Lateral pressure-relief by Geotextile Encased Columns (GEC) at piled bridge abutments: two case studies-Paper

Paper

Pdf Summary

The paper examines the use of geotextile encased columns (GECs) to reduce lateral earth pressure on piled bridge abutments in soft soils. GECs are compacted granular columns surrounded by high-strength geotextile sleeves. They support much of an embankment’s vertical load, reduce stresses in the surrounding soil, and provide lateral ductility and drainage.<br /><br />Two projects—one in Brazil and one in Germany—used GECs beneath bridge approach embankments to protect existing reinforced-concrete abutment piles from asymmetric lateral pressure. In Brazil, an 8 m embankment was built over 5–8 m of soft clay. Monitoring recorded horizontal soil movements, total pressure, and pore-water pressure. Effective lateral stresses on the piles were estimated at 30–60 kPa, less than half the levels expected without GECs.<br /><br />In Germany, GECs were installed beneath a 7 m approach embankment over soft clay and peat. A reinforced group of columns was placed beside the abutment to provide additional pressure relief. The maximum measured total horizontal stress was about 40 kPa—below the 50 kPa design limit and less than half the predicted pressure without the GEC group.<br /><br />Monitoring in both projects broadly confirmed the design assumptions and showed that the systems performed as intended. The authors conclude that GECs can effectively reduce lateral pressure on adjacent piles while also supporting embankments and controlling settlement, making them a practical solution for bridge approaches on soft soils.

Keywords

geotextile encased columns

GECs

lateral earth pressure

piled bridge abutments

soft soils

bridge approach embankments

embankment support

lateral stress reduction

soil settlement control

pore-water pressure