Sureside was engaged by gorcpa to assess post-storm damage to the torquay surf beach seawall.

damage to the asset appeared to be due to a combination of beach loss and construction detailing in the seawalls original construction.

damage had occurred to the most seaward projection of the seawall towards the shoreline in a convex section of the seawall. intuitively, this pattern of deterioration suggests the formation of a void beneath the seawall footing. this is because a convex section is normally very successful in deflecting wave energy such that overtopping adn scour effects are normally mitigated. however, by projecting shoreward, the first point to experience severe scour is the most convex part of the wall as it is typically founded on the most narrow platform of rock. so if this is the point of weakness, then the most shoreward point is the location most likely to first show distress and movement.

at the time of inspection, there were only limited signs of movement. erosion behind the seawall had already been reinstated. sureside cautioned that the scale of erosion behind the seawall may have been substantially and alrmingly more extensive than had been apparent at first and recommended additional investigation for voids behind the wall. further, the wall may be susceptible to further damage.

unfortunately, shortly after our inspection further storms came through and this led to substantially more damage with erosion behind being extensive and movement in the seawall was now extreme. gorcpa followed the directions of deeca’s consultant to bring in rock to stabilise the seawall. this recommendation is effective in the short term but can cause continued erosion as evidenced in previous seawall damage scenarios. given the vulnerability of the seawall and the frequency of storm events it is considered a sound way forward.

project client: great ocean road coast & parks authority (‘gorcpa’)

sureside client: gorcpa

services: Condition Assessment, diagnostic analysis & technical advisory

location: torquay, south-western victoria, southern ocean, victoria, australia

time period: 2025