South Africa: Construction to Repair N1 Sinkhole in Centurion Completed

The South African National Roads Agency SOC Limited (SANRAL) has announced that construction to repair the sinkhole on the N1 near the Flying Saucer Interchange in Centurion, Gauteng, has been completed.

The repairs to the sinkhole on the N1 come shortly after another sinkhole on the nearby R21 was repaired last month.

The total cost of repairs to the two sinkholes was R424 million, with R280 million spent on the N1 and R144 million on the R21, respectively.

According to SANRAL CEO Reginald Demana, the N1 sinkhole project, which started in September 2023, was 99.9% complete.

“Given the importance of the N1 and R21 to the economy of Pretoria, South Africa’s capital city, the construction work undertaken here was very important. The Flying Saucer is a major interchange, which connects the N1 and R21, so it was critically important to ensure we minimised congestion in morning and afternoon peak traffic.

“One of our major concerns here was the extent of the damage due to the rains at the end of 2021 and early in 2022, and whether the sinkhole might extend further under the N1, which could have led to a total collapse of the road,” Demana said.

He explained that the repairs were a complex piece of geotechnical work.

“Pretoria is a dolomitic area so when it rains a lot, sinkholes develop in certain parts of the city and this was one such case. The sinkhole led to depressions of sections of the N1 and cracks developing on the entire route, so we immediately took measures to assess the damage and start the repair work.

“With sinkholes you never know the extent of the damage until you start excavating and drilling holes and piling in with concrete,” Demana said.

SANRAL was made aware of the sinkhole along the N1 in Centurion at the beginning of January 2022. To prioritise the safety of road users, the agency closed off the affected lanes and redirected traffic.

By SAnews.gov.za.