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Cleaner Technology Projects in Denmark 1997

Environmental Management of a Road Bridge Crossing a Railway

Miljørigtig projektering af en vejbro
Arbejdsrapport nr. 27, 1997, Miljøstyrelsen

Apart from the environmental impacts of the planning and construction of a bridge crossing a railway, the maintenance of the bridge is also described. The bridge is located in Hammerum as part of a new connecting road to the new highway from Herning to Århus.

The decision of location of the bridge and the fact that it has to be a bridge and not a tunnel was settled before this project started. Therefore, the environmental impacts of other alternatives have not been assessed. However, throughout the project period the environmental impacts concerning the location of the bridge have been assessed as well as mitigation measures have been suggested whenever relevant.

The environmental policy of the Vejdirektoratet (The Danish Directorate for Highway Engineering) was part of the overall priority plan.

This project was initiated in the planning phase carrying out a preliminary survey of the environmental impacts of the bridge. The survey was based on a map showing the location of the bridge and art VVM assessment (assessment of the impact on the environment) concerning the construction of the highway from Herning to Århus. The environmental statement has shown that the actual location of the bridge could cause ochredispersion and thereby increase the risk of pollution of the groundwater.

The overall selection of construction principle concerning the environmental impacts in the life cycle phases was evaluated for a concrete construction, a wooden construction and a steel construction, respectively. An overall assessment of environmental effects due to selected environmental impacts was made. The individual environmental effects were weighted by using an environmental score of each effect. The assessment concluded that compared to the alternative constructions, the concrete construction was connected with less environmental effects. The overall survey also concluded that the construction of the bridge and the selected location of the bridge result in health and safety impacts as a consequence of working by a railway which is in function and the selected building materials.

The overall survey has led to a list of environmental objectives at this stage of the project. The objectives are described in a preliminary environmental programme and action plan. The most important objectives were: To reduce the environmental effects due to the consumption of building materials and energy consumption; to reduce the emissions of noise and dust during the construction and maintenance period; and to optimise the safety precautions during construction and maintenance periods.

The survey is in this phase primarily concerned with the environmental impacts of the activities and the consumption of building materials and energy. Focus has been placed on the impacts that would result in the most important environmental effects including health and safety effects.

The aim of the survey was also to select the necessary mitigation measures to reduce the materials and energy consumption, to reduce the emissions and to reduce the health and safety effects. The priority measures were selected by use of a scoring system, which is also described in the report.

The survey points out that the major environmental impacts are: the material and energy consumption, selection of top layer of the road (asphalt), emissions from contractors’ supplies and emissions from asphalt products. The largest energy consumption was found in the production of asphalt. The asphalt also causes the major health and safety effects. Mitigation measures to reduce the energy and material consumption, to reduce emissions from contractors’ supplies and to improve the health and safety during the construction period were suggested. The subjects that need more attention in the design phase were listed. Some of these are selections of asphalt and the minimisation of emissions.

A revision of the environmental programme and action plan was carried out. The action plan at this stage included a detailed description of each environmental target and those who were responsible for each target.

Subjects evaluated at this phase of the process were the energy consumption, alternative top layers for the bridge, and surface coatings for the crash barrier. The environmental targets were described further and a set of demands for the contractors to meet the targets was listed.

The evaluation of three alternative top layers showed that the concrete layer would result in lower environmental effects than the asphalt layer and a layer of a synthetic material. The quality and the traffic security were not included in the evaluated parameters. The overall objectives of Vejdirektoratet regarding quality and traffic security meant that the asphalt layer was selected after all.

The demands to the contractor included requirements concerning documentation of maintenance quality of supplies, requirements concerning use of environmental friendly fuel for supplies and requirements concerning the plan for health and safety. A paradigm for the plan for health and safety was described.

Author/ institution

COWI and Vejdirektoratet

This report is subsidised by the National Council for Recycling and Cleaner Production

ISSN no. 0908-9195
ISBN no. 87-7810-770-9

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