The China Roads Bridge Corporation (CRBC) erected beams at the Ksh 177 million Bellevue footbridge at South C, and saved it from destruction while constructing the Nairobi Expressway.
Engineer Peter Mundinia, the Director-General at Kenya National Highway Authority (KeNHA), had assured Kenyans that the footbridge would be spared. However, the one located at General Motors (GM) will be demolished to pave way for the Ksh 62 billion elevated road.
Mundinia added that the superstructure of the Ksh 185 million GM footbridge was constructed using structural steel members which can be reassembled and repurposed at a different location.
The erection of beams at Bellevue and the construction of a shade has allowed passengers to cross Mombasa Road while passing underneath the Nairobi Expressway.
A beam is a horizontal member spanning an opening and carrying a load. The erection of the structural steelwork consists of the assembly of steel components into a frame on site. In a bridge deck, the lightly loaded longitudinal beams are the stringers. The heavier, transverse members are called floor beams.
Large beams carrying the ends of other beams perpendicular to them are usually called girders. Metal girders may be single rolled pieces or, to permit greater stiffness and longer spans may be built up in the form of an L by riveting or welding plates and angles. Concrete girders are also widely used.
For weight reduction, beams of metal are formed as an I or other shape having a thin vertical web and thicker horizontal flanges where most of the strain appears. A beam resists loads applied to the axis through deflection mode.
The processes involve lifting and placing components into position, then connecting them together. Generally, this is achieved through bolting but sometimes site welding is used.
Assembled frames need to be aligned before bolting up is completed, and the structure handed over to the principal contractor.
The Nairobi Expressway project is expected to be completed by December 2021. Motorists accessing the road will pay a toll fee to CRBC.
Facts about Nairobi Expressway
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