Julia Denny Dimitriou
1 minute read
5 Jun 2009
00:00

That sinking feeling no more — dip in N3 is fixed

Julia Denny Dimitriou

IF you have had that sinking feeling as you drive over the pronounced dip in the southbound N3 highway, just after the Hilton on-ramp, you’ll be glad to know that it has been repaired. ...

IF you have had that sinking feeling as you drive over the pronounced dip in the southbound N3 highway, just after the Hilton on-ramp, you’ll be glad to know that it has been repaired.

A spokesman for the South African National Roads Agency Limited (Sanral) said that two lanes of the highway were closed yesterday while its routine road maintenance contractor, Superway Construction, carried out temporary repairs to the road surface. Permanent repairs will be done later.

The spokesman said the dip was caused by subsidence related to the pipe-jacking operation being carried out underneath the highway by Esor Limited, a geotechnical and civil engineering contractor.

“Rocks removed from the path of the pipe caused a small cavity above the jacked pipe, which then resulted in isolated subsidence. We used a dynamic cone penetrometer to confirm that there are no other voids, which could result in further subsidence,” he said.

Esor is installing a new concrete drainage pipe under the N3 for SANRAL because the existing galvanised steel drainage pipe culvert is corroded. The culvert diverts stormwater from Hilton into a stream on the north side of the highway. The work is expected to be completed in August.

Pipe-jacking involves the use of sophisticated equipment to push sections of pipe into place underground with minimal impact on surface activities.

juliadd@witness.co.za