I chose to document the excavation and the piling process of the foundation system used in
the 1 Featherston Street Project. I also, documented the foundation system used for the
cranes which is part of the construction phase of the project and appeared to be similar to
the piling process.
12 Piles are to be casted on-site to
increase the bearing capacity.
They are casted on-site due to the
substantial size of the piles.
The pile I explored is shown on the
left, which was 26m deep and 1.5m in
Every pile varies in depth due to
uneven bearing capacity of the
Once the hole is drilled, the steel casing is
placed into the hole as a temporary formwork
and to maintain the form of the hole.
After the steel casing is placed, the reinforcing
cage is craned into place.
Shows Tremie Tube getting placed into the hole. This is used to
pour concrete in due to the substantial size of the hole. The Tremie
Tube has to be placed right down to the bottom of the hole in order
to get the concrete right down to the base of the pile. A funnel is
placed at the top of the tube in order to make the pouring process of
the concrete easier.
Shows the pouring of the concrete process. 6 trucks were used to pour the concrete for one pile.
Polymer liquid is placed into the hole to help set the
concrete and to bind the soil on the edges of the
As the concrete is poured it overflows and as a
result, drainage system has to be placed to pump the
Once the concrete is poured to the depth specified,
the steel casing is lifted off.
After the casing is lifted off, another reinforcing cage
is placed carefully in position. This allows for further
construction above the piles.
Image on the right shows the finished pile.
This is exactly what has been done on-site
as shown in all the images. However, the
4th process which involves feeding
bentonite was not mentioned.
The structural engineer checks all the
reinforcing bars and cages in order to
ensure that they are constructed properly
and as specified. The structural engineer
also, checks a report on the concrete to
ensure the crushing capacity is complied
and as determined in the specifications.
The geo-tech engineer ensures the right
depth is created for the piles and the
architects ensure that the construction
phase is done as specified.