- Bridge Specs: Tower Height = 22′: Span = 152′: Travel Width =5’: Deck = Pultruded Fiberglass: Mainline = 1-1/4” galvanized structural strand: Suspender Size = 1/2” wire rope: Anchors = Concrete dead man
- Services Performed: Design, Engineering (partial), Fabrication, Installation.
- Location: 47.606545, -122.176972
View Bellevue Botanical Garden Suspension Bridge Image Gallery.
The City of Bellevue’s Parks and Recreation Department reached out to Sahale LLC in February 2008, seeking a design/build solution for one or two bridges at one of the City’s crown jewels, the Bellevue Botanical Garden. The Garden acquired a new 17-acre parcel adjacent to the garden in 2005, but the undisturbed section was on the far side of a ravine. After preliminary scoping and discussions, Sahale directed topographic surveys and geotechnical analysis to produce an engineered bridge design in Spring, 2010, just months before the death of Sahale Principal Carroll Vogel and the dissolution of Sahale.
In the aftermath, Bellevue Parks’ Scott VanderHyden continued to drive the project forward, engaging directly with the former Sahale personnel who were then acquiring their old company’s equipment and re-forming as Seattle Bridge. Together with Michael Roberts (Section T) assuming the lead engineering role, Seattle Bridge helped Bellevue continue to advance the suspension bridge project, and it was put out for bid in Spring, 2011.
In Summer 2011, Seattle Bridge contracted to acquire the materials for, fabricate, ship, and install the bridge. Following a series of design reviews and detailing, materials acquisition began in November 2011. Upon final engineering sign-off in January, 2012, Seattle Bridge moved into full-time production behind Director of Fabrication Ken Gilman, with Steve Howell heading up extensive welding operations. Seattle Bridge punched, cut, and welded 28,250 lbs of steel; cut, swaged and tested more than 3,000′ of wire rope for fencing, railing, and diagonal cables; and mocked up all elements of the bridge prior to shipment. The bridge was fabricated and shipped in March.
Typical fixed/pinned stringer connection, featuring suspender bars with integral rails and 1/2″ gapped fiberglass decking pinned in place with angle. 
Slinging superstructure. 
Bellevue saddles milled from a single block of A588 weathering steel. 
Our Services. Steve Howell welding gussets inside the WT10x60 tower legs. 
Bellevue suspender bars fabricated and ready to ship. 
“Howell Hoops,” hand/kickrail loops integral to the 1/2″ suspender bar. 
Built-up I-beam section, used as upper crossbeam for the Bellevue bridge towers. 
Stringer circuit is completed across the 152′ span, with last piece of superstructure steel adorned with a fir bough. 
Austin Thompson, working from the bosun’s chair hung from a skyline, installs mainline cable clips. 
Marty Walz and Steve Howell wrestle 1-1/4″ mainline cables into their towertop saddles. 
Bridge towers were raised onto prepared abutments using a small rubber-tracked excavator. 
Steve Howell and Marty Walz plumb one leg of the Bellevue towers 
Our Bridges. Bellevue Botanical Suspension Bridge, 2012. 
The Bellevue bridge was completed on schedule and on budget, in time for opening on Mother’s Day 2012.
As it turned out, March, 2012 was an unfortunate time to begin installation. A near-record 7.2 inches of rain and snow fell during the month–averaging .23″ per day–and the average temperature for the month nosed just above 40 degrees. Simply staging material to the site proved problematic, but through it all Installation Lead Martin Walz III remained philosophical (or, perhaps, numb and partially frozen), and installation rolled relentlessly forward on schedule. Towers were up by March 12, mainlines, skylines, and rigging were installed by March 22, and the superstructure was hung by April 1. Decking, tuning, and punch-list items were complete one week later.
The bridge was officially unveiled on Mother’s Day, 2012, with a ribbon-cutting ceremony and an enthusiastic crowd of visitors on hand to walk the new bridge. A structure like this always has many parents, and never more than this one: Al Highberger (PE) and Brandon McGinnis performed the original engineering and design, and Mr. Roberts ushered the project through engineering peer review; Mr. VanderHyden drove this project for the City, through thick and thin; JEM Contractors teamed with Seattle Bridge to excavate, form, and pour anchors and abutments; Nancy Kartes, Director of the Park, was relentlessly cheerful and helpful no matter how soggy everything got; and, finally, Earl Anderson and Carroll Vogel, two men who are no longer with us and who would have really gotten a kick out of each other, were both integral to bringing this project to fruition.
“In addition to beautiful gardens, the 53-acre Bellevue Botanical Garden features woodlands and forests rich in native plant species. The new Ravine Experience trail allows visitors to become immersed in the most pristine of our wild spaces. The stunning new suspension bridge allows visitors to observe unique topography, native understory, wildlife, and soaring conifers without disturbing the forest floor. It has become a visitor favorite and we have seen a marked increase in daytime visitation since it opened in May, 2012.”
-Nancy Kartes, Director, Bellevue Botanical Garden
“Our newest Bellevue Botanical Garden project, the Ravine Bridge and trail additions, has been a huge hit with the general public. Garden attendance has increased dramatically since its opening in May 2012 and the parking lot has been filled to capacity throughout the summer. It’s been a beautiful and unique addition to one of the Pacific Northwest’s most beloved Gardens.”
-Scott Vander Hyden, Project Manager, City of Bellevue Parks & Community Services
View Bellevue Botanical Garden Suspension Bridge Image Gallery.