South Park Bascule Bridge Replacement

APWA Washington Public Works Project of the Year Award

Category: Transportation, More than $75 million 2015 APWA PROFESSIONAL AWARDS (electronic submitttals only) submitttals (electronic E-mail Phone City address) street box,include o ce post (if Address Agency/Organization Title Name Managing Agency Division Project Category Project Public Agency Date Completion Project Name Project Deadline Must be substantially completed (90%) and available for public public for available and 2014. 31, (90%) December of completed as use substantially be Must September 2,2014 Morethan$75Million $25Million–$75Million $5Million, butlessthan$25Million Lessthan$5Million DisasterorEmergencyConstruction/Repair HistoricalRestoration/Preservation Environment Transportation Structures January 15,2015 c W Public State/Province

orksPr Nominatio Fax Zip/PostalCode oject n Form the Y ofthe E-mail Phone City address) street box,include o ce post (if Address Agency/Organization Title Name Contractor Primary E-mail Phone Continued... City address) street box,include o ce post (if Address Agency/Organization Title Name Consultant Primary Federal Way [email protected] 253-943-4181 33455 SixthAvenueSouth Jason Silva Kiewit-Massman, aJointVenture Project Manager ear A ward State/Province State/Province WA Fax Zip-PostalCode Fax Zip/PostalCode 98003 2015 APWA PROFESSIONAL AWARDS NOTE: • be resubmittedinasubsequentyeartheothercategory. Project ofthe Year–Small Cities/Rural Communities Award cannot Nominations notchoseninaspecificyearforthePublic Works categories isnotpermitted. Works Projectofthe Year andSC/RCProjectofthe Year orintwo Simultaneous nominationofthesameprojectinbothPublic form, andphotographs. Nolettersofrecommendationplease. should includenominationformandsupportingdocumentation be usedforpromotionalpurposesbytheassociation. Submittal exclusive ofphotographs andnominationform. Photographs will • • • • • sequence belowwhenpossible. areas inyournomination, adheringtothe Please address eachofthefollowing • demonstr used. Useofalternativematerials, practices offundingthat Construction schedule, management, andcontroltechniques granted shouldbeaddressedinthesubmittal. Completion datecontainedincontract. Any timeextensions project. in technologyand/ormanagementapplicationsduringthe attention oftheprojectreviewpanel, suchasinnovations Additional considerations youwouldlike tobringthe but notlimitedto, adverseweather, soilorsiteconditions Unusual accomplishmentsunderadverseconditions, including minimize publicinconvenienceandimproverelations consultant andcontractor toprotectpubliclivesandproperty, Community relations—asummaryoftheeffortsbyagency, employed duringtheconstructionphase. per 1,000man-hoursworked andoverall safetyprogram Safety performanceincludingnumberoflost-timeinjuries other occurrencesoverwhichtherewas nocontrol. species, etc., duringtheconstructionphase. to preserveandprotecttheenvironment, endangered Environmental considerations includingspecialstepstaken Supporting documentationislimitedto20pages, ates acommitmenttosustainability. Public Works Project oftheYear Award . , or the nominationsarejudged. chapters mustbeidentifiedonthenominationformandbefore chapter willreceivecredittosubmitaPACE nomination. All within twoormorechapterslocationscanbeco-nomiated. Each public agency or APWA chapters.) chapters.) APWA or agency public E-mail Phone City Address (ifpostofficebox, includestreetaddress) Agency/Organization Title Name Nominated by: King CountyDepartmentofTransportation 206-477-3546 Seattle 201 SouthJacksonStreet [email protected] Managing Engineer Jim Markus,PE Supporting Data Form

(Can only be nominated by managing by nominated be only (Can State/Province WA

Projects thatinvolveorreside

Fax Zip/Postal Code 98104 South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

OVERVIEW

South Park Bascule Bridge Replacement The $167 million South Park Bascule Bridge Replacement Project constructed a new seismically resilient bridge over Seattle’s Duwamish Waterway parallel to and downriver from the existing bridge, which had been battered by earthquakes and age.

The new bascule bridge opened to traffic June 30, 2014, and is notable for several reasons: • It is designed to a 975-year seismic event with innovative solutions that bid within 10 percent of the engineer’s estimate. • It was constructed on an Environmental Protection Agency-designated “Superfund” site, requiring extensive environmental permitting. • The project was construction-sequenced to accommodate annual 6.5-month-long in-water work periods (fish windows) while meeting the Muckleshoot Tribe’s fishing needs. • At the public’s request, the bridge architecturally emulates and preserves aspects of the original, historic bridge.

Closing a vital, beloved bridge The original South Park Bridge, built in 1931, was a Old Bridge (1929-2010) double-leaf bascule bridge listed on the National Historic Register and designated as a King County Landmark. The 1,045-foot-long bridge, popular with the local residents for its look and importance to the community, connected Seattle neighborhoods across the Duwamish Waterway, a navigable channel used for commercial, industrial and recreational purposes.

The bridge had suffered over the years and was rapidly deteriorating. Further, it was seismically vulnerable for two main reasons: 1. The original foundation piles were not driven completely through a deep layer of liquefiable soil

1 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

into the solid glacial till below. 2. The concrete structure was weakened by cumulative damage from previous earthquakes.

The tilting and cracking of the main piers meant the bridge was susceptible to reactive movement as the bascule spans opened and closed. The bridge required extensive maintenance and operations to maintain alignment of the moveable spans and machinery.

In May 2008, King County Department of Transportation launched the ambitious South Park Bascule Bridge Replacement Project, selecting HNTB as the final design consultant.

The team overcame numerous challenges, including: “This bridge is critical to several • Permitting for construction in a “Superfund” site neighborhoods: It is critical to • Meeting unprecedented seismic performance South Park, and to Georgetown, • Historic preservation criteria and to the industrial area of • Continually informing the community to generate patience Seattle.” during a long funding pursuit and a lengthy construction phase — Dagmar Cronn, South Park • Achieving a design that enhances maintainability and community leader reliability

Ultimately, the bridge was classified structurally deficient and functionally obsolete, receiving a startling sufficiency rating of four out of 100. Without funding for a replacement, the King County DOT closed the bridge on June 30, 2010, due to safety concerns.

Replacing the South Park Bridge was a top priority for King County Executive Dow Constantine. He led the charge, securing necessary local and federal funding by October of that same year.

“I hereby pledge to do all within my capacity to secure funding for the replacement of the South Park Bridge,” Constantine said. The Partners Ed Murray - City of Seattle, Jim McDermott – House of community also responded with a letter-writing Representatives, Dow Constantine – King County Executive and campaign that attracted the attention of Patty Murray – State Senator at the Grand Opening. Senator Patty Murray.

The following funding partners responded, supporting King County’s successful application of a $34 million Transportation Investments Generating Economic Recovery (TIGER II) Discretionary Grant: • King County - $30 million • Washington State Department of Transportation, federal bridge funds - $20 million • City of Seattle - $15 million • Port of Seattle - $5 million • City of Tukwila - $3 million • Puget Sound Regional Council - $15 million • The Boeing Company – $1.5 million in real estate • Transportation Improvement Board (TIB) - $10 million • Freight Mobility Strategic Investment Board - $5 million

2 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

Restoring a community and its vital economic link Despite numerous obstacles, the new bridge was delivered successfully. It opened to traffic on June 30, 2014. The notable features of the project include: • Provides a reliable link to South Park neighborhood businesses that rely on the bridge for economic benefit. • Preserves potential economic development upriver with a bridge that provides unlimited vertical navigation clearances instead of a fixed-span crossing. • Provides capacity and redundancy to the local roadway network, especially to heavy truck volumes, which carry approximately 10 million tons of freight annually across the bridge, including aerospace parts to local Boeing facilities. • Provides a beautiful landmark bridge with art and other aesthetic features and an adjacent park to restore pride and promote new development in the beleaguered South Park community.

One-of-a-kind project

South Park Double-Leaf Bascule Bridge • $167 million, partially funded by a TIGER II Grant. • Operates using two 75-horsepower motors — • Length — 1,045 feet only slightly more power than a Toyota Prius • Four vehicle lanes, two in each direction • Main pier (south side) was sunk 70 feet below • Bike lanes and sidewalks in each direction the riverbed and contains more than 16 million • Green stormwater treatment pounds of concrete. The north pier was sunk 110 • Preservation of character and significance of feet and contains more than 21 million pounds existing bridge. Historic elements, such as gears, of concrete rockers and guide tracks, decorative light posts, • The new draw span decking is made of concrete railings and latticed steel members, deck that is 22 percent lighter than regular concrete grating, and old bricks were salvaged, restored • To minimize the interior space of the pier and, and incorporated in the new bridge and at the same time, increase the weight of the surrounding site normal concrete, steel punchings were added • Designed to sustain minimal damage and remain to the counterweight concrete operational in the aftermath of a lower-level • Contains approximately 750,000 feet of wiring, (108-year) seismic event and to experience only delivering power and control systems through a moderate damage, repairable in a short time micro-bore tunnel beneath the river bottom. following a higher-level (975-year) earthquake

3 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

SUPPORTING DOCUMENTATION

Completion date contained in contract. At bid time, the South Park Bascule Bridge Replacement Project contract targeted a completion date of September 2013. The contractor encountered difficulty in sinking the Pier 3 caisson foundation and was eventually granted 128 additional days of contract time in an effort to reduce risk for both parties, since the contractor claimed a differing site condition. Thereafter the contractor experienced added delay on the Pier 4 foundation, when the caisson sunk beyond the designed elevation. A quick design change minimized the delay.

The construction contract included interim milestones to get the bridge open to public use as soon as possible. The project was granted beneficial completion on June 21, 2014, allowing uninterrupted, two- way vehicle and pedestrian traffic across the bridge and on-demand openings for marine traffic. It officially opened to traffic on June 30, 2014. The project reached substantial completion Sept. 2, 2014. As of December 2014, final construction activities included rain garden platform installation, painting, interpretive sign installation, minor control tower finishes and final punchlist.

Construction schedule, management and control techniques Contractually, three schedule constraints applied to the project: • An allowable, annual in-water work window from Aug. 1 - Feb. 15 • Navigation channel closures, limited to a maximum of 72 hours • Required to keep at least half of the waterway open to vessels with no height restrictions

The contractor submitted an overall project schedule monthly and a three-week look-ahead. The look- ahead provided details about contractor and subcontractor activities, material delivery schedules, marine movements and resources expected on-site.

Weekly project construction management meetings were held to discuss the three-week look-ahead schedule, requests for information, requests for approval of materials, submittals and any outstanding items.

Construction management team members managed the project and moved it forward to the best of their ability by documenting all project elements and adhering to the intent of the contract.

Several efforts were made to achieve beneficial completion by June 21, 2014: • Prioritizing submittals, requests for information and issue resolution to identify items that had to be completed to open the bridge to traffic • Responding promptly to critical items • Collaborating on-site. The design team and resident engineers were on-site to help identify and resolve critical-path issues in a timely manner • Establishing good working relationships with the U.S. Coast Guard and area businesses to gain additional flexibility in performing the work • Prefabricating and preassembling the bascule leaves off-site, approximately one mile downriver, which allowed for more construction space and quicker assembly. The contractor delivered the leaves via barge

Safety performance Considering the complexity and magnitude of the $100 million (construction cost) project, there were only six minor lost-time injuries for more than 500,000 man hours worked or substantially less than one lost-time injury per 1,000 man hours.

This level of safety was achieved by a thorough safety program that emphasized:

4 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

• The contractor’s safety philosophy and culture • King County and WSDOT requirements related to procedures and required training for conducting the work • Personal protective equipment, such as safety glasses, hard hats, boots, gloves and high- visibility vests, as well as personal floating devices as needed, on the job site • A project-specific Health and Safety Plan (HASP), which outlined safety procedures. The HASP established in detail the protocols necessary for protecting workers, on-site personnel, visitors, off-site personnel and the public from potential hazards that might be encountered during removal, excavation, stockpiling, handling, sampling, transportation and disposal of contaminated soils, water and other material • A designated Safety Supervisor, who conducted project walk-throughs and job hazard analysis for each work activity • Monthly safety meetings attended by both contractor and construction management teams. • Daily “tailgate” task-specific safety meetings among various crews

Safety training and certification: As part of the contract specifications, appropriate training to protect workers was required. Below are examples of construction certifications and training requirements: • HAZWOPER: Required training for all contractor and CM personnel onsite who could potentially engage in handling and testing contaminated and hazardous materials on the “Superfund” site • Fall protection and training: All workers were required to have fall protection certification and training • Marine work: Certifications and training were required for the marine crew. Appropriate PFDs and communication methods, such as horns and tag-in/tag-out methods, were used when working over the water and constructing the bascule piers and superstructure • Confined Space: Training was required for activities in confined spaces to comply with Occupational Safety and Health Administration (OSHA) regulations • Flagger: To increase public safety, a flagger card was required for maintenance of vehicular and pedestrian traffic

Environmental considerations Because the project was in and over the Duwamish Waterway, an Environmental Protection Agency- designated “Superfund” site, environmental considerations were critical to successful project delivery. Approximately 27 permits regulated and prescribed allowable actions on the site and were needed to move the project forward. In addition to King County, participating agencies included WSDOT, the Federal Highway Administration (FHWA), the EPA, the U.S. Army Corps of Engineers, the U.S. Coast Guard (USCG), the U.S. Fish and Wildlife Service, the Washington Department of Fish and Wildlife and the Department of Ecology. “The CM Team worked with the contractor to It is important to note the project was never delayed develop and implement a variety of activity- due to permit compliance issues. specific environmental compliance measures, King County started the environmental review phase and then provided continuous oversight to with Environmental Impact Statement process. As minimize potential problems and address any part of the owner’s commitment to protect the problems that occurred. As a result, no major environment, the following extensive measures were environmental compliance violations occurred in put in place during construction: spite of the exceptional challenges posed by the • Contract specifications to meet complex construction processes that were environmental permit requirements. undertaken in a highly sensitive environment • Construction sequences designed around annual 6.5-month-long allowable in-water over a period of several years.” work periods (fish windows) while meeting the Muckleshoot Tribe’s fishing needs. — Jim Sussex, Lead environmental engineer, King County • Extensive environmental permitting, dictating

5 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

construction restrictions. • Daily inspection of the site to ensure environmental compliance and extensive on-site coordination with the contractor to resolve issues as they developed.

Below are best practices used to protect the environment during construction: • Instituted an in-water construction/fish window for endangered Chinook salmon. All work below Mean High Higher Water was required to be completed between Aug. 1 and Feb. 15. Cofferdams were placed during the work window to separate construction activities from the waterway and to allow construction to continue outside the in-water work window • Coordinated navigation channel closures two weeks in advance • Minimized the in-water environmental footprint by using caissons for bascule bridge construction, resulting in an area of 60’ x 60’ per bascule pier • Met water quality standards by treating all contaminated and processed water through Baker Tanks and chitosan-enhanced sand filters prior to discharge • Continually monitored turbidity 300 feet downstream during sediment-generating, in-water construction activities • Developed a Spill Prevention, Control and Countermeasure Plan (SPCC). The plan detailed how the contractor would prevent spills, as well as prepare for, prevent or respond to oil discharges in navigable waters and on the shoreline • Implemented Standard Temporary Erosion and Sediment Control (TESC) methods, such as a filter fabric fence, inlet protection, silt curtains and geotextile for soil stabilization, to prevent sediments from entering the Duwamish Waterway • Handled and disposed of hazardous and contaminated materials per Revised Code of Washington (RCW) regulations from the riverbed and upland areas. Soils had to be decanted, tested, separated and transported by lined trucks to appropriate facilities • Performed archaeological evaluation during excavation activities and analyzed for historical artifacts • Established and maintained a debris containment system, required during all construction activities • Placed sand drainage blankets to minimize contaminated soil disturbance during in-water construction activities

6 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

Community relations Throughout the development, design and construction of the project, King County maintained frequent, open communication with the businesses and residents near the bridge to keep them apprised of the project’s status and to solicit input from those most affected by the bridge closure.

Because the South Park community falls under Environmental Justice regulation, good communication with the local minority population was especially important. Minorities make up 56 percent of the community; 11 percent of the neighborhood lives in poverty; and 89 percent of the students at the local elementary school qualify for free or reduced-fare lunches.

In 2002, at the start of the project, a public involvement plan was developed. This plan identified ways the project team could communicate with this diverse population. All information was distributed in the area’s three most prevalent languages: English, Spanish and Vietnamese. Flyers, e-mails, website updates and numerous community meetings were used to relay information. Public open house in 2010. Translators were available during the community meetings and open houses.

In addition, a Citizen Advisory Group was formed. This diverse group of stakeholders met often and conveyed an important public perspective, which was incorporated into the bridge’s design during the long eight-year environmental documentation phase. One of the more notable action items was the group’s request to include many of the original bridge’s architectural details in the new bridge’s design, as well as to salvage and display more than 100 parts at the project site.

Because of the original bridge’s condition, user safety was an obvious concern. When the decision was made to close the bridge in 2010, communication with the community became even more important. As could be predicted, the community reacted negatively to the news. Upon learning funding had not been secured for a replacement, many residents became confrontational and angry.

To try and preserve the good relationships that had been established up to this point, the County held weekly community meetings in the months leading up to the closure. The closure would create a 3-mile detour and add 20 minutes to normal commute times. The County used these meetings to prepare residents, explaining at length why the bridge was being closed and how emergency services, transit, detour routes and other details were going to be implemented.

The South Park neighborhood was highly dependent on traffic crossing the bridge. Once the bridge closed, the core business district at the south end of the bridge experienced an instant reduction in activity. Residents, who once easily frequented establishments, now had to commute away from the bridge to cross the waterway. And, workers who previously flocked to South Park for lunch every day Public art depiction of the reaction to the bridge closure from the north side of the bridge, could no longer in 2010. access it easily.

7 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

“It doesn’t work without a Other critical issues focused on the various social and community. It doesn’t work without economic impacts to the surrounding community. The County all of us coming together and making swiftly implemented a frequent, open communication sure that a project like this gets done program to keep the community apprised of the project’s status. Officials diligently maintained a series of weekly that will serve us for generations and electronic updates and regular public meetings throughout decades to come.” the course of construction. Extensive outreach included door-to-door visits to key businesses along the closed — Larry Phillips, King County corridor, which proved to be a most effective means of Council Chair communicating and answering questions. When the language barrier became too great, translators were extremely effective in communicating with minorities. Once they heard their native language, minorities opened up and the conversation flowed easily.

To minimize public inconvenience, the County implemented the following additional measures: • Continued public outreach to other groups in the area by volunteering at the food bank and hosting an information booth at the local Spanish-speaking clinic, the South Park community’s largest employer. • Worked closely with the South Park Information Center to disseminate the latest project news. • Communicated with the South Park Business Association and the Latino Merchants Association. • Erected sandwich boards to show business access and to emphasize businesses were open. • Installed detour signs, revised signal timing and restriped the roadways to minimize confusion and increase safety. • Installed a new traffic signal to handle new detour route traffic. • Allocated business development funds and invested them in the affected businesses to help keep them afloat during the difficult time.

Confronted by the reality of the old historic bridge closing forever, the community joined the county's effort to seek funding for the new bridge. A highly successful campaign was undertaken by South Park citizen groups to write elected officials asking for their support. At the ground- breaking ceremony, Senator Patty Murray commented on how effective and important the citizen involvement was to secure funding. Construction began on May 24, 2011, with the breaking of a 26-foot- long piñata. Construction was accompanied by long hours of construction noise and other disruptions. Realizing this, the County worked tirelessly to maintain a Because of extensive outreach, community participation and appreciation good relationship with the community: was demonstrated at the grand opening. • At the request of community members, the County converted a construction staging area to a dog park once the original bridge was closed. The park brought people to the business core, directly benefited a dog-food merchant and showed the community the County was willing to work with them. The park remained open for one year until the site was developed as part of the project. • Allocated a second round of business development funds to bolster local merchants.

8 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

• Continued to walk the business core, personally checking with all merchants and continuing to address their concerns over issues, such as parking and business access during construction. Translators accompanied County staff during each walk. • Attended community festivals and hosted booths to keep people informed of the project’s status. Staff members came early and stayed late to help set up and tear down the event. • Encouraged the construction staff (25 employees) and bridge workers (up to 100) to do business with the local coffee shops, restaurants, grocery stores, taverns, tire stores and a gas station affected by the project. • Gave archeological tours at the beginning of construction to explain what was found on-site and to inform interested citizens of the area’s Native American history. • Held two-hour-long project photo shows three times a year to inform the public of construction progress and to give them a “behind the scenes” look. These meetings were very popular and allowed the community to assemble in a relaxed restaurant setting. The County hired a professional photojournalist to take the photos. The photographer and a County engineer hosted the show. • Updated the project website monthly to keep the community informed. • Attended community meetings when a certain group needed to be addressed or when the community needed more detail about a specific phase of work.

The extra investment in community relations paid off many times over. A good rapport was maintained throughout the project. Problems that did arise were typically handled by local project staff rather than escalating complaints to the County level.

Throughout construction, the navigable Duwamish Waterway had to remain at least partially open per U.S. Coast Guard requirements. Extensive coordination with South Park employer and yacht builder, Delta Marine, resulted in a good working relationship and, consequently, the business experienced minimal disruption during construction.

Coordination with the two upriver marinas was important once the two moveable bridge spans were in place and bridge openings were necessary to let recreational sailboats through. The County served as a liaison between the marinas and the contractor to enforce the bridge opening schedules and regulations for nine months until the bridge was opened to the public and a bridge tender staffed the drawbridge tower.

The extra investment in community relations paid off many times over. A good rapport was maintained throughout the project. Problems that did arise were typically handled by local project staff rather than escalating complaints to the county level.

Unusual accomplishments under adverse conditions. Contaminated soil conditions Because the project was within an EPA Superfund site and to minimize delay during construction, significant testing and identification of contaminated soils was performed during design to evaluate the amount of contaminated/hazardous material that would require special handling and disposal.

In the Duwamish Waterway, the top six to 10 feet at the bascule pier locations were deemed contaminated, requiring the contractor to separate and stockpile this material. It would be tested to confirm levels of contamination.

On the upland side, a grid test was performed to determine depth and concentration of the contaminated materials. During construction, additional testing was conducted at the locations not

9 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million accessible during design. Again, the contractor was required to separate and stockpile the material prior to disposal. To adequately handle and dispose these materials, careful evaluation, handling and testing had to be performed to meet regulatory and safety requirements.

Caisson construction To keep the contaminated water contained within the cofferdam, the contractor was required to maintain the elevation of the standing water within the watertight caisson cofferdam at an elevation of 3 feet lower than the elevation of the Duwamish Waterway. Due to tidal fluctuations of up to 15 feet and because the cofferdam was not constructed “watertight,” water was pumped continuously in or out to maintain the 3-foot elevation difference. All water pumped out of the cofferdam had to be treated prior to discharge.

Sinking of Pier 4 During construction, the contractor sank the Pier 4 caisson approximately 2 feet-2 inches below the contract-specified tip elevation. The County directed HNTB to develop a solution during construction to mitigate for the differential. A change order was expeditiously prepared to provide a new concrete pedestal to be constructed on top of the caisson cap, effectively raising the trunnion frame and bascule span to plan-specified elevations. Affected components included caisson cap, pier walls, stairs, stairwells, platforms, trunnion frame and trunnion frame anchor bolts. Further, a thorough review of the global seismic design had to be performed. The significant change allowed the roadway to be constructed and designed in a timely manner.

Preserving tribal fishing needs Muckleshoot Tribal fishing periods in the Duwamish Waterway occur between Aug. 1 and Dec. 31. During construction, the contractor was required to observe the tribal fishing period and compensate the tribe for lost fishing time, which included replacing any damaged fishing nets, paying for time lost when nets were temporarily moved to accommodate contractor operations and paying for any potential lost harvest. The contractor had to be aware of these issues and plan ahead to avoid impacts to the schedule and operations.

Working in a navigable waterway The Duwamish Waterway is a navigable waterway, and in accordance with U.S. Coast Guard requirements, the channel could not be closed to marine traffic without advance written permission. In cases where permission was granted, the closure period was generally limited to 72 hours. Therefore, to avoid disruptions to the overall project schedule, as well as marine traffic, the contractor and the County maintained close communication with the nearby Delta Marine and other mariners in the area to inform them of upcoming, permitted channel closures.

Extensive monitoring In addition to standard monitoring and to satisfy environmental permitting requirements, archaeological and hydro-acoustic monitoring was performed. Hydro-acoustic monitoring was implemented during in-water activities to ensure the contractor did not impact fish by maintaining the Sound Exposure Levels (SEL) of 187dB. Underwater noise levels were monitored during the installation of steel piles for temporary trestle.

Extensive monitoring was performed to protect historic artifacts. An archaeologist was present during all ground-disturbing activities to watch for human remains, as well as prehistoric and historic-period artifacts. A monthly report, prepared in accordance with the Washington Department of Archaeology and Historic Preservation, documented the results.

Working on and near Boeing Company property The north approach to the bridge was constructed on Boeing Co. property, which is a secured facility. Temporary construction access had to be obtained for the north approach and bascule pier, as well as contractor laydown area. In addition, crews had to abide by Boeing’s high-security requirements. All personnel were required to obtain badges for access. In addition, there was security fencing and gate- controlled access to the site, which was coordinated through the Boeing Co. security group.

10 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

ADDITIONAL CONSIDERATIONS

Design complexities and innovations The South Park Bridge Replacement Project is by far King County DOT’s largest-ever public works project. To achieve project goals, HNTB proposed and designed four innovative solutions, three of which met stringent seismic performance requirements. The fourth innovation focused on speeding fabrication and erection while reducing maintenance.

The most challenging aspect of the project, though, was designing a moveable bridge in an AASHTO Seismic Zone 4. The bridge was designed to be fully functional in the aftermath of an Operational Earthquake Level (108-year return period). Additionally, only moderate and repairable damage was permitted as a result of a Design Earthquake Level (975-year return period).

Designing a moveable span with its complex, dynamic system of structural, mechanical and electrical components to a 975-year return period was unprecedented. It was achieved with three design innovations:

1. Sunken caisson foundations Prior to HNTB’s involvement, the preliminary design called for large-diameter drilled shafts for bascule pier foundations. Beyond the high cost and constructability issues of drilled shafts, the relative flexibility of the long shafts required to reach reliable soil strata produced unacceptably large deflections when subjected to ground motion.

HNTB’s sunken caisson solution proved to be economical and provided enhanced seismic performance compared to drilled shafts.

11 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

• Because the foundations relied primarily on soil bearing pressure for resistance, the large cross-section of the caisson provided substantial area that produced relatively small bearing pressure with high rigidity, resulting in minimal deflection • The caissons were extremely efficient for resisting lateral seismic loads in terms of forces or displacements • The soil-structure interaction effects, such as rocking, accommodated seismic demands in a manner similar to isolation bearings, thus reducing displacement and force demands on the bridge • A seismic time history analysis was performed to: A. Obtain a realistic prediction of the bridge’s displacement B. Determine the relative action between different bridge parts as the bascule spans and the machinery were sensitive to movements. The analysis provided a realistic estimate of the forces and displacements and was crucial in the design of the structure’s key elements • The caisson cross-section and depths were reduced, which was more economical than drilled shafts

2. Isolated trunnion frames For the bascule leaves to remain operational without disruption after an operational earthquake, permanent relative displacements between the rack (mounted to the bridge girder) and pinion (mounted to the machinery slab) of the drive system was limited to values the machinery could tolerate.

To satisfy this stringent requirement, HNTB proposed the trunnion supports and the slab supporting the machinery be fastened to the same trunnion frame, connected to the piers only at the base and separated from the surrounding walls. This would ensure the trunnion (and the rack) moved together with the pinion of the drive system during a seismic event, thereby minimizing the relatively easy jacking of the trunnion frames to realign the bascule leaves should any permanent movement of the piers occur after a major seismic event.

3. Collapsible center joint on the lift spans The bascule leaves are connected at the tips by span lock bars that ensure the two leaves deflect together vertically under vehicle live loads. However, there are no longitudinal restraints between the two leaves. During a seismic event, the joint will experience separation and closure of up to 18 inches of total movement. If the two leaves were allowed to collide, the impact load would have been very large, making the trunnion frames challenging to design and costly to build.

HNTB’s solution was to design the draw span superstructure to be separated by 19 inches with a collapsible center joint. During a seismic event, only the leaf tip joint assemblies would collide, thus preventing large load transfers back to the trunnion frames. The collapsible joint was detailed, so damage would be easily detectable and repairable.

The collapsible center joint: • Eliminates large impact at the center joint during earthquakes • Is a more economical design of trunnion frames and bridge superstructure • Bears the brunt of damage

The design provided a bascule bridge that will survive a major seismic event with moderate damage that can be repaired, with the bridge being quickly returned to service at minimal cost.

12 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

“Trussed” plate girder design The fourth innovation, a “trussed” plate girder design – the first known use of this girder type – was developed to speed fabrication, erection and reduce maintenance. The main girders, one of the bridge’s most prominent and unique elements, were designed to emulate the historic character of the existing riveted truss bridge while leveraging the economy and efficiency of a modern welded plate girder system.

While a beloved community landmark, the original bridge’s gusset-plated joints were numerous and sizable. Multiple large plates and fasteners intersecting at various angles created geometrically complex regions at every panel point. These joints acted like pockets, accumulating dirt, debris, moisture, guano and other substances detrimental to the steel bridge’s long-term reliability.

HNTB’s innovative main girder design of a continuous welded plate eliminated the problem-prone areas of traditional gusset-plated joints and two time-consuming steps common in its construction: match-drilling and field installation of thousands of bolts. With those steps gone, the “trussed” plate girder design sped fabrication, shop assembly, alignment and erection.

Other inspection- and maintenance-enhancing design features • Clean bridge trusses • Bird control measures • Catwalks under the draw spans for easier inspection and maintenance access

Other complexities/challenges the team overcame • Meeting the U.S. Coast Guard permit requirements for maintaining vessel traffic in a navigable waterway during all construction phases • Extensive coordination with adjacent property owners, Boeing and the city of Seattle to coordinate details, such as utility design, stormwater design, roadway design and right-of- way/easements • Meeting local community demands by incorporating many of the previous bridge’s architectural features into the new design

Benefits to future projects HNTB’s innovation design offers insights that may benefit future bascule bridge projects: • Non-linear time history analysis is invaluable for realistic estimates of seismic force and displacement demands • Seismic articulation of bascule bridge components is critical in satisfying seismic performance requirements • Sunken caisson foundations provide superior seismic performance when compared to drilled shaft foundations • The innovative configuration of the web perforations and stiffeners (e.g., “trussed” plate girder design) provides the aesthetic appeal of the historic truss bridge while leveraging modern fabrication techniques to economize fabrication, speed erection, facilitate long-term maintenance and eliminate the inherently trouble-prone features of a true truss structure • The project demonstrates a commitment to sustainability by constructing a bridge that will be operational in the aftermath of a lower-level (108-year) earthquake and experience only moderate and repairable damage during a higher-level (975-year) earthquake.

Sustainability To develop a measurable degree of sustainability, the project team conducted a “green” echo charrette with King County and the city of Seattle to brainstorm ideas that met King County’s Green Building and Sustainable Development Practices Ordinance 16147.

The goal was to collect ideas for resource efficiency and low-impact development that would make a positive contribution to the built environment, such as: • Waste reduction, reuse and recycling 13 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

• Use of “green” materials • Minimizing greenhouse gas emissions • Sustainable site development • Water efficiency (e.g., low-impact development, stormwater applications) • Energy efficiency and renewable energy • Historic preservation • Aesthetics • Community benefits

From the charrette, several feasible green proposals were developed and evaluated for their potential to add high value, increase return and potentially reduce costs. These green proposals were carried forward for consideration in the project’s design. Outcomes included: • Repurposing materials, as well as historic and interpretive elements from the original bridge, to enhance the artistic elements of the project • Restoring the shoreline • Developing a low-impact, decorative rain garden that serves as landscape art while collecting and naturally treating stormwater runoff from the bridge • Erecting public education interpretive singing and creating enhanced river access to further integrate the project with its surrounding community • Adding energy-efficient mechanical and electrical systems • Engineering the new South Park Bascule Bridge with an energy-efficient drive system that can operate 3-million-pound draw spans with approximately the same amount of horsepower needed to drive a Toyota Prius • During favorable weather, the windows in the control towers can open to alleviate the need to power up the heating or air conditioning • Nearly all the steel bridge grating on the original moveable spans was reused either as art at the local solid waste transfer station or on the Port of Seattle Terminal 117 park project just upriver from the bridge. The steel trusses of the main and approach spans were ground into pellets for recycling and the concrete approaches were segregated into piles of concrete and rebar and recycled

Left photo: Steel grating from the old bridge deck was used as art at the nearby transfer station. Right photo: A rain garden was added to the new bridge.

14 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

Historic preservation The new South Park Bridge’s aesthetic appeal and historical significance were equally important as “We listened to the community so that every detail meeting the latest seismic requirements. There was from the lighting to the incorporated artwork was significant public agency and community interest in designed with South Park’s spirit and character. preserving the original bridge’s character and The towers, the roofs – shaped like the old ones, significance: clad in brick. The trusses, arched with cutouts to reflect the old bridge trusses. The bricks from the • The existing bridge was one of the few old red brick road have been reused in the rain working examples of an original rolling lift garden and several crosswalks. The four rockers bascule Scherzer bridge that were the historic feature of the old bridge are • It is listed on the National Register of still there. They’ve been mounted at the four Historic Places corners of the new bridge.” • It was officially designated a historic landmark by the King County Landmarks — Dow Constantine, King County Executive Commission

As a result, the new bridge was designed to emulate the overall look and feel of its predecessor by incorporating truss-like features without enduring the disadvantages of a traditional truss design: • The fascia treatments were selected in the original structure’s honor • Economy in the girder design yielded a shallower structure, providing the desired waterway clearance improvements while minimizing the overall height of the bridge, so it did not appear to tower over the surrounding community • Key operational and architectural elements of the original bridge were salvaged, restored and incorporated in the new bridge and the surrounding site • Gears from the operating machinery were incorporated into the sidewalk railing by project artist Barbara Grygutis • An intact gear set was restored and displayed on a plaza to demonstrate the original bridge’s drive mechanism • The rocker and guide track assemblies from the original bridge were transformed into gateway monuments at each end of the bridge • Other elements, such as the decorative light posts, railings, latticed steel members, cast concrete railing, old bricks and deck grating, were used to embellish the bridge site

In addition, the project includes several on-site interpretive signs, informing the public of the various types of moveable bridges that have spanned the river over the past 125 years, as well as the design differences between the old and new South Park bridges. These signs, coupled with the prominent display of salvaged parts from the old bridge, illustrate the marvels of moveable bridge engineering.

Left photo: The rocker and guide track assembly from the old bridge is incorporated in to the new. Middle photo: Old gears were incorporated into the pedestrian railing on the new bridge. Right photo: Bridge opening to let waterway traffic through. 15 | Page

South Park Bascule Bridge Replacement 2015 APWA Washington Project of the Year Nomination

Transportation, More than $75 million

ENTRY SUMMARY

The South Park Bridge Replacement Project’s goal was to design a moveable bridge that would be open to traffic immediately after a minor earthquake and be closed to traffic for a short time for repairs after a major earthquake. King County DOT, and their designer HNTB, achieved this goal by developing innovative design concepts, such as the sunken caisson foundations, isolated trunnion frame and collapsible center joint on the lift spans. These solutions not only proved to be economical but also enhanced seismic performance relative to the original purposed group of drilled shafts.

In addition, the South Park Bridge is a first-of-its-kind trussed plate girder design, created to reduce maintenance and ensure the structure’s longevity. As a result, the traveling public received a reliable, 100-year-life bridge, designed and built with the ability to survive a major seismic event with minimal damage.

The public can cross the bridge safely — whether driving, cycling or walking — with standard vehicle lane widths, delineated bike lanes in both directions and barrier-separated sidewalks.

The new South Park Bascule Bridge is more than a bridge. It’s a community’s lifeline. It reconnects residents and businesses on both sides of the river, improves freight mobility and provides better regional access to downtown Seattle and the adjacent industrial area.

The South Park community can take pride in a landmark drawbridge that is safe, preserves the art and historical features of the original bridge and improves the marine and land environment of the surrounding areas.

16 | Page