AllyCAD Showcase

'Port of East London Quay Wall'

National Ports Authority
Eastern Cape

Owen Hensburg has been with the South African National Ports Authority (NPA) for twenty-eight years, and has survived many industry changes in the last decade.

The NPA is owned and controlled by Transnet and has the government as sole shareholder. The various divisions within Transnet consist of amongst others, Spoornet, SAA, Petronet, and the old Portnet, which has since been split into SA Port Operations and the NPA, and looks after port infrastructure.

"The engineering department within the NPA deals largely with civil engineering and structural building projects and therefore our role as Engineering Technicians has evolved to become that of project managers," explains Owen.

Projects are mostly completed with the help of AllyCAD, while Civil Designer is used for road rehabilitation projects. "In a small port such as ours, there are very few big roads and our road rehabilitation projects are therefore not large," says Owen, adding that as part of the committee for Port Development Planning, they use AllyCAD extensively when working with the Industrial Development Zone (IDZ) areas, and the Port Development Framework Plan.

Strengthening of the West Quay
The strengthening of West Quay was necessitated by the increase in the draft of car carrier ships, and in anticipation of the increased import and export activity by DaimlerChrysler SA in May 2003.

"The 14-metre high quay wall (from foundation to top of quay) required strengthening so that contractors could dredge the river deeper and closer to the quay footing. This was necessary to create more depth for deeper drafted ships to berth alongside the quay."

"The scope of work covered the strengthening of approximately 254-metres of the West Quay. This was done through a combination of rock anchors, and the construction of a reinforced concrete extension to the coping beam overhanging the water by 1,5metres, and 1,2metres in depth. We cast fendering units integrally with the extended cope beam at 8,7m centres, extending a further 2m below the soffit of the cope beam and each 4,5m in length.

"Our in-house contractor, Protekon, was appointed to do the work. They used a purpose made mobile scaffold on tracks to form the reinforced concrete cope beam. Once this was completed, we proceeded to drill 160mm diameter holes at a 30-degree angle through the cope beam, quay wall, and finally, into the rock."

"We then inserted rock anchors ranging from 19-metres to 28-metres in length, into the drilled holes. The porosity of the rock had to be tested in each hole before the anchors were inserted, grouted up, tested and finally tensioned. We installed 41 anchors in total," explains Owen.
  "The quayside extension has been completed, but the dredging activity using a rock grab, will continue until the berthing depth of 10,7-metres has been attained, " says Owen adding that the 254 metre quay wall extension took seven months of construction and cost in the region of R8,4 million.

Dredging Service
Owen elaborates further on the dredging service that the NPA provides. "Currently, we have two dredging campaigns, a summer campaign and a winter campaign. We are allowed access to a designated disposal site once we have acquired the necessary disposal permits."

"We have a sand trap of 20 metres deep, with a 14 metre deep entrance channel, and we need to maintain this navigation area which usually results in approximately 550 000 tons of sand being dredged per year. It is also far easier to dump material than to use it for fill purposes, as this adds to the cost of dredging" explains Owen.

The dredger "Piper" visits from Durban twice a year and the dredging activity is accompanied by hydrographic surveys. This is where a designated person surveys the water's depth with the use of an Echo Sounder and GPS.

Specialised equipment is used to do the lead line soundings, so that the data is collected and input into Civil Designer's Survey & Terrain module. Once all the values have been entered into the program, Owen is able to get an accurate model of the area with exact dimensions and volumes to be dredged.

Conceptual Drawings
The NPA has recently assisted with the conceptual drawing plans for a new car terminal. "The area was previously an old quarry that had been used as a container parking area. The multi level car terminal can house approximately 2 800 vehicles, and has a dedicated road from the DaimlerChrysler factory."

"It also boasts a container area where assembled vehicles are placed in the empty containers in which the car parts arrive, so that the contained vehicles may later be exported. Each 12-metre container comfortably accommodates three vehicles. The conceptual plans of the car terminal were completed with the help of AllyCAD, in accordance with space availability, and the maximisation of traffic flow. I find that the program is incredible and we use it daily to complete our projects."

Owen displays some of his designs in order to illustrate the scope of these projects, and judging from the pride and enthusiasm that he exudes, it is clear that he wouldn't trade places with anyone else in the world.

Block I, The Terraces, Steenberg Office Park, 1 Silverwood Close, Tokai 7945.
Tel: +27 +21 701-1850 Fax: +27 +21 701-1822
Web: Email: