Coastal Protection Works, Strand
Coastal Protection Works between Strand Pavilion and Da Gama Street, Strand, Western Cape
Client: Infrastructure Transport for Cape Town, City of Cape Town
Contract value: R 82,000,000
Duration: 20 months
To upgrade the sea wall in Strand to prevent overtopping and minimise sea sand from blowing onto Beach Road.
Scope of Work
The work included:
Demolition of the existing sea wall, existing ablution block and existing bus shelters, and alterations to the existing slip way near the pavilion.
Relocation of an existing rising main, construction of a new 355mm diameter effluent line, and building alterations to an existing pump station. In addition there was 540m of culvert pipes and 80m of concrete portal culverts constructed.
Construction of a new 1.5km seawall along Beach Road, in Strand, with stairs and ramps providing access to the beach, and including the relocation of a sewer pipeline behind the new seawall and repair of existing stormwater outlets.
Removal of existing paving, construction of a raised pedestrian esplanade between the new sea wall and Beach Road, installation of new paving and construction of a concrete sidewalk and steps.
Relocation and protection of existing services and landscaping.
The new seawall was built on foundations comprising a rock fill and pioneering layer, with 1630m3 of concrete making up the wall. The wall was then finished off with 2075 of precast concrete units of two different profiles, comprising L-shaped units and standard copings with a sand blasted finish. The precast units were placed on mass concrete with a levelling layer of sand/cement mortar and grouted in their final position. 1500m3 of reno mattresses were constructed in front of the sea wall to provide support and erosion protection.
Challenges & Successes
The aggressive nature of the sea environment was a constant challenge and working below sea level at times required vigilance to ensure the dewatering and temporary earth bund seawalls provided protection for the workforce and the construction of the works.
The construction of 2690m of water pipelines and 540m of sewer pipelines and stormwater pipes required the diversion of existing live 160 mm diameter rising main and a 200 mm diameter effluent pipelines. However, the pipework was accomplished with success and the network is providing the high level of service expected.