Construction Technology and Environmental Services (L3) Flashcards
Which RIBA Stage is on-site construction?
RIBA Stage 5 - Manufacturing and Construction
What is buildability?
The extent to which the design of a building facilitates the ease of construction
What are the benefits of off-site construction over in-situ construction?
Safety - controlled factory environment
Quality - controlled factory environment
Programme - speed of installation can provide key programme benefits
Sustainability - reduction in waste produced
What is the difference between building works and civil engineering works?
Building works: all types of buildings such as houses, offices, shops, hotels, hospitals etc.
Civil engineering works: drainage schemes, highways, bridges, retaining walls etc.
What are temporary works?
The parts of a construction project that are needed to enable the permanent works to be built, usually required to provide safe access. Examples include scaffolding, formwork/falsework, propping.
What are hoists?
Designed for the vertical transportation of materials and or people
What is shoring?
A form of temporary support given to existing buildings and excavations, to prevent collapse or movement
What is a culvert?
A tunnel like structure constructed to allow water to flow under a road or similar obstruction
What is the purpose of a drainage headwall?
A small retaining wall structure to protect the end of the drain and prevent erosion of the embankment
What is the substructure of a building?
The lower portion of the building (in the ground) which supports the superstructure
Transmits the load of the building to the ground
Includes foundations, basements and retaining walls
What is ground heave?
Upward movement of the ground caused by soil swelling when wet (associated with tree removal)
What techniques are available for ground improvement?
Vibro compaction
Vibro stone columns
Vertical drains and vacuum consolidation
Soil mixing
Dynamic compaction
Dynamic replacement
What are the different forms of excavation?
Site clearance operations (removing vegetation and rubble)
Stripping topsoil
Reduced level dig (to reach formation level)
Cut and fill
Excavation for foundations
What are the key factors the contractor should consider when excavating?
Nature of the soil and the moisture content of the ground
Method of excavation
If ground support systems are required
Proximity of existing buildings
Depth of excavation
Underground services and drainage
Can you explain some of the techniques for waterproofing a basement?
Tanking - Materials such as asphalt, polythene sheeting, bitumen, etc. are applied internally or externally to provide a continuous membrane to the base slab and walls
Drained Cavity - This method accepts that a small amount of water seepage will occur. Cavity walls are formed, and the water seepage is collected in the cavity and drained or pumped away
Have you come across the term SUDS?
Sustainable Urban Drainage Systems
Designed to manage rain water locally, reducing reliance on drainage infrastructure
Can you detail a typical road build-up please?
Compacted and rolled type-1 subbase (100-250mm)
Base course (70-150mm)
Binder course (50-100mm)
Wearing/surface course (20-40mm)
What is the purpose of a foundation?
To provide support for structures, transferring their load to the ground to avoid excessive settlement
Typical considerations when selecting the type and size of foundations?
Total load of the building
Nature and load bearing capacity of the ground
Type of structure
Cost
Construction constraints
What are the different types of foundation?
Strip foundations
Pad foundations
Raft foundations
Piled foundations
What is a raft foundation?
A continuous slab that extends over the entire footprint to spread the load
What are pad foundations?
Typically used to support individual or multiple columns, spreading load to the ground below
What are strip foundations?
The formation of a strip of linear structure to spread the load across the area, usually supports masonry
What are pile foundations?
A pile is a column that extends deep into the ground
Where the bearing capacity of soil is poor or imposed loads are heavy, piled foundations are often required
There are two main types: End bearing and friction piles
There are two main methods: Bored and driven piles
In what scenarios might a piled foundation be the best solution for the project
Where the structure is heavy and underlying soil is weak
In areas where settlement issues are common
Where the sub-soil water table is high
Where load distribution of the structure is not uniform
Presence of horizontal forces
Can you explain how end bearing and friction piles transfer the load of the building?
End-bearing piles: Load is transferred through the pile to the strong layer
Friction piles: The pile transfers forces to the soil
What are the differences between bored and driven piles?
A driven pile is formed off site under factory controlled conditions
A bored pile is cast in-situ on site
What are the advantages and disadvantages of driven piles?
Advantages:
Piles can be precast to required specifications
Piles of any size, length and shape can be made in advance
Fast, neat and clean installation
Disadvantages:
Requires heavy equipment for handling and delivery
Increased noise and vibrations generated from driving the piles
It can be costly if piles are too short
What are the advantages and disadvantages of bored piles?
Advantages:
Any shape or size of pile can be formed on site
There is no risk of damage during delivery and installation
Reduced vibrations and noise
Disadvantages:
Significant spoils are generated that need to be handled
Reliance and coordination on multiple trades
Unlike driven piles, they do not improve the bearing capacity of the soil
What are secant pile walls?
A wall formed by installing interlocking piles which create a solid barrier free of gaps
Typically used to form a retaining wall
What is underpinning and why might it be required?
A method for repairing and strengthening existing foundations
What is the superstructure of a building?
The structural components of a building constructed above ground level (above the DPC)
The basic components include columns, beams, slabs, walls etc
What is the envelope of a building?
The boundary between the interior and exterior of a building
The materials and components include brickwork, cladding and curtain walls
What are the key considerations when designing external walls?
Weather protection
Fire resistance
Acoustic and thermal performance
Structural performance
Appearance / aesthetics
Expected lifespan
Future maintenance
Can you briefly explain what a retained facade is?
The facade of a building is preserved whilst the rest of the structure is re-modelled
Often used during the restoration of listed buildings
What are the standard brick dimensions in the UK?
Standard bricks are 215mm x 102.5mm x 65mm