How far Sanral has come with repairing the N1 sinkhole – 8 months later

The South African National Roads Agency (Sanral) has completed the necessary investigations, performed temporary repairs, and will now start the tendering process for the construction phase of the repairing of the N1 sinkhole near the Flying Saucer interchange in Centurion.

After the tender is awarded, motorists can expect construction time on the project to be around nine months, according to Progress Hlahla, Sanral Northern Region Manager.

TopAuto spoke to Sanral to find out how far the roads agency has gotten with repairing the unexpected sinkhole, eight months after it appeared.

January

The sinkhole in question formed in January 2022 after heavy rainfalls in the area and it affected the emergency lane as well as the left lane of the N1 southbound between Pretoria and Centurion, near the Flying Saucer interchange.

Sanral took notice of the sinkhole and blocked off these lanes with temporary barriers to avoid more potential damage.

In the first and last weeks of February, the roads agency closed off the highway to allow for gravity survey testing across both the southbound and northbound carriageways to determine the true size of the sinkhole and to perform temporary remedial repairs.

Sanral also repainted the road markings into the right-hand emergency lane to retain three lanes instead of permanently reducing the busy route into two lanes and severely impacting traffic.

August

Sanral said it has now completed the necessary investigations into the N1 sinkhole and factored in the results, and it has “decided on the optimum design solution for the remedial works,” said Hlahla.

“Sanral will consider the use of anchored piles to support the open excavation. This solution will ensure that part of the road remains open during construction.”

Currently, only temporary repairs have been carried out to ensure the stability of the carriageway and permanent solutions must still be implemented.

“Sanral will be going out to tender soon for the construction phase of this project,” said Hlahla.

“The estimated period of construction is nine months.”

Hlahla did not confirm the tender amount or when it will be awarded, and it is not yet visible on Sanral’s Open Tenders portal at the time of writing.

According to SA-Tenders, for contracts above R10 million, submissions must be open for a minimum of 30 days, and for below R10 million, usually no less than 14 days.

This means it could still take 10 months or longer before we see the N1 sinkhole disappear.