INSTALLING STEEL TUBES, SOIL NAILS AND DRILLING VERTICAL BORES FOR A NEW PRIMARY SCHOOL
Project Description
Scope of Works 109 No. Vertical Bores, 169 No. Soil Nails, 411 No. Thick Steel Tubes
Contractor BAM Construction Ltd
Equipment Boart AJ18, Klemm 806
Construction period 3rd August 2017 – 13th October 2017
Leeds City awarded BAM Construction Ltd North East the
contract to construct a two-storey new build primary school
and associated external works at Shakespeare Primary School
in Leeds. Leeds is a vibrant, extremely dynamic and successful
City. The City’s population is growing rapidly, and naturally this
is reflected in an increasing demand for school places. BAM
Construction Ltd awarded Aarsleff Ground Engineering the
foundation works for this scheme, comprising Driven Steel Tube
Piling, Drilling and Grouting of shallow mineworking beneath the
main school building, and Soil Nailing to the car park and nursery
retaining walls.
Beginning on the 3rd August, Aarsleff drilled 109no vertical bores
on a radial grid including casing under the school building with
its Boart and Klemm 806 rigs. Aarsleff then mixed and injected
OPC/PFA grout to the 4500m2 area ensuring that any surface
instability due to the shallow workings, was eliminated.
Aarsleff’s second remit of work included the design and
installation of soil nails which followed a top down construction
with a soil nail spacing of 1.5mX1.5m. Prior to the main works,
suitability tests of 4no positions took place to confirm the ultimate
bond stress used in the design. To facilitate the car park’s
retaining wall, Aarsleff employed its Boart AJ18 rig to install 105no
soil nails of 5.5m average length to the 205m2 vertical wall area.
For the nursery retaining wall, Aarsleff installed 64no soil nails of
approximately 5m in length to the 115m2 vertical wall area. Each
of the R32-280 galvanised epoxy coated bars were fitted with a
head plate and face cladded with a stone filled mesh basket using
local stone to blend with the existing stonework of the area.
Acceptance testing of 2 nails randomly selected from each wall
was undertaken concurrently with the main works to confirm
satisfactory performance at working load.
Aarsleff’s final remit of work included the driven steel tube
piling. Aarsleff utilised its Junttan PM20 rig to drive 411no thick
walled steel tube piles of varying lengths between 3m and 14m.
Aarsleff also carried out dynamic proof load testing and vibration
monitoring during the works. Soil Nailing and Piling works were
completed on the 13th October 2017.
Managing Director Chris Primett said “Working on Shakespeare
School is another great project to add to our growing portfolio of
educational builds and is testimony to the company’s technical
competence and expertise in delivering a multitude of ground
engineering services on one site. To be awarded the Drilling and
Grouting, Soil Nails and Piling works for this scheme is a huge
acknowledgement in our package solutions and our ability to
tailor our services to meet our client’s needs.”
Aarsleff Ground Engineering Manager Dave Evans said:
“This project had its challenges. The site had up to 10 vehicle
movements at any one time from other associated contractors
leading to the requirement of daily detailed planning meetings”.
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