of forms.