The Tioga Bridge

In May of 2010, authorization was granted by BLM to fund a project east of Roseburg, Oregon which provided improvements and modifications to the Susan Creek Day - Use Area. Components of this package included trail construction, improvements and modifications, the construction of new Gazebos, and the construction of a new 270 foot long pre-engineered Glulam Bridge.


The Tioga Bridge as it is known was placed on existing concrete piers which once supported a bridge that was once part of an existing road system that washed out in 1964. By utilizing the existing piers, the BLM realized considerable costs savings in the project.

The replacement bridge was advertised for bids and the specifications required design, pre-fabrication, and supply of all bridge components. Western Wood Structures was awarded a sub-contract by Timber Mountain Construction of Southern Oregon to design, supply, and install the bridge.

The original bridge was washed out in 1964.

The new bridge was supported by the existing abutments.

the bridge components were pre-fabricated and a coat of stain was applied in the shop following pressure treatment.

The center span of the new bridge was pre-assembled on site prior to installation.

The center span of the new bridge was lifted into place.

The new bridge is now in use.

The Tacoma Dome

Next April will mark the 30th anniversary of the official opening of the 530’ diameter Tacoma Dome which when constructed was the largest clear-span timber building in the world.


The idea for a multi-use stadium in Tacoma began with a group of citizens who envisioned a local facility that could host major athletic events as well as concerts and trade shows. “A dome of our own” became their battle cry. The group got their wish in March of 1980 when Tacoma voters approved a bond measure to fund their dream.

With funding secured, the city advertised its RFP nationally in July of 1980 setting a December deadline for replies. The city spelled out specific criteria that had to be met for the arena such as seating, etc.. Six firms answered the RFP by submitting drawn up proposals and from this list three finalists were chosen to submit design-build bids by the following March.

The Tacoma Dome Associates [TDA], one of the three finalists, submitted a proposal that featured a timber dome and won the award over their two competitors: one group proposed an arena with an air supported fabric roof and the other group proposed a concrete dome that would have been supported by cables. The cost of the winning timber dome was $30.2 million, the air support fabric system bid was $35.3 million, and the concrete system bid was $35.3 million.

The TDA consisted of nine separate design firms and were headed by McGranahan/Messenger Architects of Tacoma. Five firms made up the construction team which was led by Merit Construction, a General Contractor out of Tacoma. Team member Western Wood Structures engineered, supplied, and erected the dome as a sub-contractor to Merit.

Ground breaking took place during the summer of 1981 and construction took just two years. The official opening was April of 1983.

The facility is still considered one of the best multi-use facilities in the country. The 30,000 s/f attached assembly hall has hosted numerous conventions and trade shows. The arena itself has served the community well by hosting many high school and small college football games as well as the state high school basketball tournament. The arena seats 17,000 for basketball and can be increased to 23,000 for football games and soccer matches when movable seating is employed.

On the professional side of the sporting world, the Tacoma Dome has been home to six professional sports franchises, The Seattle Super Sonics NBA team played at the dome during the 1994-1995 season while the Seattle Center was being renovated. It has also been home to professional soccer and ice hockey teams over the years.


The dome has also hosted such dignitaries as Billy Graham whose presence attracted 30,000 people every night he was there in 1991. In addition many popular rock groups and entertainers have performed in the dome including AC/DC, Bruce Springsteen, The Tubes, and David Bowie.

In 2007 the city suspended a light and speaker grid from the dome. The total added load was 400,000 lbs! WWSI engineers determined the dome required minimal upgrades to support this increased applied loading.

The advantages of using wood in an application such as this are evident. Wood is nature’s oldest building material and a renewable resource. Cost is certainly an advantage as was demonstrated in this case. The acoustics in the Tacoma dome are of concert quality and insulation values of up to R-30 can be achieved. And finally, wood is more aesthetically pleasing than any other building material we can think of.

                                        Carpenters frame the cupola.

                                          The cupola is not yet framed in.

The flag pole is set with a helicopter.

                                         
                                                A view from above.

Bow Bridge of the Big Wood River

Land trusts have been in existence for more than 100 years with a purpose to protect, conserve, and restore land and water for future generations. The Wood River Land Trust of Hailey, Idaho was established in 1994 to serve such a purpose in Idaho’s Wood River Valley.


In 2007 the Land Trust acquired the Wood River Preserve from the state of Idaho in a trade. The 80 acre of parcel of land with ½ mile of frontage along the Big Wood River was once home to a dump and in cooperation with the city local volunteers representing the trust worked to remove 600 cubic yards of material in order to make it accessible.

Development of the site soon followed. An elevated boardwalk was constructed over sensitive wetland areas in order to allow access to the public without the threat of damage to the natural surroundings.

In continuation of this complex restoration project, a 160 ft clear span pedestrian bridge was built to provide access from the East side of the Big Wood River to the elevated boardwalk on the West side. The Big Wood River is hallowed ground with a rich history of the Nez Pearce and Shoshone Indian tribes who once thrived along the river. Drawing inspiration from these tribes, the Bow Bridge of the Big Wood River was designed to mimic a recurve bow that appears to have been dropped from the sky. Landing string side down, the bridge now connects the East and West banks of the Big Wood.

Leslie Howa of HOWADESIGN is responsible for the conceptual design of the bridge as well as its architectural features.

In an e-mail received from Leslie, she told me the project was spearheaded by the Wood River Land Trust but inspired by the Indian tribes that “thrived long before modern man neglected the once thriving river landscape and habitat. For all of us to remember that we borrow these protected lands from our children.”

Western Wood Structures engineered the “Pinned Arch” style bridge, fabricated the Glulam components in house, and installed it. The installation took just 3 weeks.

 Each frame was pre-assembled on its appropriate side of the river

   Cranes lifted each arch frame and pinned them to the abutments

      The arch frames were then pinned at the center

                               
     The deck system, posts, and rails were installed last

The Bijie Dome

Bijie is a city located 150 miles NW of Guiyang in the Guizhou Province of south central China. The area has a sub tropical climate with frequent year round rain and is famous for its production of Azaleas. It is a popular destination for visitors who are attracted by the beauty of the flaming red landscape or by the many birds who inhabit the area.

There was a need for an exhibition hall to display the many varieties of Azaleas, 23 in all, during the March and April blooming season. It was decided that a circular building with a timber domed roof would be best suited and an inquiry was made across the Pacific to Western Wood Structures. The question asked was - can WWS design, manufacture, fabricate, and ship the dome components within 9 weeks following receipt of a contract? The answer, of course, was yes.

After a price was agreed upon and a contract signed, WWS was obligated to meet a condensed shipping deadline of 9 weeks – not an easy task for such a complex and highly fabricated structure. But thanks to accurate preliminary design work and cooperative vendors WWS managed to beat the promised schedule by one week.

The materials were shipped in two stages: dome components were shipped first followed by the materials for the entrance canopies. This allowed the General Contractor to begin work on the dome installation early.

Seventeen containers were used to export the Glulam, 2x T & G decking, plywood, steel assemblies, and fastening hardware. WWS utilized nine [9] Portland area manufacturers and vendors to complete the order.

WWS provided the General Contractor with a set of erection drawings and sent a jobsite consultant for one month to assist with installation. After arriving on site and sorting through containers of materials, and tracking down adequate tools, the dome was erected in just 6 weeks.

 

The 6-Sector VARAX style dome spans ~ 174’, has a rise of about 33’, and bears on 18 concrete supports. Entrance to the interior of the exhibit hall is gained through any one of six entrances that rise 28’ above the ground.

 
 

Not only can Western Wood Structures claim responsibility for the design and supply of the longest clear-span timber bridge in China, but we can now claim the design and supply of the only timber dome built in China to date.

 

The Polynesian Cultural Center

The Polynesian Cultural Center was established in 1963 on the Hawaiian island of Oahu with a purpose of sharing the cultures of the nations of Polynesia with the rest of the world. The PCC has drawn many thousands of visitors over the years to its 42-acre attraction by offering interesting products such as stage shows, Luaus, canoe rides, recreated villages, and various other activities and exhibits that promote island culture. These attractions allow guests to learn about the cultures of such Polynesian island nations as Tonga, Samoa, Tahiti, and Hawaii.

The PCC has expanded over the years and added attractions and buildings such as a restaurant, retail shops, a 2800 seat amphitheater, and an IMAX Theater. Renovations to the amphitheater took place in 2009. Western Wood Structures was awarded a contract to design and install a post tensioning system to seven of the main Glulam roof members. The post tensioning system added capacity to the beams which allowed the owners to suspend new catwalks from the existing roof structure. The largest of the beams, which measure 12.25” wide x 55.5” deep and more than 100’ in length, required fourteen high strength post tensioning cables each to provide the additional carrying capacity. Renovations to the IMAX Theater are currently under way to convert it to a themed show attraction called the “Hawaiian Journey”. The existing building will remain a theater but is being remodeled using “rockwork” to give the illusion of a volcano from the outside. The interior of the remodeled structure will give seated guests the sensation of being inside a restless volcano through the use of lighting, sound effects, mist, special effects seating, and finishes that will resemble a lava tube. The building, originally constructed in 1989, is a pre-fabricated steel building with rigid steel frames spanning 90’- 9” spaced at 20’ centers. After performing an analysis of the building, structural engineers determined that the existing frames were 34% overstressed in bending which would prevent any additional loads from being applied to the roof structure. In order to bring the structure into compliance with current building code, the design team weighed their options and determined that the frames could best be code upgraded by installing an external post tensioning system.

Western Wood Structures was hired to design and implement the post tensioning system. The steel anchor brackets, cable guides, and stiffeners, were manufactured in Oregon and shipped to Oahu by barge in advance of the arrival of our crew. The steel anchor brackets, cable guides, stiffeners, and diagonal bracing members were welded into place by a local sub-contractor under the supervision of a WWS engineer and WWS personnel installed the high strength cables and tensioned them.

Not only do the steel frames now meet current building codes, but the owner has the added benefit of being able to install a new catwalk system which will be supported by the upgraded roof structure. The catwalks will be used to access the lighting and special effects required for the new show.

The Bridges of Bothell

The Sammamish River Trail extends along the Sammamish River for nearly 11 miles connecting the communities of Bothell and Redmond in the state of Washington. The 12’ wide trail is paved its entire length and is used extensively by hikers and joggers as well as by non-motorized commuters. A bridge designed and supplied by Western Wood Structures was built in 1986 to connect the Park at Bothell Landing to this trail. The “Bowstring” Truss style bridge spans 80’.

Within the past four years, Western Wood Structures has supplied and installed three more treated timber bridges in the Bothell area. They span North Creek and are located along North Creek Trail, a multi-purpose shared path linking the communities of Bothell, Mill Creek, and Everett. Two of the bridges are nearly identical spanning 100 feet. One is located next to 195th Street and the other next to 228th Street. The third bridge is located at 240th Street and spans 74 feet.

The pre-fabricated bridges were assembled on site and lifted into place as a complete unit.

The three newer bridges resemble the original curved bridge at Bothell Landing and the city of Bothell, known as a city of rivers, has adopted a small arched bridge as its new city logo.