VKE Engineers, a multidisciplinary firm of consulting engineers, was recently appointed to design the civil infrastructure for the Umhlanga Ridge New Town Centre, along with Gapp Architects who performed the urban design.

Umhlanga Ridge New Town Centre, situated 20 km north of Durban, is a private development by Moreland Developments (a division of Tongaat Huletts Group), which includes mixed land uses comprising of retail, commercial and residential - with a total planned floor area of 700 000 m².

The planning phase was facilitated by the use of MicroStation GeoGraphics, which allowed VKE to consider numerous layout alternatives in respect of cost estimates, sewer generation, stormwater generation and land use planning.

The New Town Centre covers a fairly large geographic area. A large data set had to be gathered to produce a quality base plan. VKE received information from various statutory authorities and other consultants in various CAD formats. Each design feature (such as proposed roads, stormwater, sewer, etc) was drawn in a separate DGN file and referenced into the design drawings. This method of working proved useful as selected information could be extracted quickly by simply switching on and off reference files. The general layout plan contains 70 reference files from various sources.

The scope of the project included the design of roads, stormwater, sewer, water, earthworks, and co-ordination of the utility services, all designed using GeoPak. After preliminary designs were completed TIN files were created of the roads and earthworks platforms to create 3D surfaces. Virtually all of the town centre, including buildings, bridges, and even sidewalk paving finishes were modelled to produce drive-throughs and photomatch renderings to enable the client and prospective buyers to visualise the completed works.

One of the main features of the New Town Centre is a Palm Boulevard, which includes roads of varying widths and diverging carriageways with pedestrian paved areas, grassed areas, seating areas and trees - all required at varying levels. To design this area as a roadway would have been extremely difficult. A complex contour plan was therefore produced to accommodate roadways, pedestrian areas, seating and stormwater. The Boulevard was then modelled in GeoPak DTM from the contour plan and cross sections and quantities were extracted.

As a result of an intensive investigation, VKE purchased MicroStation, GeoGraphics and Descartes in 1997, and GeoPak in 1998. One of the biggest advantages of using GeoPak was the integration with MicroStation and MicroStation commands. GeoPak Site was particularly effective in designing earthwork platforms. By drawing in required shapes and even loading single value contours from an existing DTM to produce shapes, the most irregular shaped platform designs were made easy.

MicroStation Descartes was used to assess various alignment options through the existing fig tree grove to retain as many existing trees as possible. To check the accuracy of the design and calculate quantities, a 3D surface model of the stair/seating area was created using MicroStation. GeoPak DTM also has a useful DTM tool that was used extensively, including the analysis of stormwater storage volumes. In GeoPak Road, seamless integration with MicroStation was useful for creating alignments in MicroStation. Superelevation shapes were also useful to create accurate roadway surfaces where accurate road design contours could be loaded directly into the DGN file to check for drainage deficiencies.

Bentley Systems South Africa

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