The Msikaba cable-stayed bridge at Lusikisiki in the Eastern Cape is expected to be completed in the last quarter of next year. Now that more than 50% of the concrete for the two 127-m-high pylons has been poured, construction on the bridge’s four massive anchor blocks has moved to an advanced stage, and the project’s intricate deck construction phase is set to commence.
According to Laurence Savage, project director for Concor’s Msikaba, the bridge may be the most complicated structure of its kind ever constructed in Africa. Two identical parts of the bridge, each spanning 290 meters, are being built from the north and south banks of the gorge.
The two halves will meet in the middle of the gorge. Both of them are supported by 17 pairs of cables tied to 127-m-high inverted Y-shaped concrete pylons, one on either side of the gorge. With 17 cables on each side of the gorge, 34 pairs of cables are used to back-stay the pylons into the anchor blocks.
The construction of the round pylon spires as well as the composite steel and concrete bridge deck are the project’s current key focus since the anchor blocks are almost complete and the pylons’ legs, which make up the first 20 m of their construction, are already complete.
At their starting point (the top of the inclined legs), the spires have a diameter of 6 meters. At their highest point, they have a diameter of 4.5 meters. The JV is using a four-level, 15-meter-high climbing formwork system that was particularly designed for the purpose of constructing them. September is the expected completion date for both pylons.
The strong winds that can occasionally occur at the site, with speeds up to 80 km/h, must be taken into consideration when building the bridge deck. A reinforced concrete ladder deck, or deck segment zero, or DS0, is cast into the first steel deck segment and runs for the first 24 meters on either side of the gorge.
DS0 would be slid lateral into place prior to the installation of reinforcing and pouring concrete due to crane access restrictions. By using a free cantilevering method, the remaining segments—DS1 through DS17 on either side—will be installed one at a time. There will be two gantries utilized, one on each side of the gorge, to position the deck segments.
The surface area of each of these huge 160-ton assemblies is roughly equivalent to a tennis court. The 84 t on average hefty deck segments will be launched over the gorge, rotated 90 degrees, lowered, aligned with, and then connected to the previous segments. In the second quarter of 2024, it is expected that the deck’s midpoint will be closed.
Around 70% of the CME JV’s workforce was recruited locally, and it has also helped and identified a significant number of small businesses in the area (about 40 in total), many of which have been contracted as subcontractors and suppliers.
Background
The Msikaba Bridge Project which is expected to be South Africa’s longest cable-stayed bridge upon completion will have a main span of 580m supported by a pair of 127m-tall pylons.
The deck will be 194m meters above the valley floor, making it the third highest bridge in Africa, eclipsed only by the existing Bloukrans Bridge with a height of 216m, and the Mtentu Bridge which, when completed, will be 223m high.
The bridge over the Msikaba Gorge near Lusikisiki in the Eastern Cape forms part of the N2 Wild Coast project being undertaken by the South African National Roads Agency Limited (Sanral).
The Msikaba bridge will require 43 000 m3 of concrete, 2 700 t of structural steel, 1 090 t of cables, and 3 100 t of steel reinforcing. The balance of works contained in the contract includes the construction of 1.5 km of approach roadworks on either side of the bridge.
Reported September 2018
South Africa to construct the second longest bridge in Africa
South Africa plans to construct a mega bridge dubbed Msikaba Bridge which will be the second longest bridge after the Maputo-Catembe Bridge in Mozambique at a cost of a whooping US $5bn.
The South African National Roads Agency(Sanral) confirmed the reports and said the winning bid was a joint venture between South Africa’s Concor and Mota-Engil – a major international construction firm.
The Msikaba Bridge
The Msikaba Bridge, designed by Dissing and Weitling will have a tower-to-tower distance of 580 meters. Maputo-Catembe Bridge in Mozambique will be longer with a suspension span of 680 meters.
The cable-stayed bridge will also become the third-highest bridge in Africa with a deck 194 meters high. This drop is exceeded only by the 216-meter-high Bloukrans Bridge and the 223-meter-high Mtentu Bridge, also located on the new N2 tollway bypass road.
Sanral added that the N2 Wild Coast road project will be a major job creator in an area with an extremely high unemployment rate. Sanral’s direct job creation forecast is 1.8 million man-days or 8,000 Full Time Equivalent (FTE) jobs over the construction period of four to five years.
The concrete structure will have a deck 22.8 meters wide with walkways on both edges and is expected to use some 2,700 tons of structural steel and 2,500 tons of cables. Construction is due to start in February 2019 and will last for 33 months, with initial planning proceedings set to begin in October 2018, according to Sanral.
Sanral awards Msikaba mega bridge contract to Concor Mota-Engil JV
The South African National Roads Agency Limited (Sanral) has awarded the ConcorMota-Engil joint venture (JV) a contract to construct the second of two mega bridges as part of the N2 Wild Coast project.
The US $114.6m bridge project will be erected near Lusikisiki over the Msikaba gorge. The project is expected to commence its construction work in February 2019. However, once the project kicks to start it is scheduled for completion in 33 months.
The contractor Concor Mota-Engil is a JV between civil engineering company known as Concor and an international construction firm by the name Mota-Engil. The bridge will comprise 28 000 m3 of concrete, 2 700 t of structural steel, and 2 500 t of cables.
The height of the deck will be about 195 m above the valley floor, making it the third-highest bridge in Africa. The height of the piers will be 127m and the length of the main span will be 580 m, making it the longest main span constructed by a cable-stay method in Africa.
Meanwhile, construction on the nearby Mtentu river bridge started in January. The US $113.2m tender for that bridge was awarded to a JV between Aveng Grinaker-LTA and European construction firm Strabag in August 2018.
Reported July 2020
Construction of South Africa’s longest cable-stayed bridge in good progress
Construction of South Africa’s longest cable-stayed bridge ‘Msikaba bridge’ is in good progress. This is after construction works were temporarily halted due to the COVID-19 (Coronavirus) pandemic which led to a nationwide lockdown.
Workers on the project are strictly observing social distancing and all the regulations put in place to ensure the safety of workers; Concor Infrastructure and Mota Engil construction a joint venture tasked with the project confirmed.
Reported in September 2021
The Msikaba bridge construction project is now underway
The Msikaba bridge construction project is now underway in the Eastern Cape province of South Africa. According to President Cyril Ramaphosa, the project is set to create 36 000 jobs and produce R4 billion in income for local companies.
Already, R120 million has been spent on small, local businesses. President Cyril Ramaphosa announced this on Thursday during a visit to the bridge’s under-construction foundation in Lusikisiki.
When addressing near the site, Ramaphosa stated that the project would generate between 21 000 and 28 000 indirect jobs during construction and 8 000 direct full-time jobs once completed.
The project has resulted in 28 000 indirect jobs being produced. Considering another 8 000 jobs generated during the project’s lifetime, a substantial number of jobs have been created overall.
The president also claimed that the salary cost would be R720 million. This is with both expert and unskilled workers already on board. According to Ramaphosa, the bulk of the workers would be trained on the job. Locals put up 62% of the 330-person crew on the bridge build. The principal contractor employed 156 workers, while local subcontractors hired 173.
According to Ramaphosa, 600 engineers and support staff will assure a fantastic conclusion during the building process. The cable-stayed bridge should be completed by the end of 2025 or early 2026.
Reported on April 27, 2022
Msikaba bridge construction project’s latest update
The Msikaba Bridge Project continues to chalk up significant milestones. The south pylon legs of the Msikaba Bridge were hydraulically jacked apart this month, marking an engineering milestone for the project.
According to Savage, these two legs make up the first 20 meters of the inverted Y-shaped pylon and are designed as free cantilevers with no lateral support. According to Laurence Savage, the lateral support was put on the sixth lift of the pylon construction after 520 m3 of concrete had been poured to reach a height of 20 m.
Two parallel sets of hydraulic jacks were constructed, and a jacking force of 1 750 kN was delivered to the two pylon legs to counteract the bending moment for the unsupported cantilever legs. To provide the needed force, the two 150t hydraulic jacks were loaded to 90 t, producing 41 MPa of pressure. The jacking was done at 5 MPa intervals, and the structure’s deflections were monitored by dial gauges and surveying.
The punching force on the flat face of the pylon legs caused by the jack load was a critical issue, according to Savage. This also determined the size of the bearing plates attached to the interior of the legs, allowing for force dissipation across the suitable surface area. This prevented any structural damage caused by the loading of the concrete surface. Because the jacks only had a 50 mm stroke, the installations had to be precise – the 41 MPa pressure had to be attained before the jack ran out of stroke length.
Also Read: Construction works on US $4bn Mtentu bridge in South Africa halts
The foundation plates were mounted on the pylon leg structure with 29 mm non-shrink grout, making the stroke length as short as possible. After the lateral support was properly oriented and placed, a grout biscuit was cast to fulfill two purposes. It did two things: first, it absorbed any tolerances in the installation after the original base plate installation, and second, it aided in the removal of the lateral support.
Once the seventh lift was cast, and the legs were firmly linked together, breaking out the grout biscuit relieved strain in the lateral support. Savage stated that the temperature of the pylon structure and lateral support was measured to guarantee an average of 22 °C in order to prevent any unplanned variations in force owing to temperature fluctuations during the casting lift seven-building cycle.
To prevent temperature change movements and any associated changes in prop forces, the lateral support was covered in a 25 mm thick thermal blanket. A two-part mechanism was used to secure the lateral support: the locking ring on the hydraulic jack and the locking ring on the super-shore jack housing. The jacking preparation required three months of planning and study, while the setup took nine days. The actual jacking procedure took less than eight hours from start to finish.
Msikaba bridge construction to conclude in 2024
The Eastern Cape’s Msikaba Bridge deck, which is geographically situated near Lusikisiki, commenced construction in December of 2022. When construction is complete, the 580-meter bridge will span the 195-meter-deep Msikaba River gorge, making it South Africa’s longest cable-stayed suspension bridge.
The estimated completion date is the end of 2024, according to the South African National Roads Agency (SANRAL). The N2 Wild Coast Road (N2WCR) project’s “green fields” portion is supported by the Msikaba Bridge, situated about 23 kilometers east of Lusikisiki. The part of the bridge deck that protrudes over the gorge is where vehicles will drive as they cross from one side to the other.
There are 36 segments overall on the deck, with 18 segments on each side. Each is made of two truss girders and two box girders. It will take 108 trips overall, including four abnormal loads for four boxes of segment zero at the north and south sites, and three trucks are needed for each segment.
The deck’s construction material is made completely of South African steel. The deck parts are being built in Middelburg, Mpumalanga. Once complete, the Msikaba Bridge will be crucial in reducing travel times, connecting the region’s once-separate communities, and opening a business and community-based tourist opportunities for the Wild Coast.
By providing a high-mobility route through a region that is extremely isolated and underserved by road infrastructure, the completed road will reduce the travel time between Durban and East London for heavy freight by three hours. The route will also have huge social and economic benefits and be a catalyst for local and regional development.
