Aids to Decisions for Selection of Process
In view of the selection possibilities as well as the very involved piping-specific bordering conditions and other factors to be taken into account (such as structures, plant growth and traffic), the provision of decision aids that make it possible to choose the best possible structural rehabilitation process for application cases while taking process-technical, ecological, economic and legal considerations into account becomes increasingly important.
The first steps were taken with the "Leitfaden zur Auswahl von Bauverfahren für den Bau und die Instandhaltung erdverlegter Leitungen unter umweltrelevanten und ökonomischen Gesichts-punkten" (guidelines for the selection of construction methods for installing, rehabilitating and maintaining of earth-laid piping under environmentally-relevant and economical points of view) of the German Society for Trenchless Technology (GSTT) [GSTT96] [Stein97m], which will be discussed in greater detail below, as well as the computer-aided selection process presented in [Alldr97]. This latter does not yet contain any economic efficiency points of view.
The newest almost complete computer assisted decision aid system for selecting the most suitable rehabilitation process for a particular application case has been developed by the IfK Bochum, Germany and Prof. Dr.-Ing. Stein und Partner, Bochum, Germany, consultancies.
The aim of this development is to make all the existing rehabilitation processes "in the marketplace" available in an economical and technically useful manner. In this way:
- It takes into account the individual character of each rehabilitation process;
- gathers together all the influencing factors relevant to the decision, and
- takes into account their importance with reference to the local limiting conditions.
By using this tool, future poor planning and its resulting consequences such as over-investment and follow-on costs for the network operator (direct costs), massive nuisances due to noise, dust, traffic deviations and traffic back-ups in sensitive areas (indirect costs) and unforeseen danger potentials for people, ground, groundwater, etc. (ecology) are reduced.