Project details:

Contract Value: R 4.2 million
Contractor: Chris Africa Civils cc
Contract Period: 4 Months
Completion Date: 31st August 2015
Resident Engineer: Suresh Rampersadh

Client: KZN Department of Transport

Introduction

On Thursday the 2nd of April 2015 a 5m deep x 6m wide sinkhole appeared on main road R33 (P6-3) just 2.8km north-east of Greytown, before Easter weekend.

This was deemed to be an emergency situation and was allocated special priority status by the Department of Transport due to the importance of this road.

Sinkhole on the R33

This however did not deter Nankhoo Consulting Engineers and once we were notified of the problem it was all systems go because the safety of road users was of utmost importance to us. Firstly a detour road was created and the main road was closed to the public. Within 2 weeks of the incident all contract documentation and administration was completed which allowed work to commence on the 24th of April 2015. Designs were drawn up for a cast Insitu concrete barrel culvert in no time at all and construction began.

The sinkhole appeared due to the collapse of the ARMCO structure beneath the road which was a culvert formed using corrugated iron sheets. It is believed that this occurred due to theft of some of these sheets which affected the structural integrity of the structure. This portion of the road was excavated to make room for the new structure. Due to the nature of the ground the foundations had to be mounted on piles which are up to 6m deep. This was then followed by casting of the foundations, floor slab, culvert walls, wing walls and deck. Modifications were made to the stream's flow path to provide a more streamlined flow.


Piling

Casting of Concrete Foundations

There were some challenges over the duration of this project which were slight setbacks. The majority of these issues had to do with maintaining the detour road which was a 2km long dirt road running from the site to Maitland street in Greytown. One incident was an accident which occurred due to bad driving by a medical transport bus. Another occurred during a storm event which resulted in the road needing emergency regrading to re-establish access, but through rain or shine the detour was kept open, dust free, and signage was always in place.

Click on the Youtube video below.

This was all achieved with excellent quality and efficiency by the contractor, Chris Africa Civils cc, who opened the bridge to the public on the 7th of August, just 3 and a half months after construction started and for a total cost of only R 4.2 million. This was a huge relief to the locals and the people who traffic this road often.


Road Moments Before Opening

First user On New Road

We would like to commend all the parties involved as this outstanding performance could not have been achieved without the coordinated efforts between the consultant, the contractor, the community and the client. A safe crossing has been re-established and will continue to serve the community for many decades to come. Nankhoo Engineers are now involved in the inspection of ARMCO structures around the province to come up with innovative ways of preventing this type of incident from occurring again. We are confident that similar results to this project will be achieved during our execution of this task.


Upstream View Of The Finished Structure

Downstream View Of The Finished Structure

- Compiled by: Suresh Rampersadh