Failure Behaviour of Cantilever Retaining Walls – Soil-Retaining Wall Interaction
2016 - 2022
The civil engineering industry is increasingly focused on the maintenance of existing structures, with the aim of extending their service life while reducing costs and environmental impact. In Switzerland and Austria, the integrity of cantilever retaining walls along the road and railway network has attracted much attention after destructive tests carried out in 2012 revealed severe corrosion leading to significant loss of the cross-section of the main tensile reinforcement. This damage, located at the construction joint between the wall stem and the base plate, was identified as a high risk of sudden collapse of these walls. A lack of detailed knowledge of the structural behaviour of corroded retaining walls and the earth pressures acting on them has led to considerable uncertainty in the assessment of these structures, resulting in extensive preventive strengthening measures at an estimated total cost of 800 million Swiss francs.
The aim of this project was to improve the geomechanical understanding of cantilever retaining walls, with particular emphasis on soil-structure interaction and corrosion-induced damage. In particular, the evolution of the earth pressure acting on these walls during their service life (from construction to potential collapse due to corrosion) was investigated through an extensive parametric study on a scaled setup, where different initial stress conditions and soil behaviours were investigated.
The results obtained allowed the development and validation of an analytical solution for determining the ultimate load on corrosion-damaged walls and numerical tools to simulate the wall unloading process. The developed model also allowed to investigate the effects of temperature fluctuations in the wall and to provide support to the researchers of the Insititue of Structural Engineering to run hybrid tests.
Based on the improved knowledge gained, a guideline for the safety assessment of locally corroded cantilever retaining walls has been developed in collaboration with the Institute of Structural Engineering. It consists of a multi-stage verification procedure consisting of four different stages with an increasing level of detail.
Funding
Swiss Federal Roads Office and Swiss Federation office of Transport (Grant AGB 2015/029)
Researchers
Dr. David Perozzi
Dr. Balz Friedli (2016-2017)
Publications
Contact
Professur für Geotechnik
Stefano-Franscini-Platz 5
8093
Zürich
Switzerland