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Shannon & Wilson scientists and engineers are world-class experts in their fields. Called upon to provide expert commentary, explanation, or consulting, their work is presented at professional conferences, in trade and professional publications, at workshops, as well as in daily newspapers.

Ten Years of SR 520 Bridge: Pontoon Casting Facility
September 21, 2016

This is the second in a series of articles discussing different projects associated with the SR 520 Bridge project for the Washington State Department of Transportation (WSDOT).  View all posted articles here.

This $367 million design-build project was a major contributor to the overall SR 520 project. Built at the Aberdeen Log Yard site in Grays Harbor County, Washington, it involved the construction of a 200 feet by 900 feet by 25 feet deep pontoon casting facility.  The casting basin was used to construct 33 concrete pontoons needed for the new SR 520 floating bridge on Lake Washington. Shannon & Wilson was part of the Kiewit-General Joint Venture, a team that also included HNTB and KPFF.  Shannon & Wilson provided geotechnical design and construction services for the project including:

  • Strong ground motion time history development for the 1,000-year return period.
  • Driven 18- and 24-inch steel pipe pile recommendations including axial and lateral resistance and pile drivability for crane gantry, basin slab, and gate structure pile foundations.
  • Two-dimensional numerical modeling included dynamic, non-linear, effective stress, and soil-structure interaction simulations. 
  • Numerical groundwater modeling to evaluate dewatering well spacing, depth, and configurations that are required to lower groundwater levels 20 feet.
  • Settlement estimates of the surrounding ground surface as a result of the groundwater lowering.
  • Temporary and permanent sideslope recommendations for the basin excavation.
  • Pavement recommendations to support construction equipment traffic, including a large gantry crane that transported precast slabs that were used in the pontoon construction.
  • A geotechnical instrumentation program to monitor groundwater levels below the basin slab during flooding and unwatering cycles, groundwater levels in the surrounding areas around the basin, and settlement of the adjacent ground surface and existing facilities.






Ten Years of SR 520 Bridge:
Floating Bridge & Landing

August 25, 2016

This is the first in a series of articles discussing different projects associated with the SR 520 Bridge project for the Washington State Department of Transportation (WSDOT).  View all posted articles here.

The SR 520 FB&L project incorporates the world’s longest floating bridge.  It’s true, you will find it in the Guinness World Records book.  The floating portion of the bridge is about 1.4 miles long, with an overall project length of approximately 1.7 miles. 

The 1960s era floating bridge deck sat directly on top of its concrete pontoons and was only a few feet above lake level.  During high, sustained winds, waves would crash across the bridge deck making it rather dangerous (and exciting) to drive across.  At times WSDOT had to close the floating bridge to traffic because the waves and wind were too high.  The old bridge carried two lanes of traffic in each direction, but did not offer shoulders or a pedestrian/bicycle crossing.  Not only did the lack of shoulders mean that a car breakdown or wreck would cause a traffic backup, but WSDOT had to close the bridge for maintenance tasks because their vehicles and personnel had to be in the traffic lanes. 

The new floating bridge deck is built on a bridge structure which sits on top of the new concrete pontoons – a bridge on top of a bridge.  The deck is about 22 feet above lake level so waves won’t be crashing across the roadway.  Maintenance trucks can access the pontoons from beneath the bridge structure so they do not interrupt traffic.  The new bridge includes shoulders and a protected pedestrian/bicycle path across the lake (soon to be connected to Seattle once the West Approach Bridge – North is completed in 2017).  The new floating bridge structure was designed for a larger storm event than its predecessor.  

In addition to the floating concrete pontoons, the project also included four piers that were founded in the glacially overridden deposits: one overwater pier each to the west and east, along with two on-land piers to the east.  The east approach climbs a bluff up into Medina, where a Maintenance Facility Building was constructed into the hillside requiring an excavation height of around 65 feet.

Between 2006 and 2010, Shannon & Wilson, as part of HDR’s General Engineering Consultant (GEC) team, Shannon & Wilson observed:

  • Drilling and sampling of almost 60 borings,
  • Installation of 9 observation wells and 7 vibrating wire piezometers,

The majority of the borings were drilled in Lake Washington for the pontoon anchor design; these borings went through approximately 200 feet of water before soil sampling could begin.  Soil and groundwater conditions included thick lightweight, diatomaceous lakebed deposits and unconfined, confined, and perched groundwater aquifers.  Flowing artesian groundwater conditions were encountered near the Maintenance Facility Building, and there is an upward groundwater pressure within the lake because it is a regional discharge point for groundwater. 

For the Floating Bridge and Landing Project, we completed preliminary design for:

  • 3 East Approach piers
  • Pier 36 (immediately west of the floating bridge)
  • Three types of floating bridge anchors – fluke, gravity, and drilled shaft
  • Maintenance Facility Building
  • Maintenance Facility Dock
  • Stormwater bioswale on top of the bluff
  • Driven pile foundations for two potential pontoon construction sites at the Ports of Olympia and Tacoma, WA

The fluke anchors, consisting of large rectangular vertical plates, were located in about 200 feet of water and founded in very soft, diatom-rich silt.  Gravity anchors, consisting of honeycomb precast concrete blocks filled with quarry spall/ballast rock, were located towards the east and west ends of the floating bridge, where the lake water level was deep enough to provide boat clearance overtop the gravity anchors.  Large diameter, laterally-loaded, drilled shaft anchors were located at and near to the east and west ends of the floating bridge where the lake water level was too shallow to accommodate gravity anchors. 

WSDOT decided to use the Design-Build (DB) delivery system for this project.  To assist WSDOT, Shannon & Wilson prepared a Geotechnical Baseline Report (GBR), Chapter 2.6 of the Request for Proposal (RFP) document, a Geotechnical Data Report (GDR) and associated addenda, a seismic criteria memo, preliminary engineering reports to proof the conceptual design, and provided review and comment on DB questions throughout procurement.  Throughout DB design and construction, Shannon & Wilson, working alongside WSDOT’s geotechnical representative, provided submittal and anchor test results reviews and made periodic site visits.

Check out WSDOT’s drone video of the completed FB&L project here: https://www.youtube.com/watch?v=Nzd1G2ErB-I&feature=youtu.be


Ten Years of SR 520 Bridge Project

July 29, 2016

For the past ten years Shannon & Wilson has been providing geotechnical, geological, hydrogeological, environmental, seismic, and related GIS services on the SR 520 Bridge Replacement and HOV Project for the Washington State Department of Transportation (WSDOT).  This project, located between 108th Avenue NE in Bellevue, Washington, and I-5 in Seattle, traverses approximately 6.5 miles of diverse and challenging soil and groundwater conditions, and has involved an extensive variety of design elements. 

WSDOT divided the project up into several stages.  As the floating bridge portion of this project recently opened, we thought it was a great time to take a trip down memory lane reviewing our work on this historic project over the past decade.  In the coming months, we will be posting a series of articles highlighting different components of the project and the geotechnical breakdown by the numbers.  Be sure to follow us on social media or check back on our website for future editions. 

 

ODOT Foundation & Seismic Expert Joins Shannon & Wilson
June 8, 2016

Jan L. Six, a senior geotechnical engineer formerly with the Oregon Department of Transportation (ODOT), has joined Shannon & Wilson’s Portland-area office. His impressive career at ODOT focused on soil-structure interaction at bridge foundations, seismic retrofits, drilled shafts and driven piles. He led the agency’s statewide program to investigate “unknown foundations” of bridges built in the early 1900s and the developed ODOT’s Geotechnical Design Manual and geotechnical-related construction specifications. Six was the lead geotechnical engineer for major ODOT projects including the Sunset Highway, Corvallis Bypass, I-5 Columbia River Crossing, and more than 200 new bridges. Six also represented ODOT on many oversight and working groups with the Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO). He is a registered professional engineer and licensed geotechnical engineer. 

Six’s retirement from ODOT after 33 successful years opens the door for his new role at Shannon & Wilson, where he will parlay his public sector technical expertise and experience to transportation projects in Oregon and throughout the country as part of the firm’s national transportation practice. Shannon & Wilson works with state departments of transportation from Alaska to the East Coast, as well as several federal transportation agency clients. He will provide senior review and technical oversight, working with staff to meet the unique requirements of public agencies. Mark Vessely, Shannon & Wilson’s Transportation Market Director states, “With the addition of Jan Six, we can offer our DOT clients an even greater level of expertise that considers the context and perspectives of public sector owners.”

 

Tustin Hangar Project Earns Awards
March 8, 2016

The Marine Corps Air Station (MCAS) Tustin, Hangar 1 Emergency Roof Stabilization project has received awards from the American Society of Civil Engineers (ASCE) and Engineering News Record (ENR).  The ASCE Region 9 (California) award is for Small Project of the Year, which will be announced at the California Infrastructure Symposium on March 18, 2016.  In February 2016, Engineering News Record (ENR), awarded it Best Small Project (under $10 million).

The award-winning project on Hangar 1 involved an emergency roof stabilization effort following a partial collapse of the roof in October of 2013. The design solution involved the construction of two 177-foot steel towers on either side of the hangar to support the damaged roof trusses via anchor cables.  These cables extended from the trusses to the tops of the towers then down to the ground where they were secured with helical anchors.

Shannon & Wilson was part of the design-build team led by Michael Baker Jr., Jacobs Engineering, and Kellogg, Brown, and Root Construction Company, selected to provide a stabilization solution so that the roof could later be repaired without further risk of collapse. Shannon & Wilson provided geotechnical engineering recommendations to aid in the design of the proposed tower foundations and guy wire anchors.

Both Hangar 1 and Hangar 2 were constructed in 1942 to store and repair blimps. Each hangar roof was built from 52 parabolic trusses made of Oregon Douglas fir. The hangars have been designated as National Civil Engineering Landmarks by the ASCE. 

 

Peggy Ganse Earns Tunnel Inspection Certification
January 25, 2016

Shannon & Wilson’s Senior Tunneling Services Project Manager, Peggy Ganse, P.E., P.G., recently obtained National Certified Tunnel Inspector (NCTI) certification to perform safety inspections of tunnels nationwide. Ganse attended training provided by the National Highway Institute (NHI) of the Federal Highway Administration (FHWA) and earned the certification under NHI’s new NCTI program.

In July 2015, FHWA established new National Tunnel Inspection Standards (NTIS) for highway tunnels. This NCTI certification is now required for inspection of all tunnels on public roads and on and off Federal-aid highways. All key elements of highway tunnels are covered under this program, including structural, civil, mechanical, fire/life safety/security, and electrical and lighting. 

Ganse is a geologist and geological engineer with 23 years of experience designing, managing, and performing geotechnical services for tunneling projects across North America. As nationally-recognized experts in tunneling and underground services, Shannon & Wilson has performed tunnel work for railroad, utility, and transportation clients for more than 60 years.

Senior Vice President and Denver Office Manager, Greg Fischer, stated, “We are excited to have NCTI certification as part of our condition assessment capabilities. It will allow us to better serve our clients by guiding them through the NTIS requirements and regulations. It also serves as another tool to help our clients with the important task of asset management.” 

 

 

Shannon & Wilson Annnounces 2016 Promotions
January 20, 2016

Shannon & Wilson announces the following promotions for 2016: Hisham J. Sarieddine to Vice President; Rob Clark, Wendy L. Mathieson, and David C. Ward to Senior Associate; Dan McMahon, Elliott C. Mecham, Brian S. Reznick, and Scott R. Walker to Associate.  

Hisham J. Sarieddine joined the firm’s Seattle office as a geotechnical engineer in 1988, and has progressively expanded his experience and expertise on projects ranging from small structures to large federal highways. His clients include ports, state and federal agencies, and transit clients. He holds both a bachelor’s and master’s degree in civil engineering and is a registered professional engineer in the states of Washington and Hawaii. 

Rob Clark joined the firm’s Seattle office as a geotechnical engineer in 1985, and has developed a specialty with the design, implementation, and monitoring of geotechnical and structural instrumentation for the evaluation of movement and property changes in buildings, excavations, dams, landslides, and tunnels. He holds a bachelor’s degree in civil engineering and is a registered professional engineer in the states of Washington and New York.

Wendy L. Mathieson joined Shannon & Wilson’s Seattle office in 1999 as a geotechnical engineer. She has developed innovative solutions for slope stabilization, ground improvement, and shoring. She holds both a bachelor’s and master’s degree in civil engineering and is a registered professional engineer in the states of Washington and Alaska.

David C. Ward joined the firm’s Seattle office in 1997. He is a licensed civil engineer and licensed engineering geologist in the state of Washington, working primarily on tunnel and underground projects in both soil and rock. He holds a master’s degree in geological engineering.

Dan McMahon is an environmental scientist in the firm’s Anchorage office. He first began working with Shannon & Wilson in 1997 and has been active with projects involving environmental investigations and cleanup activities in Alaska and Washington. His bachelor’s degree is in environmental conservation.

Elliott C. Mecham joined the firm’s Portland office as a geotechnical engineer in 2014 bringing more than 10 years of experience with pipelines, pump stations, treatment facilities, and other water/wastewater-related public infrastructure. He holds both a bachelor’s and master’s degree in civil engineering and is a registered professional engineer in the states of Oregon, Idaho, Utah, and Washington.

Brian S. Reznick joined the firm’s Seattle office as a geotechnical engineer in 2002. His technical experience encompasses design of shallow and deep foundations, shoring, ground improvement, slope stability analysis, settlement analysis, and liquefaction evaluation. He holds both a bachelor’s and master’s degree in civil engineering and is a registered professional engineer in the state of Washington.

Scott R. Walker joined the firm’s Denver office as a geotechnical engineer in 2006. The majority of his projects have been in the fields of water resources and underground engineering. He holds both a bachelor’s and master’s degree in geological engineering and is a registered professional engineer in the states of Colorado and California, and a registered geologist in the states of Missouri and California.

 

Shannon & Wilson Ranked as 2015 Top Trenchless Design Firm
January 7, 2016

Shannon &  Wilson was ranked 35 among Trenchless Technology's 2015 Top 50 Trenchless Design Firms. View the entire list here. Previously ranked 43 in 2014, the firm continues to grow its Underground Services Department with the recent addition of Dr. Axel Nitschke as the firm's new Director of Operations for Underground Services. Nitschke is a 20-year veteran of the underground services industry working on road, rail, and utility tunnel projects for infrastructure and mining clients in both urban and remote areas throughout North America, South America, and Europe. He is an active member of numerous professional associations and a regular contributing author for tunneling and shotcrete publications and associations, including the 2016 World Tunnel Congress.

 

Axel Nitschke Authors "Memo" in Shotcrete Magazine
December 11, 2015

Dr. Axel Nitschke, PhD, PE, Vice President and Director of Operations for Underground Services for Shannon & Wilson, was a recent contributor to the Committee Chair Memo section of the Fall Equipment Issue of Shotcrete Magazine. Read Axel's article here, as well as the rest of the e-Magazine hosted on the Shotcrete Magazine website. 

 

New Denver/Corporate Marketing Manager
December 11, 2015

Shannon & Wilson is pleased to announce the addition of a new Marketing Manager in the firm’s Denver office. Stephanie Fortner joined the firm as both the Marketing Manager for Denver and to lead corporate marketing efforts. She brings nearly 25 years of experience with the full spectrum of professional services marketing, including business development, proposal management and PR/communications. Over the last 20 years she has helped Denver area architecture, engineering, and design consulting firms grow their businesses and market presence.

 

New Director of Operations for Underground Services

September 14, 2015

Shannon & Wilson recently hired Dr. Axel Nitschke, PhD, PE, as Vice President and Director of Operations for Underground Services. Dr. Nitschke will operate out of Shannon & Wilson’s new Washington D.C. Metro office, located in Tysons Corner, VA.

Dr. Nitschke’s hire is a strategic move as Shannon & Wilson widens its national underground services portfolio. Shannon & Wilson is highly recognized for its geotechnical consulting and engineering services for underground projects, including but not limited to geotechnical exploration, testing, and instrumentation, and monitoring services. The company has long provided underground services for the full range of underground construction, including small, midsize and large diameter pipeline tunnel projects as well as geotechnical and structural inspection services for existing tunnels and on-site support for rehabilitation of underground infrastructure projects. By hiring Dr. Nitschke, Shannon & Wilson has taken steps to become a full-service underground services provider, adding and emphasizing structural design, cost estimating, scheduling, and construction management to its portfolio of underground services.

As Director of Operations for Underground Services, Dr. Nitschke will jointly lead Shannon & Wilson’s Underground Services department with Red Robinson. In addition, he will be in charge of Shannon & Wilson’s upcoming pursuits of underground projects nationwide, and he will actively increase Shannon & Wilson’s presence in the Northeast Corridor.

A 20-year veteran of the underground services industry, Dr. Nitschke has experience in wide-ranging aspects of tunneling, including design, management, QA/QC, safety, and construction. He has worked on road, rail and utility tunnel projects for civil infrastructure as well as mining clients in both highly congested urban areas and remote conditions with clients including Sound Transit, New Jersey Transit, CALTRANS, DC Water, and agencies throughout Europe, as well as a multitude of construction companies. His practical experience builds on a solid scientific knowledge of tunneling, which he has gained during his graduate and post-graduate studies as a research assistant at Ruhr-University Bochum (RUB) in Germany.

 

Take a Virtual Tour of the SR 520 Project

November 17, 2015

Take a virtual tour of the SR 520 bridge replacement project over Lake Washington. For the past 9 years, the Shannon & Wilson team in Seattle has worked extensively on this mega-project for WSDOT that includes a new floating bridge and approaches. As part of the GEC team and as geotechnical engineer of record for some portions, Shannon & Wilson performed advanced probabilistic seismic studies, dynamic soil-structure interaction analyses, contaminated materials characterization, groundwater analyses, and support for DB and DBB procurement.


Virtual tour of the SR 520 floating bridge: https://youtu.be/naPoDAIOzB0

Virtual tour of the SR 520 West Approach Bridge North: https://youtu.be/P53ejxjV6A8

 

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