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Building indeterminacy modelling – the ‘ZCB Bamboo Pavilion’ as a case study on nonstandard construction from natural materials

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Abstract

If unprocessed natural materials are the most environmentally friendly construction materials available, how do we develop and communicate design model and construction information that allows dealing with their volatile indeterminacies? This paper discusses the design and development of the ‘ZCB Bamboo Pavilion’, a 30-metres-spanning, light-weight, bending-active gridshell from hand-tied bamboo poles, as a case study for the computational design and building information modelling of nonstandard architecture where both applied materials and employed craftsmanship are highly unpredictable in terms of accuracy and precision. Reflective practice and participatory action research are used to extract knowledge on and challenge the environment of practice, and improve design and construction strategies. The project is used to discuss how traditional construction can be augmented through the strategic injection of computation in the design and construction process, how computation allows for a different mode of collaboration with increased impact for the designer, and how bespoke building information models enable an expanded architectural design solution space. The paper concludes by arguing for a mode of digital design practice that more proactively operates within a field of real-world indeterminacy. The risk and ambiguity of working with indeterminacies are to be strategically balanced out against idealised digital set-ups and onsite opportunities.
C A S E S T U D Y Open Access
Building indeterminacy modelling the
ZCB Bamboo Pavilionas a case study on
nonstandard construction from natural
materials
Kristof Crolla
Abstract
If unprocessed natural materials are the most environmentally friendly construction materials available, how do we
develop and communicate design model and construction information that allows dealing with their volatile
indeterminacies?
This paper discusses the design and development of the ZCB Bamboo Pavilion, a 30-metres-spanning, light-weight,
bending-active gridshell from hand-tied bamboo poles, as a case study for the computational design and building
information modelling of nonstandard architecture where both applied materials and employed craftsmanship are
highly unpredictable in terms of accuracy and precision.
Reflective practice and participatory action research are used to extract knowledge on and challenge the environment
of practice, and improve design and construction strategies. The project is used to discuss how traditional construction
can be augmented through the strategic injection of computation in the design and construction process, how
computation allows for a different mode of collaboration with increased impact for the designer, and how bespoke
building information models enable an expanded architectural design solution space.
The paper concludes by arguing for a mode of digital design practice that more proactively operates within a field of
real-world indeterminacy. The risk and ambiguity of working with indeterminacies are to be strategically balanced out
against idealised digital set-ups and onsite opportunities.
Keywords: High-tech versus low-tech, Protocol for error, Bamboo architecture, Bending-active gridshell, Form-finding,
ZCB Bamboo Pavilion, Participatory action research, Reflective practice
Background
Like the relationship between intensive and extensive
logics, or the relationship between matter force logics and
codification systems, architects are inevitably implicated
in the tension between the generative and limiting poles
of both. (Reiser & Umemoto, 2006, p.112)
Demand for responsible eco-friendly architectural
practice continues to grow. The search for sustainable,
regionally accessible, and renewable materials plays a
vital role in reducing the overall carbon footprint of
global building production, especially in the most rapidly
urbanising regions of the world. Bamboo is one of the
fastest growing natural construction materials and is lo-
cally available in most of the developing world, including
South America, Africa, and Asia. Certain giant bamboo
species suitable for construction grow up to a metre a
day and can be harvested in three to 5 year cycles, mak-
ing bamboo far more sustainable than any wood species.
Although bamboo has been a vernacular construc-
tion material for centuries, natural unprocessed
bamboo poles are hardly incorporated as a viable
structural material in todays construction industry.
The plants unique cellular build-up, however, results
in a highly efficient section profile very suitable for
use in not only compression or tension, but especially
Correspondence: kristof.crolla@cuhk.edu.hk
Chinese University of Hong Kong, School of Architecture, Room 402, AIT
Building, Shatin, New Territories, Hong Kong
© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.
Crolla Visualization in Engineering (2017) 5:15
DOI 10.1186/s40327-017-0051-4
when being bent (see Fig. 1). Yet, when used, the ma-
terial is most commonly employed in processed form
or as a traditional wood or steel member replace-
ment. This is partly due to the widely varying dimen-
sional and structural properties of the plant in its
natural form, as these for example may differ with
varying soil composition or climatic conditions during
growth.
This paper uses the design and construction of the
ZCB Bamboo Pavilion(see Fig. 2) as a participatory
action research (PAR) case study that, through reflect-
ive practice (Schön, 1983), aims 1) to improve strat-
egies, 2) modes of practice, and 3) to extract
knowledge on the environment in which is being
practiced. Concretely, the project illustrates 1) how a
traditional, non-digital craft can be augmented
through the strategic injection of computation in the
design and construction process, 2) how computation
allows for a different mode of collaboration in which
the role of the designer is expanded to that of
construction process engineer, and 3) how alternative
usage of building information models can enable
expansion of the practices design solution space.
Participatory action research
Methodology and aim
The research component of this projects design and
construction is framed in a participatory action research
based methodology. The aim is to improve strategies,
practices, and knowledge of the environment of practice.
This method involves combining immediate and specific
project problem solution with a reflective process of
progressive problem solving. Reflecting on this actively
participating in a constantly changing situation is done
to enable extracting future alternative guidelines or
directions for best practice. Here, this methodology led
to proposing new courses of action when dealing with
indeterminacy in material or craftsmanship in a digital
project design environment.
The project development is set up in a spiral of steps.
Each step is composed of a circle of planning, action,
and analysis of the results of this action, before advan-
cing the project with more embedded detail. This spiral
enabled the crucial components of the final construction
to be identified, tested, and included into a flexible
design model that encompassed both the digital and
physical. Interactive enquiry allowed the balanced
problem-solving process to result in a design model that
gradually gained concreteness until it was materialised
in the final full-scale prototype: the built project.
Local community of practice
The project team was composed of all parties commonly
found in regional practice, including architects,
structural engineers, an AP (authorised person), contrac-
tors, and specialist consultants. One particular local craft
that was incorporated in the team was Cantonese bam-
boo scaffolding building. In Hong Kong, bamboo has
traditionally been used as scaffolding in construction
and for the building of temporary event spaces. Without
architectural plans or drawings, but by following rules of
thumb and century-old hand-tied knots, Cantonese
bamboo scaffolders are capable of quickly erecting the
large and complex scaffolding structures needed for the
construction of the citys many high-rise and other
buildings (see Fig. 3).
This locally important and cultural identity defining
craft is at risk of being pushed aside by a more easily
regulated construction environment using steel scaffold-
ing. Rather than imposing alternative techniques, this
research project recaptured the counter-narratives from
the bamboo scaffolding tradition and integrated them in
an adapted contemporary workflow. Thus, the ZCB
Bamboo Pavilionresearch project investigates how,
through the combination of digital design technology, a
culturally valuable yet imprecise local craft and an
ecologically desirable yet volatile natural material can be
practically applied as structural component in light-
weiht, sustainable architecture.
Case description
The ZCB Bamboo Pavilionis a temporary public
event space capable of seating 200 people, completed
Fig. 1 Bamboos structural build-up
Crolla Visualization in Engineering (2017) 5:15 Page 2 of 12
in October 2015 in Kowloon Bay, Hong Kong, where
it was used for 8 months before being recycled. It is
a bending-active gridshell structure that spans 37
meters, is four stories high, and is wrapped in a light-
weight translucent glass-fibre reinforced polymer
membrane. Its design development works through im-
mediate and specific problem solution on-the-go until
sufficient confidence is built up to initiate final
construction.
Design development
At the start of the research project in early 2014, no
building code and hardly any information were available
on the use of bamboo as a structural material in archi-
tecture, especially not as a bending-active application
(Rockwood, 2015). Only reference material on general
bamboo architecture was at hand (Jayanetti and Follett,
1988 Janssen and Jules, 2000, Hidalgo-Lopez, 2003, and
Velez, 2013).
An iterative series of steps was set up to design and co-
ordinate the project with consultants, client, engineers,
and contractors, and to deal with material deviations,
construction inaccuracies and human error. Digital pro-
cedural design tools, virtual physics simulation engines
and physical model prototyping were used at a variety of
scales (see Fig. 4). Digital environments were set up to 1)
develop a geometry defining workflow from initial phys-
ical sketch models, and 2) to procedurally create building
information output suitable for deployment in the field.
Physical prototyping created opportunities to test and in-
sert newly found information back into the digital model
for re-computation and further analysis. This constant di-
alog between digital simulation and visualisation on the
one hand, and analogue testing and physical prototyping
on the other, continued throughout the construction and
assembly process as serendipitous occurrences required
constant design system changes. Except for its scale, the
final construction takes no different position from earlier
prototypes in this workflow.
The projects structural concept was established
through a series of five physical design study model iter-
ations at 1 to 20 scale, made from long bamboo splits
(see Fig. 5). Representative geometric behaviour was an-
ticipated by choosing the same material as the final pro-
ject. Responding to observations on structural stability,
connection, and geometry layout, these study models
gradually evolved into the final triangulated diagrid shell.
This shell is built up from three layers of bamboo and
Fig. 2 ZCB Bamboo Pavilionduring a night-time event
Crolla Visualization in Engineering (2017) 5:15 Page 3 of 12
folds onto itself in three large hollow columns with
quadrangulated and free hanging linear members.
During model assembly, the bamboo splits were manu-
ally elastically bent into shape and connected at the
intersection points, defining a fully doubly curved axis
model for the overall geometry. Internal bending forces
were transferred continuously between members
through the knots until a global force equilibrium was
reached. Thus, a strong and stable lightweight system
was created, capable of spanning large distances.
With the fifth physical study model iteration as a basis,
a first digital member axis model was developed in
McNeels Rinoceros® software environment using pro-
cedural modeller plug-in Grasshopper® and physical
force simulation engine add-on Kangaroo® (see Fig. 6).
In this model, the bending forces that operate in the
physical models were abstracted into corresponding
vector forces applied on a discretised curve network
represented by a spring-particle system. Each member in
this interconnected setup aimed at maintaining its
length and straightening itself out. Although all force
vectors were defined by abstract numbers with no pre-
cise correlation to actual physical material properties, a
macro-level behaviour could be perceived that was simi-
lar to that found in the physical models. The digital
setup would find its force equilibrium in comparable
emerging geometries.
Thegeometryfromthisfirstdigitalmodelwasused
to extract conventional architectural plan, section,
and elevation drawings for client and contractor com-
munication during public tendering and for oper-
ational license applications at a later stage. The
model was also used by structural engineers to assess
the viability of the project. It further served as a basis
for a physical prototype at scale 1 to 30, made from
two metres long bamboo sticks following the geom-
etry axis lines. This prototype used a straightforward
mark-up system in which node intersections,
Fig. 3 Hand-tied bamboo used as typical temporary scaffolding in
Hong Kong
Fig. 4 Design sequence using digital and physical models
Fig. 5 Original geometry concept study model (bamboo, 1:20)
Crolla Visualization in Engineering (2017) 5:15 Page 4 of 12
extracted from the digital files, were accurately
marked up onto long, straight, unbent, bamboo mem-
bers. Corresponding intersection labels on different
members were then brought together one by one
while bending the members during the assembly. As
matching labels were joined, the form gradually
emerged and stiffened up.
The 1 to 30 model revealed several unforeseen
challenges that could problematically affect the final full-
scale structure. First, in terms of installation sequence,
members practically could only be laid up from the top,
rather than placed from below (impossible to reach) or
woven in (impossible to bend). Secondly, approximation
of the layer thicknesses and member shape needed to be
more accurately digitally incorporated. Lastly, the two
metres length of the used bamboo sticks could not be
scaled up thirtyfold onsite. Only roughly the central 12
metres of a bamboo pole is suitable for construction,
meaning members would need to be assembled from
separate bamboo culms.
A second digital model addressed and incorporated
most of these issues. The originally idealised single
surface geometry was split up and offset into three
layers spaced according to anticipated average
bamboo material thicknesses. All membersaxis
geometry was adjusted to meandered in between only
these three layers in a way that followed a carefully
orchestrated installation sequence laying-up members
from the outside onto previously placed members.
This prevented tight bending radii while remaining as
close to the original shape as possible.
From this second digital model, a 1 to 4 scale proto-
type was built. This model was used to assess practicality
of improvements in terms of installation sequence and
to test large-scale structural behaviour (see Fig. 7).
Instead of bamboo, three metres long rattan sticks with
diameters of three centimetres were used. Rattan is a
reed far more flexible than bamboo, thus exaggerating
the prototypes structural behaviour. The long members
of the structure were made ahead of assembly by
arbitrarily tying rattan sticks together with sufficient
overlap to transfer bending forces. Having a correctly
scaled diameter, the prototype confirmed the usability of
the labelling system and the newly developed installation
sequence. The high flexibility of rattan allowed us to
assess creep and deflection over time. The outer shell
was found to be extremely strong and stable, but the
underside of the shell, the belly, slumped. In response, a
suspension system was introduced into following
models. Six points of the belly edge linewere sus-
pended from the more stable shell above using metal
wire or cable. Furthermore, the arbitrary interconnection
of rattan rods into long continuous axis lines revealed
knotting challenges in node areas where all three axis
Fig. 6 Digital model 1: spring-particle physics simulation engines are
used as equilibrium geometry form-finding tool
Fig. 7 Second prototype, used for structural behaviour assessment
(rattan, 1:4)
Crolla Visualization in Engineering (2017) 5:15 Page 5 of 12
directions happened to have overlaps. Knots had
appeared with up to six poles meeting. Also, overlaps
close to the end points caused structural difficulties.
Hence, the exact positioning of overlaps needed to be in-
cluded in the following design models.
The final digital model, tested in a third prototype at
scale 1 to 20, incorporated all information used for final
construction (see Fig. 8). Following a physical maximum
bending radius test with several bamboo poles, a digital
member curvature analysis was done to check geometry
appropriateness. Road transportation restrictions confirmed
that the maximum length of bamboo culms that could be
transported was 7.2 m, and testing with the actual bamboo
poles revealed a needed overlap of 1.5 m to guarantee
proper transfer of bending force without kinking or
buckling. This information was incorporated in the model
and the pole overlapping pattern was designed. An
approximate pole diameter of 12 centimetres was
used in the digital models as exact pole diameters
ranged from 12 to 15 centimetres at the base and
eight to 12 centimetres at the top.
A geometry comparison of a 3D scan of the third
prototype and the digital file was made to graphically
visualise the similarity between both. This revealed suffi-
cient approximation of the digital emulation model by
the physical translation (see Fig. 9). Scaled up, most
areas fell within five centimetres of the digital model.
Only one area where a model stick broke had a much
higher deviation (see blue area in Fig. 10). This provided
sufficient confidence in our digital emulation model and
implementation methodology to continue with the final
step of full scale construction.
Construction information modelling
Setting up a pliable digital model allowed gradual updat-
ing of assumed variables relating to physical material
properties, construction techniques, detail design, and
structural concerns. As data had become more specific
throughout the design and prototyping process, the un-
predictable nature of both material and assembly method
now required for novel construction instructions to be de-
ployed. These needed to be clear enough to minimize any
misinterpretation of data, assembly technique, or order of
operations, while remaining an open system that could
adapt to urgent changes in detail or geometry.
Although the final digital model embedded all the in-
formation necessary to automatically produce common
graphic representations such as architectural drawings
and renderings, only highly selective building informa-
tion was taken for construction documentation. This re-
duced the projects complexity into the simplest of
Fig. 8 Third prototype: final installation sequence testing
(bamboo, 1:20)
Fig. 9 Comparison between final digital model and scaled-up
3D-scanned third physical prototype: red = less than 50mm
deviation, blue = more than 1000mm deviation; Top view (left);
bottom view (right)
Fig. 10 Digital geometry model
Crolla Visualization in Engineering (2017) 5:15 Page 6 of 12
possible instruction sets. The continuous bamboo axis
lines were digitally unrolled into long straight lines.
Intersection points with other members were then
mapped out onto these lines (see Figs. 10, 11 and 12).
Onsite, the hand-measured marking of these intersec-
tion points onto the culms was done using customised
sticker labels containing the number information of the
poles intersecting at that specific point. The stickers were
manually placed on interconnected individual bamboo
poles that made up the long continuous members (see
Figs. 13 and 14). These members were then lifted on site
and manually bent into place. By matching corresponding
labels, the overall shape gradually emerged (see Fig. 15).
The construction documents maintained a high level
of accuracy in setting out the connection intersection
point markings onto members of variable thickness.
These markings became guides for an assembly process
that included tolerances and human error, resulting in
an interconnection that allowed a level of in-situ form
finding. The method was straightforward enough to
allow for the onsite crossing of language and cultural
barriers. A certain level of self-correction took place dur-
ing the installation: as the system relied on the materials
natural bending behaviour, installation errors that devi-
ated too far from the exactsimulated digital geometry
would become impossible as the real-world material
would fight back to find its balance. Large human anno-
tation errors would be spotted and corrected instantly
by the spontaneously balanced construction system.
As-built vs. digital model
The ZCB Bamboo Pavilionwas built in an overall
seamless construction time of under 90 days. The bam-
boo structure was realised without any substantial
Fig. 11 Pole intersection point coordinates
Crolla Visualization in Engineering (2017) 5:15 Page 7 of 12
problems using the same construction methodology as
used in the small-scale prototypes, and using the same
fixing techniques and materials found in the traditional
local craft. Only in areas of tightest bending radii were
additional notches in the culms needed to meet the re-
quired curvature an unusually hot summer had dried
and stiffened the onsite poles to an unanticipated degree.
The construction documentation system worked well to
direct contractors with a clear set of instructions and
order of operations for assembly. Stable grid-shell geom-
etry gradually emerged as each member was bent and
fixed onsite (see Fig. 16). Natural dimensional variations
of the bamboo and tolerances in the knots, however,
made it impossible to perfectly match each label every-
where as cumulative slippage occasionally built up (see
Fig. 17). Also, members sporadically were too short or
too long at their foundation connection points due to
added deviations, requiring ad hoc detailing solutions.
The hyper-precise pole intersection coordinate points
from the digital emulation model (see Fig. 12) eventually
materialised into an approximative spheremeasuring
roughly 20 cm in diameter.
Like the geometry comparison between the 1 to 20 scale
physical model and the digital model, a high-resolution
3D scan was made of the final built geometry and mea-
sured against the digital data (see Fig. 18). Most bending
members found their final form within 50 millimetres
from the simulated model. In two areas of minimal curva-
ture, however, the structure attempted to flatten out with
two of the three members straightening up more than an-
ticipated, resulting in deviations of over 1 metre. This
spontaneously occurred deviation was deemed acceptable
as the synclastic nature of the surface in those areas of the
surface remained. This meant that no local buckling or
amplified continuous creep under the anticipated load
was to be expected. Also visually, the difference did not
pose any problems as the public still perceived the form to
be in its pristine platonic shape. Thus, the deviation was
considered part of the projects natural form finding
behaviour. Considering the complexity of the project, the
limited amount of time on site, its unique digital design
and documentation process, and the experimental nature
of assembly, the overall construction was concluded to be
successful.
Fig. 12 Sample of annotation drawings used for onsite implementation, showing the intersection point coordinates mapped out onto unrolled
lines of interconnected bamboo poles
Fig. 13 Bamboo poles are interconnected into long continuous
members
Fig. 14 Sticker labels with connection information are applied using
a measuring tape
Crolla Visualization in Engineering (2017) 5:15 Page 8 of 12
Building indeterminacy modelling
Since a gap between the BIM and the building is
inevitable and potentially advantageous, the question
remaining is: how big a gap should there be? (Willis &
Woodward, 2010, p. 184)
The ZCB Bamboo Pavilionchallenges the role building
information models (BIM) can play in facilitating
alternative architecture production. Although traditional
architectural drawings and visualisations were extracted
from earlier models for communication and licensing
purposes, for construction itself the focus lay on
managing selective unconventional types of data. BIMs
purpose is hereby pushed to go beyond the optimising
and streamlining of generic building production. Since
there will always be a gap between digital and real-world
environments (Willis and Woodward, 2010), tolerances
always will continue requiring being absorbed in the
design somewhere. But what if these tolerances are an
order of magnitude larger than what is common
practice? Or what happens if the structure itself is
expected to drastically move, and change during the
construction process as it finds its equilibrium form?
A fully accurately detailed and precise BIM model that
aligns with conventional building models could hypo-
thetically be created for the ZCB Bamboo Pavilion,
offering full control and predictability over all involved
materials, components and their tolerances. To set up
this model, each bamboo pole would need to be scanned
and measured ahead of time at high accuracy. That
bespoke data set would then be brought into the virtual
environment. A live recording of the pole behaviour
would feed back into the system in real-time as poles are
bent and fixed in place onsite, allowing for constant re-
calculation and assessment, and so forth.
There would be advantages to this hypothetical model.
Embedded digital monitoring could display or predict
abnormal or undesirable material deflections or defor-
mations and could suggest in real time where adjust-
ments need to be made. Yet, although probably
technologically feasible, this level of control is currently
not practical nor cost effective. More importantly, ultim-
ately it is not necessary and redundant. The level of
Fig. 15 Onsite installation by matching corresponding labels
Fig. 16 Completed bamboo structure
Fig. 17 Typical example of labels mismatch
Fig. 18 3D scanned fabric vs. originally designed fabric: red = less
than 50mm deviation, blue = more than 1000mm deviation; Top
view (left); bottom view (right)
Crolla Visualization in Engineering (2017) 5:15 Page 9 of 12
sophisticated and automated decision-making this model
would bring is currently already to a large extend em-
bedded in construction implementation, as the design
and construction team can rely on experience, intuition,
and common sense to solve unforeseeable issues on-the-
go. The gap between the virtual and the real can never
be fully sealed. The role of physical prototyping and
material testing and the inclusion of their findings into a
flexible digital model hence needs to be valued as
essential.
If unprocessed natural materials are to be incorporated
more pervasively in construction, then alternative design
information models and implementation systems are
needed that allow dealing with their volatile indetermin-
acies. This project eventually positioned the digital
emulation model not as an exact, ideal, and finished
model that needs real-world replication, but as an elem-
ent in a chain of back-and-forth between simulation and
prototyping. The digital model should embody variability
so that its physical materialisation can lead to singular
expression. Unavoidable serendipitous occurrences could
thus be exposed and incorporated more effectively. This
shifts the BIM models focus from a quantification and
simulation tool to a much more open-ended environ-
ment that works with the peculiarities of the material
world rather than in isolated abstraction ahead of
construction.
Discussion and evaluation
Permitting natural variability
The ZCB Bamboo Pavilionpioneers in pushing the
boundary of which 3D model based data transactions are
incorporated in construction. As highlighted, certain bene-
fits can only be found in more detailed or alternative BIM
models. However, the information modelling tools most
commonly used in practice are not developed to accommo-
date the variety of material inaccuracies, tolerances, and
indeterminacies faced onsite. Although digital models are
commonly updated to achieve a final as builtmodel, this
information flow does not incorporate the indeterminacy
back into the design process. This can result in a final
model which potentially dramatically differs from original
design intent. The assimilation of naturally variability in
digital environments is not possible with conventional tools
but would be a requirement if we want to use raw materials
that dont undergo extensive industrial standardisation.
Open source API
The ability for building information modelling technology
to move forward and improve in areas such as indeter-
minacy could be facilitated by the incorporation of a more
open-source application program interface (API). Such an
interface can allow for greater direct access to database
fields and tables, enabling designers to take more direct
and spontaneous control of their model data. This open
interface then allows direct access to the software for
autonomous development of more accurate customised
tools that could be configured with greater sensitivity
toward material attributes and structural behaviour be-
yond convention. An open-source attitude, whereby the
appropriation and sharing of content is encouraged, will
greatly enhance the versatility of BIM managers in areas
of design, allowing them to introduce solutions more
comprehensively to construction indeterminacy by devel-
oping their own ad-hoc solutions. To some extent, this
API is becoming available in the form of scripting
languages such as Python®, Visual Basic® and graphical
versions such as Dynamo® or Grasshopper®, which are,
albeit somewhat proprietary in nature, steps in the right
direction.
Analogue/digital futures
The developed workflow discussed in this paper provides
a very timely practice-based working model to deal with
unforeseen in situ occurrences. Architectural designers
now globally have easy access to cheap computational
power to allow its practical incorporation even in small-
scale projects. Sufficiently powerful software became
accessible and versatile enough to allow for bespoke
customisation in one-off designs. In the meantime, today,
still, the majority of onsite construction is done almost ex-
clusively by hand, onsite, without the use of sophisticated
construction and fabrication technology, relying on what-
ever craftsmanship or skill is locally available. These two
realities need to be brought in close dialogue.
The ZCB Bamboo Pavilionhas pushed the boundaries
of the design solution space of bamboo architecture. Its
mode of practice, though, could be employed into the
arenas of other analogue construction systems as well.
Through setting up a mutually enforcing feedback loop
between the digital and physical world and relaxing the
rigidity of digital design models, a geometrically, struc-
turally, and spatially wider range of architecture will
become possible.
While technological conditions continue to advance
rapidly, the material and digital worlds need to be
brought closer together through a balanced workflow. In
this, the architects fundamental task is the definition
within the overall design and construction process of the
comfortable balance between what digital tools allow for
and what is appropriate onsite.
Conclusion
As a participatory action research project, the ZCB
Bamboo Pavilion(see Fig. 19) illustrates how strategies,
modes of practice, and understandings of the environment
of practice can be identified and with computation be
adapted and expanded to allow the extension of the
Crolla Visualization in Engineering (2017) 5:15 Page 10 of 12
architectural design solution space. The project is an ex-
periment in the ability to manage onsite expectations
based on an initial set of unknowns within a construction
system. Through time, investigation, refinement, and de-
velopment using both physical prototypes and digital
models, gaps in the design process were clarified and rein-
serted into the workflow. Information gained on-the-fly
thus became part of ongoing simulations eventually cap-
able of anticipating volatile system behaviour.
Paramount to the projects success was a digital
configuration capable of flexibility with respect to the
tolerances of real-world materials and onsite assembly
techniques, as well as the conception of the final project
as a self-correcting analogue material computer that
takes over when the digital emulation no longer is
applicable. For this, alternative types of construction
documentation and reference material extracted from
the complex original data needed to achieve a level of
practical simplicity.
The adoption of digital tools needs to be applied sensi-
tively to accommodate and take advantage of a wider array
of raw materials and regional labour skills. The relationship
between absolute accuracy and a system with indetermin-
acy will remain open as the adoption of natural materials
and varied construction practices are further explored.
Through the innovative use of computational tools in archi-
tectural practice, customised building information models
can adopt an ad-hoc approach toward balancing risk,
probability, and ambiguity against an idealized design.
Abbreviations
AP: Authorised person; API: Application program interface; BIM: Building
information model; PAR: Participatory action research; ZCB: Zero carbon
building
Acknowledgments
Design research team: Principal Investigator, CUHK: Prof. Kristof Crolla; Co-
Investigator, CUHK: Mr. Adam Fingrut; Research Assistants, CUHK: Mr. IP Tsz
Man Vincent, Mr. Lau Kin Keung Jason; Consultants: Dr. Goman Ho and Dr.
Alfred Fong (Structural Engineering), Mr. Vinc Math (Bamboo Consultant);
Authorised Person: Mr. Martin Tam; Registered Structural Engineer: Mr.
George Chung; Project Documentation: Mr. Ng Ka Hang Kevin, Mr. Grandy
Lui, Mr. Michael Law and Mr. Ramon van der Heijden.
CIC/ZCB Client Project Team: Executive Director, CIC: Dr. Christopher To;
Publicity, ZCB: Ms. Yan Ip; Technical Services, ZCB: Dr. Margaret Kam.
Fig. 19 Aerial view of `ZCB Bamboo Pavilion' by day
Crolla Visualization in Engineering (2017) 5:15 Page 11 of 12
Construction Team: Main Contractor: W.M. Construction Ltd.; Bamboo
Construction: Sun Hip Scaffolding Eng. Co., Ltd.; Fabric Contractor: Ladden
Engineering Ltd.; Lighting: CONA Technology Co. Ltd. & Brandston
Partnership Inc.
Funding
This Chinese University of Hong Kong (CUHK) School of Architecture project
research was partially supported by a grant from the Research Grants
Council of the Hong Kong Special Administrative Region China: Project No.
CUHK24400114, Project Title: Architectural design and building of light-
weight, bending-active, bamboo shell structures for Hong Kong, using live
physics engines.
Authors contributions
Kristof Crolla is the sole author of this paper.
Authors information
Kristof Crolla is a Hong Kong-based licensed architect and Assistant Professor
in Computational Design at the Chinese University of Hong Kong, School of
Architecture. His research focusses on the strategic implementation of
computation in architectural design. He graduated Magna Cum Laude as
Civil Architectural Engineer from Ghent University and practiced in Belgium
before moving to London in 2005 to attend the Architectural Association
School of Architecture (AA)s Master of Architecture programme Design
Research Laboratory. Following this, he worked for several years for Zaha
Hadid Architects, while teaching in parallel at the AA and other institutions
worldwide. Since 2010, he is based in Hong Kong where he set up his
practice Laboratory for Explorative Architecture & Design Ltd. (LEAD). He has
been invited as a jury critic, lecturer, and tutor in numerous institutions
throughout Europe, Asia, Chile and South Africa. He is best known for
projects such as Golden Moon (Hong Kong, 2012)and ZCB Bamboo
Pavilion (Hong Kong, 2015), which internationally received over two dozen
design awards and accolades, including the G-Mark (Japan), Architizer A+
(USA) Awards, and most recently the 2016 World Architectural Festival Award
- Small Project of the Year 2016, nicknamed «The Architectural Oscars».
Competing interests
The author declares that he has no competing interests.
PublishersNote
Springer Nature remains neutral with regard to jurisdictional claims in published
maps and institutional affiliations.
Received: 16 January 2017 Accepted: 30 June 2017
References
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Crolla Visualization in Engineering (2017) 5:15 Page 12 of 12
... Both types present important opportunities and restrictions. Prior research illustrates that computational tools considerably facilitate their development (Crolla, 2017(Crolla, , 2018); yet, no scholarly study exists on further typologies or hybrid structures, and limited research exists on bamboo applications. ...
... Similar to how the ZCB Bamboo Pavilion commenced with a conceptual 1:20 scale bamboo model to inform its novel structural system, here too physical scale models are used as analogue material computers to point towards possible future directions for bamboo architectural construction (Crolla, 2017). While many items and challenges will need to be resolved in far greater detail before the project's actual construction could become possible, a clear and novel pathway is identified. ...
... This can however be timeconsuming when each small design change could require the remodelling of the entire model (Jabi, 2013). As (Crolla, 2017) writes, "The assimilation of naturally variability in digital environments is not possible with conventional tools but would be a requirement if we want to use raw materials that don't undergo extensive industrial standardisation." (p. ...
... Another plug-in is Kangaroo which is a Live Physics engine for interactive simulation, optimization and form-finding directly within Grasshopper (Piker, 2013). An example of the use of Kangaroo to design with full-culm bamboo is seen in Crolla (2017) where it is used to produce a digital model based on previous physical models which would find its force equilibrium and produce a design geometry. On this project AD tools are crucial to accommodate in the design process, "the variety of material inaccuracies, tolerances, and indeterminacies faced onsite" (Crolla, 2017, p. 10). ...
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Designers use a range of tools to conceive and visualise our built environment. Design for bamboo structures requires an understanding of the material and methods of construction in the initial design stages more so than with standardised man-made materials. This paper discusses and advocates for a mixed media of design tools which includes: concept sketching; physical model-making; computational design, specifically an algorithmic design (AD) approach; and full-scale construction; and discusses the opportunity afforded through the inclusion of an AD approach. Using methods of: self-observation; evaluation; and surveys, this paper reviews the application of this mixed media delivered through participatory action research in Panama in early 2022.
... Bamboo has the advantages of fast growth, wide distribution, high strength, high strength-to-weight ratio, and high rigidity-to-weight ratio [4][5][6][7][8][9][10]. It has been successfully applied in several projects [11][12][13] and is a new kind of green building material with great development potential. China is one of the main distribution centers of bamboo resources in the world and Phyllostachys edulis (moso) bamboo is the most widely distributed bamboo species with the highest economic value. ...
... where x is a random variable, representing the measured UCS, MOR, UTS, USS, and CCS in this study, a and S are the mean value and standard deviation, respectively, b is the average value of lnx, and c is the standard deviation of lnx. The calculation formula for the standard value of strength conforming to normal distribution is shown in Formula (12), and the calculation formula for the standard value of strength conforming to Lognormal distribution is shown in Formula (13) [25]: ...
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In order to determine the design strengths of P. edulis bamboo material, this research carried out a series of material tests on the full-culm P. edulis bamboo specimens, including compression tests parallel to the grain, bending tests, tension tests parallel to the grain, shear tests parallel to the grain and compression tests perpendicular to the grain. The standard values of different strengths for bamboo material were obtained by the Bootstrap method. The influence of the load combination and load effect ratio on the relationship between reliability index β and resistance factor γR was analyzed. A method for calculating the target reliability index of bending strength was proposed. The design strengths of the P. edulis bamboo material were determined and the adjustment method considering different design situations was also put forward. The research results show that the target reliability of the bending strength of bamboo material is suggested to be 3.57. With the same β value, γR is the maximum under the combination of constant load + snow load, and γR is the minimum under the combination of constant load + live load on the office building floor. Under the same load combination and load ratio, the shear strength along the grain has the maximum γR and the compression strength along the grain has the minimum γR. The design strengths of the P. edulis bamboo material were determined by the larger γR of two cases (one is that the load ratio of constant load over live load on the residential building floor is 1.0 and another is that the constant load over live load on the office building floor is 1.0). The design strengths can provide reference for the design and application of bamboo structure.
... As one of the main building structures, the bamboo structure can realize the harmonious coexistence with the ecological system, which is one of the major trends in the future development of the building. At present, the typical applications of bamboo structure include Green School in Bali Island, 1 Nomadic Museum in Mexico, 2 Suntory Museum of Art in Japan. 3 In China, its main application can be observed in village characteristic buildings, tourism buildings, 4 the roof of large characteristic stadiums. ...
... And the density of specimens were measured after the test. (2) The characteristic values of mechanical properties of bamboo were analyzed statistically. (3) The relationships between the mechanical properties and density were established. ...
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Moso bamboo has strong mechanical property and high economic efficiency. However, its anisotropy and inhomogeneity will increase the time and cost of mechanical properties testing. Aiming to solve this problem, in this paper, a series of tests were systematically carried out to test the parallel-to-grain compressive resistance, bending resistance, tensile resistance, shear resistance and perpendicular-to-grain compressive resistance, tensile resistance. Then, the characteristic values of mechanical properties of bamboo were analyzed for establishing the relationship between mechanical properties and density of bamboo and finding a kind of conversion method among mechanical properties. The results show that the parallel-to-grain properties of bamboo are better than that perpendicular to the grain. There is a high correlation between Mechanical properties and density of bamboo and can be well fitted by Linear functions. This research provides mechanical properties conversion parameters that can be used to evaluate and predict the properties of the moso bamboo.
... presented [14]. The ZCB bamboo pavilion, built in Hong Kong, is one of the few projects that focused on the procedure for the design and management of digitised construction data from which a bespoke assembly process for the structure was produced [163]. The drawback from Crolla's project was that the bamboo poles were simply idealised as straight cylindrical tubes with average properties, which is a practical assumption for a preliminary design (top-down) ...
... This characteristic has been exploited to develop bamboo structures that can span medium to long distances including roofs, pavilions and footbridges, among others [14,72,151,152,163]. As a lightweight material, constructability is very practical as sawing, handling and positioning of poles are easily performed during the assembly procedure of a structure. ...
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... Increases in the complexity and choice of design software have significantly improved the "design solution space" available to designers. However, compared with the development of digital software and tools, the speed of change in construction methods is slow, which means that existing construction methods cannot satisfy more complex design proposals due to the significant difference between building techniques and digital design goals (Crolla, 2017). ...
... Bamboo's cylindrically hollow shape and fibre composition promise its structural efficiency when used in construction, hence, recent design studies have been expanding the formal repertoire of bamboo architecture. By relying on the material's bending property, experimental projects like ZCB Bamboo Pavilion (Hong Kong, China, 2018) (Crolla, 2017), INBAR Pavilion of the International Horticultural Exhibition (Beijing, China, 2019) (Laverde, 2022) and IBUKU green school (Bali, Indonesia, 2021) (Stathaki, 2021) illustrate the potential of using bamboo poles in non-standard design practices. YIBPTC contains a curved roof that is supported by bamboo trusses. ...
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... Therefore, structural design workflow progresses by building and testing multiple prototypes [21,22]. Each design iteration addresses issues encountered in the previous stage, improving the performance, until sufficient confidence is developed to construct the final structure [23]. In this context, being able to realistically simulate the response of bamboo structures could reduce the need for extensive prototyping and experimentation, and thus facilitate the design and development process of contemporary bamboo structures. ...
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... Original bamboo is a kind of building material that is natural, environmentally friendly and renewable with a short growth cycle of 3-5 years, featuring high compression and tensile strength parallel to the grain, good elasticity and tenacity, and a high strength to weight ratio (Wang et al. 2021;Hadi et al. 2018;Osorio et al. 2018;Wei et al. 2020;Tan et al. 2020;Akinbade et al. 2020). Therefore, it is increasingly used in civil engineering, especially in landscape architecture and tourist architecture (Jiao and Tang 2019;Crolla 2017;Das and Mukhopadhyay 2017). The physical and mechanical property test of materials is the basis of material performance research and an important basis for engineering applications. ...
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Due to the complexity of the physical and mechanical properties of P. edulis (moso) bamboo, existing research on the material properties of moso bamboo is scattered and nonsystematic. Taking into consideration the factor of bamboo nodes, in this work, experiments on the mechanical properties of moso bamboo under compression parallel to the grain (UC), shear parallel to the grain (US), tensile parallel to the grain (UT), compression perpendicular to the grain (CC) and tensile perpendicular to the grain (CT) were conducted in a profound and systematic way. The failure characteristics, typical values of the physical and mechanical properties and probability distribution model were investigated, and the distribution laws of the physical and mechanical properties along the height growth direction as well as the correlations between those properties were analyzed. The formulas of predicting the corresponding physical and mechanical properties at other heights based on the physical and mechanical properties of moso bamboo at a certain height were derived and established, and the calculation formulas of predicting other mechanical properties based on compression strength parallel to the grain were further derived. The findings prove that the normal distribution, lognormal distribution and 2-P-Weibull distribution have a good fit with the distribution of the physical and mechanical properties of bamboo materials, and the physical and mechanical properties of bamboo are highly correlated with the height of moso bamboo. The performance prediction formula has high accuracy and can serve as a reference for the evaluation of the mechanical performance of moso bamboo materials.
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Bending Blossom provides visitors with the feeling of being in a bamboo forest. The structure takes advantage of bamboo’s elasticity. Bent bamboo poles of the structure transfer horizontal loads and reduce the risk of buckling under vertical loads. A green roof serves as a thermal buffer that provides a comfortable micro-climate with natural ventilation. The bending green roof and bamboo create an elegant form in harmony with nature.KeywordsBambooBending-activeGridshellSustainable design
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This highly illustrated text brings together two areas which have both grown in popularity in recent years: gridshells and bamboo. Bamboo is a fast-growing, naturally available, renewable resource which is quite strong and lends itself to structural applications. In this unique text, David Rockwood demonstrates the viability of bamboo as a building material and considers the advantages - as well as the challenges - of working with bamboo. Its properties, workability, connections, assembly, erection processes, structural behavior, and final use are explored in detail through a series of design-build experiments and case studies from Hawai'i and Vietnam. The only book available on the subject, Bamboo Gridshells provides a comprehensive introduction to this emerging technology which will be of interest to anyone working in the areas of sustainable or environmental design, ecological construction, low technology strategies, or alternative materials.
Diminishing difficulty: Mass customization and the digital production of architecture
  • D Willis
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Designing and building with bamboo. Eindhoven: International Network for Bamboo and Rattan (INBAR)
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