The overall strategy of the structural system is minimizing the use of concrete for achieving decarbonized buildings. Since the research regarding mass timber building has been conducted not only for single houses but also for tall buildings or long-span structures like the below reference, I decided to use mass timber as a structural material. Two cores are selected for structural stability in case of a striking earthquake.
Secondary timber beams can be connected by using a connector so that connectors can be concealed for aesthetic purposes. By hiding the connector, the smooth material connection can be emphasized. This attachment method also can be considered for the connection between the cores and girders.
Beams and columns are mass timber, and Girder and secondary beams will support the CLT slabs. Mass timber cores will be prefabricated so that minimizing on-site works and construction waste. By leveraging prefabrication, construction costs and schedules also can be saved significantly. For the sustainability of the material, The same amount of wood used for the frame system will be planted during the procurement. Most of the columns are supported by the isolated foundation, but the mass floor supports tilted columns for structural stability.
[Second Floor Structure Plan]
Second-floor columns are placed along with the grid system. Since some places have no floor on second floors, such as an indoor exhibition center, café, or kids' zone, some secondary beams are not installed.
[Third Floor Structure Plan]
On the third floor, there are more secondary beams compared to the second floor to support the structural floors. The right corner core position has been changed to secure enough space for the purpose of fire protection.
[Roof Floor Structure Plan]
On the roof floor, some skylights overlapped with the secondary beams. Therefore, the skylights are repositioned as below. Since the position of beams affects some architectural elements, BIM model coordination check-in is extremely important to prevent design changing in the construction phase. This process will be conducted again to coordinate with the MEP model.
The most challenging structure in this building is installing slanted columns. Since there is no second story in the main indoor exhibition space, and the curtain walls will be installed for the shell, one long prefabricated column is selected. To support these huge columns mass foundation is installed, and the depth will be double, 24’’ for this foundation. Through advanced structural analysis, those columns could be substituted with steel columns for structural stability.
References
Bezabeh, M. A., Bitsuamlak, G. T., Popovski, M., & Tesfamariam, S. (2018). Probabilistic serviceability-performance assessment of tall mass-timber buildings subjected to stochastic wind loads: Part I - structural design and wind tunnel testing. Journal of Wind Engineering and Industrial Aerodynamics, 181, 85–103. https://doi.org/10.1016/j.jweia.2018.08.012