CONSTRUCTION TECHNOLOGY Flashcards
What are Building Regulations and what are they supported by
Statutory Documents which set out the minimum performance standards for design and construction
They are supported by the Approved Documents and Codes of Practice
Name the Approved Documents
A. Structure.
B. Fire safety.
C. Site preparation and damp proofing.
D. Toxic substances.
E. Sound proofing.
F. Ventilation.
G. Hygiene.
H. Drainage and waste disposal.
I. Not in use.
J. Heating appliances.
K. Protection from falling, collision and impact.
L. Conservation of fuel and power.
M. Disabled access and facilities.
N. Glazing.
O. Not in use.
P. Electrical safety.
What are British Standards
Publications issued by the British Standards Institution which give recommended minimum standards for materials, design and construction practices. They have the prefix BS
What are International Standards
Publications issued by the International Organisation for Standardisation, which give recommended minimum standards for materials, design and construction practices. They are compatible with the British Standards and have the prefix ISO
What is a party wall
In simple terms a party wall divides the buildings of two owners with the boundary between ownerships usually
What is the Party Wall Act
• The general principle of the Party Wall Act is that all work which might have an effect upon the structural strength or support function of the party wall or might cause damage to the neighbouring side of the wall must be notified
• A framework for preventing and resolving party and boundary wall disputes, when one owner of the party wall disagrees with works the other owner is undertaking.
What is a site investigation and what are the typical investigations undertaken in a site investigation
Collect and record data about the site to aid design and construction decisions
Investigations include
a. Soil Investigations
b. Ground Water Conditions
c. Utilities surveys
d. Existing trees
e. Existing buildings
f. Size, depth and location of services
What is the purpose of a soil investigation
They help us to determine soil conditions and assist with identifying a suitable foundation solution for the proposed works
What are some main site considerations
a.Access
b. Storage
c. Accommodation
d. Fencing and Hoarding
e. Health and Safety Risks
What is a Borehole
A borehole can be used for soil investigation or for geothermal heating solutions (Geothermal boreholes are permanent boreholes that use the Earth’s natural heat to raise the temperature of circulated water which can be used to heat the building above.)
Boreholes are the most suitable method of soil investigation when foundations are over 3m deep.
What is the Substructure
All work under the Damp Proof Course (DPC)
What is a foundation?
A foundation refers to the lower part of a structure, which is designed to distribute the weight of the new building evenly and provide a firm footing.
What are some foundation types
Piled
Strip
Raft
Pad
What are the classified types of foundations
Shallow foundations
Are used where the immediate ground conditions (upto 3m) are strong enough to accept the imposed and transferred load of the building. They include foundation structures such as Pad, Strip and Raft Foundations.
Deep foundations
Are used when the immediate ground conditions arent strong enough to accept the imposed or transferred loads, therefore a deeper level of the ground needs being reached that is able to withstand the load. They include foundations such as Pile foundations solutions or deep concrete retaining structures
What are piles
A series of columns that are constructed or inserted into the ground to transmit the load of a structure deep into the soil
When would you consider the use of pile foundation solutions?
• When the ground water table is high
• When heavy loads are expected to be imposed from the superstructure
• When the soil conditions arent strong enough to accept the loads
What are the different types of piles
a. Precast - Produced off site and hammered into the ground
b. Bored (Insitu) - The soil is excavated and concrete is poured in
c. Secant - Interlocking piles to provide a waterproof structure
d. Sheet - A deep trench is excavated and concrete is poured in
What are the methods of installing piles?
a. Dropping weight (displacement method)
A weight about half the pile is raised and guided to drop on the pile
b. Vibrating method (displacement method)
Vibration is prodcued by an electrically powered tool attached to the pile head which can graulise the soil
c. Augored boreholes (non- displacement method)
A auger can be used to drill a borehole which can then be later filled with steel cage and insitu concrete
What are the different ways that the piles transfer their load to the surrounding ground?
a. End bearing piles - through a low bearing capacity soil to a strong material like rock
b. Friction piles - uses frictional resistance between outer surface and soil
c. Tension piles - resist uplifting forces which could cause the structure to lift from the ground e.g. eartchquakes
What is the difference between bored vs.pre-cast piles?
Bored is used when forming piles close to existing buildings as it has less vibration that a pre cast pile
Precast piles are used when there is soft soil, and they are driven into rock etc
What are the advantages with Precast Concrete piles?
• Can be fast If ordered in advance
• Quality of pile can be controlled
Pre-cast piles can be driven under the water
The piles can be loaded immediately after it is driven up to the required length
What are the disadvantages with Precast Concrete piles?
• Breaking during mobalisation and installation
• They need heavy and expensive equipment to drive
Once the length of pile is decided, it is difficult to increase or decrease the length of the pile afterward.
What are the advantages with Insitu Concrete piles?
• Can’t break when installed
• Additional piles can be installed easily If required
Length of piles can be varied easily.
What are the disadvantages with Insitu Concrete piles?
• Can’t be installed where under ground water has heavy flow
• Installation requires careful supervision and quality control.
Needs sufficient place on site for storage of the materials used for construction.
What is a raft foundation
They are a foundation solution to spread the load of the superstructure over a large base
They are usually used in low load bearing soils
Used for light load buildings (eg industrial)
They can be a solid raft slab or a beam and raft slab (ground beam system and suspensed precast concrete ground floor)
What is a strip foundation (How are they formed)
Strip foundations are used to accept and transfer the load linear structures
They are formed by excavating a shallow continuous trench, which will support the perimeter and internal walls
Suitable for light structural design e.g. houses
What are pad foundations
They work by providing a base for reinforced concrete or steel columns
They spread the load to a layer of load bearing soil below
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 secant piles
Secant piles – interlocking piles are bored to provide a combination of foundations and basement walls.
They go someway in providing a waterproof structure.
What is contiguous piles
A Contiguous bored pile wall is an earth retention system formed by installing closely spaced Bored piles, with a small gap between adjacent piles.
What are retaining walls
They are used to support and retain soils horizontally so it can be retained at two different levels on each side
Retaining wall near to a boundary, it may be subject to the provisions of the Party Wall Act
What is a party wall
In simple terms a party wall divides the buildings of two owners with the boundary between ownerships usually
What is the Party Wall Act
• The general principle of the Party Wall Act is that all work which might have an effect upon the structural strength or support function of the party wall or might cause damage to the neighbouring side of the wall must be notified
• A framework for preventing and resolving party and boundary wall disputes, when one owner of the party wall disagrees with works the other owner is undertaking.
What are Rights of Light
A form of easement to allow an existing building to maintain the same level of light, despite of new developments.
What are the main types of excavation
Cut and fill excavation
The material that is cut or stripped is then re-used elsewhere on the site
Trench Excavation
For services or foundations
Basement Excavation
What is a basement
A storey constructed below ground level
What are the major/ main risks when constructing a basement?
Collapse of excavation
Collapse of existing buildings
Falls from height
Waterproofing failure
What are the 3 main types of excavation to form a basement
Open Excavation
Perimeter Trench Excavation
Complete Excavation
What are the 3 different types of basement construction?
- Retaining wall and raft which consists of a slab raft foundation to serve as the basement floor that
distributes the building load. The basement walls serve as the retaining walls. - Box and Cellular raft which is similar to above however the internal structural walls are used to transmit
and spread loads over the raft and divides the basement into cells. - Piled solution where the main superstructure loads are carried to the basement floor by columns and
transmitted to the ground via pile caps and bearing piles. In this example the basement has numerous
columns passing through it.
What are the main methods of waterproofing a basement?
Tanking
A continuous waterproof barrier is applied to the inside or outside of the basement structure
Drained cavity
Cavities are formed within between the internal and external wall and floor constructions to collect and drain away water entering the basement using a sump and pump