Diaphragm Walls for Deep Shafts for the Anchorage of a Suspension Bridge in Africa

For the conventional suspension bridge under construction in Maputo, MZ, the 2 main cables are tied into a massive counterweight of over 100,000 ton on each side of the Bay. This structure is placed in a circular shaft constructed by diaphragm walls of 1.20 m in thickness. With an outer diameter of 50 m, panel depth of 56 m and an inner excavation depth of 17.50 m and 37.50 m these shafts are among the largest presently being constructed worldwide. The depth was defined by the soil conditions, groundwater and the counterweight solution. Insight to the design, construction and excavation, additional foundation works, measurements and soil improvement inside of the shaft are given. The shafts have recently been closed after inside-filling of concrete and homogenous sand in chambers and the erection of the steel construction for the main cables are on their way.