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By Stephen Press
Hometown Weekly Staff
Construction on the Elliot Street Bridge connecting Central Avenue in Needham and Elliot Street in Newton has moved into a new phase. After an initial stage of pre-construction that involved tree trimming, arch repair and erosion control installation, the Aetna Bridge Construction Company has begun more disruptive work. Reflecting the disruption, the bridge was closed to traffic on July 7 and will remain as such until early December, it is estimated.
Among the major repairs occurring along the bridge is the drilling and installation of micro piles. A micro pile is a small-diameter beam that is driven through a structure and directly into the ground. It functions as a support that transfers the load of a structure (in this case, the Elliot Street Bridge) to the earth beneath it.
While the installation of micro piles is particularly well suited to busy areas due to its low levels of noise and vibration, it is also slow compared to other methods of structural support. The act of drilling and flushing a hole for micro pile construction can be slow and laborious – and that’s only the first step of the process. After the drilling has been completed, the bore holes will be filled with steel reinforcements and grouted.
After completing the micro pile placement, the construction company will set up a temporary cofferdam (that is, a water-tight enclosure that is pumped dry to enable construction below the waterline) on the northwest wall of the bridge, where it will continue to work.
While the construction on the Elliot Street Bridge will undoubtedly cause some disruption in the short term, it will also ensure the safety and structural integrity of the bridge going forward.
In the meantime, it will also make for some entertaining eye-candy for construction and civil engineering enthusiasts alike.
For additional progress reports, detour maps, impact analyses and more about the Elliot Street Bridge project, visit http://www.needhamma.gov/index.aspx?NID=4121.
