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BEST
PR
O
JECTS
76
CONSTRUCTION WORLD
DECEMBER
2015
Professional Services
C
Project information
• Company entering: Hatch Goba
• Client: eThekwini Municipality
• Project start date: March 2011
• Project end date: July 2015
• Consulting engineer: Hatch Goba
Hatch Goba and SANRAL have been
collaborating successfully for a
number of years on such flag-
ship projects as the Gillooly’s Inter-
change in Johannesburg, one of the largest
and busiest of its kind in the Southern
Hemisphere. Hatch Goba was originally
appointed by the South African National
Roads Agency (SANRAL) in 2009 to complete
the detailed design and relevant documen-
tation for the extensive upgrade of the inter-
change. Construction commenced in March
2011 and was expected to be complete at
the end of July 2015.
Umgeni Road has been a major trans-
port hub for decades, and has seen consid-
erable urban development over the years.
This meant that a major consideration was
to minimise traffic disruption during the
construction phase along the N2 and M19
major routes. Another constraint was posed
by the Umgeni River, along with existing
commercial and residential areas that had
to be accommodated.
To overcome these challenges, two
directional ramps were built by means of the
incremental launch construction method.
While this by itself is not new, having
to design and construct using extremely
tight radii on a global curve was a com-
plex process.
This entailed the entire bridge deck
being built from one end of the structure,
as opposed to the traditional segmental
construction method where the bridge is
built one span at a time. The application of
this innovative technology had a substantial
impact on the construction requirements, as
well as minimising traffic disruption.
The 20-m-high elevated casting yard,
combined with the stunning sight of the
two incremental launch bridges being
constructed at the same time and crossing
each other, was a first in South Africa and
attracted a lot of attention.
The three bridge decks over Umgeni
Road were designed to include precast
beams to minimise disruption to traffic
during construction. Twelve 30 m and twen-
ty-three 20-m-long beams were constructed
off-site and erected during overnight road
closures. The remaining bridge decks were
cast in situ.
Particular attention was paid to the
aesthetics of the concrete structures during
design and construction.
The bridge pier heads were designed
to have elegant and fluted shapes. The
excellent quality of the concrete finishes
produced has enhanced the appearance and
Umgeni Road Interchange Project
durability of the structures on this project.
The overall bridge works were 1 200 m
long, with a surface area of 14 000 m
2
. The
roadworks alone comprised 56 000 m
2
of
asphalt, while the bulk earthworks totalled
100 000 m
3
of cut material and 200 000 m
3
of fill material.
Another major challenge was posed
by the fact that a large quantity of existing
services not only had to be relocated, but
had to be searched for and identified. These
ranged from electricity, Transnet and water
reticulation to sewerage and telecommuni-
cations infrastructure. This was an excep-
tionally demanding and challenging process.
Hatch Goba monitored the project
continually to ensure correct procedures
were followed. This was in order to avoid
negative impacts on the environment, such
as extensions of construction time on the
project, materials used and product wastage
or disposal.
Concrete trucks were returned to the
Roadhouse plant in the Umgeni Area to
release any extra concrete on a daily basis so
as not to leave any material behind on-site.
eThekwini Municipality undertook monthly
checks/audits to ensure the impact on the
environment was kept to a minimum.
The completed Umgeni Interchange
upgrade project has significantly alleviated
traffic congestion by allowing the free flow of
about 14 000 vehicles during morning peak
hour and about 16 000 vehicles during after-
noon peak hour.