Yellowstone River Cofferdam

coffer-dam-5
Wilson Brothers of Cowley, Wyo., and Associated Underwater Services of Spokane, WA build a coffer dam as work continues Tuesday on new water intake in the Yellowstone River for the city of Laurel.

Sep 21, 2016

BY: Casey Page, Gazette Staff

A contractor crew and a specialized underwater construction subcontractor helped guide heavy equipment on Tuesday, sinking 3,200-pound sand bags into the Yellowstone River.

They worked three miles upstream from Laurel atop a man-made rock weir — a miniature peninsula that juts halfway across the river. The sandbags will form a cofferdam around the weir, allowing workers to install the long-awaited water intake.

The current unit, dubbed the 2003 intake, sits below the Highway 212 bridge south of town. It’s been plagued with issues since a flood swept through the area in 2011 and changed the riverbed topography.

Now in its ninth week, the $12 million intake project is underway. The work has been a long time coming for city officials. Laurel Public Works Director Kurt Markegard said that it defines critical infrastructure — a working intake brings millions of gallons of water to its residents, as well as the CHS refinery.

“This is probably one of the most important jobs we’ve done since 2003,” Markegard said.coffer-dam-2

Once the cofferdam is finished, pumps will pull out the remaining water, and the intake infrastructure will be installed. Markegard said surveys identified that upstream spot as one that’s more unlikely to be ruined by a flooding event.

Large blue piping will carry water back to the city’s treatment plant, which sits at shore near the old intake. Nick Wilson of Wilson Bros. Construction said that the pipes will sit an average of 14 feet underground. But it’s a gravity-fed system, so the pipes will gradually get deeper as they reach town.

About 25 trucks have arrived to pile up the pipes at the job site, Wilson said. About 75 more are expected.

A Wyoming firm, Wilson Bros. is the contractor. Montana-based Great West Engineering is handling the engineering work. Representatives from those companies meet each week with the city of Laurel and others involved in the project to discuss progress.

Meanwhile, temporary rock weirs were built just downstream from the Highway 212 bridge to keep the river level up above the old intake. Since the 2011 flood eroded the riverbed, the intake has suffered from ice jams in the winter and summer water levels that are too low.

Much of the construction cost will be covered by the Federal Emergency Management Agency, which approved nearly $43 million in public assistance to Montana after a 2011 disaster declaration.

The funding requires a local match of 25 percent of the project cost. Finding a source for that 25 percent has kept the Laurel project at bay before, and it’s likely to persist in the future.coffer-dam

Laurel officials had a rocky road to find $3 million for 25 percent of the intake project. The funds didn’t make it to a vote in the 2011 or 2013 sessions of that Montana Legislature. In 2015, the infrastructure bill failed.

Gov. Steve Bullock directed his office to piece together various money streams for the project, but it was announced in October 2015 that the money was no longer available — gone toward other projects.

So Laurel took out a $1.7 million loan from the State Revolving Loan Fund Program and used $1.3 million in city reserves, according to City Councilman Tom Nelson. But it wasn’t an easy pill to swallow, as the town neared its borrowing capacity.

“They gave us the loan. We had to take it,” Nelson said. “We had no choice.”

Nelson expressed some rancor over the 2.5-percent-interest loan, because he felt the state was obligated to pay the 25-percent match of FEMA funds as Laurel recovers infrastructure from the flood.

He’s not the only city official who felt that way. At a July 12 city council meeting, Councilman Douglas Poehls said Bullock’s office “essentially betrayed the city,” according to meeting minutes. City Chief Administrative Officer Heidi Jensen said at that meeting that the governor hasn’t given an official written statement about the state’s responsibility to the funds.

Nelson traveled to Helena in August to talk to state officials. Accompanying him were Billings state Rep. Kelly McCarthy, Laurel Civil City Attorney Sam Painter and Laurel state Rep. Vince Ricci.

Ricci declined to comment on the meeting. The governor’s office didn’t respond to a request for comment on Tuesday afternoon.

Nelson said Monday that Andy Huff, Bullock’s chief legal counsel, and Adam Schafer, Bullock’s policy director, heard him out on the manner. He said he requested an answer within two weeks but didn’t get one.

“The government’s still responsible for it,” he said. “The state still requested the emergency declaration from the president. That was given.”

The city’s hopes are pinned to the 2017 legislative session, when repayment for the state loan could end up tied to an infrastructure bill.

coffer-dam-3Ultimately, officials see it as a welcome sign that earth is moving west of town, near the end of Red Bridge Road.

Work is expected to be completed around April.

By MATT HUDSON mhudson@billingsgazette.com

Ryan Dam

In the winter of 2014, AUS spent 2 1/2 months in Great Falls, MT overhauling the waste gates at Ryan Dam.

Ryan Dam

We removed the gates and gate stems, installed new gate guides and replaced the reworked gates and stems.

SAMSUNG DIGIMAX A503

Utilizing Nitrox breathing mixture throughout the project, we made 194 dives to a depth of 66′. 120 No-D dives and 74 decompression dives.

 

 

520 Bridge Now Open

After nearly six years of construction, AUS is proud to announce the opening of the new highway 520 floating bridge that helps travelers across Lake Washington.
The new route 520 bridge is the world’s longest floating bridge at 7,710 feet long, bringing it 132 feet longer than the old highway 520 bridge.

Once the new pontoons were established, AUS assisted in the development of the bridge from the water line down during construction. With the ability to utilize the old 520 anchor cables, AUS welded and installed deviation frames to hold the new 520 in place. Other responsibilities included all joining steps like preparing the pontoons to be mated together by through bolts and repairing rock spall in the concrete. Inspecting, cleaning and overall maintenance of the anchor cables were crucial responsibilities for AUS as well.

The new 520 bridge offers six lanes compared to the old bridge which only had four, allowing for a HOV lane in both directions. See more details on Washington State department of Transportaion webpage 520 – Floating bridge facts. 

 

Sitka’s Blue Lake Expansion Project Wins Grand Award for Best Construction Project of 2015

24717134822_e7eaa7b3db_o.56e83303dd83eOriginally posted HERE

March 10, 2016

Barnard Construction Company of Bozeman, Mont. Wins Associated General Contractors of America’s Alliant Build America Grand Award and Merit Award for Marvin M. Black Partnering Excellence

Sitka’s Blue Lake Expansion Project was the most impressive construction project of 2015, the Associated General Contractors of America announced today. As a result, the project’s contractor, Barnard Construction Company was the Alliant Build America Grand Award winner and best Federal and Heavy Renovation project. This project was one of 23 winners to receive an award and one of nine to receive a Merit Award.

“The contractors working on these projects stood out among their peers by demonstrating the finest traits of our industry: skill, dedication, and ingenuity,” said Charles Greco, the association’s president and chairman of San Antonio-based Linbeck Group. “This is the kind of project that inspires other contractors to push even harder as they work to improve our built environment.”

Barnard Construction Company raised the then-145-foot-tall Blue Lake Dam by 83 feet to its maximum geotechnical height and built a 15.9 megawatt powerhouse. Construction was undertaken on a fast-track schedule under the intense scrutiny of a heavily-invested public, reliant on the dam for power and on Blue Lake for drinking water. The team successfully completed construction in difficult conditions including the dam’s remote island location in one of the rainiest locations in the U.S. Throughout construction, there were no interruptions to the city’s drinking water and the team was mindful of the natural fish barrier just below the dam, using construction methods that allowed salmon to spawn downstream of the dam.

“Celebrating these well-deserved accomplishments promotes continued creativity and excellence among peers and showcases the dedication and inspiration that the construction industry offers,” said Peter Arkley, Senior Managing Director, Alliant Insurance Services.  “Alliant is proud to be a longtime sponsor of the Build America Awards.”

The association also released a new report(link is external) analyzing the elements that made the winning projects so successful.  The report found that contractors are most likely to succeed when they rely on a mix of planning ahead, ensuring safe work environments, performing quality workmanship and overcoming unexpected challenges. The association is distributing the report to its members so other firms can benefit from the lessons these projects and their contractors have to offer.

The Alliant Build America Awards highlight the nation’s most significant construction projects. A panel of judges, representing all areas of construction, evaluated an impressive number of submissions this year, assessing each project’s complexity, use of innovative construction techniques and client satisfaction, among other criteria.  The awards, which were announced during the association’s annual convention in San Antonio, are considered by many to be the most prestigious recognition of construction accomplishments in the U.S.

View all the Alliant Build America Award winners.  View(link is external) pictures of Build America winners.

– See more at: https://www.agc.org/news/2016/03/10/sitka%E2%80%99s-blue-lake-expansion-project-wins-grand-award-best-construction-project-2015#sthash.LfTZqNHv.dpuf

AUS receives prestigious award at this years AGC Convention.

AUS receives prestigious award at this years AGC ConventionAUS was awarded the AGC 2015 Build Northwest Award Subcontractor -Renovation for the Nine Mile Dam Rehabilitation Project General Construction. This is a yearly event with numerous contractors submitting entries in all categories. The award was received at the Annual AGC Convention in January, 2016.

Nine Mile Falls Dam is located on the Spokane River and is approximately 16 miles from downtown Spokane, Washington.  The dam is owned and operated by the AVISTA Corp.  The recent project being worked on is a generator upgrade for Units #1 and #2.  Due to mechanical failures and the high cost to repair the early 1900’s vintage generators, units #1 and #2 have not operated for several years.

Preliminary underwater work on the project started in 2012 with Associated Underwater Services performing an underwater ROV inspection of the tailrace and inside each of the four draft tubes.    One major finding from the inspection was that the #1 and #2 draft tubes were nearly full of sand and debris from not operating for several years.

The generator upgrade contract went out for bid and Max J. Kuney, based out of Spokane, was awarded the contract. Associated Underwater Services was chosen to perform the underwater work.  The construction project started in the summer of 2014.  The critical path underwater work was to create a dry work area inside Units #1 and #2.  This work started with the installation of two dewatering bulkheads upstream.  This allowed work to begin on the removal of the old generators and the modification of the penstocks to accept the new generators.   Sand removal started during the summer of 2014 and continued throughout the diving project with new sand constantly migrating back into the work area.

The most challenging part of the project was the dewatering of the downstream side of the dam.  Working adjacent to the constant flow of water over the spillway created challenges in securing the work barge into position and rough working conditions.  To keep the work schedule, AUS provided three dive crews with two day shifts and one night shift.   New draft tube stop log guides would need to be installed underwater on the sides of the piers.  AUS performed detailed surveys of the existing slots and found that the original guide slots were not in line with each other and they were not plumb.  A new design was developed by URS Engineering.  The new design required the existing guide slots to be enlarged and new steel guides to be installed inside the larger guide slots.  To accomplish this task a wall saw was set up on a vertical track to make vertical cuts in the concrete on both sides of the guide.  The concrete was then chipped out by the divers.  A bottom sill plate needed to be installed and this required several cuts in the floor to create a keyway for the new bottom sill plate.  An underwater core drill was used to drill the holes for the rebar dowels and these were installed with epoxy.  The new guide beams were installed in one piece with a full sized alignment frame.  Once the new guide was in the slot the entire assembly was jacked into position tight and rock bolted.  The grout forms were wet welded into position by the divers.  The forms were sealed with Splash Zone Epoxy and then the guides were grouted into position.    After the grout cured, the alignment frame was retracted and removed with the crane.  New guides were installed in all four draft tubes.  New draft tube stop logs were installed in Units #1 and #2 so that those entire units could be dewatered to continue the generator replacement work in the dry.  This phase of the underwater work was completed in April of 2015.  Work on the generator upgrade is still ongoing.

Water authority’s new straw at Lake Mead starts to fill

After seven years of construction, the Las Vegas Valley’s new straw into Lake Mead now has some water in it.

General contractor Vegas Tunnel Constructors began sending the first 11 million gallons into the 3-mile tunnel beneath the bed of the lake Thursday afternoon, marking the latest milestone for a complicated and risky $817 million project on track for completion within the next month or so.

Water authority's new straw at Lake Mead

Before the valves were opened to let the water gush in, workers rode the elevator out of the intake tunnel for the last time. In the coming weeks, some 52 million gallons of water will fill their old work space, where they spent years digging and fortifying a 20-foot diameter tunnel from the shore to one of the deepest spots in the reservoir.

“This is a major milestone for everyone on the project,” said Erika Moonin, an engineer and project manager for the Southern Nevada Water Authority.

It’s especially big for the contractors. “They’re going to be done with the tunnel. Once they start filling, no one is going back into that space,” Moonin said.

The water authority considers the project critical drought insurance for a community that draws 90 percent of its drinking water from Lake Mead. The third intake — coupled with a $650 pumping station due to be built over the next five years — will keep water flowing to the valley even if the lake shrinks low enough to dry out the community’s two existing straws and prevent Hoover Dam from releasing water downstream.

So how does one fill 3 miles of intake pipe 600 feet underground? Slowly and carefully, Moonin said.

The process that officially began Thursday is expected to last several weeks.

The new deep-water intake is linked to the valley’s existing straws by a connector tunnel completed in 2013. A temporary bulkhead currently keeps water in the connector tunnel from seeping into the intake. To remove the bulkhead, workers must seal the tunnel off from the lake and drain it so they can work inside.

Moonin said a crew on a barge floating on Lake Mead finished the first part of the job last week by lowering a water-tight lid over the mouth of one of the existing straws used to supply water to the valley.

The roughly 11 million gallons left in the sealed connector tunnel is now being drained through valves in the temporary bulkhead and down into the new intake — the first significant amount of water allowed into the structure, though not enough to fill it.

Once the bulkhead has been removed, another 52 million gallons will be let in at a controlled rate using a mix of raw lake water piped in from above and groundwater from the surrounding rock. That seeping groundwater has caused fits for contractors since excavation began at the site in 2008, but now they can shut off the pumps and let it flood in, Moonin said.

As soon as the entire tunnel is full and the water pressure inside equals the pressure around it, a crane floating on the lake will be able to lift the cap — a 19,000-pound disc of stainless steel, 16 feet across and an inch and a half thick — from atop the new intake, opening its mouth to the reservoir above.

Moonin expects that to happen in early October. All that will be left to do then is take a drink.

Contact Henry Brean at hbrean@reviewjournal.com or 702-383-0350. Find him on Twitter: @RefriedBrean

– See more at: http://www.reviewjournal.com/news/water-environment/water-authoritys-new-straw-lake-mead-starts-fill#sthash.ydKoyPQL.dpuf