Analyses & Construction Challenges of Deepest Bored Cast-in-Situ Raker Piling for Bridge Across Volta River, Ghana-Video

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The Volta Bridge is a 300 m railway bridge with five 60 m spans, built across a man-made reservoir in Ghana. A revised seismic code increased the design peak ground acceleration from 0.16g to 0.35g, requiring a complete redesign of the foundations. Engineers replaced the original 2 m vertical piles with more efficient 1.6 m raker piles inclined at 1:5.<br /><br />Construction was especially challenging at piers P2 and P3, where thick sand layers and highly variable rock levels complicated design and installation. Teams coordinated real-time site assessments with designers in India, revising pile designs when rock levels differed significantly. The marine works required temporary platforms, long steel liners, repeated vibro-hammer and rotary-drilling operations, rock socketing, reinforcement cages up to 76 m long, and tremie concreting.<br /><br />Despite difficult logistics, liner refusal, and soil instability, the optimized raker-pile solution reduced quantities while meeting lateral-load requirements. The project highlighted the importance of adaptable design, close coordination, and construction-stage validation.

Keywords

Volta Bridge

railway bridge

raker piles

seismic redesign

foundation engineering

Ghana reservoir