Design and Geotechnical Studies of Deep Foundations for Bridges in the Peruvian Lowland Rainforest-Paper

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The paper presents geotechnical investigations and deep-foundation designs for five single-span bridges—Yaverija, Primavera, Noaya, María Cristina, and Alerta—along the Southern Interoceanic Highway in Peru’s Madre de Dios rainforest. The studies, conducted in the 1990s, addressed challenging ground conditions and the logistical limits of construction in a remote region.<br /><br />Investigations included boreholes with Standard Penetration Tests (SPT), test pits and trenches, piezometers, permeability tests, and laboratory testing. The profiles consisted mainly of saturated clays and silty or sandy layers. Pile capacity was assessed using empirical SPT-based methods and analytical software, while settlement and pile-group efficiency were also evaluated.<br /><br />Open-ended, driven steel piles were selected for all bridges because they were practical to transport and install under local conditions. Recommended piles were generally 0.30 m in diameter and 8–10 m long, with final allowable capacities of 300–510 kN. Estimated settlements ranged from 2.7–5.6 mm for individual piles and reached 35 mm for groups, within acceptable limits for bridge structures. Static load tests at Yaverija confirmed capacities above the original design values.<br /><br />The studies also identified river scour and runoff erosion as threats to foundation stability and recommended protective and drainage works; some protection was subsequently implemented. The authors conclude that driven steel piles are a suitable foundation solution for the region. They recommend pile-driving and load tests to verify designs and suggest adding geophysical surveys, particularly MASW, to future investigations.

Keywords

geotechnical investigation

deep foundations

bridge design

driven steel piles

SPT

pile capacity

settlement analysis

river scour

Madre de Dios

Peru rainforest