Theoretical Feasibility Study For A Conceptual Approach To Trenchless Replacement Of Culverts
Calderon, Diego R.
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Culvert damage and collapses and their renewal alternatives are a raising concern in today's infrastructure topics. In most cases damages are irreversible; however, in many cases opportunities exist to correct and renew. While conventional open-cut construction brings inconvenience to the public, trenchless technology brings a greener, reliable and more socially acceptable alternative to renew culverts. Considering the strong dependency on highway transportation by the American lifestyle, collapses of culverts in major roads may produce chaotic traffic redirections. To reduce this risk, this research sets a path for a construction and feasibility study on a new culvert replacement method based on an exploratory means; therefore, the specific objective is to design and estimate construction costs for a conceptual trenchless method and determine its feasibility. With a comprehensive literature review for culverts and its engineering principles the author introduces the topic while investigating also on the factors that lead to culvert underperformance. Preceding a general study on cellular sheet piling, the thesis investigates on trenchless technologies and other tunneling methods capable of replacing culverts. The results of the literature search direct the author to develop a new method, potentially suitable for replacing culverts. By combining pipe ramming, pipe jacking, cellular sheet piling and pipe roofing altogether, the method encases the host culvert allowing its later removal. The installation steps are formulated along with a general recommendation on equipment and materials. Advantages and limitations are explained for the process giving the reader a broader view of the proposed method. To start demonstrating the feasibility and other factors for the new methodology, a survey was conducted among the industry which resulted in a positive acceptance. The survey also assists the researcher on topics such as advantages and limitations, feasibility, crew sizes, project durations, and future research recommendations. In an ultimate step towards feasibility and cost estimation analysis, a theoretical detail cost estimation for the proposed methodology is performed. A replacement project on an imaginary two-way road with one single line in each direction is studied and cost estimated. The backbone of the cost estimation is the combination of the results of the survey and information from construction cost databases. In conclusion, this research proved the economic feasibility of the new method by successfully analyzing its direct costs. The direct costs for the proposed methodology seem high; however, they prove the economic feasibility when the social cost savings by trenchless technologies are considered; also, when comparing the estimated costs with other similar technologies, the new methodology resulted less expensive.