Construction Tech Flashcards
When would you use pile foundations?
In weak or water baring soil.
When would you use strip foundations?
In houses or buildings where the perimeter walls transfer load to the ground.
When would you use pad foundations?
For lighter structures such as warehouses. Wide span light weight buildings.
When would you use raft foundations?
On soils with good bearing capacity.
Name four different types of foundations.
Pad
Raft
Pile
Strip
What types of piles are you aware of?
Pre-Cast Sheet Bored CFA Contiguous
What are the advantages of steel over concrete frame?
Quicker erection
Recyclable
Tensile strength
High strength to weight ratio
Foundations may cost less due to lower dead load
Larger spans
Less wet trades on site than for in-situ, potentially lower prelims
How does rainwater harvesting filter the water?
Using ultra violet light
What are the advantages of concrete over steel frame?
Thermal mass Fire resistance Acoustic and thermal performance Cost fluctuates less Can achieve complex shapes Compressive strength
What types of façade are you aware of?
Stick
Unitised
What are the advantages of a stick system?
Stick systems use mullions and transoms (sticks) to hold glazing against the structure. It is more economically friendly for small volume facades.
What are the advantages of a unitised system?
High quality due to off-site manufacture
Quick installation due to no glazing being installed on site
What is the build-up of a stick system?
Transoms and mullions fixed into floor slabs
Glazing fixed to transoms and mullions
Aluminium cap over glazing to hold it in place
What types of basement construction are there?
Traditional (battering, ramped sides to stop it collapsing)
Retaining walls
Top-down
What strategies of basement waterproofing are there?
Barrier (tanking)
Structurally integral (additive)
Drained (cavity drained)
How would you reduce the amount of excavated material taken on and off site?
By doing a cut and fill exercise
Reuse of materials on site
What types of demolition are there?
Top down
Bottom up
Blast
How do you calculate rebar weights?
Using the bending schedule
What methods can be used for fixing unitised façade panels?
Crane them in
A monorail system
On floor manipulators
Which one is used will depend on site constraints and programme.
Why would you do a cut and fill exercise?
To minimise the amount of material needed to be brought to site to make up levels, as this is expensive.
How would you carry out a cut and fill exercise?
Mark-up a grid on a drawing
Take the average of the highest and lowest points within that grid
The difference from this to the desired level is the cut/fill amount required
What are the types of ground anchor?
Tensioned
Non-tensioned
Pre-fabricated
What are British Standards?
Publications issued by the British Standards Institution – prefixed BS
They give recommended min standards for materials, components, design and construction practices
What are international standards?
Prepared by the International Organisation for Standardisation – prefixed ISO
Compatible with and complement BS’s
What are the typical components of site investigations?
Anything on adjacent sites that may impact Boundary hedges / fencing Existing trees Size, depth and location of services Existing buildings Ground water conditions Soil investigations – trial pits etc
What is landfill tax?
The tax, administered by HM Customs & Excise, applies to all waste disposed of, at a licensed landfill site, unless specifically exempt.
In force since 1996
At what rates is landfill tax charged?
Landfill Tax is charged at 2 rates:
£2 per tonne for all inert waste
£38 per tonne for all other taxable waste
What is a tower crane and how do you erect one? What would stop a tower crane from working?
A tall crane used for lifting objects into high places. The boom allows a longer reach with 360 access. A longer boom reduces the payload capability.
Use a smaller crane to erect a tower crane
Weather conditions could prevent it from working, in particular high, strong winds.
What is shoring?
Form of temporary support given to existing buildings
Purpose is to provide a precaution against damage or injury for collapse of structure
What are hoists?
Designed for the vertical transportation of materials or people
What is a borehole?
A borehole can be used for soil investigation
Boreholes are the most suitable method of soil investigation when foundations are over 3m deep
What are the problems to the PQS regarding cost control with piling? Whose risk is the piling?
The end depth of the piles are never a certainty and the procurement route used determines who takes the risk (traditional/ D&B = the main contractor; management contracts = employer)
What are the different parts of a steel beam?
A simple I Beam is made up:
Flange (Top and Bottom of the vertical steel)
Web, which is the vertical steel part of the I
Root, which is where the Flange and the Web join.
What is powder coating?
A tough durable factory applied organic coating on metals, such as aluminium or galvanized steel, available in many colours.
E.g. polyester, polyurethane, acrylic, and epoxy which are sprayed on, followed by heat curing to give a film thickness of 50 to 100micorns.
Any holes should be made and any cutting done before the coating is applied.
What is an RHS / SHS?
RHS = Rectangular Hollow Section SHS = Square Hollow Section
What are the different types of brick bond?
Stretcher – most common, walls just a half brick wide
English – alternating courses of headers and stretchers
What is an air brick?
A perforated brick to allow for ventilation into a room or an underfloor space. NOT a weep hole.
What are bonded and unbonded types of screed?
Bonded Screeds – Laid on to a ready prepared rough, cleaned concrete base
Unbonded Screeds – Laid on to a sound, clean Bitumen damp proof membrane to BS4483
What is a shear force?
A perpendicular force
What is torsion?
A twisting force
How do you counter torsion?
With outriggers
What is the typical build-up of a unitised façade
Back-up wall Structural build-up / steel frame Insulation Waterproofing Rainscreen
What types of excavation are there?
Open and trenched
with or with trench box supports
What are connections in steel?
Plates, bolts or welding. Around 12.5% by weight.
What is a composite floor?
Consist of profiles steel decking and in-situ reinforced concrete.
Decking acts as permanent formwork for the concrete and provides sufficient shear bond to the concrete that the two materials act in composite together.
Usually used in steel frames.
What are Building Regs?
Statutory instrument that sets minimum standard for performance for the design and construction of buildings.