Replacement Piles for the Houphouet-Boigny Bridge, Cote D'ivoire-Video

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Adrian Mercer presents the rehabilitation of the Houphouët-Boigny Bridge in Abidjan, Côte d’Ivoire, an essential route linking cacao-producing regions to the port. The 1957 bridge required replacement foundations while road, rail and marine traffic remained operational. Because new piles could not extend below the existing piles, the design team proposed four piles beside each pier, supported by jet-grouted columns beneath their toes. This approach improved ground stiffness and bearing capacity, allowing the piles to meet higher loads with less concrete and reinforcement than the reference design.<br /><br />Two preliminary load tests confirmed reduced settlement in piles with jet-grouted bases. Parallel seismic surveys established the depths of the existing piles, avoiding the risk of undermining them. The team then installed 56 replacement piles from floating platforms, followed by 224 jet-grouted columns, with coring and strength tests verifying their dimensions and quality. The ground-improvement strategy reduced concrete use and spoil by approximately 30%, while careful marine logistics enabled construction amid strong currents and heavy traffic.

Keywords

Houphouët-Boigny Bridge

jet grouting

foundation rehabilitation

Abidjan bridge

load testing