When the Port of Anchorage (POA) initiated its Test Pile Program earlier this year, careful attention was paid to potential noise impacts. Long- and short-term noise monitors collected data at locations in Government Hill and Joint Base Elmendorf-Richardson's Cherry Hill residential area. The monitoring equipment captured baseline noise levels, and compared this to noise generated by the vibratory, diesel, and impact hammers used to drive the 10 48-inch steel pipe indicator piles. Weather data, a potential influence on data recording, was also collected.

The POA also heard community concerns about ground-borne vibrations caused by the pile driving and initiated a vibration monitoring program in conjunction with the noise-monitoring effort. Both in-air and ground-borne data was analyzed carefully following completion of the pile driving effort.

The monitoring team found that noise levels during construction were below the Municipality of Anchorage's code limit, with vibratory pile driving having the least noise impact. Ground-borne vibrations were also found to be below detectable levels. The feeling of vibration may have been the result of low-frequency noise rattling structures/windows, which can mimic some of the characteristics of ground-borne vibration. Complete study results have been posted on the POA's website: Anchorage Port Modernization Program In-Air Noise and Ground-borne Vibration Analysis Monitoring Report.

POA representatives will present the results of the Test Pile Program Noise monitoring program to at the September 15, 2016 Government Hill Community Council meeting. We hope to see you there!

 View Full Report – pdf

Executive Summary

Aging infrastructure at the Port of Anchorage (POA) has far exceeded its economic and design life. Some of the oldest parts of the current infrastructure date back to the early 1960s. The POA is planning to undertake a reconstruction project—the Anchorage Port Modernization Program (APMP)—to improve and update these facilities. The APMP is planned for construction between 2017 and 2022 or later, dependent on available funding.

In advance of the APMP, the POA conducted a smaller‐scale effort during spring 2016, known as the Test Pile Program (TPP). The TPP consisted of installing 10, 48‐inch steel pipe indicator test piles adjacent to existing POA facilities. The primary purpose was to evaluate the performance of the pile installation equipment and methods under conditions similar to what will be used for production pile installation during the APMP. The information obtained during the TPP will be used to help inform, design, and implement the APMP.

The TPP was multifaceted, and a number of investigations and data sets were collected as the piles were installed. One of the efforts entailed an in‐air noise and ground‐borne vibration technical analysis to assess the potential impacts from the future construction of the APMP. The goal of this analysis is to evaluate how construction noise and ground‐borne vibration during the APMP might affect residences close to the POA as well as workers within the POA boundary. This report summarizes the in‐air noise and ground‐borne vibration analysis conducted during the TPP. In general, results of the in‐air noise and ground‐borne vibration monitoring are summarized as follows:

In‐air noise monitoring synopsis (residential areas): Monitored noise levels from pile driving did not exceed the Municipality of Anchorage (MOA) code limit of 80 A‐weighted decibels (dBA) Leq (equivalent continuous noise level, hourly). According to the long‐term monitoring effort, sound levels in the Government Hill neighborhood during pile‐driving activities ranged from 56 to 73 dBA Leq, while sound levels in the Cherry Hill neighborhood ranged from 54 to 78 dBA Leq. The loudest monitored pile driver sound levels were generally associated with the hydraulic impact pile driver followed by the diesel impact pile driver. Vibratory pile driver sound levels were measurable, but were lower than impact pile driver sound levels.

In‐air noise monitoring synopsis (POA tenant locations): Monitored pile‐driving noise levels were below the Occupational Safety & Health Administration maximum allowable impact levels, but fall within ranges for adverse occupational exposures during the course of an 8‐hour workday. All personnel required to work outside at the shoreline or within 150 feet of pile‐driving operations are recommended to wear hearing protection. Common types of hearing protection include ear plugs (disposable or reusable), semi‐insert ear plugs, and ear muffs. Noise levels collected inside facilities near the piledriving test locations do not indicate any exposures of concern.

Ground‐borne vibration monitoring synopsis: Monitored vibration levels attenuated quickly with distance from the piles driven. As a result, ground‐borne vibration from pile‐driving activity was not perceptible or of a level that could be readily identified over baseline ground‐borne vibration levels in the neighborhoods. The phenomenon experienced by some residents in the Government Hill neighborhood is most likely a result of low‐frequency noise associated with impact pile driving rather than ground‐borne vibration.

 View Full Report – pdf

Construction activities on the Port of Anchorage's (POA) Test Pile Program are now complete. The last pile was driven to 150 feet below mudline on June, 7, 2016, and restrikes on the 10 test piles began the next day. The piles, which were driven up to 185 feet below the mudline, experienced no more than 10 inches of additional movement as a result of the restrikes. Seven of the 10 piles have been cut off within 2 feet of mudline to avoid potential impacts to marine traffic. The remaining 3 piles will be utilized in the Anchorage Port Modernization Program, Phase 1, in-water construction, scheduled to begin in 2018.

Project team members will spend the next few months analyzing data from the restrikes to confirm pile capacity and information gathered during in-air and ground vibration data collection efforts. The POA anticipates that the final noise and vibration monitoring report will be available later this fall and plans on presenting findings at the September 15, 2016 Government Hill Community Council meeting.

Thank you to Government Hill residents, community council members, and others who participated in program meetings and events. We look forward to keeping you informed as we begin the next phases of our Port's modernization program.

Work is nearly complete on the Port of Anchorage's (POA) test pile program. The remaining three piles will be driven this week (Wednesday, Friday, and Saturday) near Terminal 1 and at the north end of the Port, pending tidal or other construction constraints.

Restrikes on each of the ten test piles will start the first week in June and be complete by June 18, 2016. Each pile will be struck up to ten times to confirm structural capacity. Following the restrike effort, seven of the ten piles will be cut off below the ground level. The remaining three piles will be utilized in the Anchorage Port Modernization Program, Phase 1, in-water construction, scheduled to begin in 2018.

Test Pile Program successes continue and we are now at the half-way point! Last week, the Port of Anchorage (POA) drove two more test piles to the target depth of 174 feet below mean low water (MLW) line. Previous piles had been driven to depths ranging from 133 feet to 175 feet below the MLW line. This data will be used to refine further design and construction requirements for Phase 1 in-water construction, scheduled to begin in 2018.

The POA's noise monitoring program is also showing promising results. Preliminary data collected at the Government Hill and Cherry Hill monitoring sites during previous pile-driving efforts indicates that in-air noise levels are below Municipality of Anchorage noise thresholds. The full report detailing the noise and vibration monitoring effort will be available later this fall.

This week, construction on the sixth test pile is planned for Wednesday, May 25, 2016, near Terminal 1 (Indicator Pile #7 on the map). The Derrick Barge General will move south later in the week, and one additional pile will be driven prior to the Memorial Day weekend break. Both piles will test bubble curtain noise mitigation systems as an in-water noise reduction technique. The Port remains on schedule and the last pile is currently anticipated to be installed on June 4, 2016, pending tidal or other construction constraints.

Our next e-mail update will be sent Tuesday, May 31, 2016. Have a safe and wonderful Memorial Day holiday!

Pile driving on the fourth of ten test piles began early this morning near Terminal 1 (Indicator Pile #5). Following initial placement using the vibratory hammer, diesel hammer impact driving will begin around mid-day, pending marine mammal or technical issues. Work should be complete by late afternoon. Construction on the fifth pile (Indicator Pile #2) will begin early Thursday or Friday morning, pending results from today's efforts. Noise monitors will be in place in Cherry Hill and Government Hill during both pile driving efforts to gather in-air noise data.

Port of Anchorage project team members will provide an update on construction schedule and noise monitoring activities at 6:30 pm this Thursday evening (May 19, 2016) at the Government Hill Community Council meeting. See http://communitycouncils.org/servlet/viewfolder?id=269 for the Council's complete agenda. We hope to see you there!

On May 14, 2016, the Derrick Barge (DB) General changed position to the next test pile location near Petroleum, Oil, and Lubricant (POL) 1. The next planned pile driving is set for Wednesday, May 18, 2016.

Similar to previous pile installation, work will begin with the vibratory hammer, followed by the hydraulic impact hammer. Work will last approximately 4 to 5 hours, pending marine mammal, tidal, technical, or safety issues.

Starting early this week, the Derrick Barge (DB) General will move north and stage in a new location near the Port of Anchorage's (POA) Terminal 3. The POA plans on installing the Test Pile Program's third pile starting Thursday morning, May 12, 2016.

Installation will begin with the vibratory hammer, followed by the hydraulic impact hammer. The vibratory phase is expected to take approximately 30 minutes. After an equipment change, the pile will be driven into the harder subsoils by the impact hammer. Depending on soil conditions, the impact hammer phase may take 1 to 2 hours. The fourth pile, scheduled for installation on Saturday, May 14, will follow the same process. Work on both days should be complete by late afternoon, pending marine mammal, tidal, technical, or safety issues.

In-air noise monitors in place during the first (hydraulic hammer) test pile installation on May 2, 2016 indicate promising results. Early reports suggest that noise levels at Brown's Park were in the mid-50s decibel range and in the high-60s range at Nightingale Park, both below the Municipality of Anchorage's noise permit levels. As a comparison, noise monitors noted that small airplanes flying toward Merrill Field clocked in at the low-80s decibel range.

The POA plans to initiate ground vibration monitoring in concurrence with in-air noise monitoring. Thank you to the Government Hill residents who brought this issue to our attention! The POA will use this new information to better assess this potential issue moving forward.

A full report on the POA's noise and ground vibration monitoring efforts will be shared with the Government Hill Community Council at their September 2016 meeting.

Construction concerns? Let us know at 907-379-9979.

The Port of Anchorage's (POA) Test Pile Program gets underway this week with the installation of the first test pile today, May 2, 2016. The second pile is scheduled for installation on May 5, 2016. Both pile locations are near the existing Petroleum, Oil and Lubricants (POL) 1 terminal at the south end of the Port.

Long-term noise monitoring stations near Government Hill and Cherry Hill were set up the week of April 25, 2016 to collect ambient noise data. Mobile monitoring stations will be positioned in various locations throughout the neighborhoods during active construction. Join us at Nightingale Park at noon (12 pm) today to meet the sound technicians and learn more about how sound data is collected.

Did you miss Alaska Public Radio Network's three-part series on the POA's Anchorage Port Modernization Program? Hear the stories here:

April 19, 2016 – Crucial cargo point only ‘marginally adequate’ say officials

April 20, 2016 – ‘Slow motion disaster’ threatens state’s key port

April 21, 2016 – “It Just Didn’t Work”: Legacy of botched project haunts port’s future

The Derrick Barge (DB) General arrived in Anchorage from the Port of Seattle on April 20, 2016. The barge's arrival at the Cook Inlet Tug and Barge dock marks the start of the Port of Anchorage's (POA) month-long test pile program, which will install 10 indicator piles at key in-water locations. This critical test program will collect design information, investigate construction methods, and identify potential impacts that may occur when in-water construction begins in 1028 on the Anchorage Port Modernization Program (APMP).

Following mobilization and setup on April 28th, the first indicator pile will be installed near the existing Petroleum, Oil and Lubricants (POL) 1 terminal at the south end of the Port. Kiewit Infrastructure West, the Port's construction contractor, estimates each pile will take up to four hours to install. Construction on the first pile is scheduled to begin April 29, 2016.

Installation of the second pile is anticipated to begin May 2, 2016.

Long-term noise monitoring stations will be set up near Government Hill and Cherry Hill, Joint Base Elmendorf-Richardson (JBER) prior to the start of construction. These monitors will be in place throughout construction and collect data on ambient noise, construction noise, and weather conditions. Area residents may also see POA contractors taking noise measurements at various locations throughout the Government Hill and Cherry Hill neighborhoods during active pile driving.