Valley West Pavilion and Covered BridgesJun 03 2014 · 0 comments · Bridges, NISHKIAN MONKS, Small Projects ·0
Valley West Subdivision is a 309-acre master planned community on the west side of Bozeman, Montana featuring a variety of beautiful homes with lovely front porches, tree-lined streets, parks and green spaces reminiscent of Bozeman neighborhoods of past generations. The Valley West vision was founded on a desire to transform the unique setting of the land into a place with truly exceptional quality of living while still preserving the area’s peaceful beauty. In conjunction with the City of Bozeman, Phoenix-based developer, The Aspen Group collaborated early on with Intrinsik Architecture, Nishkian Monks PLLC, and other consultants to incorporate Meyers Park–a dedicated public land, which is defined by a five-acre lake, streams, wetlands and open acreage into the neighborhood landscape maintaining the integrity of the land and the region. A comprehensive package of park amenities were designed to provide greater access and safety while accentuating this neighborhood’s extensive trail system including two covered bridges, an entry pavilion/bridge, and a central community pavilion located on the banks of Meyers Lake, a large man-made lake offering scenic views and community recreation.
Nishkian Monks served as the prime structural design firm providing project management, development and construction administration of the pavilions and covered bridges. The firm was involved in fabrication oversight as well as design concept focusing on a covered bridge design which is characteristic of the region. The design intent was to create such structures that spanned the creek and wetlands while providing a place of covered respite to enjoy the bridge itself and the natural habitat it spanned. Shade, shelter and seating are all offered at the crossing. The location of the seating/observation areas, yet logical architecturally, posed a real structural challenge since it eliminated the employment of traditional trusses at each side of the bridge deck. Furthermore, since the bridges were placed just inches of the ground, the trusses could neither be pushed below the deck nor consider a much simpler beam design. With additional design criteria such as the use of relatively even mixed materials of wood and steel, and tight limitations on cross sectional dimensions for each member, our engineers quickly realized that two dimensional design tools would produce overstressed and unstable models which would falsely represent actual conditions. The structural fabric needed to draw its strength from members in all directions. The final three dimensional model was carefully constructed utilizing moment frames, braced frames, trusses, and diaphragm members, all working together as an interrelated entity. Knowing that Intrinsik would act as a design-built firm on this project, Nishkian Monks developed a structural solution that assured ease of construction by modulating the fabrication of a structure which achieves its final strength only as a cohesive three dimensional unit. Hence, this process did not only require our engineers to be an integrated part in the construction process, but also allowed our engineers to be directly involved with the overall design. Due to the small member sizing and the light weight design of the bridges, our engineers were especially concerned about vibration issues. Again, by making use of every possible member that is architecturally or structurally expressed we were able to achieve an impressively stiff structure. We knew that any slight vibration would uncomfortably be felt by the public who would like to enjoy the seating and observation areas at the mid-span of the bridges. Special considerations were also given to high wind forces engaging the open roof structure. The resulting design borrows elements from early double wing aircraft construction where the roof of the bridges could be considered the upper wing, and the deck of the bridges could be considered the lower wing.
This analogy was especially vivid when it came to the design of the entry pavilion/bridge along West Babcock Street. The entry pavilion/bridge acts a marquee for the Valley West neighborhood while providing seating and shelter for bus passengers. With its middle portion of the roof being designed as a simple shed roof reaching to the sky in order to maximize viewing angles, our design for the entry pavilion needed to resist and uplift wind force similar to the total dead load of the bridge. Realizing the enormous uplift forces, our engineers considered and proportioned the double shed roof portions on each side of the single shed roof portion as wing flaps to counteract the uplift force.
As a landmark on the northern end of the site and on access with streets and trails, four structures form a central community pavilion adjacent to Meyers Lake, a large man-made lake offering scenic views and community recreation. Stocked with Westslope Cutthroat Trout, a species of trout indigenous to Montana, this lake is also ideal for recreational catch-and-release fishing. The layout of the structures allows for shade, shelter and flexible use by small or large groups while maintaining open vistas with the neighborhood, lake, streams and 4-miles of pedestrian trails.
The pavilions and bridges utilized material palette of wood and rusted steel referencing historical agricultural structures while blending with the native plants along the wetland corridor. Inspired by traditional covered bridges, the design is an actual truss system that you pass through, as each member is imperative to the bridges’ structural system. Indeed, these structures are the ornamentation and the art—justly bridging the gap between art, architecture and engineering. Early collaboration, innovative design, and thoughtful inclusion of these outdoor recreation amenities not only promote community togetherness but also make sustainable design work better.