Construction Technology and Environment Flashcards
What is a foundation?
Function is to safely sustain and transmit to the ground on which it rests the combined dead, imposed and wind loads of the structure
What are the types of pile foundation?
• Piles – Series of columns inserted into the ground to transmit the load of the structure to a lower more secure sub layer • Bored Piles – auger excavates and then concrete is pored in can be reinforced with steel • Secant Piles – Interlock male and female piles to form a wall. Provide waterproofing layer • Sheet piles – a deep trench is excavated and concrete is pored in situ
What is a raft foundation?
Used to spread the load over a larger area, useful in low load bearing soils. Can use beams to support further.
Name some types of foundation?
- Strip
- Raft
- Pad
- Piled
What is a substructure?
All structure below the superstructure i.e. all structure below ground level including the ground floor bed
What is a superstructure?
All internal and external structure above the substructure Made up of primary (ext walls, stairs, roof, structural walls) and secondary (suspended ceilings / raised floors,
Are you aware of the building regulations? What are they?
General guidance on the performance expected of materials and building work in order to comply with the building regulations Approved Doc A – Q – Structure, fire safety, Protection from falling
What is prefabrication and its benefits?
Manufacture and construction off site. Better planning, eliminates weather conditions, more uniform in design, less delays as all in one place.
Steel frames pros and cons?
Steel- quick to assemble, does not warp, strong, lasts a long time, set standards provide consistent quality. Does need fire protection, price of steel can vary.
Concrete frames pros and cons?
Marginally cheaper than steel frame buildings. Provides good sound and heat insulation. Can do complex geometry. Slower construction, more effected by weather and temp than steel. Heavier so requires larger foundations.
What are the different types of construction methods for tunnels?
• Cut and cover tunnel – constructed in a shallow and covered over • Bored Tunnel – constructed in situ without removing the ground above • Immersed tube tunnel – sunk in water and buried.
What are the different types of construction methods for bridges?
• Balanced Cantilever Method of Bridge Construction - his method is used for constructing bridges with span 50 to 250m. The bridge constructed can either be cast-in-place or precast. • Cast insitu – construct from ground – complex shapes • Incremental Launching Method of Bridge Construction – continuous concrete or steel girder bridges • Arch Method for Bridge Construction – economical- concrete or pre cast
How is a railway built up?
On embankments or cuttings
What is a retaining wall?
A retaining wall is a structure designed and constructed to resist the lateral pressure of soil, when there is a desired change in ground elevation that exceeds the angle of repose of the soil.
What are the main types of excavation?
Open – use battered excavation sides cut back to a safe angle, eliminates the need for temporary support work, can easily construct basement walls and fall BUT extra excavation costs and need a lot of free site space
b) Perimeter Trench Excavation – trench dug wide enough to form basement walls, this is supported as required – basement walls are constructed and then the inside of the basement is excavated.
• Open – use battered excavation sides cut back to a safe angle, eliminates the need for temporary support work, can easily construct basement walls and fall BUT extra excavation costs and need a lot of free site space • Perimeter Trench Excavation – trench dug wide enough to form basement walls, this is supported as required – basement walls are constructed and then the inside of the basement is excavated. • Complete Excavation – used in firm subsoils. The Centre of the basement is excavated first, then the basement slab cast while the sides of the excavation are supported by struts
What is formwork?
Anything that holds fresh in-situ concrete in place until it hardens, such as plywood shutters, steel pan forms, fiberglass moulds or profiled decking, as well as its supporting props, centering or falsework, plus accessories like wedges and clips for tightening joints and to make stripping easy.
What is an A182 mesh?
The mesh used to reinforce concrete slabs (generally). The mesh is laid down and the concrete poured over it.
How is a road or pavement constructed?
• First removal of topsoil, scraping and grading an area called the formation level. Below this level is the subgrade or ‘soil’. The subgrade must be tested prior to earth works. It needs to be strong enough to support the load above • Drainage and services should be laid underneath. • Flexible or rigid paving can be layered on top to form the base layers • On top of the base layers the surface layer is laid
What is the difference between rigid and flexible paving?
• Flexible paving has multiple base layers whereas rigid usually has a concrete slab. More wearing • Rigid layer costs more but more durable, flexible layer isn’t as strong but reacts better to temp changes.
How is drainage managed on road surfaces?
Road construction will have a fall or camber that allows water to run off into channels then gulley’s are located along the channels which collect the water
What is the standard cross fall for a road?
1:40
