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
What types of pollution are caused though construction works?
• Air pollution – gases, dust • Noise pollution- machinery, deliveries • Water pollution – cleaning, leaks, lack of drainage
What ecology can be found around a construction site?
All types of wildlife, nesting birds, and other animals in vegetation.
Name some temporary services
• Electricity supply – Generator (3K -10K+) watts or mains • Water supply – connection from existing mains or water bowsers
What are the sustainable environmental assessments to certify a project?
• Building Research Establishment Environmental Assessment Method. • Assessing, rating, and certifying the sustainability of buildings. • Leadership in energy and Environmental design (LEED)
Difference between green roof and blue roof?
• Green roof – absorbs rain water, insulation, habitats wildlife, aesthetics, helps lower urban air • Blue roof – collects water and releases it slowly when rain has stopped – e.g attenuation tank
What would you do if land is contaminated?
Contact Local authority and Environment Agency - Further testing required to see if project can go ahead and soil is suitable. - Hazardous material needs to be removed from site and disposed of properly
What is the difference between artificial stone paving and York stone paving?
• ASP: Pros Convenient to source, lots of choice, widely available, cost effective • ASP: Cons: Quicker to fade, easily damaged, very large carbon footprint. • York stone: Pros: Lasts a long time, lots of choice, easy to install. • York stone: Cons: Expensive Natural so can be varied or inconsistent between batches
What other ways could the area have been paved?
Asphalt, granite, concrete
How did you estimate the cost of the HVM’s?
I spoke to a specialist supplier who provided the associated costs of the different mitigation methods, this included installation costs. I presented the various designed units and installation costs to the Client to present a likely cost for the works. As I was not aware of the stations I could the exact cost but I could give the client the information to get an overall picture of the total cost.
What stage of the project was the HVM costings undertaken?
Feasibility stage- RIBA stage 1 – Project Manager said they had a budget of around £1m
What type of power is needed to run site accommodation?
• Generator, solar power, mains connection • Ask an electrical engineer for power requirements.
What sort of temp drainage solutions are there?
• Surface water drainage – Sustainable urban drainage systems (SUDS), permeable pavements Soak ways (disperses water gradually. • Foul water drainage – Connection to mains drainage or collection in a sceptic tank.
How did you advise on the different forms of fencing on Silvertown tunnel?
Heras – Lightweight so easy to deploy, cheap, anti-climb prevention, secure interlocking, resist weather £5 a panel
What other types of fencing are there?
• Mesh palisade • Chain-link • Wooden hoarding • Heras
How do you install palisade fencing?
Dig a hole for each fence post, add gravel and pour concrete in the hole, insert the post and ensure level and let it set at least a day.
How do you install Heras fencing?
Poles are fitted securely into concrete bracing blocks and connected using anti-tamper couplers.
On Beckton depot how did you calculate the cost impact using a tarmac road design against a propriety system?
Used the engineers design to estimate the cost of the road, over engineered for a short-term solution that would require demolishing afterwards. The propriety system could be laid quickly and not being permanent could be dismantled at low cost. Also, could be reused.
What was the design and cost of the proprietary mat system?
Heavy Duty Ground Protection mat is manufactured from 100% recycled high density polyethylene (HDPE) & weight tested to maximum load of 80* tons on both flat and somewhat uneven grounds. Connected together with couplers
£60 per matt, £5 connector - £70k About 1000 mats
How did you calculate the value saved from the temporary services over permanent supplies?
• Advised the overall cost was higher for perm solutions but Client wanted quality over cost. • The cost of hire of the temporary services over the duration of the project along with the cost to use. • Permanent solutions, cost of installation, more reliable, cheaper to run.
What are the advantages of temp services over mains services?
Quicker to install, cheaper in short term, maintained by service provider.
How do you lay drainage pipe?
Dig a trench that allows for a fall of 1:40 Laid on gravel, gravel on top of pipe, compacted fill on top.
What is buildability?
This refers to an item of the build and how easy it is to build. Appreciating design and how it will be built in real life. Get contractor to help in design for better buildability.
What are the different forms of excavation?
Vegeatation removal
Stripping topsoil
Reduced level dig to formation level
Cut and Fill
Foundations
What things does a contractor need to consider when excavating?
Nature of soil
Moisture Content
Method of excavation
How Deep you are going
Proximity of other buildings
What is scaffold?
Temporary working platform around the perimeter of the building to provide a safe working place.
How can the ground be improved if its poor?
Compaction
Replacing sublayer with firmer material
What is the purpose of foundation?
To teansmit the imposed load and wind loads of the structure into the ground.
What are the factors that determine foundation choice?
Total load of building
Nature and bearing capacity of the sub soil
What are the main components of concrete?
Cement
Aggregate
Water
What are typical surveys that would be required for a constrcution project?
Services
Topography
Ground investigation - ground bearing suitability for requirements
UXO discovery - is it an area where explosives might be present
Asbestos - what has the land been used for previously?
Ecology - are there protected species preventing works
Transport - are there restrictions on access.
What is CBR testing?
The California Bearing Ratio test is a penetration test used to evaluate the subgrade strength of roads and pavements. The results of these tests are used with the curves to determine the thickness of pavement and its component layers
What fire safety provisions would you expect to find in an office block?
Max occupancy numbers
Location of fire exits
Fire assembly point
Fire extinguishers
Sprinklers
What is fire protection?
Is designed to ensure the safety of occupants in case of fire in a building.
What are british standards?
Publications written by the British Standards Institution - recommend minimum standards for materials, design and components.
