In a joint venture, MPA Consulting Engineers and NME Engineers managed the civil and structural engineering component for the Lebomob 2010 Project. The client was the Department of Public Works and the project was undertaken for the Lebombo One Stop Border Post.

MPA Consulting Engineers is a multi-disciplinary civils consulting engineering firm committed to providing professional services to clients with a focus on maximising client satisfaction.  MPA believes in providing sustainable and excellent engineering solutions to enhance the lives of all South Africans.

The Lebombo Project required the delineation of the international boundary between South Africa and Mozambique to be “adjusted” so that both countries had direct access onto the processing area.  The project scope focused on the improvements to the border post which included:

• Construction of Pedestrian processing building
• Provision of canopy structures & ticketing kiosks
• Provision of cargo processing building
• Onsite sewage treatment facility and ancillary buildings

A number of challenges needed to be overcome during the project.  One of the first challenges faced was that the border post itself is constructed on a steeply sloping site, with the required facilities to be constructed to the north on a steeper sloping rocky site which required significant blasting and earthworks. To the south the slopes become much steeper and are even less suitable for construction.

Says Jyothi Voolla, structural engineer for MPA, “In order to avoid failure of the slope, the solution adopted was to terrace the rock surface while blasting. The width of the terrace was kept to 1.5times the width of the compactor drum.”

Pedestrian processing building

In addition construction was required to the temporary border post – termed Building 139.  The function of this building is to provide services for pedestrians at border crossing.

The structure is a single story steel frame, covering an area of 74.7m x 18m. The roof structure consist of V- shaped three dimensional lattice girders spaced at 7.2 m centers, supported by 219 x 4.5 circular hollow sections. No vertical bracing has been provided. The columns provide the overall stability of the building; 10mm gap joints at 7.2m centers control the horizontal movements. The structure is suitable to accommodate the services within the depth of the lattice girders, supported by the purlins.

The structure is designed to resist forces induced by cyclones, at which steel stresses reach their maximum yield. Roof sheeting to frame required doubling in order to prevent separation.

In addition, Building 139 required the construction of a temporary pedestrian border processing facility during construction of the new Lebombo One Stop Border Post.   This facility is to be converted to a Police Facility once the new Border Post is in operation.

Project B includes the following:

• Building 139:Pedestrian processing building then converted into police station ones the main border post is operational
• VAT canopy’s for VAT offices
• Eastern and western culvert roofs as a shade structures

Targeting Canopy’s

The function of the building is to provide shelter during the processing for vehicles including trucks and busses at the border control.

The building which is 20.2 x 20.4 m on plane and 6,7m high, also incorporates an elevated walkway for inspection purposes. The structure consists of roof trusses spanning between vertical frames made up by 356 x 6 circular hollow sections. Apart from the roof sheeting, side sheeting was also introduced at high levels to hide the lattice girders. The roof bracing and vertical frames provide the overall stability of the building, while additional stability is provided by the frame action between columns and lattice girders. Says Voolla, “The critical load for the foundation design was uplift / horizontal loads. The building motion due to wind gusts was also investigated, as it could cause concern at the level of the elevated walkway.”

MPA Consulting is committed to structuring South Africa.  They pride themselves in making a meaningful contribution to ensure the country and its people continue to progress in the trajectory of growth experienced in the last few years.