Holistic Consideration of the Sustainability on Steel-Concrete-Compo- site Motorway and Railway Bridges

Nowadays, sustainability is a key issue for the design of constructions, especially relevant for bridges with a service life of 100 years and where all the life‐cycle stages need to be considered. Therefore, at the tender stage decision making should no longer be only based on construction costs but on a holistic assessment of sustainability aspects along the whole lifespan of the bridge.

In the European research project “SBRI” and the German research project “NaBrüEIS” a holistic ap‐ proach of the sustainability on bridges has been developed. “SBRI” is devoted to the analysis of realistic case studies on motorway and crossing motorway bridges, while “NaBrüEIS” has the focus on the holistic evaluation of railway bridges. In both projects, environmental and economic aspects were assessed with the methods of LCA (Life‐Cycle Assessment) and LCC (Life‐Cycle Costing) to‐ gether with external effects.

An important difference between the motorway bridges and the railway bridges is the external ef‐ fects due to the traffic interruption, that play a crucial role on the holistic approach of the bridge. In motorway bridges, the external effects relate to the impact on the traffic flow in terms of user costs whereas in railway bridges, the external effects refer to the operation encumbrance costs linked to the operation of the railway net.