Mega-Size Sewer Lift Station Construction Requires Unique Shoring System

January 2010 Vol. 65 No. 1
Weihe and ESI were able to come up with a modified ClearSpan slide rail system with the addition of sheeting on the deep end.

Like many other communities across the country, Fishers, IN, a suburb of Indianapolis, is in the process of upgrading their aging sewer infrastructure to keep pace with growth and new development. This means replacing miles of sewer lines and manholes, and installing new lift stations. One recent lift station installation project let by the Hamilton Southeastern Utilities Company was unusual due to the sheer enormity and shape of the structure: a poured in place behemoth measuring 52 by 29 feet, with height ranging from 14 to 40-feet.

Weihe Construction of Noblesville, IN, won the job as low bidder by working closely with local trench shielding and shoring distributor, Excavation Safety International (ESI), to design a shoring system that used Efficiency Production’s Universal slide rail system in the exclusive ClearSpan configuration.

Because one side of the structure needed to be poured at a depth so much deeper than the other, the shoring challenges were immense. Working with engineers at Efficiency Production to custom design a shoring system, Weihe and ESI were able to come up with a modified ClearSpan slide rail system measuring 41 by 56-feet square, 20-feet deep, but with the addition of sheeting on the deep-end to reach the 40 foot grade.

“We’ve always said that in theory, ClearSpan can have unlimited size, and this excavation proves that a 50 foot wide pit is not just theory,” said Efficiency Production Vice President of Engineering, Mike West. “That’s possible because we are not encumbered by cross members at any time.”

Dig and push
Efficiency’s Universal slide rail is a component shoring system comprised of steel panels (similar to trench shield sidewalls) and vertical steel posts. The versatile system can be used in a variety of configurations in addition to ClearSpan, such as small four sided pits, or in a linear multi bay configuration to install lengths of pipe over 40 feet.

Slide rail is installed simultaneously as the trench or pit is excavated by sliding the panels into integrated rails on the posts – either double or triple rails depending on needed depth – then pushing the panels and posts incrementally down to grade as the pit is dug, a process commonly referred to as a “dig and push” system.

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