Thin-tile vaults are a a type of vaults that went out of fashion in the early twentieth century. Its origins are around the Mediterranean, but modern interest is mostly due to Guastavino, and the research done at MIT and ETH. The thin-tile vaults have a unique construction method without any temporary support. Eventually the increase in labour costs and the advancements in concrete and steel made the structure non-competitive.Robotics are a type of machines that can perform (semi)-automated tasks. In the past decades the development of robots have led to their implementation in the construction industry. Robots developed specifically for masonry show a high promise where they're able to lay much more bricks than even the most skilled mason.This research aims to investigate the time it takes for a robot to construct a thin-tile vault, and thereafter to advance the possibilities of research into and construction of the thin-tile vault. This is researched by answering the following question:How does a robotic construction of a parametrically designed thin-tile vault perform based on step-wise structural analyses?To answer this question a parametric model has been made to include the design of the thin-tile vault, the structural analysis and the robotic construction. This model is made in Grasshopper, but is supported by Python and RoboDK. Python performs any calculation necessary and analysis of this output. RoboDK is a robotic simulation program aimed to give users a tool to translate their design to robotic instructions. The structure of this report is based on the three aspects of the parametric model.In the first part the state of the art and the relevance of this research is stated. Thereafter the objectives, questions and methodology are noted.The first part of the model is related to the design. In the first chapter a literature review is provided on thin-tile vaults and similar vault structures. The second chapter of this part describes how the design model has been made. First the global shape of the vault is set as a barrel vault formed as a catenary arch. Then the bricks are placed on this vault surface using a similar approach as map projection. This is done with the introduction of the centre point approach. This ensures that proper information is maintained, like the course and the position within the course per brick. With this approach it is possible to fill this surface even with courses misaligned to the primary curvature. Bricks at the edge of the vaults surface are cut to fit within its domain. The last step is to thicken the bricks, which thus far had been represented as surfaces, into volumes.The structural analysis consists of three major parts. In the first chapter literature is shown to justify the use of a linear elastic analysis on masonry. Additionally the behaviour of this uncommon type of masonry is tried to be found in literature. The materials brick, mortar and epoxy are looked into as well. Bricks have time-independent properties, making these similar as found in the Eurocode, by manufacturers and in research. Mortar and gypsum plaster especially (also known as Plaster of Paris), are described in their material properties as well. Due to uncertainty in these properties, epoxy is investigated as well and found to have more theoretical values useful for this research. A small-scale experiment with bricks and epoxy has been done to verify what values from epoxy should be used.After the literature review on material properties, the structural analysis is done. The flow of this chapter starts with the form from the design model, through the forces of a cantilever, to the stresses occurring in the structure. The vault has been simplified to an arch during construction. Thrust is not present. The sectional forces are found by first considering the (partial) arch as a cantilever with a vertical shear force and rotational moment. Next this shear force is converted into the normal and shear force in the cross-section of the arch. This calculation has been worked out in a Python script.In the last chapter a possible stress distribution is shown. The analysis is based on a phased structural analysis. Each time step is equivalent to the placement of one row of bricks, which have a similar cantilever length. The stresses of the bottom and top side are shown, as well as the stresses between the wythes of the vault. In a DIANA model it is shown these wythes behave more like a monolithic material than a layered one. The last part is related to the robotic construction. First literature is shown related to masonry robotics. In the second chapter the stations the robot visits, are described. At the pallet station three instructions are described. The adhesive station has a number of instructions which is dividable by four. The vault station again has three instructions. This is similar to a pick & place work order, but with the adhesive station in between. Two configurations are considered. The first is when the robot is outside the vault, where it is closer to the support than to the apex. In the second configuration the robot is placed within the vault, where it is positioned close to the apex. In the last chapter the robot is chosen. Additionally the path is described with boundary conditions.The results are shown for 8 computations: a basis computation; one with the robot changed; one with the shape of the vault changed; one with the orientations of the wythes changed; one with an increase of the adhesive hardening time; one with a small course length of the vault; one with a different work space configuration; and lastly one with a different preferred construction sequence.In conclusion the models and results show that the construction of a thin-tile vault is similar to other masonry robotics, if the hardening time is excluded. Included, the number of bricks built per day is similar to two masons building a thin-tile vault prototype. The hardening time is the primary influence of the total construction time and any reduction here is advised. Further optimisation of the movement of the robots is possible with a more in-depth optimization of the work space configuration and an optimization where the shortest movements are considered across instructions. The linear-elastic structural analysis has been found to be possible to use for the calculation of the thin-tile vault during construction. Additionally, two construction sequence preferences work well with the multiple wythes, but one preference shows better results when more bricks with more cantilever length need to be placed, due to reducing the stresses on the edge of the extrados wythe.Further research into thin-tile vaults is still required to fully understand and model the thin-tile vault. Related to the three models (design, engineering and robotics) each have been improved in the models made for this research, but are still a long way away from full implementation.

Purpose: Additive manufacturing has enabled innovative, cost and resource efficient mass customization of products over a wide range of manufacturing industries. Under the broad spectrum of options for manufacturing of metallic components, Wire + Arc Additive Manufacturing, WAAM, offers the combination of high design freedom and productivity at a comparably low cost. As a maturing technology, the application in the building industry of steel and stainless-steel products becomes increasingly interesting. Research is nevertheless necessary for the identification of the material’s performance under dynamic loading. It has been demonstrated that the manufacturing procedure inherently produces a heterogenous material matrix and wavy surface, which may be susceptible to fatigue. Methodology: Based on a broad literature review concentrated on the material performance of stainless steels as welding consumable, stainless-steel SAE316L is chosen as the material of interest for characterization. Test coupons are extracted from heat-treated wire+arc-additive-manufactured single-bead walls to perform monotonic and fully reversed strain-controlled fatigue tests in both longitudinal and build directions. The material’s microstructural characteristics are documented. Test methods include Wavelength Dispersive X-Ray Fluorescence for chemical characterization; X-Ray Diffraction for phase identification and quantification; and Scatter Electron Microscopy and Optical Microscopy for qualitative sub-grain and grain microstructural characterization. The latter methods are subsequently used to characterize the monotonic and fatigue fracture surface morphology of post-mortem test samples. A constitutive model for the material is described based on the results of the monotonic and cyclic behavior in both orthogonal directions. Inspection of the fracture surface of the tested coupons is realized to validate the assumptions made for the application of the fatigue models at hand. Addressing a commonly cited problem, the macroscopic surface waviness of the printed material is quantified, and its effect as a stress concentrator is numerically modelled and verified through a smaller group of tested coupons retaining the original surface waviness. Finally, suggestions for the extrapolation of these results are done for the design of structural components produced with the studied material and designed for Fatigue Limit State. Findings: Microstructural characteristics include a strong metallurgical texture in the build orientation, limiting the validity of X-Ray diffraction results. Ferrite is quantified at approximate 13% volume ratio through image analysis of SEM micrographs. Possible traces of σ-phase are identified through optical microscopy, specifically in inter-grain boundaries, although further work is necessary to confirm their constitution. Fracture surface analysis indicates mostly ductile material deformation, confirmed by the elongation capacity of tensile test results, and a predominantly smooth fatigue fracture surface populated by ridges with isolated striation locations, indicating crack propagation at a low stress intensity amplitude. The material shows marginally lower performance in terms of quasi-static characteristics when compared to the one cited by the consumable manufacturer for all-weld material. This remains nevertheless consistently higher than the allowed design values published by commercially available standards. A notoriously low elastic modulus is observed, source of which remains unidentified; the elastic modulus is measured between 54% and 58% of that of commercially available hot-rolled stainless-steel alloys. Cyclic material performance corresponds with all-weld predicted performance for ferritic-austenitic stainless-steels, where the first few cycles are characterized by a slight material hardening, followed by a consistent softening throughout the cyclic life of the material. Average fatigue performance is undistinguishable from mean design values proposed for structural stainless steels under standardized testing conditions. At a 95% reliability and 75% confidence interval, the material performance is superior to the design curves proposed by ASME. The theoretical stress concentration obtained through numerical analysis of the surface geometry is modeled as a function of maxima between 3.150 and 3.927 in the build orientation with a 75% reliability for component lengths of 20 mm for the former value and 100 mm for the later value. Similarly, the values 1.944 and 2.413 in the longitudinal direction describe the stress concentration effect for 20 mm and 100 mm component lengths correspondingly. Originality / Value: The research contributes to the characterization efforts made for the improvement of Wire+Arc additive Manufacturing technologies. This work is carried out both at a microstructural and a bulk level, allowing to establish a correlation between the manufacturing parameters, the microstructural morphology and the mechanical behavior of a given material. Design aids are presented at a typically cited reliability level for engineering practice, accompanied by a thorough description of design considerations based on the material’s inherit characteristics as a product of WAAM process.

Geometric patterns inspired in historical Islamic ornamental art have attracted the attention of contemporary designers worldwide. The large variety of shapes, symmetries and combinations is a source of inspiration, but at the same time makes it difficult to provide general rules when used in a technological application. Structural small-scale applications have been object of research, but there are potential applications at larger scales that deserved attention. In view of some recent proposals of Islamic patterns as structural grids for tall building skins, the question of their structural efficiency, especially compared to conventional grids, arises. The purpose of this research is to assess the performance of structural grids based on geometric Islamic patterns as outer skins of tall buildings. For this purpose, several historic patterns have been classified. An equivalent meta-material has been defined for each pattern, based on the homogenization method for a series of saturations or beam sizes. Their response in different orientations has been studied to identify their structural behaviour based on the pattern geometry. Their relative performance has been assessed for all patterns against themselves and against the conventional diagrid system. All this process has been collected and summarized in a predesign tool made of graphs, pictures and tables Finally, the predesign tool accuracy has been assessed and applied to three tall buildings. All those steps have been structured in three distinctive levels: At the method level, the conclusion is that the developed predesign tool is a success as it provides a higher level of accuracy than modelling all the beams. It is also faster and easier to implement, than modelling all the beam elements, to compare alternatives in early stages as the complexity of modelling the patterns is postponed to later stages. As the saturation decreases and the effective beam length influence in the beam model results diminishes, the beam model will become more reliable than the predesign tool and vice versa. At the pattern level, the most interesting finding is that the patterns with square symmetry (symmetry directions at 90º) display a perpendicular isotropic behaviour, whereas the patterns with pentagonal symmetry (symmetry directions at 72ª) display an orthotropic behaviour, and the patterns with hexagonal symmetry (symmetry directions at 60ª) display an isotropic behaviour. It has also been studied the effect that would have filling the stars as an alternative to building the patterns as an assembly of beams. At the building level, it has been found a few geometric Islamic patterns that could be suitable alternatives to the conventional diagrid systems, a pattern with a similar performance and even a pattern with a higher structural performance than the conventional diagrids. This highly performing pattern is currently been used for some architects such as Shigeru Ban in their parametric designs. In this regard, it can be concluded that the objective of finding suitable alternatives to conventional diagrid systems has also been a success and it can affect some designers engineering judgement. The homogenization process obtained an equivalent ideal material corresponding to a plane infinite panel that will not correspond with the built structural grid. The use of complex geometries and its application to tall buildings introduce effects not considered in the homogenization that will disrupt the expected structural performance. Those effects are minimized in the case of other shells structures such as domes but can be important in the case of tall buildings. It is not advisable to account for the squeezing effect by adapting the saturation with the change of the modulus size in the x-direction as the relative beam depth has a greater impact in the overall stiffness than the change of geometry due to the squeezing effect. The distortion effect cannot be accounted for directly and it depends on the angle of the distortion and the pattern. However, in the studied case it has been found a required correction factor of 1.2-1.3, in line with other uncertainty factors used in practice. Finally, the intermediate supports can have a great influence in the final drift. It depends on the pattern used and the number of diaphragms inside the module. Nevertheless, the use of intermediate supports is always beneficial and not considering them will always lead to more conservative solutions. In conclusion, this document successfully bridges the knowledge gap regarding the structural behaviour of historic Islamic patterns, with comparative tables. It identifies the best performing patterns and their best orientation, and it provides a useful tool for the decision making in the design process of in-plane bearing geometric Islamic patterns.

Timber and complex designs are making a move in the building industry, as the building industry is on the brink of a significant change toward a 100% customized, more sustainable architecture. Robotic fabrication and Cross-Laminated Timber (CLT) can play an important role in this change, but there is a lot of uncertainty and ignorance about the design process of robotically fabricated CLT elements. This uncertainty is primarily caused by the application of linear workflows instead of integral ones. Within the fields of robotic fabrication and CLT, the research narrows down to the robotic milling process of CLT connection panels. Therefore, this research intends to answer the following question by means of four different parts: What does an integral workflow for robotically fabricated customized CLT connection panels look like, that promote exploration of the structural performance of CLT structures in the preliminary design phase? Part I Literature Study Part II Pilot Study Part III Integral Workflow Development Part IV Discussions The Literature Study focusses on two fields, namely the field of CLT and the field of robotic fabrication. In the final chapter of this part, the mutual affordances and constraints of these fields are discussed as these significantly influence the design space of the integral workflow. The second part concerns the production of a small mock-up to explore the process of robotic fabrication. The literature and pilot study together serve as input for the development of the integral workflow in the third part of the research. This workflow is developed in the parametric environment of Grasshopper and is divided in three modules: Global Structure, Joint Design, Robotic Fabrication. For the Joint Design, focus is laid on CLT connection panels of which the principle is derived from a reference project in Alblasserdam (NL). The main conclusions on the research question consist of the relationships and (in)dependencies between the different modules. Another important conclusion is that one cannot apply CLT in the outdoor environment without applying shedding to ensure complete moisture control. To increase the integrality of the workflow as developed in this research, more feedback loops across the three modules should be integrated. For instance, the affordances and constraints of the robotic fabrication process should be integrated within the relationships between the three modules. Hence, if doing so, this information was available in an early stage of the design process and would decrease the uncertainty of it. This implementation could be investigated by producing a mock-up study along the integral workflow.

The demand for high-rise building has been increasing over the past decades which has induced new developments such as modular construction. Modular construction has advantages in terms increased speed, safer construction and less construction waste. Applying modular construction in high-rise however brings about great complexities for the structural design of the building. Therefore, a design aid is created which generates a structural model from any arbitrary shape and uses structural optimization techniques to explore a range of designs for the early design stage. Existing optimization techniques have been studied, including Cross-Section (CS-) optimization (size) and BESO (topology). CS-optimization adapts the size of each member, considering utilization and displacement conditions whereas BESO removes or adds elements from the model based on stress level and Target Ratio (TR). Performing the methods successively further decreases the structural weight at certain TR. Generally, weight increases as more elements are removed. By developing the two-way coupled ESO<>CS-optimization method, elements are removed by lowest strain energy density, while the cross-sections of the remaining members are updated in each iteration, thus coupling ESO (topology) and CS-optimization (size). This results in a logical load path and additional weight reduction especially in the braced frame structures loaded by lateral loads when displacement is governing. In multiple load case design, the removal of elements is somewhat hard to interpret, however the method consistently results in the lowest structural weight for the considered cases. In order to create a modular structural design, boundary conditions are assumed by standardizing column and beam dimensions and considering multiple realistic load cases (wind+vertical load). By transforming arbitrary shapes into structural models and optimizing these, a range of solutions for the structural design is presented in which the number of elements and the structural weight are generally negatively related. For the considered rectangular buildings, the results are more efficient than core or outrigger structures and almost as efficient as mega frame structures, with the added benefit that it can be applied to any shape. Exploration of these solutions is a useful contribution to the early design stage of modular high-rise buildings, while the coupled ESO<>CS-optimization method could also be useful in other optimization problems.

Steel trusses are the preferred structures when large distances are required to span due to its lightweight, the reduced deflection and its load bearing capacity. Although nowadays with the help of computational tools more efficient designs can be achieved, the geometrical shape of trusses has barely changed. This is mainly due to the ease of the required structural calculations and due to the available standard manufacturing and assembly procedures. Although a standard shape could be seen as an advantage, studies suggest that the relationship between the efficient use of material and design rationalization is not balanced, leading to design-overcapacity of the structure. The use of optimization procedures provides new opportunities to engineers. New design solutions and near-optimal structures can be achieved when implementing optimization processes. Optimization processes could generate economical alternatives in terms of weight reduction. Despite optimization techniques are becoming increasingly available, optimized structures are not commonly used in real practice due to the complex configuration an optimized structure might have, especially when using layout optimization. Due to the non-conventional node-members configuration, realizing these optimized trusses in real practice with conventional joining mechanisms, such as bolted and welded connections, will probably lead to complex designs and higher costs. Therefore, innovative joining technologies are required to be implemented. Snap-fit connections are widely used connecting mechanism for joining plastic components. Due to its simplicity and efficiency while connecting two or more elements together are suitable for different applications. Despite it is not commonly used in the building industry and it is frequently used on small scale applications, the principle based on snap-fit connections could be used to connect the structural members of optimized trusses. First, a literature study provides a clear understanding of truss structures, focusing mainly on the importance of their joints. Structural optimization is also discussed, paying special attention on a new layout-optimization approach, which is based on two steps: first, the less-weight possible layout is obtained (the benchmark) without taking into account any buildable considerations. The second step consists on rationalizing the benchmark contemplating practical and buildable restrictions. Finally, a representative case-study steel truss is presented. The second part of this research explores the structural design and the optimization procedure applied on the case-study truss. Here the layout optimization approach is applied using Peregrine (plugin for Grasshopper). After an optimized layout is generated, it is design structurally using Karamba3D. Finally, the case-study truss and the optimized truss are compared. To explore the opportunity of implementing optimized trusses in practice, the conceptual design of an innovative joint based on snap-fit connections is developed. A representative internal node from the optimized truss is chosen and based on a general concept, three design concepts are created. Extensive Finite Element (FE) analyses are carried out to study the structural behavior of the innovative joint during three main phases. All FE analysis were performed using the FE software Abaqus. To conclude, this research project is an exploratory feasibility study of the use of steel snap-fit joints as internal nodes for optimized steel trusses.

In this thesis, research is performed into parametric design of balanced cantilever bridges within the total road design. The main research question is: What can be achieved by using a parametric model in the preliminary design phase, with the possibility to optimize and compare concrete bridges on material usage, costs and environmental impact? And to answer this question, the cantilever bridge and all other elements in the road design are investigated and a parametric model is developed. In this model the total vertical alignment of the road design is implemented along with approach bridges, substructure and foundations. Furthermore, the results of the designs are visualized in a 3D environment compared with an overview of the material costs and environmental impact. In the "Discussion", the following is concluded: Although the parametric model for the preliminary design of concrete cantilever bridges took a long time to develop, this time investment can be regained by using the model several times. Because by using the parametric model for the preliminary design of concrete bridges, the design time per procurement is decreased significantly. Furthermore, the design process of the balanced cantilever bridge has become more flexible since changes are automatically implemented for the whole model. Also the chance for (human) errors is decreased, for instance the risk of data loss is minimized due to the model’s single environment. Since only a limited amount of calculations is performed by the model, the results of the analysis must be used with caution. Another advantage is the instant results as produced by the model. These results consist of a visualization of the design and an overview of the material amounts, with their costs and environmental impact. Furthermore, the model is also able to optimize these results in a fast way due to a smart evolutionary solver. This all together makes the parametric model a useful tool with high potential, but it should be further
developed and improved.

Fibre reinforced polymers, or FRP, are increasingly used in structural engineering applications. Permeating the construction field from the aerospace industry, FRP are applied in both the rehabilitation of existing degrading structures as well as the conception of new projects such as pedestrian and traffic bridges or building facades. The increase of interest and use in FRP in recent decades is driven by the material’s advantageous properties. Its tailorable mechanical properties, long-term durability, customizable free-form design, and its light-weight feature have engrained FRP as a noteworthy alternative to traditional construction materials such as concrete, steel, or timber. This is of paramount importance in light of the climate change challenge facing structural engineers today. While the material properties have been extensively investigated over the past decades, the structural use in FRP have remained limited to specific applications. As such, FRP, material of the future, has fallen short of its aspirations, disappointing its most ardent proponents. A rift is identified between the academic setting of laboratory testing and the pragmatic essence of the construction industry. This research situates itself as part of the efforts interrogating the industry limits and attempting to bridge these two spheres. It proposes to answer the following research question: What strategies capitalize on FRP’s favorable mechanical properties in order to promote formal exploration with the material in the preliminary phase of a design considering its durable and sustainable potential? This research proposes then a tool that capitalizes on the advantageous mechanical properties of FRP and encourages formal exploration in FRP at the conception phase of a design. Considering the climate change threat, the stakes of such a catalyst framework are high. The Wilhelminaberg Viewpoint, a landmark project in Landgraaf (NL) designed by Ney & Partners, is used as case-study to implement the proposed framework. It also allows to draw a contrast between what is structurally feasible in FRP and what is realistically buildable in FRP. A multi-step single-objective optimization is developed. First, stiffness for a certain design boundary is maximized. Using a brute force algorithm, the first level iterates through all the possible laminate layup combinations to find the combination which generates the stiffest structure. The second level of the optimization finds the lightest geometries using a genetic algorithm. This suggested framework offers an answer to the research question, mentioned hereinabove. Completely integrated in one interface (Grasshopper 3D), the developed tool stimulates formal exploration in FRP structures exhibiting shell-like behavior. The user defines the design boundaries, design constraints, load-cases, and material properties and implements the framework.