OPEN TRENCH METHODS CHANGED TO TRENCHLESS METHODS AT NO ADDITONAL COST TO THE UTILITY OWNER

摘要

Open trench methods using excavators have been and still are the leading constructionrnmethod today for installing water and sewer mains and can provide consistent low costrninstallations. However there are still several industry concerns associated with thisrnmethod such as the large amount of disruption to local communities, dangerous workingrnconditions and the large amount of fuel consumption. Directional drilling equipment,rnnow being considered a modern day excavator, can now meet the same low cost andrnconsistent installation requirements as open trench without these associated drawbacks.rnThere are benefits for all parties involved when open trench projects are changed torntrenchless, the utility owners save on possible change orders, they have stronger longerrnlasting pipe installed and there is less disruption to the public and all at the same cost asrnopen trench. All the utility owner has to do is pay all unit prices associated with openrntrench method. Benefits for the general contractor include safer working conditions forrnemployees, no return visits, more projects completed, same consistent successes, less fuelrnconsumption, less wear on excavators and an increase in profits. Over several yearsrninformation was gathered from actual bid units and projects completed in many areas ofrnthe country, and it was found that open trench projects have all the benefits listed abovernand more to offer. However the lack of consistently accurate methods using newrntechnology horizontal directional drilling machines or HDD was the general contractorsrnnumber one concern and whether or not the equipment could be used by generalrncontactors to ensure the same success as open trench methods for water and sewer mainrninstallations. These general contractor concerns have been the primary obstaclernpreventing HDD from being used more over open trench in the public works industry.rnThe industry needed a construction process that would come with a full trainingrncurriculum which holds the trenchless crew accountable for the installation and ensuresrnconsistent success, while allowing general contractors entry into the trenchless marketrnand full involvement from the utility owner's inspector. A patented trenchlessrnconstruction process licensed by Advantica named ArrowBore is now being used torninstall water and sewer mains of all sizes and depths with consistent accuracy. Thernpresentation given will provide a discussion of the process and how it fits the needs of thernpublic works and contracting industry. To implement the process it will be necessary tornmake minor changes to existing competitive bid open trench sewer and water projects,rnthese changes will promote trenchless methods while developing the skills required in the trenchless contactor. Detailed information regarding bid evaluations and project designrninformation gathered from actual projects using ArrowBore in St. Louis, Missouri,rnChicago, Illinois, Baton Rouge, Louisiana and Clearwater Florida here in the USA.rnLocal contractors with a modest investment in training and a license will be able tornminimize the use of existing excavation equipment and start utilizing the modern dayrndirectional drilling excavator to install water and sewer lines for cities across the US andrnabroad utilizing the ArrowBore trenchless construction method. The paper will providernproven information that open trench projects have ample funds in the unit price contractsrnto change open trench method to trenchless.