Karu–Jikwoyi Dual Carriageway
9.6km of dual carriageway with 14 box culverts, solar street lighting and pedestrian infrastructure, delivered through two rainy seasons without a single lost-time incident.
The engineering challenge
The corridor crosses three seasonal streams and carried live traffic of 22,000 vehicles daily. Conventional phasing would have closed the route for eight months — politically and economically unacceptable — while lateritic subgrade CBR values as low as 4% ruled out standard pavement design.
How we solved it
We ran night-shift half-carriageway construction with precast box culverts cast off-site, cutting stream-crossing closures to 72 hours each. The pavement was redesigned as cement-stabilised subbase over geogrid, lifting effective CBR above 30% and shaving ₦640M off the earthworks bill — savings returned to the client against solar lighting.
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