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.

TBM Expert Joins Shannon & Wilson's Underground Services Practice
December 29, 2016

Shannon & Wilson is continuing its expansion of their underground services practice with strategic hire Edward R. Kennedy. Kennedy joins the firm as a Vice President and Senior Project Manager for Tunnels and Systems. He has more than 40 years of experience in all major phases of heavy civil construction projects and significant expertise with soft ground and hard rock Tunnel Boring Machines (TBMs).

Kennedy has served as Resident Engineer for large, complex water/wastewater, transportation, and other infrastructure-related projects in challenging urban environments. He is also an established leader and innovator in the tunneling/underground industry having participated in much of the development history of the TBM, working with Robbins who pioneered hard rock TBMs and disc cutters. He is recognized by contractors, engineers, owners, and manufacturers as an innovative engineer and hands-on TBM expert with unique knowledge of mechanical excavation and its application. He also has worked on the design, operation, and troubleshooting of both soft ground and hard rock TBMs around the world.

“Adding Ed to our team strengthens Shannon & Wilson’s construction management and engineering services for TBM projects, and adds capabilities to our growing eastern U.S. services” states Axel Nitschke, Director of Operations for Underground Services and the manager of Shannon & Wilson’s DC Metro office.


Ten Years of SR 520 Bridge: West Connection Bridge (WCB)
April 14, 2017

This is the fourth 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 West Connection Bridge (WCB) routes eastbound traffic from the existing West Approach Bridge to the new floating bridge. In a future phase, 10 of the 19 WCB drilled shaft foundations will be reused to support the proposed West Approach Bridge – South (WABS). The WCB is a vital link to keep traffic flowing during the SR 520 Bridge Replacement project.

The WCB is a 1,335-foot-long, 65- to 160-foot-wide, 11 pier, conventional bridge structure, extending entirely over water. Lake water depths vary from about 10 to 35 feet along the alignment. The eastern end of the bridge connects to Pier 36 which was constructed by the floating bridge design-builder. The WCB drilled shaft foundations were designed to not only support the loads during the life of the WCB, but also be forward-compatible with the future WABS design-builder design.

Between 2009 and 2012, Shannon & Wilson, as part of HDR’s General Engineering Consultant (GEC) team, coordinated and then observed:

• Drilling and sampling 23 overwater borings,

• Installation of triple-stacked vibrating wire piezometers in 3 boreholes, and

• 1 overwater shear wave velocity test. 

The stacked vibrating wire piezometer cables were bundled together, laid across the lake bottom over to the existing West Approach Bridge where a solar panel and readout box were mounted. The vibrating wire data was transmitted via cellular technology to WSDOT and then forwarded to Shannon & Wilson for evaluation. The instruments indicated the presence of a pressurized, confined aquifer with groundwater readings about 5 feet above lake level.

WCB Piers 25 through 30 widened the existing West Approach Bridge by adding 8-foot-diameter drilled shafts adjacent to the existing bridge pile caps. The Pier 25 through 30 drilled shafts are within 7 to 11 feet horizontally from driven pile foundations supporting the existing West Approach Bridge.  The shafts also extend approximately 27 to 42 feet below the driven pile foundations. To protect the existing pile foundations, the shafts have permanent casing installed to about 15 feet below the existing pile tips.

Where the WCB is an independent structure, Piers 31 through 34 are founded on 10-foot-diameter drilled shafts, and Pier 35 is on 12-foot-diameter shafts.

Slurry head, along with temporary and/or permanent casing, were used to address the groundwater pressure and maintain drilled shaft integrity during construction.

As the geotechnical engineer of record, Shannon & Wilson completed 100% design for the Design-Bid-Build WCB project, submitting a geotechnical report and a Summary of Geotechnical Conditions as well as helping prepare geotechnical- and environmental-related specifications. We also developed a geotechnical instrumentation plan to monitor construction-induced vibrations and deformations of the adjacent West Approach Bridge and buildings located on shore near the work zone. During construction, Shannon & Wilson reviewed Contractor submittals and provided WSDOT construction support in matters related to drilled shaft foundations and geotechnical instrumentation.

West Connection Bridge

Years of SR 520 Bridge: Eastside Transit and HOV

October 19, 2016

This is the third 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 Eastside portion of the SR 520 Bridge project successfully relieved traffic congestion by improving transit facilities, service, and HOV operations.  In addition, landscaped “lids”, typically 500 feet in length, were constructed to reconnect the communities on either side of the highway.

The Eastside project is about 2.5 miles long, extending from Evergreen Point Road in Medina, WA, just shy of Lake Washington, to 108th Avenue NE in Bellevue, WA.

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

  • Drilling and sampling almost 300 borings,
  • Installation, development, and slug testing of 98 observation wells,
  • Installation of 38 vibrating wire piezometers,
  • 6 pressuremeter tests, and
  • 7 shear wave velocity tests.

Soil and groundwater conditions included landslide/landslide prone areas, a glacially-overridden lake deposit with sheared/diced/disturbed zones, and unconfined, confined, and perched groundwater aquifers.

We completed 60% design for:

  • 10 fish passage structures
  • 12 stormwater facilities
  • 5 major intersections/interchanges with lids or bridges
  • Multiple pedestrian facilities
  • Nearly 100 cut and/or fill retaining walls ranging in height from a few feet to over 70 feet

We also completed four Phase 2 Environmental Site Assessments (ESAs) and one supplement Phase 2 ESA.

Shannon & Wilson conducted phased corridor-wide seismic studies for 1,000-year ground motions.  First, we performed a literature review of published research on seismic sources, directivity, and basin effects that had not yet been incorporated into the 2009 AASHTO ground motions maps, and provided preliminary design ground motions.  Second, we performed a site-specific probabilistic seismic hazard analysis (PSHA), incorporating the research and recently published ground motion attenuation relationships.  From the PSHA results, we developed design response spectra along the project alignment.  Additional seismic studies were completed as the overall SR 520 project progressed.

When WSDOT decided to use a Design-Build (DB) delivery system, we prepared a Geotechnical Baseline Report (GBR), Chapter 2.6 of the Request for Proposal (RFP) document, a Geotechnical Data Report (GDR), a seismic criteria memo, and provided review and comment on DB questions throughout procurement.  We also provided preliminary engineering reports for the various design elements listed above.  Throughout DB design and construction, Shannon & Wilson provided submittal review and support, working alongside WSDOT’s geotechnical representative.

The bulk of our Eastside exploration and preliminary design effort was completed in a couple years’ time.  Shannon & Wilson worked collaboratively with WSDOT to keep on schedule while juggling multiple tasks.  As the project evolved over several months, we were moving the geotechnical design forward to 60% at the same we were preparing DB RFP documents.  By utilizing our combined geologic, hydrogeologic, environmental science, and GIS specialties, we were able to assist the GEC team and WSDOT in applying for and reducing stormwater treatment requirements along portions of the Eastside alignment based on historic peat areas and their impact on infiltration.

East Side Evergreen Point Road Lid

East Side 84th Ave Lid

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:

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.

To commemorate the one year anniversary of the completion of the SR 520 Floating Bridge, the Washington State Department of Transportation created a short documentary video, an online “booklet,” and a blog post. These are really great pieces that show how the project came to be.


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.


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