Construction Technology Flashcards
What are the various house types you’ve built?
Detached, semi-detached, terraced, blocks of flats (3 storeys high) (really meant standard house types with house builders)
Have you ever dealt with any kind of brickwork defects?
▪ Efflorescence
▪ Mortar deterioration
▪ Cracking (compromise structure of building)
▪ Wall ties corrosion
▪ Damp penetration
▪ Damage by the brick cleaners
What bonds of brickwork have you come across and which is the most popular?
Types of bonds - Stretcher, Header, English, Flemish, English Garden
What is the purpose of a foundation?
Provide support for structure, transferring their load to the ground. They should bear the load of the superstructure.
You’ve mentioned you have experience of various types of foundations. Can you give me some examples?
▪ Strip foundations - strip of linear structure that spreads the weight across the total areas of the ground. Typically used to support masonry. (Used in housebuilding)
▪ Raft foundation - a continuous slab that extends across the entire building footprint. This is over a larger area to reduce stress on the ground. Typically used when ground conditions are poor.
▪ Pad foundation - usually square or rectangular structures that are used to support columns. Spreads the loads to the ground. Can be reinforced (as Portland Park)
▪ Pile foundations - columns that extend deep into the ground. Use where bearing capacity of the soil is poor or imposed loads are very heavy. (Distribution of structure isn’t uniform / subsoil water table is high))
What are the 2 types of piles?
- End bearing piles (reply on the resistance f the soil or the rock at the tip of the pile to support the load)
- Friction piles (transfer load by friction between the surrounding soil and the surface of the pile over its full length - like when you step in the mud!)
What are the 2 main construction methods of installing piles?
- Bored piles (manufactured / cast on site)
- Driven piles (formed off site under factory-controlled conditions)
What is underpinning?
Process of strengthening the foundation of an existing structure / Method for repairing and strengthening foundations.
Briefly explain the construction of a swimming pool?
▪ After surveying & marking the area, area is excavated and soil taken off-site
▪ Steel formwork was used to form shape of pool and rebar placed at base
▪ Concrete was poured and cured. Concrete contain Xypex which is a waterproofing solution. At this point we filled the pool with water (with help from the local fire brigade) to test for cracking.
▪ Installation of pipes and wiring for MEP works (filers, pumps, drainage, lights)
▪ Pool was emptied then tiled using a waterproof grout
▪ Installation of MEP
▪ Complete areas around the pool (floor tiles)
▪ Fill. Test systems and chemical balancing
▪ Inspection & handover
What are SUDS?
Sustainable Urban Drainage Systems - designed to efficiently manage the drainage of surface water. Alternative or in addition to typical drainage (pipework)
What are some of the advantage & disadvantages of using a steel frame?
Advantages
* Faster to erect than concrete (prefab)
* High Tensile strength therefore can span long distances (good for a swimming pool)
* Strong and Durable - resistant to decay, pests and weather
Disadvantages
* Cost - Price of steel is volatile
* May need Fire Protection
* Poor thermal conductivity
* Corrosion
What are the components needed to measure steelwork?
- Structure steel frame including all components - columns, beams, braces, struts (in Tonnes)
- Connections / Fittings and fixings (e.g. holding down bolts) - in Tonnes. Usually 10%
- Fire protection £200/t
What are some of the advantage & disadvantages of using a concrete frame?
Advantages
* Fire protection is naturally part of the structure
* Good acoustic & thermal properties
* High compressive strength - suitable for multi-storey buildings, bridges, handling heavy loads
Disadvantages
* Slower to construct on site & Long curing times (max strength 28 days)
* Environmental impact - high carbon emission during cement production and transportation
* Weight - heaviest therefore increased foundation costs
What are the components you would need to measure for a concrete frame?
- Formwork
- Concrete (columns, beams, walls, floor slabs - nr, size, reinforcement, formwork finish)
- Designed joints?
- Reinforcement (would measure using a bar bending schedule)
- Tanking
What is formwork?
The structure (usually temporary) used to support wet concrete until it cures and acts as a mould to create required dimensions. Usually stripped away once concrete has hardened.
What are some of the advantage & disadvantages of using a timber frame?
Advantages
* Quick to erect on site
* Relatively lightweight - easy to transport & handle (reduce costs)
* Sustainable (if from a responsible supplier) - timber is a renewable source with lower carbon footprint
* Aesthetically pleasing (if exposed)
* Thermal performance
Disadvantages
* Requires specialist (joiners) achieve good quality finish
* Potential for wet rot, dry rot, woodworm without treatment/protection
* Need additional fire protection - more combustible that steel or concrete
* Not suitable for long spans / very heavy loads
What are retaining walls?
Holds back (or retains) the soil behind it. Typical purpose is resist the lateral pressure of soil where there is a change in ground elevation.
Can you give me some types of retaining wall please?
- Gravity - relies on its own weight to resist the pressure. Made using stone, concrete or masonry. Shorter walls or space for a wide base available.
- Cantilevered - made from reinforced concrete or masonry. Thinner stem, uses leverage via a base slab. Taller walls, less materials than gravity.
- Gabion - basket structure (wire mesh boxes), can be used as a more aesthetically pleasing alternative. Basket is then filled with tightly packed rocks. Flexible, permeable, and eco-friendly, often used in landscaping and erosion control
- Crib Retaining Wall - built form interlocking concrete or timber frames filled with soil or gravel. Lightweight and allows water drainage, idea for slopes and landscaping (Benwell - health & Safety issue)
- Sheet piling - temporary measure where sheet piles are driven into the ground. Steel or timber planks driven into the ground. Good for tight spaces or soft soils. Also used in temp works or waterfront applications (Rowlands Gill)
What are Building Regulations?
Regulations to ensure that new buildings, conversions, renovations and extensions are going to be safe, healthy and high performing.
Can you name some of the Building Regulations Approved Documents?
Part A - Structure
Part B - Fire Safety
Part C - Site Preparation
Part D - Toxic Substance
Part E - Sound resistance
Part F - Ventilation
Part G - Sanitation, hot water safety and water efficiency
Part H - Drainage & water disposal
Part J - Combustion appliances and fuel storage systems
Part K - Protection from falling, collision and impact
Part L - Conservation of fuel and power
Part M - Access to and use of buildings
Part O - Overheating
Part P - Electrical safety
Part Q - Security in dwellings
Part R - High speed electronic communications networks
Part S - Infrastructure for charging electric vehicles
What different types of underpinning are there?
1) Mass concrete
2) Beam and base
3) Mini piles
You note you are aware of the fire safety products of various materials, with this in mind can you talk me through various frame options that you are aware of and the pros and cons of each?
Refer to advantages & disadvantages plus…
Concrete - built in fire protection
Steel - Needs additional fire protection
Timber - Needs additional fire protection
You note that you identified the Criblock wall as being a potential Health and Safety hazard, why was this not raised by Principal Designer. Why was it deemed a risk?
It was missed by the PD and picked up on a site walkaround.
This was a climbing risk, particularly as it was in the back garden of a family house.
You note undertaking a cost analysis of various other types of wall – can you advise what these were?
Cantilevered Concrete retaining wall with reinforcement, sheet piling with aesthetic brickwork wall, gabion baskets. Instead we covered with anti-climb mesh.
What type of building would timber frames be most suitable?
Houses - quick to erect, easy to transport & good thermal properties
Which is best from a carbon perspective?
Timber - this is a sustainable product
Concrete has a high footprint sue to the creation of the cement. Steel also high in the production phase.
