57
December 2013
CONSTRUCTION WORLD
Specialist Contractors or Suppliers
B
Piling for Nyalazi River Bridge
S
tefanutti Stocks Geotechnical, a division of Stefanutti Stocks,
was appointed by Namandla Roads and Civils to install the deep
foundations for the Nyalazi River Bridge.
The contract is located in a regionof KwaZulu-Natal whichhas been
historically impoverished by a lack of infrastructure.The newbridge is
located at the Nyalazi River crossing, on the main road P745 between
Mispah and MR 495, in the Hluhluwe/Mtubatuba area.
The project entails the construction of a 45 m long, three span
bridge. The bridge will consist of two traffic lanes and a walkway.
The newly constructed bridge will replace the existing low level, six
cell, precast box culvert that is regularly submerged by flood water.
The two bridge abutments and piers were founded on 21 verti-
cal and 18 raked piles. All the piles were installed utilising 1 180 mm
diameter Bauer temporary casings and 900 mm diameter galvanized
permanent casings. The pile holes were formed using a 20 t metre
torque, Casagrande B200 auger piling rig to depths ranging between
4,5 m and 10,3 m in highly variable soil and rock drilling conditions.
This project forms part of the KwaZulu-Natal Department ofTrans-
port’s special projects. These projects focus on the improvement of
infrastructure in rural areas, which is accomplished by providing better
access to schools and clinics, better employment as well as business
opportunities for local communities.
Due to the specialised nature of the work not a large number of
local labourers were employed; however, the contractor did liaise and
meet with the local Project Liaison Committee from time to time and
this was seen as an essential facet of the project.
Stefanutti Stocks Geotechnical placed special emphasis on the
Nyalazi River and special care needed to be taken to avoid spoiled
and contaminated water from flowing into the river.
Project OH & S Management System was based on the method
known as Plan-Do-Cheek-Act (PDCA) and was very successfully
implemented by the site team and there were no lost time injuries
or restricted work cases or even near misses reported for the project.
Some of the challenges which were experienced on site included
the drastic rise of the water levels of the Nyalazi River due to rainfalls
upstream in the river catchment area. The required 1,5 m rock sock-
ets which were socketed into much harder rock as anticipated and
independent test on the classification of the rock confirmed that the
rock can be classified as R5 rock as indicated on table 6113/1 of the
COLTO standard specification.
Project information
• Name of project: Piling for Nyalazi River Bridge
• Company entering: Stefanutti Stocks Geotechnical
• Project start date: 3 December 2012
• Project end date: 22 January 2013
• Client: KwaZulu-Natal Department of Transport
• Main contractor: Namanda Roads and Civils
• Consulting engineer: Royal HaskoningDHV
• Project value: R2 728 724
