2. CL3 - Construction technology and environmental services Flashcards
What are Building Regulations?
- Statutory instruments that sets out the minimum performance standards for the design and construction of buildings
- Supported by the Approved Documents A to M and other codes of practice
- Part L - Conservation of Fuel & Energy – 20% of energy consumption must come from renewables
- Part B Fire Safety – apartments over 5 storeys must have 90 minute vertical compartment lines
- Part E - Sound – 53db minimum between floors and walls of living spaces
What is substructure?
All elements of work that are undertaken below the damp proof course that provides the basis for the superstructure to be constructed upon.
What is superstructure?
All internal and externa l works items above the damp proof course. • This is ma de up of: o External walls. o Stairs. o Roof. o Structural walls. o Suspended ceilings. o Raised floors.
What is the external envelope?
- The materials and components that form the external shell or enclosure of a building.
- Th e s e m ay be load or non-load bearing.
What are the typical components of site investigations?
Their objective is to collect and record data to help with the design and construction process. This should include matters in relation to the site that may impact the development for example :- o Boundary hedges & fencing o Existing tree s. o Size, depth and location of services including g a s, tele p hone , electricity, water & drains. o Existing building s. o Ground water conditions. o Soil investigations. o Trial pit information.
Tell me more about ground investigation and why they are useful?
- Purpose is to determine the suitability of the site for the proposed works and determine adequate and economic foundation design
- Should determine the potential difficulties
- Identifies depth of rock, soil density, soil types
- The method chosen will depend on type of building – function, size etc
- Soil lab testing will identify potential risks in disposal off site i.e. categories of waste linked to disposal costs
What kind of ground tests are there?
- Dynamic probe tests – steel rods are driven into the ground using a slide hammer. Resistance determines density of ground and locating
- Plate load testing – determines load bearing capacity of the ground and likelihood of settlement under a given load – this is done with a hydraulic rig against a reaction weight such as an excavator. Settlement is measured at set increments.
- Boreholes – boreholes are used for soil investigations to determine the geology and nature of ground
What is the purpose of soil investigations?
Their purpose is to determine the suitability of the site for the proposed works and determine an adequate and economic foundation design.
The investigation should determine the potential difficulties associated with the ground conditions and assist with identifying a suitable foundation solution.
What are piles?
- A series of columns constructed or inserted into the ground to transmit the load of a structure to a lower level of subsoil
- Used where no suitable foundations conditions near ground level or high water table
What are the different types of piles?
- Sheet piles – sections of sheet material with interlocing edges driven into the ground to provide earth retention and excavation support – can be made of steel, timber or RC concrete. Steel most common as it can withstand high stresses and has excellent water tightness
- Secant piles – interlocking piles (male and female, often different diameters and hardness)
- Bored Piles – a piping rig drills and inserts casing, reinforcement in then inserted and concrete poured in
- Pre-cast piles – pre-cast piles are brought to site and hammered into the ground. Not often favoured due to the high noise levels associated with installation and the lack of flexibility in terms of depth required.
How do piles transfer load?
o Friction piles – transmit load with friction
o End bearing piles – transfer load to the end – combat gravel, hard clay or rock
o Short bored piled foundations – domestic application – shallow builds
What are the 3 main methods of waterproofing a basement?
- Structural – basement designed and built to form a watertight space using high quality reinforced concrete,
- Tanking – e.g. membranes applied internally or externally to provide a continuous membrane to the base slabs and walls
- Drained Cavity – i.e. eggcrate system. water seepage will occurs and collects into a drain. Inner non-load bearing forms a cavity
What are the technical advantages of steel frames?
- Quick assembly
- 100% recyclable - inorganic - will not warp, split, crack or creep –
- Highest strength to weight ratio of any building material
- Not vulnerable to termites or any type of fungi or organism
What are the technical disadvantages of steel frames?
- Needs fire protection
- Parts may need replacing
- Price of steel is variable
- Need experienced builders – additional cost
- Even though steel components will not burn they will actually fail
What are the technical advantages of concrete frames?
- Concrete is less susceptible to fluctuations in price unlike steel
- Fire protection as part of structure
- Maintenance of an insitu concrete frame is low
- Cladding can be fixed to it and replaced easily.
- Good sound and heat insulation.
- Insitu allows for alteration at late stage of construction
- Can deal with complex geometry better than steelwork
