CONSTRUCTION METHODS BASICS BTCE-503-18
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The document discusses various types of foundations and construction methods, including strip, raft, pile, and modular foundations, highlighting their design, suitability, and construction processes. It also covers different building techniques such as traditional stick framing, modular construction, light gauge steel, and precast concrete, emphasizing their benefits, drawbacks, and applications. Additionally, it mentions specialized construction methods like slip forming for tall structures and various types of scaffolding and formwork used in building construction.
CONSTRUCTION METHODS BASICS BTCE-503-18
- 2. CONTENT • TYPES OF FOUNDATIONS AND CONSTRUCTION METHOD • BASICS OF FORMWORK AND STAGING • COMMON BUILDING CONSTRUCTION METHOD • MODULAR BUILDING CONSTRUCTION METHOD • PRECAST CONCRETE CONSTRUCTION METHOD • BASICS OF SLIP FORMING FOR TALL STRUCTURES • BASICS CONSTRUCTION METHODS FOR STEEL STRUCTURES • BASICS CONSTRUCTION METHODS BRIDGES
- 3. PAD FOUNDATION RAFT FOUNDATION STRIP FOUNDATION PILED FOUNDATION TYPES OF FOUNDATIONS
- 4. PAD FOUNDATION Foundations provide support for structures, transferring their load to layers of soil or rock that have sufficient bearing capacity and suitable settlement characteristics. they can be used to help to prevent settlement and other movements of structures and can permit construction on ground that might otherwise have insufficient bearing capacity.
- 5. Strip foundations are used where the soil is of good bearing capacity. The key sizes of a strip foundation for concrete cavity wall construction and timber frame cavity wall construction are similar. The size and position of the strip is directly related to the overall width of the wall. The principle design features of a strip foundation are based on the fact that the load is transmitted at 45 degrees from the base of the wall to the soil. The depth of a strip foundation must be equal to or greater than the overall width of the wall. The width of the foundation must be three times the width of the supported wall. STRIP FOUNDATION
- 7. it is vital that the strip foundation is strengthened through the inclusion of steel reinforcement. a compacted hardcore base of minimum 150mm is installed to form a platform for the subfloor and the subsequent loads of the dwelling. the 150mm concrete subfloor is poured on the hardcore in order to provide a strong, smooth platform for the insulation. a radon barrier is installed to form a continuous seal on the entire footprint of the house. a damp proof course is installed in order to repel any rising moisture. it is vital that the dpc is carried up into the blockwork to form a water tight seal over the entire floor area. the dpc must run through the blockwork at a minimum of 150mm above finished ground level.
- 8. 100mm of rigid insulation is installed below the finished floor to ensure that there is no heat lost through the foundation. 75mm concrete screed then provides the finished floor.
- 9. RAFT FOUNDATION • The foundation consisting of a thick r.c.c slab covering the whole area of a mat is known as raft foundation. Method of construction of raft foundation: • In raft foundation construction the whole area is dug out to the specified depth and 30 cm more wide than the area to be covered. • The bed is compacted and sprinkled over with water. • Then a layer of lime concrete or lean concrete ( 1: 8 : 16 ) is laid to a suitable thickness to act as a bottom cover. • After this, the reinforcement is laid. the reinforcement consists of closely spaced bars placed at right angles to one another. • Then the cement concrete (1 : 2 : 4 ) is laid and compacted to the required thickness. • The concrete slab so laid is then properly cured • When loads are excessive, thick concrete beams running under the columns can also be constructed.
- 10. SUITABILITY • This type of foundation is useful for public buildings, office buildings, school buildings, residential quarters etc, where the ground conditions are very poor and bearing power of the soil is so low that individual spread footing cannot be provided.
- 11. PILE FOUNDATION •A foundation (spread footing or grillage) supported on piles is called a pile foundation. A pile foundation usually consists of a base of spread footing or grillage supported by piles at their bottom. Piles distribute the load of structure to the soil in contact either by friction alone or by friction combined with bearing at their ends.
- 12. SUITABILITY •This type of foundation is suitable under the following situations ; •When the soil is very soft and solid base is not available at a reasonable depth to keep the bearing power within safe limits. •When the grillage and raft foundation are very expansive. •When the building is very high carrying heavy concentrated loads. •When it is necessary to construct a building along the sea shore or river bed.
- 13. FORMWORK • It is a temporary structure which is used as a mould to pour the concrete. it is a vertical or horizontal arrangement made to keep concrete in position until it gains strength & shape. • Have you seen the below mentioned shape of column of bridge in the image? ever wondered how to bring the concrete in such a shape. this all possible by formwork. firstly, the desired mould is prepared using steel or iron, and then formwork is fixed in position without any gaps to pour the concrete.
- 14. •It is a part of formwork, or you may call it as derivative of formwork. shuttering is a vertical temporary arrangement which is arranged to bring concrete in a desired shape. or formwork which supports vertical arrangement is known as shuttering. •In a technical point of view, formwork for columns, footings, retaining walls is called as a shuttering.
- 15. CENTERING •Centering is a temporary arrangement & part of formwork which is arranged to support horizontal members. or In a technical point of view, the formwork for floor beams & slabs is called as a centering.
- 17. SCAFFOLD • Scaffolding, also called scaffold or staging is a temporary structure used to support a work crew and materials to aid in the construction, maintenance and repair of buildings, bridges and all other man-made structures. Scaffolds are widely used on site to get access to heights and areas that would be otherwise hard to get to. unsafe scaffolding has the potential to result in death or serious injury. scaffolding is also used in adapted forms for formwork and shoring, grandstand seating, concert stages, access/viewing towers, exhibition stands, ski ramps, half pipes and art projects. • There are five main types of scaffolding used worldwide today. these are tube and coupler (fitting) components, prefabricated modular system scaffold components, h- frame / facade modular system scaffolds, timber scaffolds and bamboo scaffolds (particularly in china and india).
- 18. COMMON BUILDING CONSTRUCTION METHOD TRADITIONAL STICK FRAMING This process involves a building system in which workers will assemble the main skeleton of your home. the construction system actually begins when skeleton items including wall studs, ceiling joists, roof trusses, rafters and then all flooring systems are installed. these items will be installed step-by-step and then eventually build a platform for the entire home.
- 21. MODULAR HOMES • Modular homes continue to use the same type of method for conventional stick framing but they are built-in off-site conditions. this can often lead to a home that can be built much more efficiently and then hold its value well. modules are built entirely in a factory and then assembled on the job site. they get moved into a place with a crane and they are constructed in some of the same measures that a traditional stick framing method is used. the only opposing change with traditional stick framing homes and modular homes is that these homes are assembled in small modules and then trucked to the site.
- 22. MODULAR HOMES
- 23. •Builders will take modular homes and knit the various modules together to create a custom-built home that follows extremely complex designs. popular architectural features can be added into modules to produce almost any type of home.
- 24. LIGHT GAUGE STEEL • Light gauge steel is a process that involves building in a similar way as traditional stick framing but with a light difference. instead of the wooden design of the stick-built home, each of the components is instead made out of metal. the big advantage here is that any of this deal will not rot, shrink or experience damage from termites. steel can last longer than any type of wood frame and there is less worry for things like drywall cracks, warping or shrinking.
- 26. •Light gauge steel designs are often a bit more expensive for a build but they can often be beneficial for adding rigidity to the home as well as a longer lifespan for any type of property. light gauge steel is a common tool for many types of commercial buildings and it’s starting to make its way into many residential buildings as well. •Steel studs do pose a number of challenges for plumbers and electricians. The overall cost of steel also fluctuates far more than other building materials in the market which can lead to costs going up substantially.
- 27. STRUCTURAL INSULATED PANELS •A structural insulated panel is otherwise called sip. this solution is a small sandwich of rigid foam installations that are placed between an oriented strand board. this can create the structural panel that makes up the main element of a home. •SIPs often come with door openings and precut windows and they are usually constructed with areas for electrical wiring. these building methods are common for use in producing ceilings and walls. specifically trained crews are required to assemble them on the job site.
- 29. •These types of building processes are the most common for producing traditional timber frame, post-and-beam structures as well as self- supporting homes. sip homes are often designed with improved insulation and they are built to be draft-free. this can also ensure that she save money on the cost of their electricity bills and the labor on the home as well. because the materials take far less time and labor to assemble and the insulation is already in place, this is an option that is less expensive for the future of the building.
- 30. CONCRETE •Concrete has also become one of the most popular materials which are available for the foundations of homes and for a series of single-family homes for walls too. wood framing is commonly used as part of concrete installations and for accenting the concrete installations themselves. the wood framing can be used with concrete forms to produce ceilings, internal walls, and roofs.
- 32. CMUS •Concrete masonry units are made using hollow concrete blocks which are stacked on-site and then covered with a foam insulation board. the blocks provide a thermal mass which can slow down the transfer of heat. the inside of a home often stays cooler on a hot day and this is what makes these products so popular throughout the southern states. cmu homes are surprisingly affordable and they can actually be priced quite competitively with wood framing.
- 34. ICFS • Insulated concrete forms are designed to be blocks that work like lego. there assembled directly on-site and are often filled with steel reinforcing rods as well as concrete for improvements in insulation. their value is much higher than most of the wood-framed walls and they’re perfect for almost any climate. icfs are only slightly more expensive than wood-framed homes and they deliver a similar design. the actual price of these materials can depend on the local market but these have become a very popular type of material for areas that face high winds and hurricanes.
- 36. •No matter what type of modern building construction method that you would want to use for your industrial, commercial or residential building, it can be helpful to have an idea of how it will be constructed. deciding between some of these materials could help you to prepare the best option for your property.
- 37. MODULAR BUILDING CONSTRUCTION METHOD 3D Volumetric Construction • Using this modular construction technology, 3d units are produced in controlled factory settings using needful construction and building materials. Finished units are transported to site in various modules, basic structural blocks or final touched up units with all amenities installed, for assembly. blocks can be erected rapidly at site and properties of concrete like fire retardant, sound resistivity, thermal mass etc. are retained.
- 39. PRECAST FLAT PANEL MODULES • These are primarily wall and floor modules which are manufactured away from the actual site and then transported to site for erection. load bearing components like decorative cladding and insulation panels can also be produced. Also called cross-wall construction, the technology has gained momentum due to seamless adherence to specifications and ease as well as swiftness of construction.
- 41. TUNNEL FORMWORK SYSTEM •With this tunnel technique, construction is paced up for cellular structures of repetitive patterns through the building of monolithic walls or units in a single operation per day. Expeditious work is achieved by deploying formwork and readily mixed concrete with the convenience and agility of factory conditions. formworks in tunnel form are stacked and used at the site with cranes.
- 43. FLAT SLABBING TECHNOLOGY • This technique utilizes the simplicity of contemporary formwork for quickly building flat slabs to facilitate easy and swift placing of horizontal amenities and for partitioning. Maximization of pre-fabricated services occurs as services can be carried out in an uninterrupted manner in zones underneath the floor slabs. Every top-notch building construction company is using the same as internal layouts can be conveniently modified for accommodating alterations at a later date. further, reinforcement needed is lesser which cuts down labour costs significantly.
- 45. PRE-CAST FOUNDATION TECHNIQUE •Foundations can be built swiftly with precast concrete units which are produced in a factory and are high on quality quotient. strength is imparted to foundation related building construction materials through interconnected concrete piles. This technique allows construction work to progress even in inclement weather and minimizes excavation activity.
- 47. HYBRID CONCRETE BUILDING TECHNIQUE •This technique expedites construction turnaround time by blending the advantages of concrete pre-casting with the in-situ building. quality improves, whereas the cost of construction plummets. Hybrid concrete structures are easy to build, competitive in nature and perform consistently.
- 49. THIN JOINT MASONRY TECHNIQUE • Utilization of this technique leads to the reduction of the quantum of mortar applied by slashing it depth from 10mm to lesser than 3mm. consequently, mortar can be laid swiftly with enhanced productivity on the longer wall panels. • With large sized concrete blocks, higher construction efficiency along with significant cost reduction can be achieved. within a single day, the number of mortar courses laid is higher as curing of mortar takes place quickly without compromising on bonding strength resulting in the elimination of floating problem.
- 51. INSULATING CONCRETE FORMWORK (ICF) TECHNIQUE •ICF technique employs polystyrene blocks that feature twin walls and can be rapidly put together for creating building wall formwork. the formwork is then pumped in with high quality, ready mixed, factory-made concrete. The building construction process becomes fool-proof and the resultant structure has a high level of sound and thermal insulation.
- 52. INSULATING CONCRETE FORMWORK (ICF) TECHNIQUE
- 53. PRECAST CONCRETE CONSTRUCTION METHOD •Precast concrete is an alternative to cast-in-situ concrete. While cast-in- situ concrete is cast in its actual location, precast concrete is cast at another location, either at the building site or in a factory, and is then lifted to its final resting place and fixed securely. this means that unlike cast-in-situ construction, which is monolithic or continuous, precast concrete buildings are made of separate pieces that are bolted or connected together.
- 54. ADVANTAGES OF PRECAST CONSTRUCTION • The construction is done on the ground rather than at a height. • It can be done inside a climate-controlled structure, eliminating problems of rain, dust, cold, or heat. • Specialised formwork (moulds) can be built for doing many repetitions of the same component. • Specialised equipment can be used to make, move, and pour the liquid concrete. • Curing of the concrete can be done in a controlled environment.
- 55. DISADVANTAGES OF PRECASTING •Since each piece is made separately, the structural frame or system is not monolithic or continuous like regular concrete construction. The joints between pieces create structural discontinuity. The forces of the building will pass through these joints, so they have to be designed to transfer these forces safely and properly. Note that precast concrete can be used for non-structural members too. •Again, as the building is made of discrete components, the joints between adjacent members have to be sealed with special sealants to make them waterproof.
- 56. •Each precast component is usually large and heavy. This means that cranes are required to lift them in position; these cranes are required to operate over the entire building volume. Since there will only be a few cranes at site, the time taken by the cranes to pick up a piece and shift it to its final position becomes critical in determining the building schedule.
- 57. HOW AND WHERE PRECASTING IS USED •Reinforced concrete is a material usually used for structural systems due to its strength, durability, and affordability. Precast concrete is used in the following ways : to make beams, columns, floor slabs, foundations, and other structural members for buildings •To make wall or cladding panels for buildings. •To make precast pre-stressed elements for buildings.
- 58. •To make components for infrastructure projects: elements such as bridge spans, or metro line viaducts are often precast in a casting yard •To make products for sale: precast water tanks, septic tanks, drainage chambers, railway sleepers, floor beams, boundary walls, water pipes are all available •Since it can be moulded into any shape, it can also be used to create one- off unusual forms such as boats, sculptures and suchlike..
- 59. BASICS OF SLIP FORMING FOR TALL STRUCTURE • The slipform construction method has undoubtedly become one of the most popular and commonly used construction techniques. Simply put, slipforming is a method in which concrete is poured into a formwork that is in a state of continuous motion. In nature and application, slipform can be considered similar to climbing form or jump form. What distinguishes the techniques is mainly how the formwork is moved. In climbing / jump form the formwork is regularly dismantled and re-assembled at the next casting position. In slipforming, on the other hand, the formwork is already moving while casting takes place.
- 60. WHY USE SLIPFORM •Slipform is undoubtedly the fastest and most economical construction method available for high-rise concrete structures. the technique offers a construction rate of 4m-8m per 24h (about 5-7 times faster compared with conventional methods). •Slipform is also a very safe construction method since there is no need for continuous dismantling and re-assembly of formwork by crane during the construction phase– the complete set-up is assembled only once at ground level before “take-off”. during an entire construction project, this also saves a lot of time.
- 61. BENEFITS OF SLIPFORMING •The main reason why the slipform technique has become commonplace in construction projects worldwide, is because of its numerous advantages. as mentioned, the construction speed with slipform is many times faster than other methods. Slipforming is also known for its high rate of output. However, the process requires careful planning and execution because there is little scope for change once the continuous concretin commences.
- 62. BASICS CONSTRUCTION METHODS FOR STEEL STRUCTURES The priority during the construction is to minimise on-site construction and provide extensive prefabrication. Proper planning during design stage is required, with consideration of column and beam spacing for the following: •Unpropped metal deck during concreting . • Hoisting of precast facade panel for external walls . • Ensure the steel member sizes are easy to hoist, manage and install on site.
- 63. Other site constraints such as accessibility and limitations of hoisting equipment need to be considered. these constraints may subsequently affect the sequence of construction for the development. SEQUENCE OF INSTALLATION • Figure 3.1 erection of steel column and beams - temporary bracing was Required to ensure verticality of steel columns when bolt connections from beams to columns were tightened
- 64. Figure 3.2 bolted connection for column to beam with laying of metal decking for second storey and deck.
- 65. Figure 3.3 Installation of precast facade walls to beams
- 66. •FIGURE 3.4 FASTENING OF CONNECTION
- 67. BEAM BRIDGES •Beam bridges are either simple beam or cantilever structures generally constructed from steel truss or pre-stressed concrete units. The simple beam bridge is horizontally self-supporting and transmits loads vertically through piers or abutments. The cantilever bridge transmits loads through piers central to the beam.
- 69. CONSTRUCTION OF BEAM BRIDGES • There are a very wide range of construction methods available, however, bridge foundations constructed in water will usually involve the use of cofferdams or caissons. Foundations on land may be piled, often capped off to receive a pier foundation. • Piers will generally be constructed above the foundations, and then beams or girders lifted on to them by crane which can either be erected on false work around the pier or from ground level. After the main girders have been placed, the bridge deck can be positioned or cast in situ. Decking to steel bridges: Steel trough filled with concrete. Steel beams encased with concrete. Reinforced concrete slab on steel beams. Steel deck on steel beams.
- 70. • Decking to concrete bridges Integral bridge deck with polystyrene formers. Beam and slab deck. • If the bridge is to span water, barges or pontoons may be used to float materials out to the lifting position. A temporary system of trestles may be used as a means of placing the beams or girders. For bridges spanning high drops, plate-girders or trussed-girders may be hauled across the opening using rollers. Alternatively, cantilever launching may be used, where the beam is launched from one bank, with sufficient ballast to counteract the overturning force, and hauled across the span using a winch
- 71. ARCH BRIDGE • Arch bridges consist of a load-bearing arch in a state of compression, the strength and stability of which allows them to carry greater loads than beam bridges. The arch can support the horizontal deck of the bridge either from above or below
- 73. CONSTRUCTION METHODS FOR ARCH BRIDGES The construction methods for arch bridges typically include: • Supporting the arch using trestles until construction is complete. This is suitable for low arch bridges. • Cantilevering the ribs out from the sides of the span. This is suitable for bridges over high drops which cannot be spanned with trestles. Where the spans are very large, the arch may be cantilevered in sections using a creeping crane that is mounted on top of the arch. The crane lifts rib sections from barges or pontoons below. The bridge deck is then constructed from both ends, meeting in the middle.
- 74. SUSPENSION BRIDGES •Suspension bridges consist of towers secured by cables that suspend the central structural span or deck. The tower foundations may be constructed using caisson or cofferdam techniques, whilst the cable anchorages can be secured through anchorage tunnels to suitable ground on either end of the bridge.
- 76. • From these three basic options, a very wide range of designs are possible. The choice of bridge design will be determined by the height, ground conditions and the clear span required. • Traditionally, steel construction has been most commonly used for very long spans, however, concrete arches are now also being used for big bridges. For large single-spans bridges, suspension bridges are the most common, with the high-tensile strength of the steel cables providing a design solution that is very economical compared to other support options. • Where there are suitable support points available, multi-span bridges may be used to create long bridges, and these may include combinations of beam, arch and suspension spans. • Moveable bridges are moveable variations of the three basic forms, generally used in situations where greater headroom under the bridge is sometimes necessary, for example to allow the passage of a ship underneath. The most common types of moveable bridge are: Swing: the structure pivots on a central pier. Bascule or pivoted cantilever: 'drawbridges' which use a counter-weight behind the pivot point to raise and lower the deck. Vertical lift: simple beams or girders that are raised by cables from towers.
- 77. CONSTRUCTION OF SUSPENSION BRIDGES • The anchorage foundations are usually constructed deep into a hillside on both banks. The towers are typically constructed using steel or in situ concrete, built on large concrete bases. Cable housings generally take the form of massive concrete blocks either positioned in water at either bank or cast deep into the bank itself. • Multi-strands of high tensile wire are used to build up the suspension cables, which are then carried between anchorage points by means of a grooved wheel. • The deck can may be erected either by lifting sections from pontoons below or by cantilevering sections out from each end.