Construction Technology Flashcards
1
Q
What is substructure?
A
All structure below the superstructure i.e. all structure below the ground including the ground floor bed.
2
Q
What is superstructure?
A
All internal and external structure above the substructure.
3
Q
What is meant by primary superstructure?
A
External walls, stairs, structural walls, roofs
4
Q
What is meant by secondary superstructure?
A
Raised floors, suspended ceilings, balustrades, doors
5
Q
What is meant by internal finishes?
A
Paint, tiles, carpet, stair nosing
6
Q
What is the external envelope of a building?
A
The materials and components that form the external shell or enclosure of a building.
May be structural or non structural
7
Q
What are the building regulations?
A
Statutory instruments that set out the minimum performance standards for the design and construction of buildings.
Supported by approved documents A - R & regulation 7.
8
Q
Name the approved documents.
A
A - Structure
B - Fire safety
C - Site preparation and resistance to contaminants and moisture
D - Toxic substances
E - Resistance to the passage of sound
F - Ventilation
G - Sanitation, hot water safety and water efficiency
H - Drainage and waste disposal
J - Combustion applications and fuel storage systems
K - Protection from falling, collision and impact
L - Conservation of fuel and power
M - Access to and use of building
N - Glazing safety (withdrawn, ss by park K)
P - Electrical safety
Q - Security
R - Physical infrastructure for high speed electronic communication networks
Regulation 7 - Materials and workmanship
9
Q
What are British Standards?
A
- Publications issued by British Standard Institution (BS)
- Give recommended minimum standards for materials, components, design and construction practices
10
Q
What are International Standards?
A
- Prepared by International Organisation of Standardisation (ISO)
- Compliment BS
11
Q
What are the typical components of site investigation?
A
Objective - to collect and record data to help in design & construction
Should include info of adjacent sites that impact:
- Boundary hedges/fencing
- Existing trees
- Size, depth and location of services
- Existing buildings
- Ground water conditions
- Soil investigations (trial pits)
12
Q
What are soil investigations?
A
Objective:
- Determine suitability of site for proposed works & adequate and economic foundation design
- Identify potential issues
13
Q
What are the main site considerations for a contractor setting up on site?
A
- Access considerations, approach roads etc
- Storage considerations
- Accommodations
- Temporary services
- Plant
- Fencing/hoarding
- Health and safety
14
Q
What is a retained facade?
A
Facade of the building is retained whilst everything behind the front wall is demolished.
15
Q
Why are facades retained?
A
- Often listed
- Aesthetics
16
Q
What considerations would you make if you were to retain a facade?
A
- Temporary support structure
- Cleaning/restoration requirements of facade
17
Q
What are temporary works?
A
- May not appear on construction drawings
- Methods that are required to ensure safe construction, e.g. propping. These will be removed once permanent supports are in place.
18
Q
What is a scaffold?
A
- Temporary working platform erected around the perimeter of a building or structure to provide a safe working place at a convenient height
- Usually required for working above 1.5m high
19
Q
What is shoring?
A
- Form of support given to existing buildings.
- Precaution against damage or injury caused by collapse of structure.
20
Q
What are foundations?
A
Foundations provide support for structures, transferring their load to layers of rock and soil that have sufficient bearing capacity.
21
Q
What is a dead load?
A
- Permanent and static loads
- Predominately the structure itself
22
Q
What are live/imposed loads?
A
- Usually temporary
- Changeable and dynamic
- Occupants, furniture, equipment, vehicles
23
Q
What are wind loads?
A
- The movement of air against the structure
- Particularly important on tall buildings and buildings with a light-weight dead load
24
Q
What are the main components of concrete?
A
Water, aggregate (rocks, sand etc), cement
25
What is aggregate?
Natural stone, crushed rock, gravel
26
What is a borehole?
- A borehole can be used for soil investigations or geothermal heating solutions
- Boreholes are the most effective solution for soil investigations where the foundations are to be over 3m deep
27
What are piles?
A series of columns constructed or inserted into the ground to transfer the load of a structure into the soil
28
What are the different types of piles?
- Replacement/Bored piles (reinforced concrete insitu)
- Displacement/Driven piles (pre-cast, steel, composite)
- Basement walls (secant piles, sheet piles)
29
What are sheet piles?
- Sections of sheet materials with interlocking edges that are driven into the ground to provide earth retention or excavation support.
- Typically made of steel
- Often used for retaining walls and underground structures
30
What are secant piles?
- Intersecting steel reinforced concrete piles
- Primary female piles are installed first, with secondary male piles installed in between them. Overlap of roughly 3 inches creating a flush finish
- Useful in top-down construction and temporary waterproofing
31
What are bored piles?
- Auger is used to excavate soil, then concrete is poured in
- Variation of this is where a continuous flight auger is used to bore piles and fill core with bentonite slurry. Concrete is then poured into core, displacing the bentonite slurry due to it's denser makeup. Rarely used now due to environmental impacts of bentonite
- Minimal vibration
32
What are pre-cast piles?
- Piles brought to site and hammered into the ground
- High noise levels associated with installation
- Lack of flexibility in terms of depth required
33
What are the different ways that piles transfer their load into the surrounding ground?
- End bearing piles: Pass through soft strata onto firm strata. Load transferred through toe of pile
- Friction piles: Through sheer stress against side of piles
- Tension piles: Through the length of the pile to reduce overturning moments on the building caused by uplift forces
- Laterally loaded piles: Horizontal forces in situations such as bridge piers. Similar to above.
34
When would you use bored piles?
- In cohesive subsoils for the formation of friction piles
| - When close to existing buildings due to noise/vibration limitation
35
When would you use pre-cast concrete piles?
- When there is soft soil deposits lying on firmer strata
| - When noise/vibration isn't a concern
36
What is a raft foundation?
Used to spread the load of superstructure over a large base and reduce load/m2 of area.
Generally reinforced concrete slabs.
37
When would you use raft foundations?
- In low bearing capacity soils
- Where settlement is likely
- Where floor areas are small and structural load low
38
What is a strip foundation?
Shallow foundations used to provide a continuous, level strip to support a linear structure such as a wall
39
When would you use a strip foundations?
- Most subsoils
| - Light structural design
40
What are pad foundations?
A form of spread foundation formed by often square pads that support single-point structural loads such as columns
41
What are retaining walls?
They act as an earth retaining structure for the whole or part of their height
42
What considerations should a Contractor make when building a retaining wall?
Pressure of water/earth acting on wall
43
What are the main types of excavation?
- Open
- Perimeter Trench Excavation
- Complete excavation
44
What is open excavation?
- Use battered excavation technique which is excavating the soil with the sides left at a safe angle so as to not collapse
- Save money on temporary support work
- Extra excavation costs due to extra soil being removed to ensure sides are at a safe angle
- Requires free space on site for angled sides. Wouldn't work on site boundary.
45
What is perimeter trench excavation?
Trenches are dug with required support around basement perimeter. Basement walls are formed, then inside of basement is excavated.
46
What is complete excavation?
- Centre of basement is excavated
- Basement slab is cased while sides of excavation are supported by struts
- Basement walls formed
- USED WHEN SUBSOILS ARE FIRM
47
What is a basement?
A storey below ground floor.
48
What are the 3 main types of basement construction?
a) Retaining wall and raft (monolithic) - slab raft foundation distributes building load. Basement walls are retaining.
b) Box and Cellular - similar to above but internal structural walls transfer and spread loads over raft, dividing basement into cells
c) Piled - superstructure load carried to basement floor by columns and treasferred into ground via pile caps & piles
49
What are the 3 main methods of waterproofing a basement?
a) Dense monolithic - basement designed to form watertight space
b) Tanking - asphalt or similar resin applied internally or externally to provide continuous membrane to base slab and walls. External better as it protects substructure.
c) Drained cavity - Accepts small about of water seepage, collects and drains this away. Inner non-load bearing wall forms cavity wall for water to drain into, CAN BE USED ON REFURB WORK
50
What are the technical advantages of steel frame construction?
- Quick to assemble
- Recyclable material
- High strength to weight ratio
- Not vulnerable to termites, fungi etc
- Consistent material quality as produced in strict accordance with national standards
- Non-combustible so won't contribute to spread of fire
- Lighter than concrete
51
What are the technical disadvantages of steel frame construction?
- Needs fire protection
- Parts may need replacing
- Price of steel is variable, could be high market dependent
- Requires experienced builders
- Will fail (collapse) before wood in a fire in spite of not being combustible
52
What are the technical advantages of concrete frames?
- Could be cheaper than steel dependant on market price of steel
- Doesn't require additional fire protection
- Slower construction will help cashflow
- Low maintenance with insitu concrete frames
- Cladding can be fixed to it and replaced easily
- Good sound and heat insulation
- Insitu allows alteration at later stages
53
What are the parts of an I Beam?
- Flange (top and bottom of the "I")
- Web (the vertical steel, runs between the two flanges. Long part of the "I")
- Root (where the flange and web meet)
54
What is a steel table?
Table that provides standard information on steel sections.
Different table for different beams/columns, e.g. UB and UC.
55
What is the weight of steel?
10mm3 steel = 0.0078kg
56
What is powder coating?
- A durable factory applied organic coating on metals available in many colours
- Polyester, acrylic, epoxy spray followed by heat curing
- Any holes made/cuttings should be done prior to application of coating
57
What are the advantages of powder coating?
- Stops corrosion
- Stops abrasive damage
- Stops metal reacting with other chemicals
58
What are UBs and UCs?
Universal beams & Universal Columns respectively
59
What is intumescent paint?
Fire resistant paint
60
What are connections (steel) and what percentage would you expect them to be?
- Plates, bolts or welding
| - 5%-10% by weight
61
What is an upstand?
- A vertical strip or skirting, such as the weatherproofing where roofing meets an abutment wall.
- It can be the roofing itself, particularly for mastic asphalt, the top part of a one-piece apron flashing, a mortar skirting or upstand flashing.
62
What is power floated and why?
- Concrete
- Power float is a hand-operated machine
- Used to produce smooth, dense level surface finish to insitu concrete beds
63
What is post tensioned concrete?
- Post tensioning is a technique to reinforce concrete formed insitu
- Can be used to join a series of pre-cast units
- The concrete is cast around ducts or sheathing in which the tendons are housed
- Steel tendons are pulled tight once concrete is cured using hydraulic jacks from one or both ends
- The stretched steel tendons are then capped
- Essentially, the steel tendons are pulling the concrete slabs together by trying to contract
64
What is formwork?
- Anything that holds in-situ concrete in place until it hardens
- Can be plywood shuttering, steel pan forms
- Can be supported by props, centering (formwork for floors/slabs) or falsework
65
What is A182 mesh?
Mesh used to reinforce concrete slabs. Metal lattice.
66
What is a cavity tray?
A damp proof course that crosses the 50mm wide cavity of the cavity wall, stepping up at least 150mm between the outer and inner leaves, to form a gutter that leads to a weephole in the outer leaf
67
What is a damp proof course?
A strip of impervious material the same width as brickwork or block work wall to stop moisture rising from the ground up the external leaf of the wall.
68
In a brick/block wall, how are window openings dealt with structurally?
Through use of a lintel - a small beam over the window or door head to carry the wall load
69
What is the size of a brick?
Standard size - 215mm x 102.5mm x 65mm
70
What is the frog and which side does it go on?
- The frog is an indentation in one of the bed faces of a brick, usually the top
- Bricks with two frogs are known as "double frogged", though these are less common
- Bricks should be laid frog (or larger frog) facing up, with the mortar filling the frog
- Creates a stronger wall and superior sound insulation
71
How many bricks are in a m2?
60 approx.
72
What are the different types of brick bond?
Flemish bond - The bond has one stretcher between headers, with headers centred over the stretchers below
Stretcher bond - most common, walls just half a brick wide. Stretcher face side showing
73
What are the different faces of a brick called?
Stretcher = long side of brick face
Header = short side of brick face
Sailor = When bricks are stood up vertically, the wide face is called the sailor
Soldier = When bricks are stood up vertically, the thinner face is called the soldier
Rowlock Stretcher/Shiner = When the brick is sitting on it's stretcher, the wide face that was previously the top is called the shiner
Rowlock = In the above situation, what was previously the head is called the rowlock
74
What is a rain screen cladding system?
- Non-structural external surface
- Protects everything inside from external weather
- Formed of outer protective skin (metal, timber, glass, composite panels), supporting frame, a cavity and water-resistant internal materials which includes a layer of insulation
- Three basic types are drained and ventilated, vented, and pressure equalised rainscreen systems
75
How are cladding panels fixed to a steel frame?
- Bolted (useful when may require being undone & cheaper than welding)
- Riveted (fastest, like a nail)
- Welded (melted together, maximum strength)
76
What other elements will be affected by type of cladding used?
- M&E
- Roof
- Frame
77
What is an air brick?
A perforated brick to allow ventilation into a room or under a floor space.
NOT A WEEP HOLE
78
What factors may affect the choice for internal partitions?
- Fire rating requirements
- Noise requirements (Db rating)
- Visual requirements (glazing etc)
- Flexibility required (movable/fixed)
- Strength (to hang things from walls etc)
79
What is a rebate?
A cut into a material to house another material e.g. glass
80
How do you construct a glazed partition?
- Glass is fixed into a frame, steel or wood
- Glass placed into a rebate, rebate is filled with putty/beading to hold it in place
- This frame is then placed within walls/columns where required, usually held in with putty
81
What is bonded screed?
Laid onto a ready prepared rough, cleaned concrete base
82
What in unbonded screed?
Laid onto a sound, clean Bitumen damp proof membrane
83
What is floating screed?
Screed laid on acoustic or thermal insulation. This is a type of unbonded screed.
84
What is the purpose of a threshold strip?
A metal strip between the floor finishes or coverings that meet under the door leaf
- Prevents fraying, creates a more fluid look and interrupts the spread of fire for combustible floors.
85
What is a ridge in terms of roof construction?
Apex beam in a roof.
86
What is a hip rafter?
The rafter extending from the wall plate to the ridge and forming the angle of a hip roof
87
What are the jack rafters?
The rafters that runs from the hip to the eaves
88
What are principles/common rafters?
Run from the ridge to the eaves. Main structure of the roof.
89
What are wall plates?
Receive the feet of the rafters at the top of external wall
90
What are purlins?
Horizontal beams that are used for structural support
91
What are battens?
Small lengths of wood that run between rafters horizontally. To these, the roof cover is fixed.
92
What are the jack rafters?
The rafters that runs from the hip to the eaves
93
What are principles/common rafters?
Run from the ridge to the eaves. Main structure of the roof.
94
What are wall plates?
Receive the feet of the rafters at the top of external wall
95
What are purlins?
Horizontal beams that are used for structural support
96
What are battens?
Small lengths of wood that run between rafters horizontally. To these, the roof cover is fixed.
97
What types of roof covering may you find on a pitched roof?
- Slates
- Pan tiles
- Zinc
- Copper
- Thatched
98
What are the elements of a flat roof?
Joists – fixed to wall plates to act as main support
Firrings – fixed to the top of joists to give required incline
Particle board (chipboard) – fixed to top of firrings to give flat surface
Felt – 3 layers bonded with bitumen to give waterproof covering
Stone chipping – To give protection to felt and to reflect sunlight
99
What is a single layer membrane?
- One layer of felt consisting of a base sheet of glass fibre or polyester reinforcement, impregnated with hot bitumen during manufacture
- Coated both sides with weatherproof bitumen compound
- Easily punctured and rarely used
- Cheapest option
100
What is built up felt?
- Constructed using three layers of a single layer membrane.
- First is laid at right angle to the fall, second laid parallel to fall, third at right angle.
- Covered with stone chippings
- Easily punctured if care not taken
- More common than single
101
What is asphalt roofing?
- Aggregate with bituminous binder which is cast into block ready for reheating at site
- Heated into cauldrons to 200 degrees Celsius (dangerous)
- Transported in liquid form to roof
- Two coats usually required
- Reduce risks of defects as no risk of damage en route to site
- Cools quickly, must be heated close to roof
- Hard wearing and designed to allow transit. Some companies offer 60-year guarantee
102
A door requires a 30 min fire rating. What features would you expect that door to have?
- 3 hinges
- Intumescent strip around door or frame
- Self-closing devise
- 6mm thick glass
103
What is a MF ceiling?
Mineral fibre plasterboard suspended ceiling, typically used in office spaces
104
What is a metal grid ceiling and what are the benefits?
- Suspended ceiling system formed by square grid
- Quick construction
- Allow services to run through the voids allowing greater floor to ceiling height
- Easy access to services
- Damaged tiles can be replaced
105
What are the benefits/disadvantages of rolled carpets?
- Rolled carpets generally better quality
- More expensive
- Used in dwellings.
106
What are the benefits/disadvantages of carpet tiles?
- Hard wearing
- Lower quality
- Individual tiles can be replaced therefore easy to maintain
- Used on offices
- Easy access to flooring, useful when raised flooring is used
107
What is top down construction?
- Used to speed up construction for buildings with basement levels
- Ground floor slab cased with access hatch
- Ground below excavated and another slab is formed
- Piles used as foundations and act as retaining walls.
- Struts/propping required for retaining walls
- This allows building above to be constructed at the same time as basement
108
What is bottom up construction?
- Forms the basement then works upwards in a traditional manner.
- Simpler but longer programme
109
How is power distributed to floor boxes in raised floor?
- Power supply connects to low voltage switchboard which in turn connects to a distribution board
- The distribution board will have under floor busbar connected to it. The busbar has a number of sockets to which the floor box plugs into via a flexible lead.
- The floor box has sockets which appliances can plug in to
