Tag: conceptual-structural-design

With a design framework applicable to any site in the world, the Pluma installation envisions a lightweight future where structures generate more energy than they embody. Earned honorable mention at the IASS 2020 Design Competition.

Pluma demonstrates how form can follow function across disciplines and performance metrics. The design features photovoltaic membranes suspended in a lightweight cable system, resembling a flock of birds in flight.

The shape and orientation of the membrane ensemble is precisely tuned by an optimization algorithm to maximize solar radiation exposure and power generation on the site in Surrey.

Its supporting frame consists of standard timber elements assembled into cruciform sections, with simple, repeated connection details that are cost-effective. The foundation is a concrete slab hollowed out with compressed sawdust blocks as lost formwork, reducing the embodied energy compared to a typical slab by half.

The INFRAME pavilion is a temporary timber elastic gridshell structure built on the MIT campus in September 2019 as part of Judyta Cichocka's CEE MEng thesis.  The structure transforms the function of the public staircase between buildings E15 and E25 on the MIT campus into a performance area. A single layer gridshell becomes a real temporary outdoor stage for electronic music performances, a canvas for a video-mapping show, and has multiple imaginary roles invented by potential next owners. The ultimate goal of the project was to design an elastic timber gridshell, which can be constructed in real-life scenario, providing a functional space for experimental artistic performances and which endeavors to embody the principles of structural art: economy, efficiency and elegance. The challenge lied in development of the design strategy, which allows rapid construction by a small group of inexperienced builders at minimum cost while complying to the building code in Massachusetts (which was required by MIT).

This paper presents a developing platform of design strategies for concrete construction in India. More specifically, this paper will discuss three strategies for the design of horizontal spanning concrete elements. Each strategy involves a different method of structural optimization with varying performance levels based on material reduction and structural capacity. Designed for India’s affordable housing construction, the elements are constrained by the fabrication methods and materials available to India’s construction industry, merging structural design with the development of affordable housing technology. Material savings range from 16% to 50% depending on the strategy. The strategies are used to design, fabricate, and structurally test prototypes, exploring their potential for India’s construction needs.

The paper presents the results of the design method for a simply supported cavity beam, along with fabrication and load testing results. An optimization algorithm determines the location and rotation of empty plastic water bottles within a prismatic reinforced concrete beam in order to reduce material usage without reducing strength. Designed for India’s affordable housing construction, the beam is constrained by the fabrication methods and materials available to India’s construction industry. This is an effort to merge structural design tools with the development of affordable housing technology, potentially reducing the economic and environmental cost of construction through material efficiency. The designed beam results in a theoretical concrete volume reduction of 16%. Two cavity beams are designed and constructed, and then load-tested in comparison to two solid beams with the same dimensions.

This ongoing design project looks at an "eco-modernist" custom greenhouse to be built in Portola Valley, California.  The objective of this greenhouse is to meet requirements for extended-season plant growth while requiring limited intervention for operation and applying approaches of structural efficiency. Tools such as our Design Space Explorer suite are used to explore and select among a wide design space that meet performance objectives to varying degrees.  Local materials and custom structural joinery will be used in the greenhouse construction.

Innovations in mass timber have ushered in a resurgence of timber construction. Historic timber structures feature joinery connections which geometrically interlock, rarely featuring in modern construction which utilizes steel fasteners for connection details. Research in the geometric potential and mechanical performance of joinery connections remain disparate. This study seeks to develop a performance-driven design framework for the geometry of joinery connections. Experimental and analytical models for three types of joinery connections are presented and compared. The T* type joint, which uses a T-shaped tenon instead of a dovetail, experimentally showed the highest rotational stiffness. The analytically predicted rotational stiffness of the T* type joint comes within 20% of the experimentally determined value. A preliminary parametric study through the analytical model demonstrates how geometric parameters can be varied to achieve desired rotational stiffness.

Mohamed presented his paper entitled "Resistance Through Form: Synthesis Structures in the Design of a Residential Architecture for Khartoum, Sudan" at the Association of Collegiate Schools of Architecture's (ACSA) 106th Annual Meeting in Denver, Colorado, on March 17th, 2018. He presented his paper in the session "Architecture of the other 99%? – Power, Economy, and the Dilemma of History", and then joined a panel discussion moderated by Professor Ole Fischer of the University of Utah.

Despite the longstanding craft of interlocking wood joints in North American and East Asian carpentry, modern timber structures frequently use metal connectors in mid-rise construction. This research explores the structural capabilities of interlocking joints between beams and columns for mid-rise timber frame construction.  Research methods include parametric design, structural modelling, digital fabrication, and experimental load testing.

In More Economically Developed Countries (MEDCs) such as the United States, labor costs constrain affordable construction. As a result, architects and engineers design with systems that reduce the time and complexity of assembly – making use of standardized structural components, nominal sizing, and elements that are not materially efficient or optimal for estimated loading conditions. On the other hand, in Lower Economically Developed Countries (LEDCs) material costs, rather than labor, inhibit affordable construction. Conservatively, materials account for an estimated 60-80% of construction costs in LEDCs such as India. This incongruity highlights an opportunity for structural components optimized for material efficiency and suit the context of a developing LEDC such as India.

This paper explores the use of data-driven approximation algorithms, often called surrogate modeling, in the early-stage design of structures. The use of surrogate models to rapidly evaluate design performance can lead to a more in-depth exploration of a design space and reduce computational time of optimization algorithms. While this approach has been widely developed and used in related disciplines such as aerospace engineering, there are few examples of its application in civil engineering. This paper focuses on the general use of surrogate modeling in the design of civil structures and examines six model types that span a wide range of characteristics. Original contributions include novel metrics and visualization techniques for understanding model error and a new robustness framework that accounts for variability in model comparison. These concepts are applied to a multi-objective case study of an airport terminal design that considers both structural material volume and operational energy consumption.

In a session titled Structure as Design Knowledge, Renaud presents a paper that connects the history of computation in architecture and structural engineering to current and future digital developments.

Geometric patterns, pioneered centuries ago as a dominant form of ornamentation in Islamic architecture, represent an abundant source of possible topologies and geometries that can be explored in the preliminary design of discrete structures. This diverse design space motivates the coupling between Islamic patterns and the form finding of funicular grid shells for which structural performance is highly affected by topology and geometry. This thesis examines one such pattern through a parametric, performance-driven framework in the context of conceptual design, when many alternatives are being considered. Form finding is conducted via the force density method, which is augmented with the addition of a force density optimization loop to enable grid shell height selection. A further modification allows for force densities to be scaled according to the initial member lengths, introducing sensitivity to pattern geometry in the final form-found structures. The results attest to the viable synergy between architectural and structural objectives through grid shells that perform as well as, or better than, quadrilateral grid shells. Historic and cultural patterns therefore present design opportunities that both expand the conventional grid shell design vocabulary and offer designers an alternative means of referencing vernacular traditions in the modern built environment, through a structural engineering lens.

This thesis encourages interdisciplinary design exploration through consideration of constructability in conceptual structural design. Six new metrics are introduced to measure variability in structural components, impose reasonable construction constraints, and encourage standardization of structural characteristics which can improve the ease, efficiency, and costs of construction. This thesis applies these original constructability metrics to truss façade structures for an objective, quantitative comparison with structural performance metrics. The primary contribution of these new metrics is a computational method that can aid in identifying expressive, high-performing structures in the conceptual design phase, when decisions regarding global structural behavior have the greatest impact on multi-objective project goals.

Funicular structures, which follow the idealized shapes of hanging chains under a given loading, are recognized as materially efficient structural solutions because they exhibit no bending under normal loading conditions and minimize the amount of required members, often reducing the amount of material needed. However, non-structural conditions, such as aesthetics, functionality, and geotechnical issues, often prohibit selection of a structurally ideal funicular shape: bending moments inevitably arise, decreasing the structural efficiency of the design.

This paper briefly describes how a new design philosophy consisting in the introduction of additional loads, using external post-tensioning cables, can convert a non-funicular structure into a funicular one without changing its starting geometry. This system is based on the possibility of introducing external forces into the main structure through a system of stressed tension cables and compressive or tension struts resulting in changing internal force distribution.

The theoretical approach, based on graphic statics, has been generalized for any two-dimensional geometry. The method has been implemented in a parameterized and interactive environment allowing the fast exploration of different equilibrated solutions.

This paper focuses on the physical modeling, testing, and validation of structures implementing this approach. The structures are modelled through reduced-scale non-funicular geometries fabricated through additive manufacturing (3D printing), with the post-tensioning system constructed with thin cable and precise laser-cut struts. Slow motion video captures show how three different non funicular geometries (pointed-arch, circular arch and free form curve), made of discrete elements and without bending strength, stand only if the cable is working in the appropriate way, demonstrating the efficacy of the new system.

Furthermore, this paper introduces a built example on the scale of real building systems. The paper describes the design and construction process of a post-tensioned pavilion structure. This pavilion, called Funicular Explorations, serves as both a validation and demonstration of this new method, expressing the creative freedom of designers and the structural performance of the results. The design is an array of eight two-dimensional curves, made from custom-cut corrugated cardboard and nylon webbing. The array begins with a funicular parabolic arch, and progresses toward a visually expressive but structurally arbitrary shape. The external post-tensioning system contributes increasingly from one curve to the next, finally allowing the terminal free-form shape to be achieved with axial forces only.

The use of physical models, independent of their scale, is informative but also didactic, illustrating the possibilities and trade-offs in funicular explorations for architectural design. Furthermore such models demonstrate the structural concept behind the post-tensioning system in an intuitive way. The aim of this research is to allow architects and structural engineers a way to achieve high-performance, efficient, and safe designs, even when the global geometry departs from classical funicular shapes.

Principal stress lines, which are pairs of orthogonal curves that indicate trajectories of internal forces and therefore idealized paths of material continuity, naturally encode the optimal topology for any structure for a given set of boundary conditions. Although stress line analysis has the potential to offer a direct, and geometrically provocative approach to optimization that can synthesize both design and structural objectives, its application in design has generally been limited due to the lack of standardization and parameterization of the process for generating and interpreting stress lines. Addressing these barriers that limit the application of the stress line methods, this thesis proposes a new implementation framework that will enable designers to take advantage of stress line analysis to inform conceptual structural design. Central to the premise of this research is a new conception of structurally inspired design exploration that does not impose a singular solution, but instead allows for the exploration of a diverse high-performance design space in order to balance the combination of structural and architectural design objectives. Specifically, the thesis has immediate application for the topological design of both regular and irregular thin shell structures predominately subjected to in-plane and compressive structural actions.

In traditional optimization, an algorithm can be applied to a well-defined problem to return a single solution. In architectural design, problems are rarely this simple—building design is a process full of human preferences and interrelated performance tradeoffs. Multi-objective optimization (MOO) is often more appropriate for managing the various design influences and priorities in conceptual design, but it is inherently dependent on human input throughout the process. This research presents a variety of visualization techniques and computational methods that have been developed to facilitate the use of MOO in conceptual architectural design.

During early stages of design, an architect tries to control space by “finding a form” among countless possible forms, while an engineer tries to control forces by “form-finding” an optimized solution of that particular form. Most commonly used parametric tools in architectural design provide the user with extensive geometric freedom in absence of performance, while engineering analysis software mandates pre-determined forms before it can perform any numerical analysis. This trial-and-error process is not only time intensive, but it also prohibits exploration beyond the design space filled with already known, conventional solutions. There is a need for new design methods that combine form generation with structural performance.

This thesis addresses this need, by proposing a grammar-based structural design methodology using graphic statics. By combining shape grammars with graphic statics, the generative (architectural) and the analytical (engineering) procedures are seamlessly integrated into a simultaneous design process. Instead of manipulating forms with multiple variables as one would in the conventional parametric design paradigm, this approach defines rules of allowable geometric generations and transformations. Computationally automated random generator is used to iteratively apply various rules to generate unexpected, interesting and yet structural feasible designs. Because graphic statics is used to embed structural logic and behavior into the rules, the resulting structures are always guaranteed to be in equilibrium, and do not need any further numerical analysis. The effectiveness of this new methodology will be demonstrated through design tests of a variety of discrete, planar structures.

Grammatical Design with Graphic Statics (GDGS) contributes new ways of controlling both form and forces during early stages of design, by enabling the designer to: 1) rapidly generate unique, yet functional structures that fall outside of the expected solution space, 2) explore various design spaces unbiasedly, and 3) customize the combination of grammar rules or design objectives for unique formulation of the problem. Design tests presented in this thesis will show the powerful new potential of combining computational graphic statics with shape grammars, and demonstrate the possibility for richer and broader design spaces with much more trial, and less error.

Funicular structures, which follow the shapes of hanging chains, work in pure tension (cables) or pure compression (arches), and offer a materially efficient solution compared to structures that work through bending action. However, the set of geometries that are funicular under common loading conditions is limited. Non-structural design criteria, such as function, program, and aesthetics, often prohibit the selection of purely funicular shapes, resulting in large bending moments and excess material usage. In response to this issue, this paper explores the use of a new design approach that converts non-funicular planar curves into funicular shapes without changing the geometry; instead, funicularity is achieved through the introduction of new loads using external post-tensioning. The methodology is based on graphic statics, and is generalized for any two-dimensional shape. The problem is indeterminate, meaning that a large range of allowable solutions is possible for one initial geometry. Each solution within this range results in different internal force distributions and horizontal reactions. The method has been implemented in an interactive parametric design environment, empowering fast exploration of diverse axial-only solutions. In addition to presenting the approach and tool, this paper provides a series of case studies and numerical comparisons between new post-tensioned structures and classical bending solutions, demonstrating that significant material can be saved without compromising on geometrical requirements.

Funicular structures, which follow the shapes of hanging chains, work in pure tension (cables) or pure compression (arches), and offer a materially efficient solution compared to structures that work through bending action. However, the set of geometries that are funicular under common loading conditions is limited. Non-structural design criteria, such as function, program, and aesthetics, often prohibit the selection of purely funicular shapes, resulting in large bending moments and excess material usage. In response to this issue, this paper explores the use of a new design approach that converts non-funicular planar curves into funicular shapes without changing the geometry; instead, funicularity is achieved through the introduction of new loads using external post-tensioning. The methodology is based on graphic statics, and is generalized for any two-dimensional shape. The problem is indeterminate, meaning that a large range of allowable solutions is possible for one initial geometry. Each solution within this range results in different internal force distributions and horizontal reactions. The method has been implemented in an interactive parametric design environment, empowering fast exploration of diverse axial-only solutions. In addition to presenting the approach and tool, this paper provides a series of case studies and numerical comparisons between new post-tensioned structures and classical bending solutions, demonstrating that significant material can be saved without compromising on geometrical requirements.

Funicular geometries, which follow the idealized shapes of hanging chains under a given loading, are recognized as materially efficient structural solutions because they exhibit no bending under design loading, usually self-weight. However, there are circumstances in which non-structural conditions make a funicular geometry difficult or impossible. This paper presents a new design philosophy, based on graphic statics, that shows how bending moments in a non-funicular two-dimensional curved geometry can be eliminated by adding forces through an external post-tensioning system. An interactive parametric tool is introduced for finding the layout of a post-tensioning tendon for any structural geometry. The effectiveness of this approach is shown with several new design proposals.

In the field of digital fabrication, additive manufacturing (AM, sometimes called 3D printing) has enabled the fabrication of increasingly complex geometries, though the potential of this technology to convey both geometry and structural performance remains unmet. Typical AM processes produce anisotropic products with strength behavior that varies according to filament orientation, thereby limiting its applications in both structural prototypes and end-use parts and products. The paper presents a new integrated software and hardware process that reconsiders the traditional AM technique of fused deposition modelling (FDM) by adding material explicitly along the threedimensional principal stress trajectories, or stress lines, of 2.5-D structural surfaces. As curves that indicate paths of desired material continuity within a structure, stress lines encode the optimal topology of a structure for a given set of design boundary conditions. The use of a 6-axis industrial robot arm and a heated extruder, designed specifically for this research, provides an alternative to traditional layered manufacturing by allowing for oriented material deposition. The presented research opens new possibilities for structurally performative fabrication.