EXTENSIVE repair work, expected to take anything up to six months, is required to rehabilitate a sinkhole estimated to be 6m wide, on the median on the N14 (Ben Schoeman highway) south of Jean Avenue in Centurion.
The sinkhole has led to the closure of two lanes, leading to serious disruption of traffic.
A leak in a water pipe crossing the freeway south of Jean Avenue led to the development of the sinkhole on the median between the northbound and southbound carriages. Preliminary geological tests carried out over the past week had shown that plenty of work would have to be done to repair the hole, the Gauteng Department of Roads and Transport said yesterday.
The department’s head of communications, Octavia Mamabolo, said: “We have to fill the underground cavities under the road (the lanes that have been closed off) and reconstruct the section of the freeway affected by the sinkhole.”
Mamabolo said the scope of the remedial work required had already been determined by the department and a tender would be issued within the next three weeks. Meanwhile, the sinkhole had been cordoned off for the safety of the public.
“Due to the close proximity of the sinkhole to the inner edges of the road and the subsidence of the road surface on the middle lane on the southbound carriageway, it was decided that we should close off two of the southbound and one of northbound lanes as a precautionary measure,” Mamabolo said.
The necessity of closing off these lanes was confirmed by the geological tests. Interim measures are being put in place to ensure the safety of road users. The construction of additional lanes to widen the road on the outer lanes of the slow lane will start in the next week to ensure that two lanes are open to traffic in both directions.
Mamabolo said: “The construction of a temporary additional lane to bypass the sinkhole on the southbound carriageway to alleviate the traffic congestion will be completed before the end of July.”
She said the recently resurfaced shoulder lane on the southbound carriageway would be used as a second lane until the construction of the additional lane was finished and opened to traffic by the end of August.
The construction of the additional lane on the northbound carriageway will take longer as it will also include the widening of the Jean Avenue off-ramp on the freeway to alleviate traffic congestion. Mamabolo said considering the extent of the work, technical complexity of the project and traffic and safety considerations, a contract period of between four and six months would be required for completion. A section of Jean Avenue was closed off for about eight months between last September and May for repairs to a sinkhole which measured 25m by 15m.
A number of services were disrupted and traffic was diverted. The rehabilitative work included the reconstruction of road pavement layers and surfacing and reinstallation of the stormwater system.