Structures

SSI has responded to the present shortage of structural design capacity in our country and the growth in demand for infrastructure such as building structures, bridges and reservoirs, by providing a complete range of services associated with bridges and structures.  We harness sophisticated computer-based methods for geotechnical, static and dynamic structural analysis and our design staff is experienced in the use of the full spectrum of construction materials, including structural steel, reinforced and pre-stressed concrete, timber and masonry. In this area of expertise, SSI has pioneered several innovative techniques, including jacking of substantial structures under rail tracks with minimal disruption to traffic, incremental launching of bridges along the radius of a sphere and cable stayed incremental launching of bridges of up to 66 m lengths. We have also gained invaluable experience in the design and construction of bridges over undermined ground, where foundations are subject to differential settlement and earth tremors. Scope of expertise: Structural steel and reinforced concrete bridge design Piling design Reinforced concrete retaining wall design Causeway design Culvert design Reinforced concrete water retaining structure design Structural steel designs for shopping complexes Structural frame and load bearing brick work designs for building structures which include schools, hospitals, clinics, prisons, welfare offices and shopping complexes Structural Stability Investigations Site monitoring/supervision and site administration Detailing of these structures utilising the AutoCad package

PROJECTS The Mohale Feeder Road Bridges project, part of the phase 2B Mohale Dam project for the Lesotho Highlands Development Authority in Lesotho. SSI’s work comprised a single lane incrementally launched vehicular bridge, 449 m long and 91 m high,  a single lane incrementally launched vehicular bridge, 308 m long and 69 m high, a footbridge incrementally launched 273 m long and 60 m high. All the bridges consisted mainly of concrete spread footings and hollow rectangular piers. The decks comprised structural steel box girders. We were involved with the structural design of the pedestrian bridge and site monitoring and administration of the construction of the three bridges. The construction period was 20 months despite extreme weather conditions which included floods, snow, high winds and temperature spirals.  Structures Biographies: Anton Mellet has 15 years’ experience in the fields of structural steel, framed building structures, bridges and reservoir design. He has been involved in many structural design upgrading projects, including welfare offices, schools and oil refineries, as well as numerous bridges for KwaZulu-Natal Department of Transport, SANRAL (SA National Roads Agency Ltd) and the Lesotho Highlands Authority. His experience includes project management of building projects as well as site supervision of numerous large bridges on the Highlands Project in Lesotho. Gerrit Visser has 15 years’ structural experience and has been involved in numerous bridge projects varying from pedestrian bridges to large road interchange bridges. He has also played a key role in bridge rehabilitation and bridge management projects. His experience includes project management, design and construction supervision of projects. His Masters thesis highlights the strengthening of structures using carbon fibre plates. Contact details: Anton Mellet Service line Head: Building and Structures Tel: +27 (0) 33 846 1000 antonm@pmb.ssi.co.za Gerrit Visser Service line Head : Bridges Tel: +27 (0) 33 846 1000 gerritv@pmb.ssi.co.za