Geotechnical & marine construction projects
We undertake geotechnical and marine construction projects (piling, lateral support, grouting etc) across South Africa and Southern Africa for clients from a broad selection of industries, including mining, oil & gas, transport infrastructure, building construction as well as marine, river and dam infrastructure.
SHEET PILING PROJECT AT MOHEMBO BRIDGE IN BOTSWANA
The sheet piling project, undertaken for the Itinera and Cimolia JV at the Mohembo Bridge in Botswana, included:
- the installation of the original two boxes around the bridge towers and the quay wall;
- the installation and removal of the sheet pile walls on the sides of fourteen piers;
- the installation and removal of three additional boxes around three piers of the bridge; and
- the installation and removal of two sheet piles walls for the fixing of the river banks to the construction sites.
PERCUSSION PILING PROJECT AT TEMBISA MALL
The percussion piling project at Tembisa Mall was undertaken for Tembisa Property Investments (Pty) Ltd and was divided into two parts: a geotechnical investigation to determine the rock profile and the piling project.
The geotechnical investigation took place over a seven-week period and entailed proof drilling the entire site. This included drilling 418 holes (foundation positions), to an average depth of 19m deep, in order to inform the design engineer as to the suitable foundation type for each of the required footing positions. The piling project that followed was successfully completed and handed over to a satisfied customer, within the 12-week contract duration.
N4 KARINA LATERAL SUPPORT
The N4 Karina lateral support project, during which Terra Strata installed lateral support covering an 880m2 area, was undertaken over a ten week period. The permanent lateral support project, undertaken for Raubex, covers the cutting for the N4-Karina interchange just outside Nelspruit. The project scope included the drilling of a combination of 485m of soil nails and 580m self-drilling anchors (SDA). The extremely difficult and irregular geological conditions encountered on site necessitated the spraying of an additional 145m3 shotcrete to fill the overbreak and collapsing materials.
PORT OF EAST LONDON
- Removing an existing 101m long capping beam,
- Excavating 5 870m3 to lower platform,
- Installing fifty 165mm diameter micro piles, seventeen metre deep to protect the platform, as the existing dead-man anchors were rusted through,
- Installing thirty one-metre diameter tubular piles (totally 299,5 ton), vibrated fifteen metres below the existing platform, whereafter the tubes were hammered down into the rock platform,
- Coring a two-metre rock socket in 65MPa rock,
- Vibrating sheet piles to the same level: 141 ton of sheet piles,
- Filling between an old and new wall: 527m3 concrete and 586m3 stone,
- Constructing a new capping beam,
- Pumping 689m3 compaction grouting into the platform through 106 percussion drilled holes to a depth of fifteen metres each,
- Installing ??? 572kN permanent anchors (between 25 and 30 metres) through the newly constructed capping beam, and
- Ancillary works including fenders, bollards, wooden fenders, services and paving.
BROOKLYN APARTMENTS
TRILOGY
92 RIVONIA ROAD, SANDTON
TIME SQUARE, MENLYN
PENGE RIVER BRIDGE
EASTGATE MALL – UNDERPINNING
PORT ALFRED
SUMMIT PLACE BUILDING G, MENLYN
- Drilling 72 soldier and structural piles (750mm diameter) up to 23 metres deep;
- The installation of lateral support comprising of a total of seventy-five 450kN and thirteen 600kN anchors, and 708m2 of 100mm thick gunite.
- Drilling and installing 82 structural piles ranging between 750 to 1 200mm diameter, to a depth of up to eleven metres.
105 WEST STREET, SANDTON
MASEVE SOUTH PORTAL
140 WEST STREET
MTHATHA BRIDGES
SANDTON SKYE
MALL OF AFRICA – LATERAL SUPPORT WALL
PILING TO BRIDGE – N4 HIGHWAY
LATERAL SUPPORT FOR MINE BOX CUT
Drilling for lateral support, including:
- Drilling and installation of soil nails of various lengths:
- 3m x 1733No for a total of 5 199m.
- 6m x 491No for a total of 2 946m.
- 9m x 3No for a total of 27m.
- Drilling and installation of two-metre resin bolts, 486No for a total of 972m.
- Drilling and installation of two-metre Splitsets,168No for a total of 336m.
- Drilling and installation of Cable-lock anchors 33No for a total length of 295m.
- Total metres of installation support equates to 9 775m on 2 914 positions.
Meshing and wetcreting for lateral support, including:
- Installation of 6 732m2 of 50x50x4 diamond mesh.
- 2 347m2 and 340m3 of 25MPa wetcrete application with an average thickness of 150mm.
SDA’s (Spiles)
- SDA’s (spiles) are planned for the hitch area of the box cut.
- Total SDA’s planned: 264No, eight metre deep with one metre protrusion using R38N. This equates to 2 112m of drilling and 13 140 litres of grout.
ENVIRONMENTAL: DEEP GROUNDWATER SEEPAGE CONTROL DRAINS AND BARRIERS
- Line C: Construction of a 233 metre long, ten to 13.5 metres deep cut-off drain:
- The drain was constructed by drilling a series of secant 1050mm diameter piles, backfilled with alternating concrete and drainage material (filter sand) to form a continuous drain.
- The sand filled piles were lined with a geotextile sock which ranged between ten to 13.5 metres deep.
- Extraction wells were installed in various sections along the line comprising a geotextile lined, 19mm stone filled hole with a central perforated pipe.
- Line D: Construction of a 160 metre long by four- to eleven metres deep cut-off barrier and drain:
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- The cut-off barrier was constructed by installing a continuous row of sheet piles to refusal depth up to 11.5 metres.
- A 4.5 metre deep geotextile lined drain was installed in front of the sheet pile barrier and filled with drainage material (19mm stone).
- Perforated extraction points were installed along the drainage line.
