Tuesday, November 13, 2012

Anchorage Port Design Seriously Flawed, Engineers Say

Three of four new sections built at the Port of Anchorage were not constructed correctly, and due to shifting land, could fail during an earthquake, a federally commissioned study has found.

The danger comes mainly from a foundation system called Open Cell Sheet Pile, or OCSP, where instead of building a traditional dock on piling, interlocking sheets of steel are hammered into the sea floor to form U-shaped cells, which are then backfilled with dirt and gravel.

“The suitability study determined that the OCSP system is not adequately designed to meet global stability and seismic displacements based on the design criteria,” the report states. “The study also concludes that the open cell system is adequately designed to meet initial internal stability structural design requirements, assuming it was constructed without defects. However, at the end of 50 years, it will be slightly overstressed due to corrosion and will not meet safety standards.”

The $2.2 million sustainability study was conducted by engineering firm CH2M Hill on behalf of the US Maritime Administration and the US Army Corps of Engineers. The Corps requested the study be conducted after it assumed control of the Port of Anchorage expansion project from MARAD on May 31.

The expansion, which has been in the works for more than a decade, was originally estimated to cost $360 million, and was supposed to be complete by 2011. Instead, cost estimates have jumped to more than $1 billion and continue to climb. A completion date is at least a decade away, according to port estimates.