Cement production is responsible for 8% of the anthropogenic CO2 emissions [1]. Reducing this share will be a strenuous task as the global population and urbanization rates are increasing and, therefore, the need for concrete will remain high [2], [3]. Simultaneously, despite the alarming statistic, a vast majority of demolished concrete buildings are structurally sound [4]. Therefore, this thesis aspires to push beyond the abundance of new concrete and outlines a design workflow for using reclaimed concrete. To enhance the material savings, the workflow focuses on double-curved, compression-only structures that benefit from the principles of structural geometry.

To implement the workflow, a novel stacking algorithm is designed using COMPAS [5], an open-source Python framework. It positions quadrilateral voussoirs on a funicular geometry’s thrust surface in a sequential one-by-one manner. The placement is guided by three global design principles. First, a pair of opposing voussoir sides are aligned parallel to the force flow while the remaining pair, which represents the load-transferring faces, is aligned perpendicular to it. This is done to prevent sliding failure. Second, the thrust surface is confined within the middle third of the voussoir to prevent the formation of hinges and cracks. Third, voussoirs are cut into hexagonal shapes and staggering is ensured among neighbouring voussoirs to create an interlocking geometry. Once a structure is completed, its stability is ensured by finding a compression-only equilibrium using the Rigid Block Equilibrium method [6].

The algorithm is then studied using various stocks with different voussoir dimensions of both regular and irregular side lengths, various deployment strategies that enable the user to customize the launch of the algorithm, and different thrust surface shapes. It is primarily assessed what fraction of the initial concrete volume can be retained in the structure. It was found that on average 47% of volume per voussoir is retained and that voussoirs of regular dimensions retain approximately 5% more of the initial volume. Minor differences exist in the results among different thrust surfaces with shapes of more uniform force flow retaining more concrete. Furthermore, smaller voussoirs mostly sized 0.7x0.7x0.2m required 20% less volume to construct a shell than a stock of 1.0x1.0x0.2m voussoirs. At the same time, the smaller stock required almost double the amount of voussoirs, thus, indicating competing goals that require the decision-making of the designer.

Next, high-level waste minimization was performed by checking if offcuts could be used to create other voussoirs from the remaining structure or if they could be returned to the stock for future placement. A pessimistic and an optimistic scenario were studied and it was found that 70-85% of the initial voussoir volume can be efficiently retained within the shell and the stock.

These results served as the basis for reflecting on how the stacking algorithm influences the suggested workflow by bringing design and fabrication-specific constraints to an earlier design phase. It is described that to improve the retained volume the designer can, first, alter their way of deploying the algorithm, second, modify the input geometry, third, custom select what stock is used for placement, and, fourth, inform the contractor of the level of detail to which a building should be deconstructed and post-processed. Thus, a designer is brought closer to the construction process, and incentives for a more collaborative cross-disciplinary workflow are outlined.

Finally, suggestions are made on how to improve the functionality and efficiency of the algorithm. The primary conclusion made is to expand the criteria based on which a voussoir is selected for placement. An emphasis is directed towards using criteria such as distance-to-staggering, local radius of curvature, local force flow, and dimensions of the surrounding voussoirs to limit the offcuts that will be created to ensure complete tessellation.

Overall, this study provides a workflow that is enabled by a stacking algorithm. It outlines how to design double-curved, compression-only structures and how their design can influence the entire workflow.

In recent years the AEC industry has started implementing more new technologies. Still, the adoption process is slow. One of the crucial steps during the building designing is a justification of design according to previously defined requirements. That process is still manual to a large extent, therefore unnecessarily time-consuming and prone to errors. The need for automation of requirements compliance checking has been rising in recent years, and the science community presented various approaches for automation. Still, most of the proposed methods has similar problems: using a black-box approach, require that the designer is highly skilled in programming, focusing on only geometric requirements and not covering whole process of compliance checking. Therefore, there is a need for a new approach that can solve all these problems. The rise in popularity of parametric design and tools like Grasshopper opens the possibility to overcome some of the current limitations. Also, the possibility of using requirements management software to have the process fully organized supports the belief in automating compliance checking. The fundamental objective of this project is to explore the possibilities of automating the requirements verification for a building design by using requirements management software to systematically structure the requirements and Grasshopper to generate the rules, which afterwards can be verified. To achieve this objective, the project was divided into three main parts. First, the conceptual framework for automated code checking is developed. Afterwards, the system architecture of the prototype tool was explored, and instructions for scripting the tool were given. Finally, after the tool was scripted, it was tested on a real building model.

From the literature review the two main types of requirements are found, the functional and performance requirement. Since the functional requirements are qualitative and cannot be quantified, that category is not suitable for checking with the approach proposed in this project. Therefore, the focus was on performance requirements. The central part of the project is the creation of a framework for automated compliance checking. The five steps are defined and these are:
1.) Requirements defining and logical structuring into RMS
2.) Interpretation of requirements
3.) Building model preparation
4.) Checking phase
5.) Reporting phase

After the theoretical basis is set, the modelling of the tool is elaborated. Firstly, the requirements for the tool are set. Afterwards, the system architecture is explored, and finally, instructions for scripting the tool are developed.

After the prototype tool is scripted, it is tested on a real building model, and it shows clear advantages compared to other approaches or manual work, still, it also has some disadvantages.
Test of the tool proved that the Visual programming language environment is a great platform for developing a white-box approach for automated compliance checking. Also, testing on the real-world building model shows that a five-step approach for automated testing of building design works and can be used. Lastly, the test shows that the proposed system architecture and instructions for scripting the tool can result in a well-operating tool.

Finally, recommendations for future research are given.

The objective of this project is to devise and develop a design tool that lets the user explore different force flows during conceptual design, with the goal to inform different geometries, thereby realizing an integrated design process. Key characteristics that this tool must incorporate to be successful are defined as feedback (the ability to provide rapid and reliable analysis results), guidance (the ability to guide the user towards better designs), design freedom (the ability to allow users to make their own decisions and use their own expertise) and structural overview (the ability to make the general structural behavior clear instantly). Graphic Statics has been identified as a suitable method to model and compute the force flow with, and has been incorporated as the base of the tool. A workflow has been devised where the user first identifies and investigates a design problem manually, creating an initial design that must be used as input for the tool, which includes a definition of joints, members. loads, supports and certain boundary conditions. Due to the nature of Graphic Statics, this initial design must be statically determinate. The tool has been developed for Grasshopper, a parametric and associative modelling plugin of Rhinoceros, which provides a platform that meets the defined development criteria of accessibility, real-time modelling, geometric flexibility, extensibility, and presentation independence. The developed prototype bearing the name of GSDesign consists of custom components scripted in C# containing the main functionality, as well as Grasshopper clusters for specific visualization sequences. GSDesign facilitates the design of 2D truss-like structures, which can be interpreted as force flow designs, whose efficiency is quantified in the total load path. Feedback is generated in real-time, and is presented in a force diagram, form diagram, unified diagram, and/or as numerical values, providing precise and accurate results. Guidance is incorporated intrinsically through Graphic Statics, but also by the incorporation of an optimization process using the total load path value and the genetic optimization component Galapagos native to Grasshopper. Design freedom is ensured through the general setup of the tool, which allows for maximum utilization of the design flexibility that Grasshopper offers. The tool provides a clear structural overview through the visualizations that characterize Graphic Statics, which can be customized to preference by the user. A user experiment has been set up to test the functionality and workflow of the tool in a simple design case carried out by structural engineers to ensure its practical value. Eleven participants were asked to first create an initial design by hand, and subsequently reproduce that design in GSDesign and improve it with optimization. The use of GSDesign visibly led to new insights towards more efficient structural forms, which was supported by an average drop of 31% in structural material volume when comparing the fitness data of the optimized design with the initial design. Also the participants on average rated their own optimized design more than 40% higher on structural efficiency than their initial manual design, importantly without compromising on practical feasibility.