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Aluminum structural plate pipe drops in to complete causeway.
Prior to 1991, the coastal community of Petit Forte, located on Newfoundland's Burin Peninsula, was only accessible by boat. The Petit Forte access road was a welcome link for the people of that community. McNamara Construction Ltd. of St. John's, NL was the successful bidder on the initial phase of the grading project that included the construction of a causeway. The causeway would cross seawater and was required to allow small boat passage and accommodate a 1.2 m tide.
Dur•A•SpanTM, the proven lightweight champion.
The Department of Works Services and Transportation project engineer, Gary Gosse, P.Eng. specified an aluminum structural plate pipe. It's light weight, fast installation, low cost and ease-of-handling were major advantages at the remote site. The Dur•A•Span™ structure, designated DSO-21, was a 6.4 m round aluminum structural plate pipe, 20 m in length.
Keeping pace with the tide.
McNamara's project engineer, John Singleton, P.Eng., decided to construct the causeway from both ends and work towards the middle, leaving a gap in which the pipe would be quickly placed. The pipe was assembled on one end of the causeway and supervised by AIL's Wade Abbott, P.Eng. Once assembled, it was carried out by an excavator and placed adjacent to the opening. The bedding was prepared at low tide. At high tide, the pipe was quickly lowered in place and held by two excavators while crushed stone was placed simultaneously on both sides until the backfill was well above the high water line. Riprap and gabion baskets were placed at both ends to complete the installation.
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