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RhinoCircular: Development and Testing of a Circularity Indicator Tool for Application in Early Design Phases and Architectural Education


Abstract and Figures

RhinoCircular is a CAD plugin developed within the Circular Construction Lab (CCL) at Cornell University that assesses a building design’s environmental impact in respect to its embodied carbon values and circularity: the degree to which design solutions minimize extraction and waste in favor of reusable, recyclable and renewable material resources. Over their full life cycle, current buildings account for 39% of carbon dioxide emissions [1] and more than 50% of resource extraction and solid waste production. [2,3] As a way to overcome the social, economic, and environmental problems of this linear economic system, the concept of the circular economy is increasingly gaining attention. Activating the built environment as a material reserve for the construction of future cities would not only provide valuable local resources, but also potentially prevent up to 50% of the industry’s emissions by capitalizing on embodied carbon. [1] However, this requires radical paradigm shifts in how we design and construct buildings (e.g. materials selection/ design for disassembly), and in how resources are managed within the built environment. Buildings and regions need to anticipate stocks and flows of materials, documenting and communicating which materials in what quantities and qualities become available for reuse or recycling where and when. RhinoCircular allows direct and immediate feedback on design decisions in respect to formal deliberations, structural considerations, material selection and detailing based on material passports and circularity indicators. It can be integrated in existing and complex workflows and is compatible with industry standard databases while providing its own essential dataset complementing missing information.
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2020 AIA/ACSA Intersecons Research Conference: CARBON 1
Keywords: circular construcon, circular economy, circularity
indicator, recycling, reuse
RhinoCircular is a CAD plugin developed within the Circular
Construcon Lab (CCL) at Cornell University that assesses
a building design’s environmental impact in respect to its
embodied carbon values and circularity: the degree to which
design soluons minimize extracon and waste in favor of
reusable, recyclable and renewable material resources.
Over their full life cycle, current buildings account for 39%
of carbon dioxide emissions [1] and more than 50% of
resource extracon and solid waste producon. [2,3] As a
way to overcome the social, economic, and environmental
problems of this linear economic system, the concept of the
circular economy is increasingly gaining aenon. Acvang
the built environment as a material reserve for the construc-
on of future cies would not only provide valuable local
resources, but also potenally prevent up to 50% of the
industry’s emissions by capitalizing on embodied carbon.
[1] However, this requires radical paradigm shis in how
we design and construct buildings (e.g. materials selecon/
design for disassembly), and in how resources are managed
within the built environment. Buildings and regions need
to ancipate stocks and ows of materials, documenng
and communicang which materials in what quanes and
quali es be come availabl e for re use or recycl ing wh ere and
when. RhinoCircular allows direct and immediate feedback
on design decisions in respect to formal deliberaons, struc-
tural consideraons, material selecon and detailing based
on material passports and circularity indicators. It can be
integrated in exisng and complex workows and is compat-
ible with industry standard databases while providing its
own essenal dataset complemenng missing informaon.
Globally, the construcon industry is the biggest consumer
of energy and materials. Over their full life cycle, buildings
account for 39% of carbon dioxide emissions [1] and more than
50% of resource extracon and solid waste producon. [2,3]
As a way to overcome the social, economic, and environmental
problems of the current linear economic system, the concept
of the circular economy (CE) is increasingly gaining aenon.
A CE has been dened as “ that is restorave and regen-
erave by design and aims to keep products, components,
and materials at their highest ulity and value at all mes.”
[4] The consequent closing of producon and consumpon
loops oers not only the possibility to end the loss of valuable
nite resources, but also to reduce dependencies on global,
volale resource markets, prevent greenhouse gas emissions,
migate the eects of the climate crisis, and support new busi-
ness models and green job opportunies. [5-6]
Since rates of construcon are signicantly higher than
demolion and discard, society is building up an important
economy-wide anthropogenic material stock. [7] Today, the
amount of many metals and minerals bound within the built
environment has already outgrown their respecve naturally
occurring reserves. [8] By some esmates, exisng buildings
account for as much as 90% of all materials ever extracted, [9]
hastening calls for the development of technologies and strat-
egies for circular resource ulizaon. Addionally, as global
and local actors seek to address climate concerns the implicit
value associated with embodied carbon, labor, knowledge and
water can impact material valuaon going forward. The loss
of this signicant exisng stock of materials and the related
embodied values due to the current pracce of demolion
and landlling will consequently no longer be viable praccally,
environmentally, or economically.
Acvang the built environment as a material reserve for
the construcon of future cies would not only provide valu-
able local resources, but also potenally prevent up to 50%
of the industry’s emissions by capitalizing on embodied car-
bon. [1] However, this requires radical paradigm shis in how
we design and construct buildings (e.g. materials selecon/
design for disassembly), and in how resources are managed
within the built environment. Buildings and regions need to
ancipate stocks and ows of materials, documenng and
communicang which materials in what quanes and quali-
es become available for reuse or recycling where and when.
The current waste of resources is facilitated by the absence of
such relevant data on materials: Historically, the construcon
industry has not documented the stocks, ows, specicaons,
and values of building materials and components over me,
nor has it prepared this data for future use. In business, what
gets measured gets managed, so the availability and ulizaon
of this data represent one of the keys to developing material
loops crical to the CE.
RhinoCircular: Development and Tesng of a Circularity Indicator Tool
for Applicaon in Early Design Phases and Architectural Educaon
Circular Construcon Lab, Cornell University
Circular Construcon Lab, Cornell University
2RhinoCircular: Development and Tesng of a Circularity Indicator Tool for Applicaon in Early Design Phases and Architectural Educaon
Eorts by a number of organizaons over the last ten years
in creang and making available such data have oered
several dierent approaches, each with their advantages
and shortcomings. While top-down approaches focus on
macro-economic stascs as informaon source, boom-
up approaches extrapolate urban material stock and ow
informaon based on a combinaon of indicators such as the
material composion of typical buildings and oor surface
area. As an example, the TABULA project by Intelligent Energy
Europe surveyed exisng buildings and compared them to
one of several building types, organized regionally, in order
to enable esmaon of the material stock in the already-built
environment. [10] Expanding on this methodology, a study of
the city of Chiclayo, Peru, used Google Street View and munici
pal cadasters (legal registers of property boundaries and
value) as an ecient means to survey the city’s residenal sec-
tor. [11] Most recently, several studies combined boom-up
approaches with geographical informaon systems (GIS) and
airborne light detecon and ranging (LiDAR) data as addional
indicators to esmate the building stock of Esch-sur-Alzee
(FR), Luxembourg City (LU), Atlanta (US), Melbourne (AU),
Beijing (CH), Odense (DK), and Ithaca (US). [12-17]
The emerging concept of materials passports (MP) oers a
technical soluon to the missing building data documenta-
on, by providing digital twins of buildings, containing detailed
inventories of materials and products used, as well as their
specicaons, locaon and connecon details. Eorts by
Madaster, BAMB or EPEA in Europe oer plaorms for storing
such comprehensive informaon about materials, oen inte-
grang building informaon modeling (BIM) as the source for
volume calculaons. As a case-in-point, the Urban Mining and
Recycling (UMAR) [18] Unit by Werner Sobek, Dirk E. Hebel and
Felix Heisel within the Empa NEST in Dübendorf, Switzerland,
wa s desi gned and con s tructe d as a ful ly cir cula r prototypol o g y,
[19] achieving a 96% circularity rang [20] on the Madaster
plaorm - the highest of any known building registered on the
plaorm so far.
However, the broad applicaon of MPs to date is restricted
by several conceptual and technical limitaons: Firstly, MP
generaon unl now has been largely concentrated on the
documentaon of newly constructed buildings, consequently
missing out on two important phases of the building use cycle:
1) The already exisng building stock including the aforemen-
oned - so far undocumented - material stock / urban mine, as
well as 2) the early-design phase where MP thinking and inte-
graon could play a signicant role in both closing the current
supply/ demand mismatch of reusable materials and trans-
forming new construcons into the material depots (rather
than urban mines) of the future. A consequent standardizaon
and central registraon of MPs covering all buildings and com
ponents of the built environment in material cadasters will be
a prerequisite for the circular management of resources.
Secondly, while the calculaon methods for circularity indi-
cators have been established in the past years (see method
secons below), the underlying and necessary data points are
sll mostly unavailable to date. Many material ow calculaons
are missing informaon especially towards the end-of-use
phase of buildings and thus complicate scienc analysis of
design decisions. In the case of UMAR, MP creaon required
building substanal databases of custom materials. Such work
is at best tedious, and at worst prohibively me-consuming
for smaller rms, individual designers, and students, assum-
ing the ne ces sar y data points can even be found . Addi onall y,
while such an approach might be suitable to record what
congured materials happen to be reusable in an already-
planned building, it cannot provide the necessary feedback to
the design decisions themselves and thus does not represent
a fundamental shi away from the linear, exploitave thinking
that is one root cause of the global resource predicament.
This paper describes the development of a new tool address-
ing these challenges. RhinoCircular is a Rhi no3D/ Gras sho pper
plugin developed within the Circular Construcon Lab (CCL) at
Cornell University, that allows a direct and immediate feedback
on design decisions in respect to formal deliberaons, struc-
tural consideraons, material selecon and detailing based on
MPs and circularity indicators (CI). It can be integrated in exist-
ing and complex workows and is compable with industry
standard databases while providing its own essenal dataset
complemenng missing informaon. The following para-
graphs will highlight the funconality of the tool and provide
an outlook for its applicaon in architectural design studios,
research projects as well as architectural pracse.
RhinoCircular is a CAD plugin that assesses a building design’s
environmental impact in respect to its embodied carbon
values and circularity: the degree to which design soluons
minimize extracon and waste in favor of reusable, recy-
clable and renewable material resources. Embedded into the
Grasshopper environment of the popular design soware
Rhinoceros3D, the tool consists of several components that
can be combined or connected through ‘visual’ scripng to suit
the specic needs of a proposed project in any design phase
or on any level of detail. The open structure further allows
the seamless integraon of RhinoCircular components into
exisng workows, be they sequenal, generave, paramet-
ric or automated.
Aiming to support a holisc approach to operaonal and
embodied carbon analyses and trade-o strategies on the
building and urban scale, RhinoCircular interacts with climate
and energy simulaon workows such as ClimateStudio [21]
or AutoZoner, [22] as well as geometr y automaon tools such
as AutoFramer. [23] The soware is further compable with
the industry standard databases such as Madaster by oer-
ing components to read materials and write MPs into specic
2020 AIA/ACSA Intersecons Research Conference: CARBON 3
porolios using available applicaon programmin interfaces
(API). In order to allow the intended seamless exchange of data
within such a generave design and simulaon environment,
the authors are currently also part of a team developing a com-
prehensive data set, namely BuildingRepo, [24] a forthcoming
open-source building repositor y available online and through
its own Grasshopper plug-in.
The CI itself is a number between 0 and 1 calculated via a set
of equaons from parameters such as lifespan, eciency of
recycling, and fracon of feedstock taken from renewable,
recycled, or reused sources. The equaons were rst devel-
oped by the Ellen MacArthur Foundaon in 2016, [25] and
further adapted for their specic applicaon in the built envi-
ronment by Madaster in 2018. [26] For their applicaon within
RhinoCircular, certain variables are computed directly from
Nurbs and mesh geometry. As summarized in Table 1, values of
interest can be organized into three categories: basic param-
eters provided directly by the user or the respecve material
databa se, compu ted pa r ame ters which ca n be wri en in terms
of the basic parameters, or metrics computed from a combi-
naon of basic and computed parameters. Values are further
organized by the period of the building’s use-cycle analysis to
which they pertain: construcon, use, or end-of-use phases.
Finally, the overall CI of a product is calculated from the linear
ow index (LFI) and ulity fac tor (F(X)), as dened below:
F(X) = 0.9/CIuse
LFI = (V+W) / (2M + (WF - WC)/2)
CItotal = 1-LFI * F(X)
Key to construcng complex models is the ability to break a
building down into a hierarchy of architectural components,
ea ch of which might it self be divid e d int o sma ller compo n ent s .
These components are referred to as products. Compung
metrics for compound products follows the general rule of
mass-weighted sum:
∑ (CIsub -product * Msub-produc t) / Mproduct
RhinoCircular consists of several components, divided into
categories of material, product, and analysis. Figure 1 depicts
the user interface of Rhinoceros3D (le) and RhinoCircular
in Grasshopper (right). Results are displayed directly in the
modelling environment for easy reference within the design
workow, while visual scripng of components is done
within Grasshopper.
Materials. A standard workow begins with the selecon
of materials; this can be accomplished through the “Load
Material” component, which displays a list encompassing
those materials from the selected database and which is
searchable by class of material (wood, stone, plasc, texle,
organic, ceramic, and metal). This can be fed into any of the
product components. A toggleable parameter of the “Load
Material” component triggers an automac download of the
latest dataset from one of a selecon of sources including
Madaster, ensuring this data remains up-to-date and ed into
an enterprise-level repository. Alternavely, one can use the
“Custom Material” component to either tweak certain data
points of a catalogue material, as for instance if one were to
use the density and lifeme esmates of a stock material but
provide gures for eciency of recycling that were more rep-
resentave of their locality; or to create a new material from
scratch using outside data, as for instance if one were to use
a building product from a specic supplier’s catalogue that
provided such informaon. Given enough informaon, the
“Custom Material” component will calculate remaining values
automacally, sparing the need to explicitly enumerate all of
the relevant elds.
Product. The second stage of a typical workow would begin
by assigning these materials to components of the 3D build-
ing geometry, called products. This 3D model can be explicitly
referenced from geometry in the standard Rhinoceros3D edit-
ing window, or can be parametrically generated from within
Grasshopper, leveraging the exibility and power of this node-
based scripng tool. Products can represent anything from a
door knob to an I-beam to an enre façade system, but begin
as an object of a single material. These inial products contain
informaon about the referenced geometry, its volume and
density (and hence mass), and the material assigned to it. In
addion to the product object itself, these components also
output the CI values for the product in the construcon, use,
and end-of-use phases, and overall.
Table 1. Parameters and metrics for CI calculaon dependent on
use-c ycle phase, based on [28,29]
4RhinoCircular: Development and Tesng of a Circularity Indicator Tool for Applicaon in Early Design Phases and Architectural Educaon
This base product can be enumerated in one of four ways,
each represented by its own constructor component: length,
area, volume, or quanty. Length-based or linear products
can reference curve geometry and must provide the cross-
seconal area in order to calculate volume, making it easy,
for instance, to iterate through dierent gauges of rope or
wire within a parametric design workow while working with
easy-to-manipulate curve geometry. Area-based products
can reference surfaces or meshes and must provide a thick-
ness. Volume-based products can reference solid geometry,
either BReps (Nurbs boundary representaons) or meshes,
from which volume is calculated directly. Lastly, for products
that do not t in these categories, or which have no explicit
3D geometry associated with them, the quanty component
allows manual entry of the volume and enables one to group
large numbers of similar products as would be useful for items
like nails, studs, and screws.
Importantly, these components display three clickable buons
labeled “Inaccessible,” “Fixed in place,” and “Nonstandardized.”
Toggling the buons changes them to read “Accessible,”
“Disassemblable,” and “Standardized.” If any of the buons
are le untoggled, the product is considered irremovable and
therefore the end-of-use CI value will default to 0. Therefore,
it is expected that these must be toggled each me; this is
a deliberate pedagogical choice to highlight the queson of
reversible joinery so that the user is consciously aware of its
eect on the overall circularity of a building.
The four base product types are the atomic units of a build-
ing circularity model, which can be viewed as a tree in which
each er represents a relevant level of organizaon within the
building, as displayed in Figure 2. In each successive er prod-
ucts from the previous er are merged using the “Composite”
component, which takes any number of products as input
and produces a single, combined product whose CI values are
taken as the weighted sum by mass of those of the inputs.
Not necessarily a unidireconally-branching tree, the hierar-
chy can contain mulple organizaons at the same er (for
instance, grouping products by supplier, or by building layer);
however, to avoid overcounng, an error is generated if the
same geometry is merged with itself downstream. The nal
merging into a single product represents the building as a
whole, giving the total values for all CIs.
Figure 1. RhinoCircular user interface in Rhinoceros3D and Grasshopper. Circular Construcon Lab, Cornell University.
Figure 2. Organizaon tree of building circularity model within
RhinoCircular. Circular Construcon Lab, Cornell Universit y
2020 AIA/ACSA Intersecons Research Conference: CARBON 5
Analysis. A subset of components are specically concerned
with the visualizaon and publishing of the computed metrics.
The “Passport” component takes as input a product, typically
the composite product represenng the enre building, and
generates a formaed, printable le displaying a summary
of all key metrics. The “Selectcomponent renes a list of
products according to an input criterion: a material to match
against, a 1D domain of CI values to test for inclusion, or the
sasfacon of the three accessibility criteria described above.
Each product contains geometry data such that by selecng its
component in Grasshopper, the corresponding geometry may
be highlighted in the Rhinoceros3D viewport for quick analysis.
In combinaon with the “Select” component, the passing of
geometry data upstream also allows for custom workows
such as highlighng geometry with a color gradient according
to CI or material type. The “Graph” component displays a bar
graph within a widget in the grasshopper canvas. From the
menu the user can select which of the calculated metrics to
display for the input product. One can addionally select how
to organize the x-axis; for example, one could display the use
phase CI for each layer in the CAD le, or the mass weighted CI
for each material in the construcon. The component outputs
include the names and values of each column of the bar graph.
An example is shown in Figure 3.
In contrast to exisng soware applicaons that document
design decisions based on detailed BIM models for the cre-
aon of MPs, RhinoCircular is developed as an early design
tool to support and inuence design decisions in the process.
This fact naturally results in a lower level of model accuracy
and detail which needs to be taken into account when cal-
culang CI and embodied carbon values. Consequently, the
soware is running certain automisaon processes to ll in
the blanks when required data points for the calculaon are
not yet available in the model or reverts to default values from
literature. While we do not see this as problemac - the goal of
the soware is indeed to allow quick informed decisions in the
mes of greater uncertainty, the level of data accuracy in the
early-design phase needs to be acknowledged. With increasing
model accuracy throughout the stages of the design process,
RhinoCircular increasingly renes its calculaons.
All CI tools are currently sll limited by the availability of data
on material ows especially towards the end-of-use phase
of the cycle. RhinoCircular aims to migate this limitaon
through compability with several sources and interfaces, as
well as through the ongoing development of its own dataset in
the background. Addionally, material cycle-specic data such
as eciency of recycling or embodied carbon values are highly
dependant on the locaon of the building, as energy mixes in
producon, transport lengths and local producon, construc-
on and recycling condions determine the calculaon of such
inputs. Consequently, RhinoCircular asks for a user-dened
parameter on the locaon of the building, however, most data
bases are not able to interpret or adjust values depending on
specic locaons.
Figure 3. RhinoCircular displays calculaon results directly within the modelling environment. Circular Construcon Lab, Cornell University.
6RhinoCircular: Development and Tesng of a Circularity Indicator Tool for Applicaon in Early Design Phases and Architectural Educaon
With live recalculaon of CI during the design process, it
becomes possible for the designer to adjust geometry accord-
ingly. However, the potenal for interoperability with other
early design analysis tools oers even greater potenal. For
example, one could adjust the span of a load bearing beam
and have the cross-secon automacally recalculated with a
nite element modeling tool such as the Grasshopper plugin
“Karamba,” [27] then instantly see the impact this has on cir-
cularity as the CI is recalculated for the beam’s new mass. This
seamless workow however will only be enabled by central-
ized material databases such as the forthcoming BuildingRepo
where material properes related to all manner of design
objecves, from circularity to environmental and mechanical
performance, can be accessed side-by-side. This contrasts
with common pracce, wherein separate, specialized data-
bases are leveraged for each simulaon tool, which can make
it dicult to ensure that data refers to the same material from
on e tool to ano ther. To this end, Rhin o Circular has be e n dev el-
oped to be as agnosc as possible to the data source, so that it
can easily be graed into more holisc workows such as the
BuildingRepo toolkit in the future.
The implementaon of a CE in the built environment through
circular construcon is technically feasible already today, as
the examples of UMAR and other lighthouse construcons
around the globe demonstrate. However, its industrial and
large-scale applicaon requires fundamental paradigm shis
in design and construcon methodologies, economic and
social models as well as material producon and sourcing. A
detailed documentaon of the built environment over me
represents a precondion for the closing of material cycles in
this scenario. Most importantly however, it is a design task to
develop circular soluons that implement and reapply exist-
ing resources in ways that do not create waste in the process
and allow for the connuous use of materials, products and
components at their highest ulity and value.
This design process requires new tools to support and allow
informed decision making and matching of supply and demand
within an urban circular system. In this context, RhinoCircular
provides an integrated tool for predicng the impact of espe-
cially early-design decisions on the circularity performance
of buildings. It allows architects, engineers, and planners to
maximize the reusability of buildings from the outset, giving
meaningful feedback about circularity even with incomplete
informaon. A 2012 survey reported that 91% of large com-
pa nie s are us ing BI M, wh ile on ly 49% of sma ller rms re ported
the same. [28] We may expect similar trends in the adopon
of tools for circular building, unless they can be easily and
seamlessly integrated in exisng and low-cost workows.
RhinoCircular aims to be one such soluon.
1. Architecture 2030. 2019. “New Buildings: Embodied Carbon.”
2. Trans parenc y Market Rese arch. 202 0. “Cons truc on Waste Ma rket - Glo bal
Indu stry A nal ysi s, Siz e, Share, Gr owth, Tre nds, and F ore cast 2017 - 2025.”
3. Internao nal Energy A gency and the Unite d Environment Pro gramme. 2018.
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... It was shown that the design process can be conceptually and technically adapted for reuse by switching inputs and outputs of a design, rendering reusability as an operational constraint for structural designs . Researchers started to implement tools for predicting the impact of early-design decisions on the circularity performance of buildings in the design environment (Heisel and Nelson 2020). Additionally, the intelligent dismantling of buildings can be beneficial for resource recovery from construction and demolition waste (Ghaffar et al. 2020). ...
Proceedings of the Design Modelling Symposium Berlin 2022, Towards Radical Regeneration
... Lastly, there is currently no available tool to track building elements coming out of deconstruction in an effort to bridge the gap between demand and supply in circular construction. Consequently, next steps at the Circular Construction Lab at Cornell University include the development of (1) a new survey methodology that supports on-site measurements with augmented reality 3d scanning technologies [21], and (2) the Rhinoceros 3D plugin RhinoCircular, which allows the immediate calculation and evaluation of circularity potential of materials and connections in 3D geometries [22]. ...
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Globally, buildings account for at least 39% of CO 2 emissions and more than 50% of resource extraction and solid waste production. Therefore, any transition to carbon neutral buildings must be paired with new resource sensibilities and a shift from linear models of material consumption to continuous material use within a circular economy. Prospecting the (urban) anthropogenic mine represents an essential step towards circular construction and requires a robust methodology for data collection and interpretation. This paper presents a comparative analysis of survey methods, evaluated by parameters of time, accuracy, equipment, and labor to determine the ability of each tool in providing the necessary data to activate the existing built environment as a material resource. Chosen methods span from on-site manual and analog surveys to off-site digital technologies on a variety of case study scales. In all cases, the output’s data format (sketch book, images, mesh or point cloud outputs) can be cumbersome to process with CAD and BIM software, increasing time to results and limiting the technology’s potential, introducing the call for a new generation of survey tools specifically addressing the needs of deconstruction and salvage in circular construction.
... BC assessment can provide insight into the material flow by indicating the material flow's completeness and tightness (i.e., the circularity rate). Various research has been executed on circularity assessment approaches in the AEC industry [11]. Almost all the existing methods used in the AEC sector are based on a CE general assessment framework, such as the Material Circularity Indicator (MCI) [12], which is also widely used in other industries. ...
Full-text available
Circular Economy (CE) has proved its contribution to addressing environmental impacts in the Architecture, Engineering, and Construction (AEC) industries. Building Circularity (BC) assessment methods have been developed to measure the circularity of building projects. However, there still exists ambiguity and inconsistency in these methods. Based on the reviewed literature, this study proposes a new framework for BC assessment, including a material flow model, a Material Passport (MP), and a BC calculation method. The material flow model redefines the concept of BC assessment, containing three circularity cycles and five indicators. The BC MP defines the data needed for the assessment, and the BC calculation method provides the equations for building circularity scoring. The proposed framework offers a comprehensive basis to support a coherent and consistent implementation of CE in the AEC industry.
... As a result of the survey, detailed 3D models of the building geometries can be constructed using Rhinoceros3D. Using the grasshopper plugin RhinoCircular (Heisel and Nelson, 2020), which is also able to communicate with the material database BuildingRepo, materials can then be applied to this geometry and the total material mass and volume calculated. A comparison of results between the semi-automated model and the detailed survey model allowed for the validation of the described material content calculations. ...
As global and local actors seek to address climate concerns, municipalities, regions, and countries are developing policies for the built environment to reach carbon neutrality. In most cases, however, current policies target new construction and operational carbon emissions only, thus omitting the significant carbon emission saving potential resulting from the reactivation of embodied carbon in existing buildings. This article describes the development of a high-resolution combined building stock model (BSM) and building energy model (BEM) on both building and urban scale using all residential buildings of Ithaca, NY, USA as a case study. The model offers a holistic, detailed and local perspective on operational and embodied carbon emissions, associated saving potentials at both the building and urban scale, and the linkages, trade-offs and synergies between buildings and energy use as a basis for decision-making. A circular economy (CE) in construction posited on the reuse and recycling of existing building materials, necessitates a detailed material inventory of the current building stock. However, the scale and nature of this endeavor preclude traditional survey methods. The modeling process described in this article instead engages a bottom-up data aggregation and analysis approach that combines detailed construction archetypes (CAs) and publicly available, higher-level municipal geospatial data with building metadata defining occupancy and systems to create an autogenerated, detailed 3D geometry. The resulting BSM and BEM can simulate both embodied carbon content and operational carbon emissions of individual buildings within a municipal study with minimal required input data and a feasible computational effort. This provides modelers with a new spatial and geometric fidelity to simulate holistic renewal efforts, and inform carbon neutrality policies and incentives towards the decarbonization of the built environment.
Construction materials are one of the main contributors to the global waste production. Compared to other industries, the reusability of building materials and components is hard to implement due to each project’s individual properties and the difficulty of sharing information across the various stakeholders. In order to foster the reuse of building components, the gap between the existing building stock and the design phase of new buildings has to be minimised by bringing suppliers’ data about the existing stock closer to the designers. This research illuminates how to provide relevant information from material passports and integrate them into the design environment. We compared nine passports and extracted relevant variables for the early design phase. Additionally, an augmented reality measurement app enables quick capturing and data exchange of materials and components from existing buildings. Finally, a compression-only design scheme is proposed to simplify the load capacities of the reused concrete components from an existing building. By providing information about existing materials and components in the strategically important role of the designer, reuse could be enhanced for a more sustainable built environment based on circular construction.KeywordsDesign with digital and physical realitiesCircular constructionAugmented realityBuilding material platform
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Improving our comprehension of the weight and spatial distribution of urban built environment stocks is essential for informing urban resource, waste, and environmental management, but this is often hampered by inaccuracy and inconsistency of the typology and material composition data of buildings and infrastructure. Here, we have integrated big data mining and analytics techniques and compiled a local material composition database to address these gaps, for a detailed characterization of the quantity, quality, and spatial distribution (in 500 m × 500 m grids) of the urban built environment stocks in Beijing in 2018. We found that 3,621 megatons (140 ton/cap) of construction materials were accumulated in Beijing's buildings and infrastructure, equaling to 1,141 Mt of embodied greenhouse gas emissions. Buildings contribute the most (63% of total, roughly half in residential and half in non-residential) to the total stock and the subsurface stocks account for almost half. Spatially, the belts between 3 to 7 km from city center (approximately 5 t/m2) and commercial grids (approximately 8 t/m2) became the densest. Correlation analyses between material stocks and socioeconomic factors at a high resolution reveal an inverse relationship between building and road stock densities and suggest that Beijing is sacrificing skylines for space in urban expansion. Our results demonstrate that harnessing emerging big data and analytics (e.g., Point of Interest data and web crawling) could help realize more spatially refined characterization of built environment stocks and the role of such information and urban planning in urban resource, waste, and environmental strategies.
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The article at hand follows the understanding that future cities cannot be built the same way as existing ones, inducing a radical paradigm shift in how we produce and use materials for the construction of our habitat in the 21st century. In search of a methodology for an integrated, holistic, and interdisciplinary development of such new materials and construction technologies, the chair of Sustainable Construction at KIT Karlsruhe proposes the concept of “prototypological” research. Coined through joining the terms “prototype” and “typology”, prototypology represents a full-scale application, that is an experiment and proof in itself to effectively and holistically discover all connected aspects and address unknowns of a specific question, yet at the same time is part of a bigger and systematic test series of such different typologies with similar characteristics, yet varying parameters. The second part of the article applies this method to the research on mycelium-bound building materials, and specifically to the four prototypologies MycoTree, UMAR, Rumah Tambah, and Futurium. The conclusion aims to place the results into the bigger research context, calling for a new type of architectural research.
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Humans are extracting and consuming unprecedented quantities of materials from the earth’s crust. The construction sector and the built environment are major drivers of this consumption which is concentrated in cities. This paper proposes a framework to quantify, spatialise and estimate future material replacement flows to maintain urban building stocks. It uses a dynamic, stock-driven, and bottom-up model applied to the City of Melbourne, Australia to evaluate the status of its current material stock as well as estimated replacements of non-structural materials from 2018 to 2030. The model offers a high level of detail and characterises individual materials within construction assemblies for each of the 13 075 buildings modelled. Results show that plasterboard (7 175 t), carpet (7 116 t), timber (6 097 t) and ceramics (3 500 t) have the highest average annual replacement rate over the studied time period. Overall, replacing non-structural materials resulted in a significant flow of 26 kt/annum, 36 kg/(capita·annum) or 721 t/(km2·annum). These figures were found to be compatible with official waste statistics. Results include maps depicting which material quantities are estimated to be replaced in each building, as well as an age pyramid of materials, representing the accumulation of materials in the stock, according to their service lives. The proposed model can inform decision-making for a more circular construction sector.
Sustainability and material efficiency are essential considerations in architecture. However, they are often evaluated late, absent optimization potentials inherent in architectural choices. Easy-to-use computational tools facilitate integration of performance parameters into design decision-making, but because different simulation environments require specific geometric input, simultaneous consideration of multiple constraints is not feasible without significant modeling. This research capitalizes on existing simulation tools and presents a novel procedure, AutoFrame, that converts architectural massing models into structural simulation input models to streamline daylight simulation, and embodied- and operational-carbon assessment during schematic design. Three reference buildings are used to validate the approach and a speculative case study demonstrates how the multi-disciplinary performance feedback guides design decisions while maintaining the flexibility of early design exploration.
The significant amount of secondary materials stocked in products, buildings, and infrastructures has directed increasing attention to urban mining and circular economy. Circular economy strategies and activities in the construction industry are, however, often hindered by a lack of detailed knowledge on the type, amount, and distribution of secondary materials in the urban built environment. In this study, we developed such an urban resource cadaster through an integration of the geo-localized, bottom-up material stock analysis with primary data on building material intensity coefficients, for a case of Odense, the third largest city in Denmark that is undergoing major construction works. We quantified the total amount and spatial (including vertical) distribution of 46 construction materials stocked in buildings (residential and nonresidential), roads, and pipe networks (wastewater, water supply and natural gas). In total, 66.7 megatons (or 329 tons per capita) of construction materials are stocked in Odense, in which aboveground stock only makes up for a third but hosts a wide variety of materials. This urban resource cadaster at high resolution can inform a variety of stakeholders along the value chain of construction industry to better plan for construction materials and component recovery and smart waste management.
Studies showed that up to 30% of a building's life cycle energy and emissions are associated with the embodied phase and this number could increase to 50% for energy efficient passive houses. The residential housing market alone has a significant impact on US emissions. This research targeted Atlanta as one of the growing metropolitan areas in the US and conducted an embodied Life Cycle Assessment (LCA) comparison of single-family residential retrofit measures considering the original construction year of the buildings. At first, the paper investigated the potential retrofit measurements to improve the operational energy consumption of the different building categories. The paper then calculated the embodied impacts associated with the retrofit measures and compared them against each other to find the most energy and environmentally efficient options in terms of the embodied impacts. The paper finally conducted a trade-off analysis to investigate the payback period of the retrofit options regarding their impact on the operational energy savings throughout the second phase of the building's life span. The main findings of this research showed that the highest environmental impacts are associated with the attic/knee insulation and heating, ventilation and air conditioning (HVAC) unit's replacement through retrofitting residential buildings. The findings also demonstrated the significant environmental impacts for foundation wall insulation and window upgrading through retrofitting dwellings built before the 1970s. The trade-off results revealed that the embodied energy payback period is generally around 3–5 years for before 1970s and 1.6–3.2 years for after 1970s buildings.
Understanding buildings as material depots radically changes the way resources need to be managed within the construction industry and the built environment. Similar to warehousing, buildings, cities and regions will have to keep track and anticipate the stocks and flows of materials, needing to document and communicate (at the right moment) which materials in what quantities and qualities become available for re-use or recycling where and at what time in the future. This paper describes the process of doc-umenting materials and products utilized in the construction of the Urban Mining and Recycling (UMAR) unit within the Madaster platform. UMAR is a fully circular residential unit of Empa NEST created from secondary resources and designed as a material depot for future constructions. Madaster is an online platform, which generates and registers materials passports and calculates a Circularity Indicator for their construction, use, and end-of-life phases. The results of the calculations show that the UMAR unit is 96% circular. Constructed from 95% non-virgin and rapidly renewable materials, the unit has a utility rate of 98% and 92% of its materials are prepared to return into pure-type material cycles at the unit’s end of life. In combination, these two case studies provide a unique opportunity to evaluate the capabilities of materials passports and the Madaster Circularity Indicator to document material stocks and flows within a circular built environment, and to assess the potential of circularity indicators as a design tool sup-porting the transition towards a circular construction industry. The continuous development of tools and systems for material cadastres undoubtedly represents a key prerequisite for the implementation of a paradigm shift towards a functioning circular construction industry.
Building stock constitutes a huge repository of construction materials in a city and a potential source for replacing primary resources in the future. This article describes the application of a methodological approach for analyzing the material stock (MS) in buildings and its spatial distribution at a city-wide scale. A young Latin-American city, the city of Chiclayo in Peru, was analyzed by combining geographical information systems (GIS) data, census information, and data collected from different sources. Application of the methodology yielded specific indicators for the physical size of buildings (i.e., gross floor area and number of stories) and their material composition. The overall MS in buildings, in 2007, was estimated at 24.4 million tonnes (Mt), or 47 tonnes per capita. This mass is primarily composed of mineral materials (97.7%), mainly concrete (14.1 Mt), while organic materials (e.g., 0.15 Mt of wood) and metals (e.g., 0.40 Mt of steel) constitute the remaining share (2.3%). Moreover, historical census data and projections were used to evaluate the changes in the MS from 1981 to 2017; showing a 360% increase of the MS in the last 36 years. This study provides essential supporting information for urban planners, helping to provide a better understanding of the availability of resources in the city and its future potential supply for recycling as well as to develop strategies for the management of construction and demolition waste.
Demolition waste represents a significant portion of the total generated waste and has a high importance from both a waste management and a resource efficiency perspective. The urban context is highly relevant to assess the environmental impact of the end-of-life stage of buildings and potential for future reduction to properly design corresponding demolition waste management strategies.The goal of this paper is the development of a framework for the characterization of building material stocks and the assessment of the potential environmental impact associated with the end-of-life of buildings at the urban scale to support decision on waste management strategies. The methodology combines a bottom-up material stock model based on geographical information systems (GIS) and a spatial-temporal database with life cycle assessment (LCA) for the evaluation of end-of-life scenarios.The approach was tested for the city of Esch-sur-Alzette (Luxembourg) and provided significant results on the quantity and the composition of the housing material stock. Two alternative scenarios involving recycling rates of respectively 50% and 70% for inert materials were assessed and an average reduction potential of 25.6% on abiotic depletion potential and 9.2% on global warming potential was estimated.
The potential of urban mining is getting greater. From the global view, the potential of urban mining, namely the estimated amount of on-surface stock which has been mine form the geo-sphere into the techno-sphere, is comparative to natural resource which is still in geo-sphere as underground stock. However, practical recycling of metals are still in the stage of developing, and depending on the country. As an example, ultimate potential of urban mine in Japan was estimated. The differences between input of each metal contents and output of it were considered to be accumulated. I/O method was combined to estimate the metal contents in exported products. Japan, which is considered a typical exporter of materials, has great potential of urban mining which comes from domestic demand of products. However, real activity of development of urban mine, namely recycling, is not so effective, especially for minor metals which sometime called rare metals from the viewpoint of the importance in industries. We need to develop the technology and system for urban mining, just now.