The project will be undertaken by South African firm Raubeck Construction.
The bridge has cameras and sensors that will mechanically enforce axle load limits.
A detailed list of equipment used in road construction.
This is part of the Trans-African Highway, which comprises a network of road projects.
Taj Mall, which opened in 2011, is said to have encroached on the road reserve.
The much-awaited 2km-viaduct still remains a project without a launch date.
The project is aimed at curtailing the number of accidents along the dangerous spot.
The project will be completed in two years at a cost of Sh2.3 billion.
The project is expected to gift Tanzania with its first high-speed railway.
World Kaihatsu Kogyo is finalising work on phase one of the Ngong Road dualling project.