Chinese crews, with the help of German supervisors, are building what will be Africa’s largest suspension bridge, in Mozambique. Slated for completion in the third quarter of this year, the 3,003-meter-long, $725-million Maputo Bridge and Link Roads project will strengthen north-south connections and provide a new road link to South Africa and Swaziland.
Chinese contractor China Road and Bridge Corp. (CRBC), with German construction supervisor GAUFF Engineering, is constructing the suspension bridge, which spans the entire entry area of the international seaport of Maputo, Mozambique’s capital city. The main-span suspension bridge is 680 m long and stands 60 m above sea level. China Exim Bank is financing the project; Portugal, which had earlier expressed interest, withdrew because of the 2007-08 financial crisis.
Flanking the Maputo-Katembe Bridge are the South Access Bridge, a 1,230-m-long precast-concrete structure, and the North Access Bridge, a 1,093-m-long cantilevered bridge, says Joern Seitz, GAUFF’s director for project. The North Access Bridge will connect the Maputo-Katembe main-span suspension bridge to access roads in the capital.
Seitz says the geological conditions pose a challenge due to their various strata, including imported fill and tidal silt in the upper layers and fine sand and clay in the lower layers. The groundwater level is shallow due to its proximity to the bay, he notes.
CRBC installed diaphragm walls for the anchorage shafts and bored piles with diameters of up to 2.2 m as deep as 110 m. The conditions required pile loading tests, which were carried out with embedded hydraulic cylinders. CRBC carried out large-scale tests to determine the friction of the shafts, driven reinforced-concrete piles and sheet piling.
In order to achieve subsoil stabilization, the contractor is using cement- stabilized earth piles and high-pressure grouting below the diaphragm walls, Seitz adds.
The suspension bridge’s design also takes into consideration the possibility of a mild earthquake and the load forces of strong winds, based on 37 years of data collected by the Meteorological Bureau Maputo. The bridge has been designed for 10-minute wind speeds of 48.5 m per second at deck level, says Seitz.
Further, the project team is faced with building—in just 36 months—three types of structures according to different code specifications. Either Chinese, South African or European construction specifications are being applied 10 different aspects of construction, says Bai Pengyu, project manager for CRBC.
“The construction requires special concrete, due to seawater exposure, and development of environmental-friendly concrete, with local cement and fly ash from South Africa,” Pengyu says.
All the steel elements and cables are fabricated in China and shipped to Maputo. “Due to the restriction of storage area at the harbor of Maputo, the steel box girders have to remain on the vessel and will be lifted from there to the final bridge position,” says Pengyu.
The bridge, which will be tolled so that Mozambique can repay the Chinese loan, is expected to accommodate 16,000 passenger car units (pcu) by 2020, which will increase to 40,000 by 2034. The bridge is on a highway that currently accommodates 10,000 pcu.
CRBC also is constructing the 115- kilometer road between Maputo and Ponta do Ouro, a popular tourist destination in southern Mozambique. Further, the existing road between Ponta do Ouro and the South Africa border will be expanded to create a shorter transportation link between Maputo and Durban, the second-most important manufacturing hub, after Johannesburg, in South Africa.
Another 65-km road will link Bela Vista, which lies halfway between Maputo and Ponta do Ouro, with Boane, opening a reliable route to Mozambique’s neighboring country, the kingdom of Swaziland. At least five existing bridges will be rehabilitated across the Rio Tembe, Rio Changane, Rio Mahubo, Boane and Umbeluzi rivers.