Developing a Methodology for Determining Design and Operating Requirements for Contracting Tunnel Works

Abstract

Directive 2004/54/EC [1] on minimum safety requirements for tunnels in the trans-European road network sets the bases for establishing an acceptable safety level for tunnel users across EU member states. Furthermore, many EU member states enforce stricter safety requirements for tunnels in their territory. The lack of a methodology for determining design and operating requirements for tunnels leads many times to an expensive over-design for tunnel works and thereafter operation and maintenance, throughout the tunnel lifetime without the expected increase in safety levels. In the present paper a methodology has been developed in order to assist all parties involved in contracting tunnel works to establish the optimum design and operating requirements. The methodology combines results of risk analysis with cost benefit analysis in different time periods throughout the tunnel design life. The results from implementing the aforementioned methodology include the optimum set of design and operating requirements for each tunnel under consideration. Concluding, the necessary contribution of each beneficiary to the funding of the different sets of design and operating requirements for certain time periods throughout tunnel lifetime, is soundly estimated and justified. The proposed methodology is an excellent tool since it can be used regardless of specific risk acceptance criteria.