The Observational Method in the rehabilitation of south road access to Ericeira harbour (Portugal)

The Ericeira harbour has an historic relevance, by the amount of goods transported to and from the western Portuguese region, as well as for the rest of the country. By the end of XIXth century, it was necessary to construct a new ramp to access the harbour from the South. This construction included an earth fill and a masonry wall. On May the 2th, 2012, a part of that retaining wall foundation failed and brought down a portion of the earth fill. The geotechnical studies to evaluate the hazard of this abutment failure made before that accident did not foresee this might happen. The design of a new structure as fast as possible to mitigate more damages was determined by the need to use the access to get to a touristic beach and part of the harbour facilities near the shore and the possibility that the remaining abutment may also fail and cause damage to the buildings and infrastructures located above it. Since the geological and geotechnical data available were limited to conceive such a project in a short time frame, it was decided to complement such solution with the implementation of the Observational Method. This would allow improving the project during the construction, with the help of observation and monitoring, and thus achieving the best solution possible for the problem. This paper will enlighten some aspects related to this process and discuss the final solution constructed.