Tuesday, August 28, 2012

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.

Thursday, August 2, 2012

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