Tunnel Business Magazine

FEB 2018

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TUNNELINGONLINE.COM F E A T U R E S T O RY 2 2 TBM: TUNNEL BUSINESS MAGAZINE // FEBRUARY 2018 It wasn't long ago that microtunnels were somewhat of a rar- e common along the East and West coasts, it may be argued tha en over as the leader in U.S. microtunneling as the result of several recent projects completed for the Ohio Regional Sewer District ) in Cleveland. As part of Project Clean Lake, a multi-billion-dollar consent de- cree program to minimize sewer overflows, the district has under- taken increasingly complex drives in the last few years, includ - ing the first curved drive completed in the and recently culminating with the longest curved drive complete America to date. Background The City of Cleveland and Ohio have long been linked with the environmental movement in the United States. In fact, the infamous Cuyahoga River fire in 1969, which was not a unique in- cident in Cleveland (or other cities in the United States), helped to prompt the landmark passage of the Clean Water Act in 1972. Since that time, Clev egional Sew- er D ) have been actively engaged in sewer upgrades that have led to significant improvement in water quality in the area's waterway 's largest undertaking – Project Clean Lake – is currently underway and involves several tunnel and un- derground construction projects. Project Clean Lake is a 25-year, $3 billion program that will re- duce the total volume of raw sewage discharges from 4.5 billion gal- lons to 494 million gallons annually. When complete, more than 98 percent of wet weather flows will be captured and treated. Project Clean Lake involves several deep, large-diameter tunnels to capture and store excess water entering the district's combined sewer during rain events, but also crucial to the overall operation of the system are smaller diameter connections and conveyance pipes that are constructed via open-cut or trenchless methods. Recently, the district has overseen the construction of pioneer- ing microtunneling projects that are helping to showcase the abili- ties of the method. Midwest First The district's first curved microtunnel was the Dugway West Interceptor Relief Sewer (DWIRS), awarded to a joint venture of Walsh Construction/Super Excavators in 2013. The microtunneling portion consisted of 7,000 lf of 72-in. reinforced concrete pipe (RCP) relief sewer, and 4,000 lf of 48-in. RCP sewer, a total of 17 drives, including nine launch shafts and 11 receiving shafts. At its own initiative, Walsh/Super Excavators JV submitted a value engineering change proposal (VECP) for design modifica- tions to the DWIRS microtunnel portion of the project. The VECP introduced a 700-lf, 72-in. tunnel curve alignment, replacing three shorter straight drives and relocating one structure. Benefits from Midwest Microtunneling Mecca Recently, the Northeast Ohio Regional Sewer District in Cleveland has overseen the construction of several pioneering microtunneling projects. Cleveland's NEORSD Blazes into Uncharted Territories

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