Construction Technology Flashcards
How much does it cost to excavate 1m3 of soil?
Excavate - 10/m3 (tender returns £6- £28)
Disposal - £45/m3
EO contaminated non-haz - £25
EO contaminated haz - £80
Landfill tax - £175
What is an ASHP and how does it work?
Air Source Heat Pump
Air is taken from outside, air boils refrigerent into a gas, gas goes through a compressor to get extra hot, transfers heat to water through plate heat exchanger to warm water to showers/baths/radiators.
What are the different types of asbestos?
Chrysotile (white asbestos)
Amosite (brown asbestos)
Crocidolite (blue asbestos)
Why was asbestos used?
Strong, incombustible, heat-resistant and sound-absorbent,
How can we protect ourselves from asbestos?
- Asbestos survey to identify and manage ACM, or to remove prior to demolition
- Asbestos awareness training, so people don’t disturb it
- Must be within management plan
What information would you expect from the design team at RIBA Stage 4?
Technical design.
- Fully coordinated services, structure & architecture
- Fully detailed
- Specialist subcontractor design & spec
What’s the difference between RIBA PoW 2013 and 2020?
Developed design is now spacial coordination
Construction is now Manufacturing and Construction
What Stages are “project” stages according to RIBA PoW 2020?
Stages 1 to 6
What level of information would you expect at Stage 2?
- Concept design
- Outline proposals for structural design, building services systems, outline
specifications - Final project brief issued
What level of information would you expect at Stage 3?
- Coordinated and updated proposals for
structural design, building services systems, outline specifications
What would you do if the level of information provided was not adequate?
- Important to ensure you communicate what you expect for each stage so this doesn’t happen
- Inform design team/PM/client of requirements
- If programme extended + design progressed, great
- If not, ensure in clarifications to state level of design information + ensure client knows
- Update risk contingencies accordingly
What would be included in the build up for piles?
Piling mat - m2
Piling plant - item
Moving piling rig into position - nr
Piles - unspecified
EO for piling casing - unspecified
Disposal for excavated arisings - m3
EO for breaking through obstructions - nr/m3
Cutting off piling tops - nr
Pile tests - item
Pile caps, ground beams also required
How would you dispose of soil?
Contaminated vs non-contaminated
Of the contaminated, split between hazardous & non-hazardous
Different types of pile foundations?
- Bored/replacement
- Driven/displacement
- Secant pile walls
- Contiguous pile walls
What type of foundation would you use in a city centre with low bearing capacity soil?
Bored piles because:
- Require deep penetration to get to soil w/ adequate bearing capacity
- Bored gives less vibration/noise, so won’t disturb neighbouring structures or tenants (likely in city centre)
When would you use strip foundations?
- Often for masonry facades where strip will follow the line of the structural brick wall
- Good soil in terms of bearing capacity
- Light load
What would be included in the build-up to a strip foundation?
- Concrete
- Reinforcement
- Formwork
What would be included in the build-up to a pad foundation?
- Concrete
- Reinforcement, though not required. Reinforcement allows for shallower pads.
- Formwork
Why would you use pad foundations?
To spread the load of a column over a wide surface area.
Possible if the load isn’t huge and/or the soil bearing capacity is good
What is tensile strength?
The strength of a material under tension, e.g. longitudinal stress, being pulled apart
What is compressive strength?
When a squeezing force is applied on the object
What forces act on a beam?
Tension on the bottom, compressive on the top
What is shear force?
Force applied perpendicular to a surface, in opposition to an offset force acting in the opposite direction
What is the price of steel?
Market fluctuates
Steel beams/columns, £2500/t
Massive steel structures, £4000+/t
Rebar/reinforcement, £1300/t
All incl subcontractor prelims
What are different concrete grades?
Compressive strength of the concrete after 28 days
For instance, C10 has the strength of 10 newtons, C15 has the strength of 15 newtons, C20 has 20 newtons strength and so on
Cost of concrete C30/40?
£195/m3
When would you use steel for frame construction?
- Where large open spans are required such as cinemas, offices
- Tall buildings as it has better strength to weight ratio
- Where flexibility is important
When would you use concrete for frame construction?
- Where large open spans are not required e.g. residential
- Flexibility is less important
Pros/cons of concrete?
Pros
- Good thermal insulator
- Good acoustic insulator
- Doesn’t require additional fire protection
- Can be cheaper than steel
- In situ good for cashflow as it’s slow
- Cladding easily connected
- Insuti means late changes possible
- Can deal with complex geometry better than steelwork
Cons
- Good concrete subcontractor important
- Bad for embodied carbon
- Heavy
Pros/cons of steel?
Pros
- Good strength to weight, lighter than concrete
- Tension strength means good for long spans
- Quality assurance, prefabricated
- Quick to assemble
- Recyclable
- Not combustible
Cons
- Bad for embodied carbon
- Requires fire protection, will fail under fire otherwise
- Can corrode
- Requires experienced builders
- May need parts replacing
- Price fluctuates
How would you fix curtain walling to a facade?
- Bolted (useful when may require being undone & cheaper than welding)
- Riveted (fastest, like a nail)
- Welded (melted together, maximum strength)
What’s the difference between glulam and CLT?
Glulam - layers of dimensional lumber bonded together with durable, moisture-resistant structural adhesives. LENGTHS OF TIMBER, GOOD FOR BEAMS/COLUMNS.
Cross-laminated timber (CLT) is layers of timber (lamellas) bonded perpendicularly to one another, resulting in structural strength across two dimensions. PANELS/SLABS