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Construction Technology and Environmental Services Level1 - Coggle Diagram

- - - - Examples
        
        1) Propping
        
        2) Scaffolding
        
        3) Formwork
        
        4) Excavation support i.e Shoring which prevents collapse or excessive movement
        
        5) Access and task lighting
  - - - Definition - A culvert is a tunnel-like structure that is constructed to allow water to flow under a road, railway line or similar construction
    - - 1) A headwall is a small retaining wall/structure built at the inlet or outfall of a storm wall drainage pipe
      - 2) They are used to protect the end of the drain as well as protect the watercourse embankment from erosion.
    - - 1) SUDS is designed to manage storm water locally, to mimic natural drainage and encourage infiltration and/or attenuation
      - 2) SUDS helps reduce the reliance on existing drainage infrastructure
- - - - What is ground heave?
        
        Definition - Ground heave is usually associated with clay soil which swells when wet, causing upward movement of the ground. As the soil generally cannot expand downwards or sideways, the result is that the exposed upper surface of the soil rises up
        
        techniques available for ground improvement
        
        1) Vibro compaction
        
        2) Vibro stone columns
        
        3) Vertical drains and vacuum consolidation
        
        4) Soil mixing
        
        5) Dynamic compaction
        
        6) Dynamic replacement
      - Excavation
        
        Definition - a cavity formed by cutting, digging, or scooping.
        
        What are the different forms of excavation?
        
        1) Site clearance operations - removing vegetation and rubble
        
        2) Stripping topsoil
        
        3) Reduced level dig to reach formation level
        
        4) Cut and fill
        
        5) Excavation for foundations
        
        What are the key factors the contractor should consider when excavating?
        
        1) Nature of the soil and moisture content in the ground
        
        2) Method of excavation
        
        3) If ground support systems are required
        
        4) Proximity of existing buildings
        
        5) Depth of excavation
        
        6) Underground services and drainage
      - Basement
        
        Definition - In the general context of buildings, a basement can be defined as a storey which is below ground. They can be constructed within a cofferdam or other temporary supported excavation
        
        Waterproofing basement techniques
        
        1) Membrane - A waterproofing membrane is a thin layer of water-tight material that is laid over a surface. This layer is continuous and does not allow water to pass through it
        
        2) Mastic asphalt tanking - tanking is used to provide a continuous waterproof membrane which is applied to the slab and walls. These are roll/sheet based membrane which is commonly stuck to the substrate with a hot tar based adhesive and using blowtorches
        
        3) Liquid applied membrane - Liquid applied membranes are either sprayed or brush applied on a surface, the liquid cures with the air to form a seamless joint-free membrane.
        
        4) Drained cavity system - this method of waterproofing collect the water through a cavity wall and drains it away via local drainage outlets within the cavity
        
        Types of basement construction
        
        a) Retaining wall and raft basement
        
        b) Box and cellular raft basement
        
        c) Piled basement
        
        Methods of installation
        
        a) Bottom up - Traditional way to construct a basement, you excavate down to basement depth, casting the basement slab and then cast the ground floor slab
        
        b) Top down - retain wall is formed and the ground floor slab is cast with an opening left out. The basement area can then be excavated and basement slab eventually poured whilst works start on the superstructure which improves speed of the programme.
      - Typical road build up
        
        1) Compacted and rolled type 1 subbase (100-250mm)
        
        2) Base course (70-150mm)
        
        3) Binder course (50-100mm)
        
        4) Wearing/surface course (20-40mm)
      - Foundations
        
        Definition - Foundations provide support for structures, transferring their load to the ground to avoid excessive settlement. Foundations should bear the loads of the superstructure
        
        Types of foundations
        
        Considerations when selecting the type and size of foundations
        
        2) Nature and load bearing capacity of the ground
        
        3) Type of structure
        
        4) Cost
        
        5) Construction constraints i.e. adjacent buildings
        
        1) Total load of the building
        
        1) Strip foundations - This is a strip of linear structure that ultimately serves to spread the weight across the total area of the ground, typically used to support masonry
        
        2) Pad foundations - Pad foundations are typically used to support individual or multiple columns, spreading the load to the ground below. They are usually square or rectangular on plan and can be reinforced or non-reinforced
        
        3) Raft foundations - This is essentially a continuous slab that extends over the entire footprint of the building. the raft spreads the load of the building over a larger area than other foundations, the stress acting on the ground is reduced
        
        4) Piled foundations - A pile is a column that extends deep into the ground. Where the bearing capacity of the soil is poor or imposed loads are very heavy, pile foundations may be required.
        
        There are two main types of pile
        
        a) End bearing piles - The bottom of the pile rests on a layer of strong soil or rock, the load of the building is transferred through the pile onto the strong layer
        
        b) Friction piles - Friction piles develop most of the pile bearing capacity by shear stresses along the sides of the piles. The surface of the piles works to transfer the forces to the soil
        
        There are two main construction methods
        
        a) Bored Piles - Manufactured on site
        
        2 more items...
        
        b) Driven concrete piles - Formed off site, delivered and driven into the ground
        
        2 more items...
        
        In what situation might piled foundations be the best solution?
        
        1) Where the structure is heavy and the underlying soil is weak
        
        2) In areas where settlement issues are common
        
        3) Where the sub-soil water table is high
        
        4) Where the load distribution of the structure is not uniform
        
        5) Presence of horizontal forces
        
        Secant Pile walls
        
        Definition - A wall formed by installing interlocking piles which create a solid barrier free from gaps. Typically used to form a retaining wall
        
        Sheet Piles
        
        Definition - A deep trench is excavated and concrete is poured in situ. The piles may be driven into the ground or placed in excavated trenches. The piles can be used to form basement walls or act as retaining walls
        
        5) Cantilever foundations - A cantilever footing is a component of a building's foundation. It is a type of combined footing, consisting of two or more column footings connected by a concrete beam. This type of beam is called a strap beam
        
        Underpinning
        
        Definition - Underpinning is a method for repair and strengthening the foundations.
        
        Why is it required?
        
        1) Stabilising foundations undergoing settlement
        
        2) Stabilising foundations that have moved because of landslip or unstable slopes
        
        3) Stabilising foundations affected by erosion, subsidence or heave
        
        4) Stabilising foundations affected by vibration damage
        
        5) To increase the load capacity of the existing foundations
        
        6) To accommodate a new adjoining building, new basement or deep sewer
  - - - What is the envelope of a building?
        
        Definition - A building envelope is the boundary between the interior and exterior of a building. The materials and components that form the external shell of a building such as brickwork, cladding, curtain wall etc
      - Key considerations when designing external walls
        
        1) Weather Protection
        
        2) Fire resistance
        
        3) Acoustic and thermal performance
        
        4) Structural performance
        
        5) Appearance/aesthetics
        
        6) Expected lifespan
        
        7) Future maintenance
      - What is a retain façade?
        
        The façade of a building is preserved whilst the rest of the structure is remodeled, or a new structure is built behind. This is often used when restoring listed buildings
      - Standard dimensions
        
        UK Brick - 215mm x 102.5mm x 65mm
        60 Bricks per m2
        
        UK Block - 440mm x 215mm x 100mm
        10 blocks per m2
      - What are weep holes?
        
        Small openings in the outer side of masonry construction. They provide ventilation to the cavity and allow moisture to drain away
      - Types of brick bond
        
        1) English bond - Alternating courses of header and stretchers
        
        2) Stretcher bond - The most common brick work method. The vertical joints are staggered each time by half a brick
      - What is a curtain walling system?
        
        A curtain wall system comprise a lightweight aluminum frame onto which glazed or opaque infill panels can be fixed
      - Movement Joints
        
        Definition - A movement joint is designed to safely absorb the expansion of construction materials. Movement joints can also allow for movement associated with ground settlement and earthquake activity
      - Screed
        
        Definition - A thin top layer of material which generally is sand and cement is poured on site on top of the structural concrete or insulation to provide a level surface to which a floor finish can be applied.
        
        Types of Screed
        
        1) Bonded - Screed is fully bonded to the substrate using a primer or bonding agent
        
        2) Unbonded - instead of being bonded directly to the base, these are applied over a damp proof membrane laid on top of a concrete base.
        
        3) Floating - the screed is laid on top of insulation to create a thermally efficient floor, usually used for underflooring heating systems.
        
        4) Resin bonded - Laid onto a clean, rough prepared concrete base. The resin acts as a ready installed damp proof membrane to the top screed
      - Thermal/Cold Bridging
        
        Definition - This is heat loss and possible condensation occurring mainly around window and door openings and at the end between the ground floor and wall. Continuous insulated throughout the entire external envelope to prevent thermal bridging.
        
        Condensation can be prevented by either
        
        1) Providing a vapour control layer on the warm side of any insulation
        
        2) Removing the damp air by ventilating the colder area
  - - - 1) Cement
      - 2) Aggregate
      - 3) Water
    - - Dead loads are static forces that are relatively constant for an extended time. Usually the weight of the material plus non structural elements such as partitions, immovable fixtures, kitchens etc
      - Live loads refer to the dynamic forces from occupancy and intended use. These loads include the weight of people, furniture, appliances, moveable equipment
    - - A retaining wall holds back/retains the soil behind it. The typical purpose is to resist the lateral pressure of soil where here is a change in ground elevation
    - - Pre-tensioned concrete
        
        1) In pre-tensioning the reinforcement, the tendons or cables are stretched across the concrete formwork before the concrete is placed
        
        2) After the concrete has hardened and a suitable strength is developed, the tendons are released.
        
        3) The tendons attempt to shorten and transfer the energy stored to the concrete
        
        4) A compressive force is therefore induced into the concrete
      - Post tension concrete
        
        1) The concrete is case around tubes or ducts which will contain the reinforcing tendon
        
        2) Once suitable concrete strength has developed, the tendons are threaded through the ducts and stretched using hydraulic jacks
      - reinforced concrete
        
        Reinforced concrete is a combination concrete with reinforcements usually steel bar, rods or mesh. The combination is made to use the compressive strength of the concrete and tensile strength of the steel at the same time, hence work together to resist many types of loading
    - - Glulam is an abbreviated term which stands for glue-laminated timber. A Glulam is made of multiple layers of solid wood bonded together with high-strength adhesive to form a single structural unit
    - - Definition - Structural steelwork is used to form the skeleton of the frame.
        
        1) Universal Beam or Column- an H or I shaped cross section
        
        2) Channels - Somtimes known as a C-section which are commonly used for columns
        
        3) Hollow sections - typically rectangular of square hollow sections
        
        4) Flat sections - where a connection between 2 beams are required
        
        5) Rolled steel angle - equal or un-equal angles in an L shape, used often to support stairs
        
        6) Circular hollow section - often used as columns
- - - - 1) Construction on-site can be faster compared to in situ concrete frames
      - 2) The structure is relatively lightweight
      - 3) Timber can be aesthetically pleasing i.e. exposed oak
      - 4) Sustainability benefits assuming the timber is harvested responsibly from a well managed forest
    - - 1) Skilled workmanship is required to achieve a high-quality finish
      - 2) Potential for wet rot, dry rot and woodworm etc
      - 3) Fire protection may be required
  - - - 1) Faster to erect than concrete frames
      - 2) Recyclable
      - 3) High strength to weight ratio
      - 4) Beams can span over a long distance, ideal for warehouses etc
    - - 1) Steel has a lower load bearing capacity compared to concrete frames
      - 2) Fire protection might be required
      - 3) The price of steel can be volatile
      - 4) Steel frames do not have the same acoustic and thermal properties of concrete frames
  - - - 1) Fire protection is inherent in the structure
      - 2) Cladding and other finishes can be fixed direct to the frame
      - 3) Provides good sound and heat insulation
      - 4) High compressive strength
    - - 1) Requires framework
      - 2) Slower to construct on site
      - 3) Requires a bulky structure
      - 4) Concrete does not span as well as steel
      - 5) Long curing time - maximum strength is typically achieved after 28 days
    - - Definition - Formwork is the temporary structure used to contain poured concrete and mould it to the required dimensions. The formwork is usually stripped away once the concrete has hardened and can support itself.
        
        1) Beam formwork - 3 sided box supported and propped in the correct position
        
        2) Column formwork - vertical 4 sided mould of the desired shape and size.
        
        3) Wall forms - conventionally made up of plywood sheeting that may be steel, plastic or wood faced for specific concrete finishes. Stability is provided by vertical studs and horizontal walling retained in place by adjustable props
    - - 1) Mixture portions
      - 2) Specified strength
      - 3) Size and shape of concrete member
      - 4) ambient weather conditions
      - 5) Future exposure conditions
  - - - Slipform construction involves pouring concrete into the top of continuously moving formwork. As the concrete is poured the formwork is raised vertically at a speed that allows the concrete to harden before it is exposed at the bottom. Typically used to construct stairs, lift shafts, towers etc
    - - Jump forming works similar in principle to slipform. The structure is cast in a series of vertical sections called lifts. After the concrete has gained sufficient strength, the formwork is moved back and then 'jumped' to the next level above
- - - - Definition - Cat B fit out follows on from a Cat A to provide a space that is ready to move into and operate. Cat B fit out can include but not limited to:
        
        a) Partitions and doors
        
        Types of plasterboard
        
        1) Standard boards (White/light grey)
        
        2) Fire board (pink)
        
        3) Acoustic boards (blue)
        
        4) Moisture resistant boards (green)
        
        Thermal insulation
        
        Definition - Thermal insulation of external elements is measure in terms of the thermal transmittance rate, known as the U-value. This is the amount of heat energy in watts m2 for every one degree kelvin between external and internal air temperature.
        
        Typical U-values
        
        1) Brick wall - 2.0 W/m2K
        
        2) Cavity wall with no insulation - 1.5 W/m2K
        
        3) Insulated wall - 0.18 W/m2K
        
        4) Single glazing - 4.8-5.8 W/m2K
        
        5) Double glazing - 1.2-3.7 W/m2K
        
        6) Triple glazing - below 1 W/m2K
        
        7) Solid timber door - 3 W/m2K
        
        b) Floor finishes
        
        c) Specialist lighting and facilities
        
        d) Cafes, tea points and kitchen areas
        
        e) Furniture
        
        f) Branded material and decor
    - - Definition - Cat A fit out typically provides a basic level of finish, this may include raised floors, suspended ceilings and partitions along with basic mechanical and electrical services. Cat A space is often a bare-bones finish that is considered a blank canvas for interior and office designers
        
        Raised access Flooring
        
        Definition - A floor sitting on pedestals above the structural slab. The system allows services to be located within the void (usually power and data cables
- - - - Single Phase
        
        Single phase power has only one live wire and a neutral (230v)
      - Three Phase
        
        3 phase power uses 3 lives wires with one neutral wire (400v)
    - - Generators are usually powered by diesel and act as a backup supply should the primary power supply fail
    - - The UPS provides an alternative 'no-break' electrical supply in situations where it is important there is no loss of electrical supply, even if the primary supply fails. Typically installed in hospitals for life critical equipment, data centers and IT server rooms
  - - - Heating
      - Ventilation
        
        Natural Ventilation
        
        Definition - Natural Ventilation is a method of supplying fresh air to a building or room by means of passive forces , typically wind speed or difference in pressure in internally and externally. This is achieved without the use of mechanical systems .
        
        Mechanical Ventilation
        
        Definition - Mechanical ventilation is the intentional fan driven flow of outdoor air into a building. Mechanical ventilation systems may include supply fans, exhaust fans or a combination of both
      - Air Conditioning
      - Types of HVAC systems
        
        1) Fan coil Unit (FCU)
        
        Definition - An FCU is used to control the temperature in the space where it is installed. A fan blows air across a heat exchanger coil that will contain hot or cold water. The return air grille and supply air diffuser will be ducted to and from the FCU. The unit gets its hot or cold water from a central plant room
        
        Advantages
        
        1) Economical due to their simplicity
        
        2) Require less space than AHUs
        
        3) Unoccupied areas of building may be isolated and shut down
        
        4) Zones can be controlled individually
        
        Disadvantages
        
        1) Can be noisy due to the fan mechanism
        
        2) Requires a higher degree of maintenance
        
        3) Can cause condensation
        
        2) Air handling unit (AHU)
        
        Definition - It is a device that is involved in the transportation, heating or cooling of air as part of a HVAC system. They maintain adequate ventilation by providing fresh, filtered air and delivering it at the condition required to the internal space. They can be used to control the temperature and humidity of the air. After heating or cooling the air, the air stream is moved to the required location through air ducts. It contains a blower, heating or cooling elements, filter racks, sound attenuators and dampers. An AHU is a large unit typically installed remotely that supplies and conditions air to multiple spaces via ducting
        
        Advantages
        
        1) Allows the temperature to be controlled throughout the building
        
        2) The air is conditioned which provides a high quality of internal air
        
        Disadvantages
        
        1) Possible transfer of odours between spaces
        
        2) Requires adequate space to be installed
        
        3) Problems with sound and vibration control
        
        3) Variable air volume system (VAV)
        
        4) Air Source Heat Pump
        
        Definition - An air source heat pumps takes heat from the air and boosts it to a higher temperature using a compressor, it then transfers the heat into the heating system. Their function resembles the workings of a fridge or air-conditioners, but in reverse
        
        Chilled Beam
        
        Definition - This is a HVAC system designed to heat/cool large buildings. Pipes of water are passed through a beam located in the ceiling, and the beam chills the air around it which becomes dense and falls to the floor as the hot air rises
        There are 2 systems - active and passive which differ in the way air is brought to the space
        
        1) Active - active chilled beams operate in the same principle as the passive with the exception of having fresh air ducted to it. Rather than air being drawn into the beam by buoyancy it is induced by the ducted air
        
        2) Passive - long rectangular units located at high level to circulate chilled water in finned pipes. The warm air rises and is cooled by the chilled beam
        
        Advantages
        
        1) Minimal noise output
        
        2) Lower cos than AHUs to maintain
        
        3) Highly energy efficient
        
        4) Requires less ceiling space than a AHU
        
        Disadvantages
        
        1) Upfront costs can be more than a AHU
        
        2) Systems are less effective at heating or cooling so supplementary heating systems are often needed
        
        3) Cannot be used alone in buildings with higher than 2.7m ceilings
        
        4) If water temperature is too low or humidity is too high, condensation can occur
- - - - Rainscreen Cladding
        
        Definition - A system which manages the flow of rainwater on a building. The system is not necessarily waterproof itself but serves as a screen and protection against rain for the rest of the building. There are two key types of system
        
        a) Drained & Ventilated systems
        
        b) Pressure equalised systems
      - Cladding Must
        
        1) Create a controlled internal environment
        
        2) Protect the building from external conditions
        
        3) Provide privacy and security
        
        4) Prevent the transmission of sound
        
        5) Provide thermal insulation
        
        6) Create an external facade
        
        7) Prevent the spread of fire
        
        8) Generate an airtight building envelope
        
        9) Provide openings for access, daylight and ventilation
  - - - 1) Single layer membrane - one layer of felt consisting of a base sheet of glass fibre or polyester reinforcement combined with hot bitumen during manufacture.
      - 2) Built up felt - Constructed of three layer of single membrane felt. The first is laid at right angles to the fall commencing at the eaves. The next is laid parallel to the fall and the final layer is at right angles. It is then covered with stone chippings
      - 3) Asphalt roofing - - mastic asphalt consists of an aggregate with a bituminous binder which is cast into block ready for reheating at site. It is heated in a cauldron to a temperature of 200 degrees and transported in liquid form to the roof. Two coats are usually required
- - - - Objective of a site investigation
        
        The primary purpose is to establish parameters for foundation and substructure design. The engineer will assess the properties and composition of the soil and rock as well as potential ground contamination that could affect construction or building safety
      - Name a type of vegetation that can cause issues for a construction project
        
        Invasive plants such as Japanese Knotweed
    - - Tests the load bearing capacity of the ground to inform foundation design and construction details for other ground bearing elements such as road
- - - - Fire fighting lift
        
        Definition - A lift designed to have additional protection, with controls that enable it to be used under the direct control of the fire and rescue service in fighting a fire... A firefighting lift is required if the building has a floor more than 18m above, or more than 10m below fire service vehicle access level.' Firefighting lifts have very specific safety requirements and the presence of firefighting controls within a lift does not necessarily mean that it is a firefighting lift. A firefighting lift includes; the lift car, the lift well, the lift machinery space, the lift control system and the lift communications system
    - - 1) Water (RED) - Wood, cardboard, textiles
      - 2) Foam (BLUE) - Flammable liquids
      - 3) Dry powder (CREAM) - Flammable liquids and electrical fires
      - 4) Carbon dioxide (BLACK) - Electrical fires
      - 5) Wet chemical (YELLOW) - Cooking oil fires
    - - Sprinkler heads are usually heat activated. when the heat of the fire reaches the sprinkler head, a solder link will melt or liquid filled bulb will shatter to activate the sprinkler, releasing water directly over the source of the heat
- - - - List of the Building Control approved documents
        
        2) Part B - Fire Safety
        
        3) Part C - Site preparation
        
        4) Part D - Toxic Substance
        
        5) Part E - Sound resistance
        
        6) Part F - Ventilation
        
        7) Part G - Sanitation, hot water safety and water efficiency
        
        8) Part H - Drainage and waste disposal
        
        9) Part J - Combustion appliances and fuel storage systems
        
        10) Part K - Protection from falling, collision and impact
        
        11) Part L - Conservation of fuel and power
        
        12) Part M - Access to and use of buildings
        
        13) Part P - Electrical safety
        
        14) Part Q - Security in dwellings
        
        15) Part R - High speed electronic communications networks
        
        16) Part S - infrastructure for charging electric vehicles
        
        17) Approved document 7 - Materials and workmanship
        
        1) Part A - Structure
      - Who reviews the design and construction phase for compliance with the Building Regulations?
        
        The building control officer or approved inspector
  - - - 1) High alumina cement in structural elements
      - 2) Asbestos
      - 3) Urea formaldehyde
  - - - How does the Equality act effect buildings?
        
        Whilst accessible design of buildings is regulated by Building Regulations Part M, the Equality Act does require "reasonable adjustments" to be made when providing goods, facilities, services and premises. This means due regard must be given to any specific needs of likely building users. Compliance with the requirements of Part M does not therefore signify compliance with the much broader obligations and duties set out in the Equality Act.