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.
What types of retaining wall are you aware of?
Contiguous pile
Concrete reinforceed retaingin wall
What types of building envelopes are there?
Cavity walls
Cladding
Glazing
brickwork
What is the make-up of a stud partition?
Base plate and top plate/keels
Vertical and horizontal timber or metal studs
Plasterboard/gyproc board screwed and fixed into partitions
Firestop and smoke seal at the top of the partition
What are the advantages of a fan-coil unit?
Good control of air movement
Quick installation
High cooling capacity
What are the disadvantages of a fan-coil unit?
The air filter requires maintenance
The fan can be noisy on a high speed setting
What is the difference between a two-pipe and a four-pipe fan-coil unit?
A two pipe FCU provides cooling
A four pipe FCU provides heating and cooling
What are the types of chilled beam?
Active chilled beam
Passive chilled beam
What are the advantages of a chilled beam?
They can be accommodated in a shallow ceiling void
Passive beams have no moving parts
What are the disadvantages of a chilled beam?
Their cooling output is limited
They require a separate ventilation system to supply fresh air
What types of basement construction are you aware of?
Traditional open (excavate) Traditional enclosed (retaining wall to perimeter then excavate) Top down (retaining wall to perimeter, plunge columns, ground floor slab leaving hole for excavation. Faster but more expensive)
What is a steel table?
They provide standard information on steel sections in tabulated form.
For each serial size and universal beam number.
What are temporary works?
Works that do not usually appear on construction drawings but are necessary for safe construction i.e. propping
What is an AHU?
An air handling unit - responsible for drawing air into the building and disposing of exhaust air
What are fire dampeners?
Effectively blades within a vent
A fire sensor will go off and close the blades in the event of a fire
What is Part B of building regulations?
The section of building regulations relating to fire safety
When was Approved Document B Fire Safety last updated?
2010
What is an AHU?
Air handling unit
Centralised plant in basement or on roof
Controls air intake and distribution into ductwork
What is MVHR?
Mechanical Ventilation Heat Recovery
What are fire dampeners?
Vents within ducts that close in event of a fire.
What are the advantages and disadvantages of stick and unitised façade systems?
Stick is suited to façades with not much repetition
Unitised is more suited to repetition
Unitised is assembled off-site so less time to install on site and higher quality
What are the different types of foundations?
Pad
Raft
Strip
Pile
How do ground conditions effect choice of types of foundations?
Soil type will effect foundation type as this dictates how the building’s load is transferred into the ground
London clay means friction piles are often used
What are the advantages of steel and concrete frames?
Steel quick to construct Steel priced more volatile Concrete has better fire resistance Concrete has better thermal mass In-situ concrete can be used to create complex shapes Concrete pour can be affected by weather
How do you price concrete or steel frames?
Concrete
Rebar
Formwork
Finish
Steel
Fittings
Fire protection
sequence / revisits
What is post-tensioned concrete?
Steel tendons are laid through the slab
Concrete poured
Once the concrete has cured a stressing jack is used to tension the slab
Stronger than RC slab as the concrete is under compression
What is pre-tensioned concrete?
Steel tendons are laid through the slab
Concrete poured
Before the concrete has cured a stressing jack is used to tension the slab
Stronger than RC slab as the concrete is under compression
What are the implications of working on an Over Site Development?
High levels of vibration and movement monitoring are required
Site B sits on bearings to reduce vibrations into the theatre
What is soft toe piling?
It is a way of creating a pile where the end is soft where no load is transferred. There are different methods of achieving this such as using a sack of water.
It used for friction piles above existing LUL assets, to guarantee that no load will be transferred through the toe of the pile and into the structure below.
How to fan-coil units work?
Contains a heating and or cooling (2 or 4 pipe) heat exchanger ‘coil’ and a fan to draw air across
They are controlled by manual on/off switches or by thermostats
The thermostat controls the throughput of water to the heat exchanger using a control valve and /or the fan speed
How does a chilled beam work?
HVAC system designed to heat or cool large spaces
It uses pipes of water passed through a beam which is either integrated into the suspended ceiling or is just above it
Active chilled beams use fans to draw air across it
Passive chilled beams rely on convection
What is a retaining wall?
A structure designed to resist the lateral pressure of soil
Sheet piled and bored piled retaining walls are used on central London sites
How was the construction methodology of one of you projects effected by the site constraints?
A ‘semi top-down’ approach was selected for basement construction in order to provide a logistics slab for site deliveries and carting away excavated material
What is SIPs
Structurally Insulated Panel systems - often manufactured off site (Meadowfilds)
What are the advantages & disadvantages of Modular construction
St Georges School
Quicker on site period
Can be cheaper in some cases
Reduced nr. of trades on site
Can create longer design stage - need to engage early in design & fabrication off site can take time (needs to be factoreed into program)
May need funding upfront and /or advance payments
How does planning permission impact on design?
Requirements for new roads, renewable energies, community use facilities, sustainability outputs / KPIs, ecological issues, resticts changes, comply with condition.
What other legislation impacts on construction?
Brexit, covid, planning, fire regulations, building regulations, sustainable product use & renewable energy targets.
How does the age of the building affect construction methods?
Pre 1999 may contain asbestos.
Listed or timber buildings - may need to match existing & may be hard and expensive to match products
What are the RIBA stages?
0 - Stategic definition 1- Prep & briefing 2 - Concept 3 - Spatial co-ord 4 - Technical 5 - Construction 6 - Handover 7 - In use
Where are these used
Design fee drawdowns, project milestones, valuing work, help identify roles & responsibilities in appointments & contracts
Can you give me examples of 2 alternative air condition systems?
Water heating / cooling system
Earth - air heat exchangers that use ground temperatures
What do you understand by the term bus bar?
Metal strip or bar for power distribution - often found in panels / switchgear fro local high power distrbution
What are the advantages of a steel framed building over a concrete frame?
Steel - lighter, quicker, greater spans, lower weight, mass production of repeat items.
Concrete can offer better thermal & acoustic properties and can achieve less uniform shapes.
What current challenges is Covid and/or Brexit bringing to Construction Technology?
Planning works with unknown certainty of cost of materials, labour & availbility - longer lead in
Flexible quickly
Impacts on labour - slower installation
Impacts on cost of materials & availbility and or able to source materials through delivery issues
Enhaned H&S - social distancing, cleaning, working methods
Enhancement of importance of AI, IT remote working, planning ahead with contingency plans, data use & control
Tell me more about the review of design details for the fire requirements at Giles Lane Student accommodation. What issues were you targeting in your review? Why?
Reconfigoration of student accomodation and fire compartments. Largely removed externally and internally to ensure compliance. Reviewed with design team to ensure met requirements.
Internal fire compartments, fire breaks in external façade & at openigns where addedd.
Give me an example of a fire protection solution for structural steelwork.
Boarding, intumescent painting, concrete encasement
Give me an example of other foundation solutions that are commonly employed in the construction industry.
Piling
Strip
Pads
Raft
Take me through the construction process of a strip foundation.
Check GI for obstructions, Setting out, excavation of tench (with formwork/tenchbox if required and working space), blinding, reinforcement (if requried), mass fill concrete & tamp, cure, remove forwork etc / concrete samples 7/14/21/28 days or as requried by spec
what are the key factors in selectiing cladding
1 - Meets fire requirements 2 - Certified system (not just cladding product but build up also) 3 - Meets plannign requirements 4 - Program impacts - lead in / access 5 - Price
Tell me more about the façade design that you refer to in your summary of experience. Explain the factors considered before coming to the final solution and the rationale for the choice made.
Gebrick at Barton Court
I looked at an alternative option to tradtional brickwork which involved liasing with design team, planning and building control.
I explored the buildability with the construction team to understand program and how the alternative option could omit some of the scaffold, improve installation time and in turn offer further savings over and above the material cost.
Arranged full mock up samples to demonstrate to planners and client the aesthetic similarities and sought all the technical data info along with report outlining benefits and savings available - in both money and time for client to make a decision.
From your experience, what are the key factors to be considered on the selection of suitable cladding? Explain the importance of each factor.
Fire compliance Acoustic & thermal compliane Certification of whole system buildup Planning requirements Lead in of materials Installation methodology / access and time Price - as every project has a budget
When would you recommend the use of prefabricated units such as the pods referred to under your level 2 experience?
High repetiton - student accomodation / hotel
High use - durability
Minimal access for maintenance required
Watertight room
Speed on site - 4 hours per pod to fit & connect pre-plumbed pod
What is Underpinning
suppport to existing struc wall
What is Shoring
Shoring - lateral support to structurual wall / structure - temporary support
What is Slip form / jump form
Form work - slip continuous moving. Slip = no joints
what is importance of construction tech
If don’t understand how something is constructed - cannot measure and value it
What is an element
functional unit
how to identify elements
NRM / BCIS
Plasterboard types
acousitic / moisture / general / fire
CAT A fitout
Uk only - building to tenant with only primary finish- i.e. they fitout (CAT B - fitout - tenants fittings & customised)
Ventilation
Natural / Mechanical / stack (warm air rising up)
Intumecent paint
Active - reactive fire protection - expands
What are the disadvantages of steel frame
STEEL - COSTLY / CORROSION / ENERGY IN MAN PROCCESS / NOT GOOD INS OF HEAT & SOUND / INSTALL - CRANE & LEAD TIME
What are the advantages of concrete frames
Adv - Conc frames - thermal & acoustic benefits / cast complex shapes, maintenance low, cashflow slower
What is formwork
formwork - holding conc in place / mould
What is falsework
falsework - temp work for supporting formwork / scaffold
What updates are you aware of to Fire post Grenfell?
21 DEC 2018 - COMBUSTABLE MAT OVER 18M - LOOKING TO RECUDE TO 11M (11M RESI SPRINKLERS) - Buildign regs part B
RICS cladding guidance
PII requirement to have fire cover
- Warm & Cold roof
a. Cold roof – insulation in ceiling
b. Warm – in roof buildup
- What are the 3 types of building notice (for building control)?
a. Full (based on plans – sign off of building in advance)
b. Building notice -simple project
c. Regularization – retrospective
- What are the implications if GDPR is not complied with?
a. 4% t/o upto £17m
