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Navigating through challenges within the marine infrastructure construction environment

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In spite of major technological advances over the past few decades, it still remains a mammoth task to plan, manage and construct a marine infrastructure project. The process often requires a lot of prudence, even more patience, as well as a very healthy respect for the forces of nature. The marine environment is not only a challenging operational environment for a construction team, but also a very taxing environment for construction materials, making it critical to design and construct structures in such a way that it ensures their durability, whilst still offering a low-cost solution to the client.

“The downside of being a niche marine contractor is that our market is linked to commodity prices, and often projects coming to market are delayed due to price fluctuations, which in turn affect capital expenditure,” says Stefanutti Stocks Coastal contracts director Andrew Pirrie. “Yet, when these projects do come to market, our track record of value engineering, quality production and safe operations often forms the basis of our being awarded projects, even when we are not the lowest on tenders.”

Design & Construct
Stefanutti Stocks Coastal’s experience within the marine infrastructure sector includes the rich heritage of Civil & Coastal, a niche marine contractor that was established in 1994, and that had, by the time it was fully acquired by Stefanutti Stocks in 2009, become well known for its culture of optimising designs.

Early contractor participation in a project, right from project inception, allows for a design to be optimised to suit not only the operating environment, but also allows for the consideration of appropriate construction methodologies, taking the project location and resources into account. The design & construct project delivery model presents a desirable scenario, that can often result in time and cost saving.

Some of the company’s design and construct highlights include the 2004 Saldanha oil jetty berth fender support where an alternative design saw the construction of a “launched” cantilever fender support from an existing caisson on the Saldanha oil jetty berth. This methodology saved Portnet nearly 50% on the postulated scheme by minimising floating plant, and employing launch-type construction and pre-cast systems.

In 2009 the design and construction of a new dock as an extension to the existing Malongo Dock in Angola was undertaken, whereby the chosen construction methodology entailed the driving of tubular structural piles (filled with reinforced concrete) followed by the installation of precast concrete trough beams and precast concrete deck slabs, with in-situ infill marine grade concrete between the deck slabs. “The reason for using precast was that the concrete quality in the region was not up to standard, therefore all precast work was done in South Africa, and then shipped to Malongo,” explains Pirrie. The in-situ infill concrete was cast using Dieci mini-concrete mixer trucks and using stone, cement and fly-ash shipped from South Africa.

In 2013 the installation of mooring and berthing dolphins for Base Titanium Limited in Kenya saw Stefanutti Stocks propose an alternative solution that entailed the use of prefabricated structural steel headstocks in lieu of reinforced concrete platforms. “The headstocks were also utilised as pile guides thus the installation of the raked piles and structural steel headstocks were concluded simultaneously,” says Pirrie. “This methodology translated into savings on cost and time, effectively killing two birds with one stone.”

Since 2014 a joint venture consisting of Stefanutti Stocks Coastal and its enterprise development partner, Axsys Projects, has been undertaking an upgrade to berths 1-4, 13 and 14 of Maydon Wharf that has seen some technical innovations including the implementation of new techniques never used before in South Africa for the installation of anchor piles as well as the in-situ construction of the submerged fender panels for the cope structure. This project was named the winner of the Railway & Harbour category in the 2016 SAICE-SAFCEC Awards.

Construction fleet & mobilisation
In addition to its years of industry experience and seasoned marine experts, a further asset Stefanutti Stocks Coastal is able to offer its clients is the company-owned specialist marine construction fleet. This plant and equipment can be mobilised, even across the ocean, to where-ever it is required. Furthermore, the contractor’s global marine network, allows it to mobilise appropriate equipment from anywhere in the world to projects that are situated in extremely inaccessible locations.

More often than not the required infrastructure, in terms of specialised equipment, plant and expertise is not readily available in many of the developing countries where marine infrastructure construction projects are undertaken.

As a South African-based marine contractor, mobilising for a local site with supporting transport infrastructure that caters for 21st century traffic conditions is not without its challenges.

Mobilising across the ocean, with the accompanying shipping logistics, import and export regulations, and bureaucracy, as well as the long transportation time frames involved, requires precise, long-term planning and a sound logistical strategy.

Stefanutti Stocks Coastal has mobilised to a number of countries, including to Kenya, Sierra Leone, Tanzania, Mozambique, and Angola, yet at times the unforeseen has still occurred. “On one occasion, during an incredibly heavy storm one of our barges, completely kitted out and en route to its project went missing at sea,” says Pirrie. “This would have been impossible to replace at short notice, and the immense relief we all felt, once we had located and secured our high-value asset again, is difficult to describe.”

Currently Stefanutti Stocks Coastal is mobilising its fleet to two marine projects in Africa, both of which require a very different approach to the logistical requirements and construction methods. In the Republic of Guinea, the contractor will be constructing a 1,5-kilometre revetment as part of a greenfield export facility, for Alufer Mining (article on p32). In Kenya (article on p33) it will be constructing an LP Gas off-loading facility for African Gas & Oil Limited (AGOL).

Safety Standards
The marine construction environment requires the application of very strict safety standards, particularly in projects undertaken for private clients across the African continent, where heavy penalties can apply to contractors who operate outside of safety standards (a fine of up to 100 000 US$ for one lost time injury).

In conclusion

“The marine infrastructure construction environment is an incredibly dynamic, constantly changing environment,” says Pirrie. “Even after 25 years in the industry, there is seldom a contract that we undertake that does not provide us with a new challenge, or a new opportunity to find an innovative engineering solution.”

Captions:

  1. An aerial perspective of the Malongo Dock in Angola, a project that was designed and constructed by the company.
  2. The Majahazi Moja Barge with its 180-ton crane positioned next to the load-out platform, where Stefanutti Stocks undertook the design and construction project (including the piling) for a conveyor trestle, a concrete decked load-out platform supporting a shiploader, two mooring dolphins and two berthing dolphins for Kwale Mineral Sands.
  3. The award-winning Maydon Wharf has provided the opportunity for a number of innovative and technical marine construction solutions.
  4. The west mooring dolphin standing proud at the Kwale Mineral Sands Project, for which the project engineers was also WSP Coastal.
  5. The rock revetment construction capability (pictured is an East London project) was a key factor in the award of the project in the Republic of Guinea.
  6. In the marine construction environment a lot of work takes place from self-propelled hopper barges and other flat-deck crane barges. Pictured are two barges that were utilised during a marine reconstruction project undertaken in 2013 at Durban Harbour's Island View Berth 5.
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