Nemetschek Structural User Contest 2013

74 X1 Category 1: Buildings Project Description The Taiwan Tower in Taichung City, Taiwan, is a direct result of the Taiwan Tower International Design Competition. The project guidelines included a construction budget of $220 million, as well as specific required architectural features, such as a base level city museum and observation decks, a restaurant and an environmental monitoring station at the top levels. In addition, the tower was required to be the tallest building in central Taiwan, with a minimum height requirement of 300 m. Primary Structural System The primary structural system for the tower consists of 4 steel framed tubes 7 m in diameter which spiral around an 8 m circular concrete core. Each tube is composed of round steel pipes in a diagrid pattern that rotates around the core, completing a full 360 degrees of rotation over 240 m of rise in elevation. At both the top and base of the structure the 4 tubes flare out to allow for occupied space. The base contains 5 occupied floors, while the top contains 7 occupied floors. Both the top and bottom are designed using composite slabs on a steel beam and girder system with large spans which accommodate open areas below. Lateral System As a result of the building’s height, the lateral system was required to resist typhoon level winds of +499.2 kg/m2 and -748.8 kg/m2 at the top of the tower. Under this lateral loading, the central concrete core transfers forces to the exterior tubes through a series of small outrigger trusses which are placed at a 12 m vertical interval for the full height of the tower. These outrigger trusses allow the structural system to utilize the exterior tubes to their full potential under all loading conditions and greatly increase the lateral stiffness of the structure as compared to a core only system. The torsion induced on the core was offset by a continuous truss which connects the tubes to each other and allows the four individual tubes to work as a single unit. Foundation System All vertical and lateral load resisting elements will terminate at a mat slab on a drilled pier foundation system. Repetitive & Modular Design Although in geometrical terms the tower is complex and unusual, the majority of the structural system is repetitive and designed to be modular. The spiraling tubes are designed to be fabricated in 3- or 6-meter sections, either on or off site and lifted into place. The tower core lends itself to a common climbing form work system. These characteristics allow for a more easily constructed structure. Design Approach & Scia Engineer Because of the tight project schedule (completed submission in 4 weeks) and the complexity of the exposed steel structure, the design team chose to utilize Scia Engineer. Scia Engineer’s flexibility in 3D modeling allowed for the structure to be modeled, analyzed and designed for gravity loads, seismic loads, including dynamic analysis and winds loads, all within Scia Engineer. After the model was optimized, it was then exported to the architect via IFC (Industry Foundation Class). Using this OpenBIM workflow enabled the design team to create a unique and collaborative 3D workflow that integrated the architecture and engineering. Ultimately, this workflow allowed the team to manage design changes and work iteratively towards the final design, while also abiding by the project’s tight deadlines. Taiwan Tower - Taichung City, Taiwan Software: Scia Engineer