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| Project
Title |
Whitehaven
Harbour Wall Reinforcement |
| Client |
Whitehaven Harbour Commissionaires
|
| Main Contractor |
Ritchies |
| Featured
Products |
Weldgrip Gripforce
® Rockbolts |
|
 |
Whitehaven harbour, Cumbria, on the
North West coast of the U.K. was constructed in the 1700’s. Over
recent years a 35 metre section of the internal harbour wall has slumped,
developing tension cracks along the causeway approximately 1.5 metres
away from the harbour side.
Weldgrip Gripforce ®
fiberglass rockbolts were chosen to reinforce the ground behind the wall
and prevent further movement. The bolts used were 31/15mm (OD/ID) injection
tubes 6 metres in length. They were installed into 120mm diameter pre-drilled
holes angled down at 15° from the horizontal.
The holes were spaced along the wall at 1 metre centres,
each row being staggered at 0.5 metre spacing. A total of 105 were used
on the project. Each rockbolt was fitted with 3 lantern type centralizers,
one at each end and one in the centre. A material sock was fitted to each
tube covering the centralizers terminating at the thread end. Every threaded
end assembly had a 130mm diameter non-metallic end plate and high load
GRN (glass reinforced nylon) nut with a threaded end capacity of 200kN.
All of the rockbolts were fully grouted using a water/cement
ratio of 0.4%. The grout was pumped through the internal bore of each
tube into the sock.
The sock was used to restrain the grout within the hole
from expanding into any breaks or voids along the reinforcement length.
Use of this system minimizes grout loss within the structure where large
voids are expected and forms a wedge locking action in the rockbolt hole.
The tubes was countersunk into the harbour wall by taking
a stone core 300-400mm deep by 152mm diameter at each rockbolt position
prior to drilling the holes.
To maintain the aesthetics of the wall structure, each
stone core was numbered and replaced in the hole from which it was taken
after the bolts were installed. All the drilling and rockbolt installation
work was carried out from a pontoon moored next to the wall in the harbour.
The advantages of using Gripforce
® fiberglass rockbolts were:
- Ease of installation
- Ease of transportation and handleability.
- High tensile strength.
- High corrosion resistance, particularly important
in the wet conditions.
- Use of the sock installation system minimizes grout
loss and forms a wedge locking action in the hole.
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- 620k |
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Weldgrip are also proud to have attained
BBA accreditation and ISO 9001 standards in recognition of our continuing
excellence in Geotechnical products and services. |
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