Development of a Decision Support System for Selection of Trenchless Technologies to Minimize Impact of Utility Construction on Roadways

Abstract

The need to replace deteriorating underground utility infrastructure and to expand utility services increases the need for utility conduits to intersect roadways. Open-trench method is currently the most widely used method for installation of underground pipelines and conduits of all sizes. However, open-cut construction has several shortcomings, chief amongst which are: health and safety concerns of workers, surface disturbance, disruption to vehicular/pedestrian traffic and reduction of pavement life. Today, other cost-effective alternatives exist to traditional open-trench construction. These methods are categorized as "trenchless technologies" as they require minimum trenching (excavation). While the benefits of trenchless technology are quite apparent when compared to the conventional open-cut process, it is necessary to carefully evaluate the suitability and appropriateness of trenchless technologies on a project-by-project basis through due consideration of site conditions such as access, right-of-way, geotechnical conditions, etc. Unfortunately, this is not always done due to the lack of a proper evaluation tool that takes into account all the project-specific criteria in a systematic fashion. Consequently, in some instances, the improper use of trenchless technologies has resulted in failures such as heaving or subsidence of the pavement, damage to nearby utilities and facilities, and even fatalities. The primary objectives of this study included the following: a) Development of a Decision Support System for the selection and performance of trenchless technologies for the installation of conduits under roadways; b) Development of specifications for selected trenchless construction methods; and c) Development of a multimedia educational tool to train Indiana Department of Transportation (INDOT) engineers. All these objectives were accomplished. The deployment of the specifications and tools developed as part of this study will be undertaken by the INDOT.