Senior Vice President
HOK, Inc., New York City
This presentation demonstrated the immense possibilities of applying architectural, façade or structural parametric modeling and optimization to the concept of façade as structural skin. While previous projects have integrated the façade as a structural element for control of wind, as part of a hybrid structural frame and enclosure, recent advances in design technology allow us to evaluate such a system in hundreds or thousands of geometries and locations, not just on a case-by-case basis.
While the non-load-bearing curtain wall has been the defining enclosure system on tall buildings, architects throughout the modern period have explored ways of integrating structure and cladding. Most approaches involved employing the exterior as a shell, and required intense coordination of structure and skin. A brief survey establishes context and precedent for this study.
The proposed enclosure retains the transparency and depth of a conventional curtain wall, while contributing to the stiffness of the tower frame under wind load, reducing serviceability-level movement and steel tonnage and/or concrete volume. We implement parametric modeling and optimization technology to demonstrate the value of such a system, in terms of minimized material and embodied CO2 in the core and shell, across a wide range of potential geometries. Optimized variables include building geometric properties, structural elements, façade elements, and imposed wind and seismic loading by location. In this way, we can evaluate the viability of the system for commercial developments across multiple density ranges and multiple cities.