Project

Generative performance-based design

Goal: This project studies the interdisciplinary design of perforated shell structures considering the structure and daylighting disciplines by using computational design and simulation tools.

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Project log

Niloufar Emami
added a research item
Many computational studies generate an array of solutions for a design problem paired with their structural or daylighting performance. An enormous investment of effort and computational time is required to create these simulation-based datasets. However, the generated data is usually bound to the specific case studies they were created to explore. Can this data be useful for application to other design cases? This study employed a generative algorithm to fill a database with perforated shell structures covering a courtyard. A shell by Heinz Isler was chosen to be mapped onto the generated solution space based on its performance. The study found that this method is effective for predicting daylight performance, while structural performance modifications can be a source of inspiration for designing other structural forms.
Niloufar Emami
added a research item
In this work, a computational interdisciplinary design approach is used to integrate assessment of the structural and environmental performance of perforated concrete shell structures. Design parameters that co-exist in these disciplines and relevant performance criteria are identified. Questions result: how do these design parameters affect performance? What is the tradeoff between performance in each? Computer-aided design tools are used for form generation and performance assessment. Statistical analyses are used to study the sensitivity of performance to each parameter. Finally, the perforation ratio is found to be the most significant parameter affecting both disciplines; a value ≤ 10% to 20% is recommended for shell structures when translucent glazing is installed without shades in a Boston-type climate.
Niloufar Emami
added a research item
With the advancement of computational design tools paired with performance assessment technologies, taking an interdisciplinary design approach at the early stages of design is largely facilitated. The Master Builder whose role has been fragmented between multiple professionals of many disciplines is being recreated, this time by facilitating seamless collaboration among a plethora of minds and perspectives. In this mode of collaboration, studying disciplinary tradeoffs also becomes part of the design process. This calls for a new design approach with an understanding of other disciplines. A building needs to stand up and needs to be illuminated, thus the structural and daylighting disciplines are associated with the purpose of architectural design. Despite the interaction between the two, there is little research showing the overlaps. Understanding this integration helps designers better understand how making a decision affects other stakeholders. This dissertation is at the intersection of computational design, structural performance, and daylighting performance assessment. Shells are the ideal typology for investigating this interrelation as their form is related with force flow, while adding holes to the shell’s surface not only introduces daylight but also affects force flow thus structural performance. By employing a computational interdisciplinary design approach, and by choosing perforated concrete shell structures as the main structural typology, I ask: How can the designer identify the design parameters that are shared between the discipline of architecture and an engineering discipline? What are the design parameters that co-exist in the structural and daylighting design disciplines? How may these parameters be used by designers? How do the design parameters affect performance in structural and daylighting discipline? What is the tradeoff between performance in structural and daylighting design? How can the results of a specific design case be useful for application to other design cases that do not necessarily have the same boundary conditions? This research demonstrates how daylighting performance can be affected in the design of shell structures, a typology that is mainly driven by its structural design criteria in the literature. Also important is its demonstration of how a continuous shell can be perforated to the point at which becomes a grid shell; therefore, continuous and grid shells are two ends of a spectrum rather than two distinct structural typologies. A high-level significance of this dissertation is its marriage of the structural and daylighting disciplines and demonstration of how the two are closely related in shells by the perforation ratio. I find that perforation ratio is the most significant parameter that affects both disciplines and a number between 10% to 20% is the recommended limit for shell structures when translucent glazing is installed without any external or internal shading. One of the most significant contributions of this research is its methodological approach, which uses a formalized framework for categorizing design parameters in the structural and daylighting disciplines and then identifying overlapping design parameters. This design method, presented as a roadmap is the fundamental new component arising from this research. The final contribution of this dissertation explores how a generated solution space may become useful for other design projects which do not necessarily have the exact same boundary conditions. By abstracting the boundary conditions of new projects to match those in the solution space, the designer can examine possibilities and compare how making a decision in one field may affect performance in other fields.
Niloufar Emami
added a research item
Employing an interdisciplinary approach in design is an important part of the future of architecture. Therefore, taking a step toward better understanding the overlaps between disciplines, and formalizing the process of integration between disciplines accelerates progress in the field. In examining an interdisciplinary design approach using computational design and simulation tools, while considering shell structures as a special case for spanning large-span roofs, structural and daylighting discipline are considered. The aim is to understand what are the design parameters that co-exist in the structural and daylighting design disciplines, and how may these parameters be implemented in a parametric model created by designers. The parametric model that includes discipline specific parameters can later be used for interdisciplinary performance-based design. Implementing design parameters calls for an understanding of the ways in which parameters affect design and performance. This research considers the application of parametric design methods at the early stages of design for designing high-performance buildings.
Niloufar Emami
added a project goal
This project studies the interdisciplinary design of perforated shell structures considering the structure and daylighting disciplines by using computational design and simulation tools.
 
Niloufar Emami
added a research item
Felix Candela designed and built one of the simplest and most practical shells: umbrella shells. Among his built umbrellas, only a few are perforated, including the High Life Textile Factory. This Factory consists of aggregated umbrella shells with distributed perforations. Although the shells are tilted towards north to create a saw-tooth cross section that brings reflected light into the space, the perforations also played a role in providing daylight. After the building was used as an iron shop, the perforations were covered with asphalt to reduce overheating of the space caused by the hot Mexican climate and the program of the factory. However, it was never studied if covering the perforations would truly have been effective in mediating the overheating. This research speculates Candela's motivations in perforating the shells. It first examines where this building falls in his career and if he continued designing other perforated shells. Next, the building is simulated to assess its structural, daylighting, and energy performance, with and without the perforations. The goal is to understand the role of perforations on performance, and if covering them has helped to decrease the cooling load. The result of this study reveals design potentials of Candela's less-talked-about project, the High Life Textile Factory, to better understand his motivation in perforating the shells: Were Candela's perforations performative?
Niloufar Emami
added 2 research items
The Design of building envelopes consists of two major phases in two different disciplines: structural design, and climatic design. Additional performance criteria such as acoustics may also be considered based on the program of the space. In general, a mono-disciplinary approach to design evaluates performance in each discipline detached from other disciplines and sometimes in a hierarchical order. This may be due to disjointed parameters that affect the design and optimization process, as well as different expertise of the designers and engineers in each field. Considering some structures such as post and beam systems, this method seems appropriate since each discipline has little influence on other fields. This provides relatively adequate freedom for the designers to decide about different design variables, such as size and orientation of the apertures, material of the cladding and the structure. However, there are some other building envelopes in which making a design decision in one field largely affects the performance in other fields. These building envelopes which cover the architectural space have a high potential for an interdisciplinary design approach. Heinz Isler is an engineer who has designed extremely efficient shells with excellent performance over time. Considering his works, there are a few shell structures which have one or multiple apertures, mainly designed to introduce daylighting into the space. But how have these apertures influenced the force flow and structural performance of the shell? What daylighting levels have they provided for the space? And by manipulating the size and number of these apertures, how may the structural and daylighting performance of a shell vary? This paper intends to look at a perforated concrete shell designed by Heinz Isler and assess its structural and daylighting performance. Then, the size, number and location of the openings is altered in order to observe the effect on the structural and daylighting performance of the shell. Rhino and Grasshopper are used as the modelling platform, while Karamba, which is a plugin for Rhino, is employed for assessing the structural performance, and the DIVA plugin for Rhino is employed to assess the daylighting performance. Finally, a comparison between different topologies is made using different numeric indicators. For structural performance, deflection, weight and maximum von Mises stress levels are considered, along with Daylight Autonomy on horizontal and vertical planes as the daylighting numeric indicator. The goal of this comparative study is to demonstrate tradeoffs among various performance criteria, regarding the relation between topology, structural performance and daylighting performance, and may be used by designers who consider multiple performance criteria in early design phases. Keywords: Shell structures, integrated design, parametric design, interdisciplinary design, structural performance, daylighting performance.
This research assesses structural and daylighting performance of perforated shell structures. By employing computational design tools and performance assessment methodologies, an array of generated topologies of perforated shell structures spanning the two extremes is studied. These generated topologies are coupled with structural and daylighting performance criteria to allow a performance-oriented exploration of the design space. ParaGen is used to automate the cycle of generation and evaluation. ParaGen is a method that uses a genetic algorithm (GA) to search for well performing geometric solutions to architectural engineering problems. By using ParaGen, the quantitative performance results are stored in a SQL database, accessible through an online website. The significance of this study is twofold: first, it studies a spectrum of generated forms of well-established structural typologies with perforations; and second, it couples structural and daylighting performance with geometry towards computational performance-based design and search of well performing alternatives. The results of the study contribute to the area of computational design, multi-objective design exploration as well as shell structures.