CESA Aon 2019

PROJECTS GREATER THAN R250 MILLION: MOUNT EDGECOMBE

T he improvement of the Mount Edgecombe Interchange was a successful combination of planning and innovative engineering design to resolve the difficult problems that were being experienced with traffic volumes through the interchange, which exceeds 1 178 500 vehicles per day. A creative geometric solution which took the form of a four level, full free flow interchange that caters for high traffic volumes, overcame the severe traffic congestion and the physical space constraints of the interchange. Of the six newly constructed bridge structures, the two incrementally launched viaducts aesthetically dominate the interchange skyline crossing the N2 at heights of 26 m and 18 m respectively.

PROJECT TEAM Client

South African National Roads Agency SOC Limited Eastern Region KZN Department of Transport

Consulting engineer

SMEC South Africa

Civils Contractor

CMC di Ravenna South Africa

Geotechnical

Franki Africa

The top viaduct has a deck length of 947 m which not only makes it one of the lon- gest in the Southern Hemisphere, but the longest bridge structure in South Africa. The design, because of space restraints, further included three different types of retaining wall structures, ranging in heights up to 6 m, as well as 8 m vertical fill retaining structures (Mechanically Stabilised Earth Walls - MSEWs), ranging between 4 m and 18 m in height. A total of 402 innovative full-length friction piles ranging from 15 m to 38 m in

length, and providing a cumulative length approaching 11 km, overcame the poor founding conditions for the bridge struc- tures. Similarly, the provision of grids of rock columns, with platforms of crushed aggregate, overcame the poor founding conditions for MSEWs. The project provid- ed employment amounting to an average of 500 persons per month for the duration of the project. Expenditure for the works, as registered at the time of the Taking Over Certificate, was within the accepted budgeted amount. z

FINALIST

24

CESA AON ENGINEERING EXCELLENCE AWARDS 2019