P 843 – Holistic assessment of steel and composite bridges according to sustainability criteria
Bridges are designed and built for a long service life. A shift from the decision making based on construction costs only towards life-cycle oriented holistic assessment of highway bridges is to be forced. Here detailed investigations were carried out by using a bottom-up approach on real bridge structures representing typical highway bridges. Results from life-cycle cost analyses, life-cycle environmental analyses and external effects are shown for three different types of highway bridges analysed in variants.
By the results of the analyses on the reference bridges influences of different criteria were elaborated and ex-amined in terms of major or minor influence towards a sustainable development. The analysis of environmental and economic aspects is carried out for the entire life-cycle whereas the processes and material consumptions on site are included. As distinctiveness of the life-cycle environmental analyses also external effects are integrated.
Within the research project maintenance strategies are used which are based on a description of the degradation of bridges and their details. Fatigue due to traffic loading can be crucial for the design of bridges. Here the fatigue resistance for cyclic longitudinal shear loading was tested on push-out tests for an innovative connection.
Different global and national assessment methods are analysed. It is important to distinguish between assessment systems and assessment methods. Especially for external costs a suitable calculation method was selected and a particularly for bridge assessment developed calculation tool was applied. An important result is that analyses are strongly depending from the bridge location in the road network and comparisons for different variants are only carried out for situations with the same boundary conditions. A comparison not taking into account the bridge location is not recommended.
By analysing five reference bridges and a total of ten different variants (different bridge details, maintenance strategies and highway situations) a comprehensive collection of examples is created. Focus is given to quantitative representation of the results and for all analyses consistent life-cycle assumptions and input data are used.
By performing calculations using different maintenance strategies it can be shown that decisions should not be made based on initial costs. An assessment should always be carried out for one bridge location comparing variants over the entire life-cycle for economic, environmental and social aspects.
The research project (IGF-Nr. 353 ZN) was carried out at Institut für Konstruktion und Entwurf der Univer-sität Stuttgart, at Versuchsanstalt für Stahl, Holz und Steine, des Karlsruher Instituts für Technologie, at Lehrstuhl für Metallbau der Technischen Universität München, at Lehrstuhl für Bauphysik, Abteilung Ganzheitliche Bilanzierung der Universität Stuttgart and at Bundesanstalt für Straßenwesen (BASt), Abteilung Brücken- und Ingenieurbau. FOSTA has accompanied the research project work and has organized the project funding from the Federal Ministry of Economics and Technology through the AiF as part of the programme for promoting industrial cooperation research (IGF) in accordance with a resolution of the German parliament.
Only available in german language.
U. Kuhlmann, P. Maier, T. Zinke, T. Ummenhofer, M. Pfaffinger, M. Mensinger, T. Beck, K. Lenz, S. Schneider, M. Fischer, H. Friedrich, R. Kaschner, J. Krieger