Geotechnical Engineering Online Library

Safety of motorway users in case of a strong seismic event is directly related to the performance of infrastructure elements, especially motorway bridges. Preventive closure until post–seismic inspection may seem as the safest option, but will unavoidably lead to severe deterioration of serviceability, and will also obstruct the operations of rescue teams. On the other hand, allowing traffic on earthquake–damaged bridges without inspection may jeopardize the safety of users and rescue teams. Seismic retrofit is the obvious solution, but the associated costs can be quite substantial. An alternative strategy is to mitigate the indirect consequences of an earthquake, through timely development and implementation of a RApid REsponse (RARE) system. The scope of such a RARE system is to ensure the safety of motorway users, minimizing motorway network closure, and optimizing post-seismic recovery at the same time. The development of such a RARE system requires an effective means to estimate seismic damage in real time. This paper presents an overview of the RARE system and some first steps that were made regarding its pilot application in the Attiki Odos Motorway in Athens, Greece.

The growing demand for public and sustainable transportation in heavily urbanized areas like Singapore requires construction of an increasing number of Metro Lines. Complicated technical challenges are associated with such an activity and settlement prediction models play a key role in assessing the tunnelling-related risk assessments and planning mitigation techniques. Although a significant amount of research has been performed to study the settlements induced by side-by-side twin tunnels, the settlement prediction of stacked tunnelling has been, relatively, limited. In this paper, stacked tunnelling induced settlements are predicted using 2D numerical simulation. The extensive data from the instrumentation measurements collected during the construction of a stacked configuration tunnel in Singapore Downtown Line MRT tunnels have been used to study the validity of the principle of superposition for stacked tunnels. Key observations are presented by comparing empirical, numerical and actual field settlement data. Using the Monte-Carlo simulation technique, the empirical trough parameter is back-calculated to fit the actual settlements observed in Kallang formation. This could be used for future settlement predictions in similar ground conditions.