Name of the Project
N2 Wild Coast Toll Road (N2WCTR) megabridge projects.

Location
The bridges will be built over the Msikaba and Mtentu river gorges, both near Lusikisiki, in South Africa’s Eastern Cape province.

The Msikaba bridge is located on the N2, which connects the Western Cape, Eastern Cape, KwaZulu-Natal and Mpumalanga provinces, and traverses the cities and major towns of Cape Town, George, Gqeberha (formerly Port Elizabeth), East London, Mthatha, Durban and Ermelo. This includes a new greenfield section of 112 km between Port St Johns and Port Edward, including the two megabridges and several additional major river interchange bridges.

Only the new greenfield section of the project will be tolled. None of the sections between East London and Mthatha or between Mthatha and Ndwalane, near Port St Johns, will be tolled. The public participation process for the tolling of the greenfield section of the road is yet to start.

Project Owner/s
South African National Roads Agency Limited (Sanral).

Project Description
The Msikaba and Mtentu bridges form part of the N2WCTR project.

The 580-m-long Msikaba bridge will be the longest main span bridge in Africa – constructed using the cable-stayed method – and the second-longest main bridge span in Africa after the Maputo-Catembe suspension bridge, in Mozambique. With a deck height of 194 m above the river valley, Msikaba will become the third-highest bridge in Africa and the 133rd-highest in the world. The Msikaba bridge cable-stay design will ensure that the construction of the bridge will have no direct impact on the pristine gorge environment almost 200 m below, which is one of the environmental requirements in building the bridge.

The 1.13-km-long Mtentu bridge, which includes a 260-m-long main span, will be one of the longest main-span-balanced cantilever bridges in the world. Only ten prestressed concrete girder bridges worldwide have a main span of 260 m or longer. Reaching heights of more than 220 m above the river valley, it will displace the Bloukrans bridge, in the Western Cape, as the highest bridge in Africa and the southern hemisphere. The 141-m-tall Pier No 9 (equivalent to a 40-storey building in height) will also be the tallest bridge pier in Africa and the southern hemisphere.

Being one of the longest main-span-balanced cantilever bridges and one of the highest bridges in the world makes the construction of the Mtentu bridge a technically highly challenging project. The remote location and local social dynamics add to this complexity.

Potential Job Creation
So far, the Msikaba project has created work for 137 unskilled local labourers and 372 jobs for skilled persons, of whom 190 are locals.

Capital Expenditure
The Msikaba bridge project will cost an estimated R1.65-billion and the Mtentu bridge project R3.5-billion.

Planned Start/End Date
The N2WCTR project started construction in 2011. However, the major greenfield portion of the route between Port St Johns and Port Edward started construction only in 2016.

Construction of the Msikaba bridge started in January 2019. More than 53% of the Msikaba bridge project was completed by February 2022, with completion projected in March 2023.

Provided that there are no significant delays on the Mtentu bridge project, the construction period is estimated to be 49 months, including a four-month mobilisation period.

Latest Developments
The Msikaba Bridge project reached an engineering milestone in April, when the south pylon legs were hydraulically jacked apart.

According to CME JV project director Laurence Savage, the jacking apart of the two legs countered bending at the bases of the cantilever legs, and was conducted using two 150 t hydraulic jacks.

The legs comprise the first 20 m of the inverted Y-shaped pylon, and are built without any lateral support as free cantilevers. 

Once completed, four lanes of vehicles and a pedestrian walkway on either side will pass beneath these legs at the start and end of the bridge deck.

The bridge includes two pylons, each 128 m high, on each side of the gorge. 

The pylons support the bridge deck using a network of 34 cable tendons strung through their upper reaches. These cables then run from the top of the pylons, back into anchor blocks located 100 m to the rear of the respective pylons. 

Each of the four anchor blocks comprises more than 1 600 t of structural reinforced and mass concrete, and extend 17 m – the equivalent of six storeys – into the ground.

Key Contracts, Suppliers and Consultants
Concor Mota-Engil, a joint venture between Concor Construction and MECSA Construction (Msikaba bridge contract); HVA Joint Venture (Msikaba and Mtentu bridge consultants comprising CH2M and SMEC); V3 Consulting Engineers (lead consultant – Ndwalane to Ntafufu and Kulumbe to Mtamvuna river); ERO Engineers (lead consultant – Ntafufu to Bambisana turn-off); Naidu Consulting (lead consultant – Bambisana turn-off to Lingeni); Aurecon Rohm consortium (lead consultants – Lingeni to Msikaba); Knight Piesold (lead consultant – Msikaba to Mtentu); and KBK Engineers (lead consultant – Mtentu to Kulumbe).

Contact Details for Project Information
Sanral project manager Craig McLachlan, tel +27 41398 3200 or email MclachlanC@nra.co.za.