The lifecycle cost concept for implementation of economic sustainability in tunnel construction / Das Lebenszykluskostenkonzept zur Umsetzung der ökonomischen Nachhaltigkeit von Tunnelbauwerken

• Published in: Geomechanik und Tunnelbau 2014-10, Vol.7 (5), p.593-600
• Main Authors: Engelhardt, Stephan, Schwarz, Jürgen, Thewes, Markus
• Format: Article
• Language: English
• Subjects: Economic and legal issues - Betriebswirtschaft/Recht; Lebenszyklus eines Tunnels; lifecycle of a tunnel; Modular-Process-Model; modulares Prozessmodell; Sustainability - Nachhaltigkeit
• ISSN: 1865-7362; 1865-7389
• DOI: 10.1002/geot.201400026

Sustainability denotes careful stewarding of available resources, observing ecological, economic and social criteria over the entire lifecycle. From the economic point of view, it is not sufficient to base a design on construction costs alone. Rather all costs incurred over the lifecycle should be taken into consideration using lifecycle cost estimation. The University of the Bundeswehr, Munich, and the Ruhr‐University, Bochum, have cooperated to develop a lifecycle cost model for tunnels in form of a Modular‐Process‐Model. The concept of lifecycle cost estimation, which is already used as standard in many fields, forms the starting point and is adapted and further developed to suit the specifications of tunnels. In order to implement a structured and transparent procedure for the determination of lifecycle costs, a hierarchic and modular structuring of the overall construction works is first carried out. The modules mostly represent independent units, which are built up in a generally valid manner for comparability. Various processes and attributes are then assigned to the modules, independent of the relevant lifecycle phase. The chosen method of structuring enables modular recording and evaluation of the lifecycle costs. Alternatively, the evaluation can be related to a process or a lifecycle phase. The modular format and the external interfaces also permit an evaluation and optimisation of singular elements. A probability‐based extension of the model is provided to consider uncertainties, using a Monte Carlo simulation. The Modular‐Process‐Model is a lifecycle cost model, which can be used to determine and optimise the total costs of a tunnel in all project phases. This makes it possible to effectively achieve the aims of economic sustainability. Nachhaltigkeit bedeutet einen schonenden Umgang mit vorhandenen Ressourcen unter Einbeziehung ökologischer, ökonomischer und sozialer Kriterien über den gesamten Lebenszyklus. Aus ökonomischer Sicht ist es nicht ausreichend, die Planung nur auf die Herstellungskosten auszurichten. Vielmehr sind alle über den Lebenszyklus anfallenden Kosten mithilfe einer Lebenszykluskostenrechnung einzubeziehen. In Kooperation haben die Universität der Bundeswehr München und die Ruhr‐Universität Bochum hierzu ein Lebenszykluskostenmodell für Tunnelbauwerke in Form des Modularen Prozessmodells entwickelt. Das in vielen Bereichen bereits standardmäßig verwendete Konzept der Lebenszykluskostenrechnung lieferte die Ausgangsbasis un