Construction Technology Flashcards

Question

Can you give more information of end bearing piles?

Answer 1

• Usually used where there is a solid bedrock low down, which the pile is extended down to.

Answer 2

* Main bearing capacity is created through friction with the material surrounding the pile. * Usually very long to create the appropriate friction.

Answer 3

Mixture of both end bearing and friction piles.

Answer 4

* Driven Piles, also known as displacement piles. * Bored Piles, also known as replacement piles. * Secant Piles, used to create retaining walls.

Answer 5

* A form on contiguous piling, which can be used to create retaining walls. * Initial piles are bored with gaps, and cast with no reinforcement and a weaker concrete mix. * The stronger, insitu piles are bored in the gaps and partially through the existing piles, which care poured in a stronger concrete mix with reinforcement cages.

Answer 6

* Concrete piles. They can come in pre-cast for driven piles, or be poured in-situ. * Steel piles. They are pre-made, and can be used when driving piles. * Timber piles. They are pre-made, also used when driving piles.

Answer 7

* Strip Foundations. * Pad Foundations. * Raft Foundations. * Ground Beams. * Pile Caps. * Piled. * Basements.

Answer 8

1. Excavate the trench. 2. Level and compact the bottom. 3. Put down heave protection if required, e.g. ground with lots of clay. 4. Pour concrete into the trench, mass fill. 5. Tamp and vibrate to remove air bubbles and give a flat finish. 6. Get signed off by the building inspector.

Answer 9

1. Excavate to reduce level. 2. Level and compact bottom of excavation. 3. Spread and compact crushed concrete sub-base. 4. Pour blinding. 5. Form shuttering. 6. Place reinforcement mesh and bar. 7. Pour concrete. 8. Vibrate and power float to achieve smooth finish. 9. Get signed off by the building inspector.

Answer 10

1. Excavate around the pile. 2. Form earthworks supporting and working space. 3. Breakout and ‘munch’ the pile down to the desired level. 4. Level and compact bottom of excavation. 5. Pour blinding. 6. Tie pile reinforcement into pile cap reinforcement. 7. Place formwork. 8. If sacrificial formwork, backfill. 9. Pour concrete. 10. Tamp and vibrate to remove air bubbles.

Answer 11

• The process of placing temporary or permanent moulds into which concrete is poured.

Answer 12

* Battered Earthwork Support. * Sheet Piled. * Secant Piled. * Contiguous Piled. * Earth Retaining Walls. * Trench Boxes – i.e. used for deep drainage installations.

Answer 13

Think: ``` Uses? Installation time? Cost of materials Quality? Properties Acoustic/thermal insulator? Weather and decay resistant? Fire reistance? Strength? Flexibility and versatility before and once onsite Common defects deleterious? Sustainable and recyclable? Timber ``` PROS Variety: Engineered glulam, cross laminated, softwood hardwood, fibreboard Sustainable and biodegradable Versatile- machined into all shapes, structural or decorative Cost - can be low Quality variable - natural product CONS High moisture content – at 12% it is still dry Can decay Beetle attack common furniture beetle, death watch beetle Fungal attack - dry/wet rot Needs fireproofing Glass ``` TYPES Toughened, laminated plastic, double glazed with air or argon gaps PROS Decorative can be blown, stained Weather proof Transparent/ reflective. Cladding, facades Can be fire resistant pyroglass Good insulator when used with a gas filled interlayer CONS ``` Fragile, easily damaged- if layered strong Expensive and intensive to make heat to high temperatures Poor insulation value alone Can be subject to inclusions causing spontenaous breakage heat soak test. Not resistant to thermal or mechanical stress Concrete Made of Portland cement aggregate PROS Strong in compression but not in tension so requires reinforcement or prestressing (pre-srtensioned and post tensioining) Compressive strength measured in C20 etc High performance admixtures available GRC, waterproof, accelterators Versatile – can be precast in moulds or cast insitu, liquid, sprayed Good fire resistance Good acoustic proerpties e.g. for resi flats CONS Takes time to cure and strength check with cube samples, temperature affects this but can put additives in the mixture o Can be susceptible to chemical attack – alkali, sulphate, Cl Deleteriours material HAC Additives can cause degradation, also mundic. o Not weatherproof but can have waterproof additive Steel PRO Strong in tension Flexible without cracking Long spans are possible CON Poor fire resistance alone needs fire protection Can corrode and expands on corroding (Regent's Street Disease) Not flexible on site as prefabricated to size, if wrong size not much can do bolt on new section, use packers etc. Intensive production process (blast furnace, make iron first from iron ore, casting, forging etc) Stone PROS Natural product Can be highly decorative or purely functional Good fire resistance as non combustible CONS ``` Naturally porous can stain and also allow corrosion of steel regents street disease if suitable gap not left! Metamorphic, sedimentary, volcanic o May not be resistant to acid etc o Affected by weather o Slate roofing Brick ``` Clay poured into moulds and fired in a kiln PROS Lower moisture content Decorative CONS o Subject to chemical attack Not strong alone weather resistance is variable - engineering bricks versus softer decorative which can erode. Gyproc Plaster, can be used wet as a mix or made into preformed sheets with insulation backers for partition walls. PROS Good for finishes Can be fire resistant CONS Not moisture resistant

Answer 14

Compacted hardcore, Poured concrete reinforcement, DPM, floateds screed.

Answer 15

Hollow pot Filler joist Waffle slab Steel composite deck - holorib?

Answer 16

- Coffered floors or waffle slab is common in a 1960s office block - precast units with steel reinformcement and precast columns. Longer spans and services run under floors - Filler joist (vacuum injection resin repair) - Hollow pot - Steel composite deck - like holorib. - Precast concrete units (like beam and block!) Pre stressed units e.g. pre or post tensioned floors The use of post-tensioned reinforcement to construct floor slabs can result in thinner concrete sections and/or longer spans between supports - tendons pulled tight once onsite.

Answer 17

hollow core - precast units longitduinal voids and reinforcment - preformed service ducts, longer spans. solid raft foundation - reinforced solid often foudnations poured in situ. Composite slab - profile steel deck Waffle slab - longer spans, less crossectional area.

Answer 18

All structure below the superstructure i.e. all structure below ground level including the ground floor bed

Answer 19

All internal and external structure above the substructure Made up of primary (ext walls, stairs, roof, structural walls) and secondary (suspended ceilings / raised floors, balustrades, doors) elements and finishes (tiles, paint, stair nosings)

Answer 20

The materials and components that form the external shell or enclosure of a building May be load or non-load bearing

Answer 21

Prepared by the International Organisation for Standardisation – prefixed ISO Compatible with and complement BS’s Example - ISO9000 is quality

Answer 22

- Objective is to systematically collect and record data to help in design / construction - Should include anything on adjacent sites that may impact and: - Boundary hedges / fencing - Existing trees - Size, depth and location of services – gas, telephone, electricity, water, drains - Existing buildings - Ground water conditions - Soil investigations – trial pits etc

Answer 23

- Access considerations – approach roads etc - Storage considerations - Accommodation - Temporary services - Plant - Fencing / hoarding - Safety and health

Answer 24

- Temporary works do not normally appear on construction drawings but demonstrate methods that might be appropriate and resources necessary to ensure safe construction i.e. propping.

Answer 25

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 work above 1.5m above ground

Answer 26

- Design for the vertical transportation of materials or people

Answer 27

- Function is to safely sustain and transmit to the ground on which it rests the combined dead, imposed and wind loads of the structure

Answer 28

- Cement, aggregate (natural rock, crushed stone, gravel) and water

Answer 29

- A series of columns constructed or inserted into the ground to transmit the load of a structure to a lower level of subsoil - Used where no suitable foundations conditions near ground level or high water table

Answer 30

- Sheet piles – a deep trench is excavated and concrete is poured in situ. The piles can be used to form basement walls or act as retaining walls. - Secant piles – interlocking piles (male and female, often different diameters and hardness) are bored to provide a combination of foundations and basement walls. They go someway in providing a waterproof structure. Secant piles are often seen when a top down construction method is used. - Bored Piles – an auger is used to excavate the soil and then concrete is poured in once complete. A variation to this is CFA (Continuous Flight Augered) where the piles are bored, Bentonite slurry is pumped in to stop the core collapsing and then concrete (which is denser than Bentonite) is poured in. Bentonite is environmentally harmful and is therefore not often used in the 21st century. - Pre-cast piles – pre-cast piles are brought to site and hammered into the ground. Not often favoured due to the high noise levels associated with installation and the lack of flexibility in terms of depth required.

Answer 31

Bored piles - when the process for removing the spoil to form the hole for the pile is carried out by a boring technique. They are used primarily in cohesive subsoils for the formation of friction piles and when forming pile foundations close to existing buildings where the allowable amount of noise and/or vibration is limited. Pre-cast Concrete piles - used where soft soil deposits overlie firmer strata. These piles are usually driven using a drop or single action hammer.

Answer 32

A raft can be used for lightly loaded buildings on sites with poor soils Heavy loads to the raft have the potential to cause the raft to move sideways as a result of raft foundations not being very deep

Answer 33

- Suitable for most subsoils and a light structural design, usually reinforced

Answer 34

- Provide a base for reinforced concrete or steel columns | - Usually constructed from reinforced concrete

Answer 35

- They act as an earth retaining structure for the whole or part of their heights - Need to consider water pressure and pressure of the retained earth in their design

Answer 36

- A storey below the ground storey

Answer 37

a) Retaining wall and raft (monolithic) – consists of a slab raft foundation (basement floor) that distributes the building loads, the basement walls are the retaining walls b) Box and Cellular raft – similar to above but internal structural walls are used to transmit and spread loads over the raft – divides the basement into cells c) Piled – main superstructure loads are carried to the basement floor by columns and transmitted to the ground via pile caps and bearing piles (i.e. your basement has a whole load of columns going through it)

Answer 38

a) Dense monolithic – this is where the basement is designed and built to form a watertight space using high quality reinforced concrete, needs good workmanship and strict control. Success will depend on water / cement ratio and degree of compaction. Joints need to be carefully designed. b) Tanking – e.g. asphalt, polythene sheeting, bitumen, epoxy resins. These can be applied internally or externally to provide a continuous membrane to the base slabs and walls. Externally is better as it protects the structure as well. c) Drained Cavity – can be used for new or refurbishment work. It accepts a small amount of water seepage will occur, and collects and drains this away. Builds an inner non-load bearing wall to form a cavity. The floor is laid to falls, moisture drains to a sump and is discharged direct or pumped d) N.B. Basements are rated as to their final use e.g. habitable, plant, storage and the waterproofing solution is often influenced by this.

Answer 39

Quick to assemble, 100% recyclable - inorganic - will not warp, split, crack or creep – Highest strength to weight ratio of any building material – Not vulnerable to termites or any type of fungi or organism Dimensionally stable - does not expand or contract with moisture or temperature changes. Consistent material quality - produced in strict accordance with national standards, no regional variations Light steel components are always straight Steel is non-combustible so it will not contribute to the spread of a fire. Lighter therefore poor soil conditions will need steel over concrete

Answer 40

Needs fire protection Parts may need replacing Price of steel is variable Need experienced builders – additional cost Even though steel components will not burn they will actually fail (collapse) before a wood component in a fire.

Answer 41

Examining the impact of the steel price rises has found that the whole project costs for concrete framed buildings are marginally less than for steel framed buildings. Fire protection as part of structure Slower form of construction at this early stage will reduce the cash flow early on Maintenance of an insitu concrete frame is low Cladding can be fixed to it and replaced easily. It also provides good sound and heat insulation. Insitu allows for alteration at late stage of construction Can deal with complex geometry better than steelwork

Answer 42

- More time consuming. Slower to construct - Edges may not be as square and surfaces not as flat as steel - The need for steel reinforcement leads to some of the cost issues associated with steel - Heavier so requires larger foundations

Answer 43

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.

Answer 44

 A 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.

Answer 45

 Fire Resistant paint, sprayed on in the factory. Touched up by hand on site.

Answer 46

 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 an upstand flashing, and either stepped, raking or level.

Answer 47

 Concrete is power floated in order to maintain a flatter surface of lightweight concrete that has been applied at a faster rate i.e. in commercial offices.

Answer 48

 Post-tensioning, concrete is cast around ducts or sheathing in which the tendons are to be housed.  Stressing is carried out after the concrete has cured by means of hydraulic jacks.  Used when stressing is to be carried out on site after casting an insitu component or where a series of pre-cast concrete units are to be joined together to form the required member.

Answer 49

 A perforated brick to allow for ventilation into a room or an underfloor space. NOT a weep hole.

Answer 50

```  Fire rating requirements,  Restriction for noise (Db rating),  Visually – Opaque/Transparent  Fixed or movable  Strength - If anything is to be fixed to the wall ```

Answer 51

 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  Floating Screed - Laid with steel or fibre reinforcements on to the insulating board, which in turn can be laid on to a suitable damp proof membrane. Sound, clean prepared base.  Resin Bonded Screed - Laid on to a clean, rough pre-prepared concrete base. The resin acts as a ready installed damp proof membrane to the top screed.

Answer 52

 A lightly rounded metal strip over the joint between the floor finishes or coverings that meet under the door leaf.  Prevents fraying, looks better and interrupts combustible flooring under fire doors

Answer 53

 Suspended ceiling system formed by a square grid. Advantages -  Quicker to construct.  Allows for service runs through the void above thus allowing greater floor to ceiling height.  Easy access for service/repairs  Damaged tiles can be replaced rather than whole ceiling.

Answer 54

 Rolled carpets generally better quality and more expensive. Used in dwellings.  Carpet tiles – harder wearing, lower quality cheaper and individual tiles can be replaced therefore easier to maintain. Used in offices, hospitals etc. Also where raised flooring systems are used carpet tiles allow for easier access to services that run in the void below.

Answer 55

Allows building above basement to be constructed at same time as basement - ground floor slab is constructed and below ground is excavated

Answer 56

Bottom up - forms the basement and then works upwards in a traditional manner. Simpler but a longer programme.

Answer 57

Green roof – absorbs rain water, insulation, habitats wildlife, aesthetics, helps lower urban air Blue roof – collects water and releases it slowly when rain has stopped – e.g attenuation tank

Answer 58

Mechanical and Natural

Construction Technology Flashcards

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