PORT ANGELES — Metal will clang and the earth will tremble in the western downtown core for another two weeks.
The pile-driving preparatory to construction of a new city pump station, which has shaken the ground during daylight hours and backed up traffic on Front Street since April 14, originally was expected to end last Tuesday.
But the noise — deafening close-up — and concussions are expected to continue to at least May 15, even with the crew of subcontractor Axis Crane of Hubbard, Ore., working six days a week, according to Jeff Bender, Port Angeles public works project manager.
“They are having problems getting down to minimum depth,” Bender said Friday.
“It has to do with soil density and hardness.
“Unfortunately, [the date of completion] is a moving target.”
The delay in completion means flagger traffic stops at the western end of Front Street where it meets Marine Drive will continue as workers complete the jarring process of pile-driving the underbelly of the combined sewer overflow (CSO) pump station at 314 Marine Drive.
The new pump station, which will replace one across the street, is the largest single component of the $15.2 million, 16-month phase two of the project. The contractor for the project is TEK Construction Inc. of Bellingham.
This phase also includes stormwater and sewer separation and new sewer and stormwater lines on Lincoln and Front streets.
Phase one construction from March 2009 through July 2012 included extensive new sewer systems as far west as Railroad Avenue and North Oak Street.
The city is operating under a 2006 agreed order with the state Department of Ecology to reduce the number of overflows from city sewers into Port Angeles Harbor during major rainstorms.
Ecology has given the city until 2016 to meet that goal or face fines.
The total cost of the combined sewer overflow reduction project is estimated at nearly $40 million.
The city imposed an $18 to $20 monthly surcharge on residents to help pay for the effort.
Construction on phase two began Feb. 23 and is expected to be completed by May 2016.
Bender said a crane operator dangling a 9½-ton hammer that slowly vibrates the piles eventually will finish pounding the steel sheets 48 feet into the ground — unless the decision is made that it’s not worth it and the piles are severed before they reach the optimum depth.
The rattling of people and machines visibly shakes computer terminals and other equipment in nearby businesses and residences.
It’s caused by the hammer’s 255-ton drive force trembling downward at up to 1,650 vibrations a minute.
Once in place, the steel piles will serve as fall-protection for workers at the base, shore up the walls of the 21-foot-tall pump station while it’s being built and keep water out of the hole during excavation and construction.
Excavation for the building, designed similarly to The Gateway transit center at Front and Lincoln streets, will begin once pile-driving has been completed.
Bender said no one has made formal complaints to the city about the noise and vibrations in the construction area.
Once pile-driving does end, neighbors of the project can expect more of the same later this year or the beginning of 2016 when the piles are pulled and vibrated out for the final phases of construction.
The shuddering should be less defined during the extraction than it is now, Bender said Friday.
Most of the remaining heavy construction will take place on the north side of Marine Drive, where pressure sewers and storm lines will be installed in trenches for the CSO project, the priciest public works effort in the city’s history.
Bender said once pile-driving is completed, the westbound traffic on one-way Front Street will continue being squeezed to one lane but should flow more smoothly with fewer flagger stops.
Traffic has recently been reduced to one lane or temporarily halted while heavy equipment trundles from the south side of Front Street, where the pump station is being built, to a staging area on the north side of the street.
Pile-driving has proven to be more difficult than expected.
Workers had to repair a crane and bring in a vibrating hammer three times larger than the previous one to penetrate a thick layer of gravel 20 to 25 feet below ground level.
They drove piles through about 12 feet of fill and 5 feet of clay before hitting sand 17 feet below ground level that once composed the original shoreline beach.
Then they hit gravel with 17 feet to go.
“The sheets weren’t driving,” Bender said.
“It’s much stiffer material than we previously encountered.”
Once the CSO project is finished, sewage will be treated at the city’s water treatment plant or stored at a 5 million-gallon tank on the former Rayonier pulp mill site before being processed at the plant.
Runoff will be discharged through a stormwater treatment manhole into Valley Creek estuary.
At 3,200 square feet, the pump station has a capacity of 28 million gallons.
“It is not anticipated for odor to be an issue; however, there is a potential,” Bender said in an email last week.
“It is unknown at this time the level of noise that will be emitted from the building from the pumps and motors.”
Installation of sewer lines on the north side of Front Street west of Oak Street will begin soon.
Asphalt will be laid beginning mid- to late May.
Then pipeline will be installed during nighttime hours below Front Street between Oak and Lincoln streets and continuing up Lincoln to Second Street.
Drivers will experience detours and delays during the workweek from 7 p.m. to 7 a.m. from about late June to early July, with final paving and striping the final stage.
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Senior Staff Writer Paul Gottlieb can be reached at 360-452-2345, ext. 5060, or at pgottlieb@peninsuladailynews.com.
