CVEN2101 Study Notes
Trimester 3, 2019
EXCAVATION
• Excavation is the process of removing soil or rock from a hole/cavity using
tools and machinery
• The excavation process is typically as follows:
o Removal
o Loading
o Hauling
o Dumping
o Compaction
o Filling
• Certain issues pre-excavation that must be considered by engineers:
o Demolition and Condition surveys
o Site establishment
o Waste management
o Contamination
o Stormwater and sediment control
o Materials handling
• Trafficability is the ability of a soil to support the weight of loading or working
machinery whilst on-site
• Loadability is a qualitative measure of the difficulty of excavating and loading
soil
• Soil swell is the increase in volume which occurs after excavation
• Freeze-thaw processes and the presence of moisture can increase the
potential of slope failure surrounding an excavation
• Engineers must consider that the density of soil is different in-situ compared
to post-excavation; this should be agreed upon with subcontractors
• Bank is rock/soil whilst in-situ, whereas loose is material that has already
been excavated
• Shoring is a technique used to reinforce the inside walls of an excavation
• Common methods of shoring include:
o Soldier pile
o Pressure/chemical grouting
o Soil nails and Shotcrete
o Sheet piling
o Hydraulic shoring
o Pneumatic shoring
o Timber/Aluminium
• A slurry wall is a permanent shoring system which is expensive to install
• Piling involves drilling boreholes to be filled with concrete in order to surround
an area to be excavated
o At high depths, anchors can be used to resist the bending moment
impacted against the pile
• Excavations should begin from the section with the highest natural elevation
in order to improve efficiency and minimise falling dangers
, • General site management requirements:
o Access to the site should be made wide enough for all
trucks/machinery to enter
o All truck loading and storage of materials must be conducted within the
site at all times
o Toilets should be placed as close as possible to outside access so that
they can be serviced regularly and easily
o Minimum of one skip bin should be allocated to every block
o Cranes and similarly large machinery should be placed so as to not
interfere with transport/loading vehicles
CONCRETING AND FOUNDATIONS
• Formwork is used as a mould within which to pour concrete
• All materials arriving on-site should have tags identifying which part of the
final structure they should belong to
• Footings are reinforced concrete piles built directly into holes excavated from
the ground, forming the base of a structure
• Steel reinforcements are added to concrete structures at points of tension
• Concrete is a mix of cement, water, fine aggregate (typically sand) and
coarse aggregate (gravel)
• Concrete generally reaches full maturity after 28 days, with a typical strength
of around 25-35MPa
• The three most favourable properties of concrete are:
o Strength
o Workability
o Durability
• Steel reinforcement bars are named with their grade (i.e. N, R) followed by
their diameter in millimetres
• ‘SL’ is a grade of mesh bars (which are produced in matrix formation)
o These are named as: SL-9-2 where ‘9mm’ is the bar diameter and ‘2’
represents a 200mm*200mm spacing in the matrix
• On reinforcement design plans, cog represents the length of anchorage
whereas lap is the length of reinforcement overlap between multiple bars
• Stirrups (often known as ‘ties’) are rectangular shaped reinforcements that
hold together other bars and support the structure in shear
• Space allowances for recesses and services must be made in the design of
concrete slabs
• Trench mesh comes in a prefabricated formation of these separate bars
• Curing is the application of moisture to finished concrete to improve the
durability and strength of the concrete
• The finishing of concrete involves three processes:
o Screeding involves levelling off the concrete and forcing the bleed
water to leave the surface
o Floating is performed with a wooden trowel in order to embed the
aggregate
o Trowelling is performed with a steel trowel to provide wear resistance
and an aesthetic finish
• Concrete is often vibrated straight after pouring in order to avoid
honeycombing and concrete cancer
Trimester 3, 2019
EXCAVATION
• Excavation is the process of removing soil or rock from a hole/cavity using
tools and machinery
• The excavation process is typically as follows:
o Removal
o Loading
o Hauling
o Dumping
o Compaction
o Filling
• Certain issues pre-excavation that must be considered by engineers:
o Demolition and Condition surveys
o Site establishment
o Waste management
o Contamination
o Stormwater and sediment control
o Materials handling
• Trafficability is the ability of a soil to support the weight of loading or working
machinery whilst on-site
• Loadability is a qualitative measure of the difficulty of excavating and loading
soil
• Soil swell is the increase in volume which occurs after excavation
• Freeze-thaw processes and the presence of moisture can increase the
potential of slope failure surrounding an excavation
• Engineers must consider that the density of soil is different in-situ compared
to post-excavation; this should be agreed upon with subcontractors
• Bank is rock/soil whilst in-situ, whereas loose is material that has already
been excavated
• Shoring is a technique used to reinforce the inside walls of an excavation
• Common methods of shoring include:
o Soldier pile
o Pressure/chemical grouting
o Soil nails and Shotcrete
o Sheet piling
o Hydraulic shoring
o Pneumatic shoring
o Timber/Aluminium
• A slurry wall is a permanent shoring system which is expensive to install
• Piling involves drilling boreholes to be filled with concrete in order to surround
an area to be excavated
o At high depths, anchors can be used to resist the bending moment
impacted against the pile
• Excavations should begin from the section with the highest natural elevation
in order to improve efficiency and minimise falling dangers
, • General site management requirements:
o Access to the site should be made wide enough for all
trucks/machinery to enter
o All truck loading and storage of materials must be conducted within the
site at all times
o Toilets should be placed as close as possible to outside access so that
they can be serviced regularly and easily
o Minimum of one skip bin should be allocated to every block
o Cranes and similarly large machinery should be placed so as to not
interfere with transport/loading vehicles
CONCRETING AND FOUNDATIONS
• Formwork is used as a mould within which to pour concrete
• All materials arriving on-site should have tags identifying which part of the
final structure they should belong to
• Footings are reinforced concrete piles built directly into holes excavated from
the ground, forming the base of a structure
• Steel reinforcements are added to concrete structures at points of tension
• Concrete is a mix of cement, water, fine aggregate (typically sand) and
coarse aggregate (gravel)
• Concrete generally reaches full maturity after 28 days, with a typical strength
of around 25-35MPa
• The three most favourable properties of concrete are:
o Strength
o Workability
o Durability
• Steel reinforcement bars are named with their grade (i.e. N, R) followed by
their diameter in millimetres
• ‘SL’ is a grade of mesh bars (which are produced in matrix formation)
o These are named as: SL-9-2 where ‘9mm’ is the bar diameter and ‘2’
represents a 200mm*200mm spacing in the matrix
• On reinforcement design plans, cog represents the length of anchorage
whereas lap is the length of reinforcement overlap between multiple bars
• Stirrups (often known as ‘ties’) are rectangular shaped reinforcements that
hold together other bars and support the structure in shear
• Space allowances for recesses and services must be made in the design of
concrete slabs
• Trench mesh comes in a prefabricated formation of these separate bars
• Curing is the application of moisture to finished concrete to improve the
durability and strength of the concrete
• The finishing of concrete involves three processes:
o Screeding involves levelling off the concrete and forcing the bleed
water to leave the surface
o Floating is performed with a wooden trowel in order to embed the
aggregate
o Trowelling is performed with a steel trowel to provide wear resistance
and an aesthetic finish
• Concrete is often vibrated straight after pouring in order to avoid
honeycombing and concrete cancer
