Obstruction Still Vexing Bulkhead Installation

By: Alan Pollock

Crews have driven most of the sheet piles that will create a new bulkhead, but have yet to clear an obstruction that keeps the work progressing toward the packing house. ALAN POLLOCK PHOTO

CHATHAM — Six or seven feet down in the mud underneath one part of the fish pier bulkhead lies a mystery. Actually, it’s more of a headache.

Health and Natural Resources Director Robert Duncanson said Tuesday that most of the new corrugated steel sheet piles that hold up the parking lot have been successfully installed.

“Right now, 95 percent of the bulkhead is in,” he said. The individual bulkhead pieces connect with one another and must be installed in order, and work has progressed to a point about 20 feet from the packing house. There, crews driving the piles into the ground encountered a buried obstruction on Jan. 25, stopping progress in that direction.

A special diver was brought in to investigate, but was hampered by the silty mud at the base of the bulkhead. Water pumps were used to clear away some of the mud, but could not keep a hole open “for more than a few seconds, so it wasn’t ever safe for a diver,” Duncanson said.

Crews intended to try and push the sheet piles through the obstruction, but early this week there was a malfunction in the giant vibrating “hammer” used to install the piles. On Tuesday, work at the site had slowed while crews awaited the arrival of a technician. Once the device is repaired, driving will continue “to see if they can get through it or get around it,” he said.

The contractor, Norfolk-based MAS Building and Bridge, is still hopeful that they can identify and remove the obstruction.

“They’re looking at potentially bringing in an underground, ground-penetrating radar so they can hopefully get a better look at what it may be,” Duncanson said.

Engineers from MAS and the town are now considering what action to take If the object can’t be removed. It is possible that the pile will be driven as far as possible and then cut off flush with the others, but it’s not clear whether doing so would provide adequate support to the parking lot above. The harbor bottom around the edge of the bulkhead is frequently disturbed by propeller wash from boats and by periodic dredging, which could destabilize the structure over time if it is not built to a uniform depth without gaps.

“That’s what the engineers need to evaluate,” Duncanson said.

Of key interest is ensuring that the project is complete before the start of the busy fishing season. The $3.65 million contract with MAS stipulates that the bulkhead work must be completed by April 28. The obstruction calls the timeline into some question.

“They’re as confident as they can be,” Duncanson said. The contractor worked last Saturday to try and keep the project on schedule, and is considering the use of additional crews or double shifts. “They’d just like to get by this obstruction, or figure out where it is,” he said.

A second phase of the project involves the replacement of the stairs leading from the upper parking lot to the lower lot. Work has not yet started on this phase, which must be completed by June 9.