LAUSR

Abstract As State Departments of Transportation (DOTs) explore efficient and economical means to repair and replace culverts, trenchless technologies are increasingly becoming the method of choice. This is because trenchless technologies provide several advantages including eliminating or minimizing the risks and social costs of the traditional open-cut method. DOTs are also faced with the option of using their in-house crew or a specialty contractor. The choice between contractor and in-house crew is considered during the value engineering process. When using their own crew, the DOT may elect to use open cut or an applicable trenchless technology. However, state DOTs have a scope and dollar limit above which they must award a project through competitive bidding. It is therefore important for DOT’s to determine if there is an adequate number of projects below this limit and scope to maximize the utilization of the equipment. Culvert installations completed by ODOT’s own crew using an acquired horizontal auger boring (HAB) machine and the open-cut method were observed, and data collected. The research analyzed the direct costs and social costs for both HAB and open cut, and the payback for the acquired HAB system. The findings in this study indicate that the HAB technique is an economical alternative over open cut for replacement of culverts with depth of cover exceeding three feet. The findings also show that both HAB and open cut had a negative impact on the traveling public during construction; however, the impact of open cut was considerably higher. This paper can serve as a platform for other agencies to determine if it makes economic sense for them to acquire trenchless technologies.