Costa Rica Circunvalacion Norte Project: Lessons Learned from Foundation Drilling-PPT Presentation

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The Circunvalación Norte project is the final segment of San José’s urban perimeter highway and includes Costa Rica’s largest viaduct, extending 2.2 km. Delivered under a design-build contract, it required 359 drilled shafts across 49 foundations.<br /><br />Investigations identified silts and silty clays, volcanic lahars, and layers of lava, ignimbrite, and tuff. A static load test on a 1 m-diameter, 24 m-long shaft did not reach failure at 10,000 kN; the Brinch Hansen method estimated ultimate resistance at 12,056 kN. Pressuremeter tests and load-test correlations informed nominal axial resistance estimates of 4,000–6,000 kN.<br /><br />Construction used dry drilling, water-supported drilling, and casing. Key challenges included groundwater flow, rock sockets, working platforms, spare parts, and delays caused by utility relocation. Crosshole sonic logging identified flaws in 11 shafts, commonly linked to poor tip cleaning or concrete segregation. Tomography cleared 16 shafts, while eight successful grout repairs demonstrated a cost-effective remediation option.<br /><br />Lessons included the value of pressuremeter testing, rapid design approvals under design-build delivery, and experience, suitable materials, and technology. The project also established procedures for managing groundwater, rock sockets, and working platforms.

Keywords

Circunvalación Norte

San José

Costa Rica

viaduct

design-build

drilled shafts

pressuremeter testing

groundwater management

rock sockets

crosshole sonic logging