Construction Technology Flashcards
(98 cards)
1
Q
1.What are the RIBA stages?
Give a project example
A
0; Strategic - Site identification 1; Preparation - 2; Concept - Site plan inc indicative layouts 3; Spatial - General arrangements, elevations, 4; Technical - By Contractor if D&B 5; Construction 6; Handover - Practical Completion 7; In-use - Tenanted
2
Q
- How would the design develop over the stages?
What cost approaches would be taken by the QS at each stage?
A
0 Strategic - Identify project requirements, feasibility -No design (potential site) Cost Model (£/m2)
1 Preparation - Developer spec, further feasibility, site info and surveys, programme
Order of Cost Estimate
2 Concept - Arch concept design, outline specification
Formal Cost Plan 1
3 Spatial - Developed design and costing
Formal Cost Plan 2
4 Technical - Developed arc, eng, civil design, building systems
Pre Tender Estimate
3
Q
- What are building regulations?
Provide two examples
A
Ensure minimum standards for design and construction to ensure the safety of people in and around buildings.
Part L - Conservation of fuel and power
Part M - Facilitate access for disabled people. e.g. ramps, automatic doors
Part B - Fire safety - Sprinklers, risers, smoke alarm, firefighting lift
4
Q
- Give examples of minimum performance for building regs?
A
Part B; Fire safety
Advisable to consult with the relevant designer i.e. Architect in respect of detailed requirements required for cost planning.
e.g. FF lift required if the building has a floor 18m above or 10m below vehicle access level.
Previously building Regulations say buildings over 30m constructed since 2007 need sprinklers
*2022 now Blocks of flats with their top storey more than 11m above ground level should be fitted with a sprinkler system throughout the building.
5
Q
- What are the recent sprinkler changes?
A
Blocks of flats with their top storey more than 11m above ground level should be fitted with a sprinkler system throughout the building.
6
Q
6.How would you categorize a building using NRM1?
Give examples of elements in each category
A
Building Works:
1 Substructure – Foundations, Ground Floor Slab, Piling
2 Superstructure – Frame, Roof, Upper Floors, Walls, Doors
3 Finishes – Wall, Floor, Ceiling
4 Fittings, Furnishings and Equipment (FFE) – Kitchens, Bathrooms, Furniture
5 Services – Heating, Electrics, Ventilation, Lighting, Waste
6 Prefabricated Buildings– Guard House, bath pods (student resi/budget hotel)
7 Work to Existing Buildings – Support to adjacent buildings
8 External Works – Roads, Paving, Planting, External Services (Utilities), Drainage
7
Q
- How would you build a warehouse?
A
Ground beams Pad foundations Portal frame Dock levellers Roof sheets Cladding & syphonics Ground floor slab White wall Office fit out M&E Externals: Attenuation Service yard Car park Fencing
8
Q
- How would you build a house?
A
Strip foundations DPM Ground floor slab External and internal brick/blockwork Roof Windows & Doors Partitions First fix M&E Plaster Paint Second Fix Kitchen & Bathrooms Externals
9
Q
- How might ground conditions dictate project foundations?
A
Weak ground conditions may require specialist foundation solutions
10
Q
- What are the main types of foundations?
A
Strip
Pad
Specialist / Piled
11
Q
- What types of piling are there?
A
Driven & Bored (Friction & End Bearing), Contiguous, Sheet
12
Q
- How would you quantify a pile?
A
mat (m2) Piling rig plant (item) moving rig (nr), piles (nr), testing (item),
13
Q
- What is prefabrication / MMC?’
What assets is it good for?
What construction needs to be completed prior to any MMC?
A
Constructed in factories off-site and then are transported to site to be constructed.
Ideal for repetitive structures such as residential, hotels and offices.
Concrete cores and foundations need to be built before any pre-fabrication work can commence.
14
Q
- MMC Pros?
A
Program gains can be significant (certainty, not subject to weather, less waste),
Quality is good,
good safety as less people on site.
15
Q
- MMC Cons?
A
Larger or individual (not square!) buildings make prefabrication difficult as efficiencies cannot be realised due to transportation.
Offsite production must be perfect or entire process can be undermined (re-building aspect may lose any gains on programme and the process is more expensive than onsite construction).
Only more economical if programme gains are achieved i.e. reduced financing, site preliminaries etc.
16
Q
- How does it differ to traditional construction? (MMC)
A
Less trades
Good controlled quality
Good health & safety (less people on site)
17
Q
- What prefab is used regularly? (Asset class)
A
Bathrooms for:
Student accommodation
Budget hotel
18
Q
- Steel pros and cons
A
Pros;
Fast to construct,
factory quality
castellated beams for services to pass through
Cons;
Poor fire resistance
Long lead times
Can’t be adapted on-site
19
Q
- Concrete pros and cons
A
Pros;
Fire resistant
good heat and sound properties
Adaptable on site and is not prone to long lead in times.
Cons;
Labour intensive / Temporary formwork required
Quality issues from weather & labour quality
Services have to be drilled through.
20
Q
- What is permeable paving?
A
Allows water to pass through the gaps between the blocks.The water goes through the subbase which also slows down the water accessing the ground.
Pros;
Decreases the total amount of runoff leaving a site
Cons;
Must be used in conjunction with other SUDs (unable to manage storm runoff volumes).
Expensive £150/m2
Require frequent maintenance.
21
Q
- What are swales?
A
Channels are sloped into a ‘V’ shape, which make it easy to maintain i.e. cutting machinery for the grass. The slope delays water runoff and reduce the runoff volumes.
22
Q
- What are soakaways?
A
Attenuation crates are dug into the ground which hold water before releasing into the ground
23
Q
- What are attenuation tanks?
Why are they needed when you build a building?
Is there a component used before water enters into the mains system?
A
Underground surface water storage tank for when flooding occurs resulting in high amounts of water passing through the system to limit the outflow into the mains drainage system.
Accounts building over land that previously would have naturally absorbed rain. Water must go somewhere.
Hydro Brake – Slows the outflow of water run off to manage high volumes (large pre-cast concrete chamber to take high pressure water impact).
24
Q
- What is the type of frame for a warehouse? Inc components?
A
Typically used for industrial/distribution buildings that are low rise with large spans.
The structure comprises of columns and rafter steels with bracing and side rails which are possible given most of the external walls do not require windows unlike say residential or office buildings.
Not suited for multiple stories as structure only suitable for bearing the weight of the roof given its long spans.
25
25. How does it vary to standard steel frames? Why does its design benefit the user?
Portal frames can span up to 50m which creates an expansive space for storage.
This approach is very popular for distribution warehousing.
Traditional frames have much shorter spans as they used over mutiple stories. Span width is not an issue as it is used for offices and flats for example.
26
28. What design assumptions did you make on the retail project (RIBA 3)?
Strip foundations,
slab thickness,
structural frame
27
29. What did you ask the SE?
Asked what foundation would likely be suitable based on the ground investigation report
28
30. How did you include this in the cost plan?
I stated in the basis the email confirmation I received
29
31. How did you cost the GFS/ NRM 2?
```
excavate
dispose
compact ground
hardcore,
insulation
damp proof membrane
concrete
```
30
What is HVAC?
| What are the different types?
Heating, Ventilation and Air Conditioning (HVAC) Systems Overview
Fan Coil Units (2 pipe & 4 pipe): (Water based)
1. Air brought in and cooled in chiller then mixed with existing air
2. Existing air is extracted
3. 4 pipe system includes boiler heating air
Variable Refrigerant Volume (VRV) OR Variable Refrigerant Flow (VRF):
1. Refrigerant vapour is compressed - increase in temperature
a. Condensing - Gives off useable heat through air or water
2. Expansion - refrigerant allowed to expand lowering pressure
a. Evaporation - Low pressure absorbs natural heat
VAV - Variable Air Volume (Suite to high rise due to ease of air distribution)
1. Control heat in rooms
2. Good for high rise offices with different temp
a. Solar gain
b. People gain
c. Laptop gain
d. Above vs cold day minimum people
3. Supply and Return duct
4. AHU - intake and outake
a. Air can be re-circulated
5. Diffuser air out vs return grille
6. Thermostat controls temperature
a. Damper allows 13degree temperature to enter to cool room
b. Electrical re-heater can warm air
31
33. What did you include in the retail project? (M&E)
No allowance as base build only- tenant to complete their own heating
32
34. What did you include on the Kings Tower (M&E)?
TBC – only allowance included
33
35. Why would you advise to use symphonic drainage?
Fewer outlets
No need for gradient pipes (easier to hide)
80% fewer downpipes are required, resulting in cost savings in materials and reducing associated groundwork. Also gives architects more freedom with design
Pipe diameters are smaller
34
36. Why is attenuation stipulated on warehouse schemes?
Underground surface water storage tank for when flooding occurs resulting in high amounts of water passing through system to limit the outflow in the mains system
35
37. What would a typical drainage system comprise of at a warehouse?
TBC
36
38. How would the wall be built up on a warehouse?
Inner cladding sheet
Insulation
Outer cladding sheet
37
39. Wall build for a house?
A cavity wall is composed of:
Two masonry walls separated by an air space.
Outer wall is made of brick
Inner wall constructed of concrete block.
The block and bricks are held together with wall ties
Insulation is added and weep holes are placed at intervals to allow water to drain.
38
41. What is asbestos?
Banned substance which is highly detrimental to long term health and requires specialist removal. Can be found in roofs, ceilings, walls and floors. Types:
- Chrysotile most common type.
- Amosite in cement sheets.
- Crocidolite in pipe insulation.
39
42. What type of survey was it?
TBC
43. What type of asbestos was it?
TBC
Demolition
| Chrysotile
40
44. How did you price it? (asbestos)
Specialist type of work and ideally costing should only be based on direct quotations (avoid estimating due to variance).H&S - Only specialists with appropriate breathing apparatus and suits should be able to remove it.
41
45. Would you have to do anything before removing asbestos?
14 days notice to to HSE
42
46. What are the main Environmental assessment methods?
BREEAM – British Research Establishment’s Environmental Assessment Method
Assesses performance of new and existing buildings – Often stipulated as a planning condition
e.g. Energy, Materials, Innovation
30= pass 45 = good 55 = very good 70 = excellent 85+ = outstanding
EPCs - Energy performance certificate. Req. resi property being sold or rented. Efficiency ratio A and G as inc. suggestions to improve
SAP Assessment - (Standard assessment procedure). Calculates the annual energy costs and CO2 emissions. Informs the EPC
SBEM - Simplified Building Energy Model for non-domestic buildings
- Calculates monthly energy use and CO2 emissions
- Design stage assessment before construction starts and then an as-built assessment
LEED Leadership in energy and environmental design
- Popular in USA but recognised internationally
- Based on a 100 point system based on 8 different categories including:
- Location
- Sustainable sites
- Energy and atmosphere
- Innovation and design process
- Rated Certified, Silver, Gold or Platinum
43
47. How has BREEAM impacted on a project you’ve worked on?
○ Management
- Contractor to monitor energy and water use during the construction period.
○ Health and Wellbeing
- Thermal modelling - An assessment will be carried out to ensure the buildings do not overheat.
○ Energy
- Efficient building fabric (insulated cladding)
- Sub-metering for ease of energy monitoring
○ Transport
- Electric vehicle charging & Cycle storage
○ Water
- Reduction of water consumption for the development
○ Materials
- Contractor to source materials from responsible suppliers
○ Waste
- Contractor to monitor and limit waste
○ Land Use and Ecology
- Development is on a previously developed site (not greenfield)
- Understand and manage ecological impact e.g. butterfly mounds
○ Pollution
- No refrigerants used
- Surface water management (flood resilience) attenuation tanks
Noise impact assessment
44
48. What is an air source heat pump?
transfers heat from the outside air to water, which heats your rooms via radiators or underfloor heating.
45
49. Retail – traditional vs steel frame? Pros and Cons
| TBC
```
Steel
+Quick
+Wide spans
+Castellated beams for services
-Specialist labour
-Fire protection
-More expensive
Blockwork
+cheaper
-slow to build
- limited spans
```
46
50. Which option did you recommend and why? (Steel vs Traditional)
TBC
Steel:
More expensive but quicker to build an had capacity for wider spans meaning that a larger single unit could be built or split up depending on tenant requirements
47
51. What is tarmacadam?
Asphalt is a mixture of asphalt cement and aggregates,
hot-mixed in an asphalt plant
and then laid hot to form the surface course of a flexible pavement.
Asphalt paving provides a stable, safe and durable road surface.
1119*£110= £123,090
48
52. Block paving? NRM 2
```
Excavate
Level
150m sub base
Sand
Block Paving
1119*£130m2= £145k
```
49
53. What was the cost saving of the tarmacadam?
£20k / 15%
50
54. How did you identify that the external wall was the costliest element? How did you undertake the VE on Kings Tower?
Superstructure was 42% of costs and external wall was £400/m2 (GIA)(Highest element) so I focused on elements that could be substituted without comprising on functionality.
51
55. What was the wall build up of the external wall?
Kings Tower
Double storey glazed units with pre-cast concrete (acid etch finish) vertical /
horizontal framing
Panelled walling; brick slip panel; corium brick slip system
Rainscreen cladding
52
56. Why are double storey glazed units cheaper than a unitised system?
TBC
Stick system is assembled on site so requires more labour
Unitised system is a component piece:
Better quality as factory assembled
Quicker to install
53
57. MWL – What was the change in BR with the sprinklers?
Buildings over 30m constructed since 2007 need sprinklers
| Now buildings over 11m
54
58. What did you advise the lender?
We sought confirmation from the council that only the Building regulations applicable at the time of achieving planning would be required and not the update.
55
59. How did you confirm this was the case? (Sprinklers Building Reg Change)
Email confirmation from the council
56
60. What is the leasehold reform? Why was this relevant?
Disallowed ground rent charges being imposed on leasehold owners
57
61. Why was it an issue? (Ground Rent)
The borrower confirmed that they would not be making charges in line with the new regulations
58
Main (standard) foundation types -
Strip (concrete and traditional block),
| Pad foundations
59
What are Strip foundations?
Where do they go in relation to the superstructure?
How deep are they typically?
Perimeter and internal trench foundations to support load bearing walls.
Circ 600mm deep and are filled with concrete.
60
Traditional masonry foundations?
| Why is concrete generally preffered?
Concrete base with blocks built out of the trench (rather than concrete)
Concrete quicker to complete which can be critical in winter when avoiding freezing weather
61
Concrete over block foundations –
Materially block foundations are cheaper but the labour makes the overall cost similar as Concrete foundations are quicker to construct which is usually preferred
62
Pad foundations -
| What is a raft foundation? When might one be used
- Blocks of concrete that support isolated loads typically associated with steel framed buildings
- contrast to strip foundations that support walls which form the building frame.
Raft – Spread over wide area – poor ground conditions – 2 storey – edge thickening
63
Specialist foundations
```
e.g. Types of piling:
Driven & Bored (Friction & End Bearing)
CFA Continous Flight Auger
Contiguous
Sheet
```
64
What is Driven piling?
Piles are pre-cast (typically concrete) and are hammered into the ground.
Pros; Pre-formed so are good quality. No excavation required.
Cons; Vibration and noise with bigger machinery (than bored) required so may not be suitable for dense, city-centre sites.
65
What is Bored piling?
Bored piling:
Earth is removed,
formwork is placed
and then concrete replaces the void to form the pile.
Pros; No vibration as the spoil is removed rather than displaced.
Cons; Excavated material needs to be removed.
Form work is required.
66
What is Continuous flight auger?
Method of bored piling whereby the concrete is poured after the earth is removed by the excavator
No support is required.
Reinforcement is placed in the pile after.
67
Friction vs end bearing piling -
End bearing piles transfers the structure load through weak material into stronger material that has suitable bearing capacity.
Friction piles transfers the load of the building through the entire length (sides) of the pile by the friction that is created.
68
Pile cap -
Thick concrete mat that is placed on the top of the piles to enable a load to be transferred through the piles into the stronger ground below.
The pile cap ties together the piles. (Pad transfers loads directly into the ground but a pile cap transfers through the piles).
```
NRM Piling
mat (m2)
plant (item)
moving rig (nr)
piles (nr),
disposal (m3),
testing (item),
```
69
Piling mat -
Layer of crushed concrete/rock/stone that is placed on site to allow the piling rig to safely move from one pile setting to another.
Piling rigs are very heavy and would become unbalanced and fall over if they traveled on an uneven or unstable site.
70
Who stipulates the depth and type of the piling mat -
Structural engineer (client or contractor) would specify the type and depth that is required for the site (strength of ground and size of machinery considered).
71
What is a Diaphragm wall?
When would you use one?
What does bentonite slurry do?
A structural concrete wall constructed in deep trench excavation.
A guide wall is formed which is excavated,
ground anchors tie base panels to the earth,
bentonite slurry is applied,
concrete/pre-cast concrete wall are placed in panel sections.
- You would use one on a congested site where you were close to existing structures or for a large basement.
- Excavation stability is maintained by using bentonite slurry (this exerts a pressure in excess of the earth on the sides of the excavation
72
What is Contiguous piling?
Piles are closely placed to form a retaining wall or basement.
Secant piles are initially placed with male piles that are reinforced then female piles fill the gaps.
After subsequent completion the area is excavated and the exposed piles are sprayed with concrete to form a continuous wall.
- Contiguous piles are used where the ground is strong enough to be supported by the spaced piles (i.e. gaps are left between them).
- Secant piles require typically twice the amount of piles and therefore are more expensive and time consuming to place.
73
What is Sheet piling?
Large metal sheets that are driven into the ground
They provide earth retention/excavation support. Typically they are used on canals and roadside to support long but relatively shallow depths (4/5 metres max).
74
Basement construction –
Tanked Internally – Applied between the external and internal wall and within the ground floor slab. If penetrated, the inner wall will have to be removed in order to fix the tanking. Water is retained within the external wall.
Tanked Externally – Applied to the external wall and within the ground floor slab. The tanking can be penetrated when backfilled. This will leak water into the basement; in order to fix the leak excavation will be required to reach the leak.
Waterproof - Water resistant concrete structure for both external wall and ground floor.
Drained - The water passes through the external wall into a drained and ventilated cavity which is drained away. The basement may use a sump pump to pump the water out of the basement. The pump will be required to run 24/7.
75
Top Down Construction:
| Bottom up construction:
```
TD:
Permanent retaining walls to perimeter; contiguous or secant piling
Foundations for columns are formed
Upper most slab is formed
Work goes down to bottom
```
BD
Perimeter retaining walls
Temporary structural support required to retaining walls
Excavate just below lowest basement level
76
Types of frame -
Portal frame,
steel frame,
concrete frame,
load bearing masonry
77
Portal frame -
Typically used for industrial/distribution buildings that are low rise with large span areas.
The structure comprises of columns and rafters with bracing and side rails which are possible given most of the external walls do not require windows unlike say residential or office buildings.
Not suited for multiple stories as structure only suitable for bearing the weight of the roof (given its large span).
78
Pros and Cons of a Steel frame?
Cladded and floors are often pre-cast concrete slabs.
Steel frames can’t be adapted on-site and require high levels of fire protection.
Not used in warehouse as span is limited.
Pros; Fast to construct, benefits from factory quality and can have castellated beams for larger spans (compared to concrete) and M&E to pass through.
Cons; Poor fire resistance. Long lead times. Specialist labour for erection.
79
Concrete frame -
Core/s will be built first.
Pros;
Fire resistant, good heat and sound properties.
Adaptable on site
not prone to long lead in times.
```
Cons;
Labour intensive.
Temporary formwork.
Quality issues from weather & labour quality.
Services have to be drilled through.
```
80
Jump formwork -
More common than slipform;
Generally built in a floor section and then moves up (jointed at each floor).
It is slower than slipform but is less expensive.
81
Slip formwork -
24-hour operation requiring continual concrete pouring,
curing and moving.
Quick but expensive.
No joints so very strong.
82
Load bearing masonry frame -
Traditional form of frame which comprises of
brick/block cavity walls from the ground floor slab upwards.
Held together with wall ties and
filled with insulation in the cavity area.
Concrete planks or timber beams typically make up the upper floor
and this process continues level upon level.
83
What are Prefabricated structures?
What type of building are they suitable for?
What is the general construction process?
Pros
Cons
Constructed in factories off-site and then are transported to site to be constructed.
Ideal for repetitive structures such as residential, hotels and offices.
Concrete cores and foundations need to be built before any pre-fabrication work can commence.
Pros;
Programme gains can be significant (certainty, not subject to weather, less waste),
quality is good,
good safety as less people on site.
Cons;
Larger or individual (not square!) buildings make prefabrication difficult as efficiencies cannot be realised due to transportation.
Offsite production must be perfect or entire process can be undermined (re-building aspect may lose any gains on programme and the process is more expensive than onsite construction).
Only more economical if programme gains are achieved i.e. reduced financing, site preliminaries etc.
84
Building regulation -
Ensure minimum standards for design and construction within domestic, commercial and industrial buildings.
Ensure safety of people in and around buildings, maximise energy and efficiency and facilitate access for disabled people.
Part B; Fire safety
Advisable to consult with the relevant designer i.e. Architect in respect of detailed requirements required for cost planning.
e.g. FF lift required if the building has a floor 18m above or 10m below vehicle access level.
Part A - Structures
Part D - Toxic substances (Asbestos)
Part M - Access (Level access for wheelchair users)
85
Process for removing petrol tanks –
```
GPR Scan
Trial Pits
Temp works (sheet piling)
Drain petrol
remove tanks
back fill
```
86
SUDS -
Sustainable Urban Drainage Systems are a drainage system that reduce natural drainage and run-off water, which reduce the environmental impact from surface water drainage.
87
Permeable paving -
Allows water to pass through the gaps between the blocks. The water goes through the subbase which also slows down the water accessing the ground.
Pros; Managing runoff - Decreases the total amount of runoff leaving a site
Cons; Must be used in conjunction with other SUDs (unable to manage storm runoff volumes).
Expensive over standard asphalt roads.
Require frequent maintenance.
88
Swales -
Channels are sloped into a ‘V’ shape, which make it easy to maintain i.e. cutting machinery for the grass.
The slope delays water runoff and reduce the runoff volumes.
89
Other SUDS -
Rainwater harvesting
| Green roofs
90
Attenuation tanks
What is a hydro brake?
Is a
Underground surface water storage tank for when flooding occurs resulting in high amounts of water passing through system to limit the outflow into the mains drainage system.
Hydro Brake – Slows the outflow of water run off to manage high volumes (large pre-cast concrete chamber to take high pressure water impact).
91
What are the main Wrexham Building Components
```
Pad foundations
Portal frame,
pre cast dock levellers
cladding surrounding (inner lining, insulation, external sheets).
Curtain wall
Office structure - fit out by tenant
```
92
Wrexham Technical Description:
Foundation depth
GFS depth
Wall build up
GIA
Site density
Construction cost £/m2
Foundations and type/thickness of slab –
Pad foundations typically 800 deep. GFS 150 deep
Superstructure – Steel Frame, Pre-cast dock levellers
External wall build up -
cladding surrounding (inner lining, insulation, external sheets).
Type of roof - As cladding inc roof lights
Nr of dock levellers - 4
GIA – 100k ft2
Site density – 40%
Con cost - £60/m2
93
Meole Brace assumptions on design for key components
Inc Topsoil strip
Road
Strip foundations - 600 deep 1m width
slab thickness - 175
Upper floors - 200 hollowcore
100 screed and insulation
External wall - Composite cladding panels
Roof - Single ply roof inc insulation on profiled metal decking
road - provisional allowance £70/m2
External services - Provisional allowance
94
Typical cost plan exclusions -
VAT,
capital allowances,
site acquisition,
finances.
95
Fire Safety:
Fire Barrier – Expandable (when hot) strip in wall cavities – stops spread of fire
Fire Curtains – Rolled up fibre glass material in top box. Isolateds spread of fire.
Sprinklers – Buildings over 11m. Building Doc B (fire). Wet riser permanently charged – dry needs to be pumped in.
Fire fighting lift – Additional protection for use in fire by fire service. Req 18m+ or 10m below vehicle access
96
Section Agreements –
278 – Works to existing highways (Wrexham junction)
38 – Adoption of highways (housing estate)
106 – Schools, public open space – CIL is prevailing
CIL - £/m2 LA levy
80 – Demolition notice – works over 50m3 – submitted 6 months prior
97
O&M Manuel
```
Requirements defined in prelims –
details of building (frame, cladding, roof)
M&E –
Warranties –
Building Control
```
98
Ground floor construction
Ground bearing – concrete laid onto ground
Compacted ground, hardcore, blinding sand, damp proof membrane, insulation, concrete slab, screed, finishing material (if required)
Beam and block - Pre-cast concrete beams with concrete blocks laid between them. Suspended. Area below the floor needs to be ventilated.
Damp proof membrane, insulation and screed
Suspended pre-cast - Similar theory to beam and block with large pre-cast concrete panels
