Light structural systems_for_covering_large_spans

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Light structural systems for covering large spans: an innovative and pioneering
Engineering and Architecture graduate course in Brazil
Article · January 2006
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Reyolando M. L. R. F. Brasil
Universidade Federal de São Paulo
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Ruy Marcelo Pauletti
University of São Paulo
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Luiz Feitosa
University of São Paulo
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2. Session T3J
San Juan, PR July 23 – 28, 2006
9th
International Conference on Engineering Education
T3J-5
Light structural systems for covering large spans: an
innovative and pioneering Engineering and
Architecture graduate course in Brazil
Reyolando M. L. R. F. Brasil, Ruy Marcelo O. Pauletti, and Luiz C. S. Feitosa
Dept. of Structural and Foundations Engineering, Polytechnic School, University. of S. Paulo
Av. Prof. Almeida Prado tv. 2, n. 271 - Cidade Universitária 05508-900 S. Paulo, Brazil
reyolando.brasil@poli.usp.br, pauletti@usp.br (www.lmc.ep/usp.br/people/pauletti), eng.luizfeitosa@gmail.com
Abstract - This paper presents the experience of the
authors in successfully preparing and giving a graduate
course on “Light Structural Systems for Covering Large
Spans” in both the Polytechnic School and the Faculty of
Architecture of the University of São Paulo, Brazil. Tensile
structures (membranes, cable nets, tensegrities, etc) are a
very modern and hi-tech way for covering very large spans
of sports fields (Georgia Dome, for example), exposition
halls (Rayleigh Arena, for example), airport halls (Denver
and Jedah, for example). To motivate students, a hands on
approach to the subject was adopted. As part of the
course, they are requested to form groups to design and
build scaled down tensile structures. Such an approach
conveniently connects theory and practice leading to a
better and more effective learning process. The resulting
scaled structures are kept mounted in the free areas of the
University. Thus, a continuously growing set of didactic
material is collected for use in future editions of the course.
The authors feel that part of the success is also due to the
fact that graduate Engineering and Architecture students
work in the same projects contributing with their
particular views on the subject..
Index Terms - tensile structures, practice based education,
graduate courses.
INTRODUCTION
In this paper we intend to report on a successful pedagogic
experience attempted in graduate courses both in the
Polytechnic School and the Faculty of Architecture of the
University of São Paulo, Brazil We also display the techniques
used to achieve this success. In the course “Light Structural
Systems for Covering Large Spans”, a new educational model
was implemented in order to get the students involved in the
learning process, with interaction between theory and practice,
in order to render a more complete course. Empirical
verification of the proposed concepts leads to a motivating and
effective learning process.
According to PINHEIRO [1], one of the challenges
involved in teaching Engineering is the promotion the global
development of the students by unlashing all their potential,
that is, to form better students not only in school but in their
personal lives. To that end, it is necessary to find motivating
mechanisms by engaging them in the learning process,
encouraging to study and initializing them in the way of their
learning responsibility.
Learning must be a fun, exciting and continuous
experience. The role of a teacher should be to teach how to
learn. His main duties are to stimulate the drive for learning of
his students and to present the foundations of the subject in a
logical and organized fashion, so to give a general overview of
the problem and to direct the students to further study and
research.
We find in the literature various alternatives to the
traditional way of teaching, i.e., formal classes, exercises and
didactic samples. AMARAL et al. [2], for example, describe a
teaching method based on scenarios, leading to some
evolution with respect to the traditional teaching, namely: a
larger level of knowledge absorbing by the participants; a
practical design experience near to real development
conditions; a full and integrated product development
procedure, called a holistic one. In short, it is important and
interesting that the students should follow a practical way,
realizing the necessary competences and abilities to their
formation.
MASETTO [3] defines competence as “the aptitude to
face in a correct, quick and creative fashion, multiple
cognitive resources: knowledge, capacities, micro-
competences, information, values, and patterns of perception,
evaluation and reasoning”.
Also in [3], we find “... emphasis must be put in the
actions of the student so that they can learn what is
proposed…”. That author also says that learning is not
possible without the partnership of the students themselves,
that is, the teachers must try to make their pupils their
accomplices in the learning process, so that they fill motivated
and interested in the subject at hand.
THE COURSE
I. General Aspects
The course “Light Structural Systems for Covering Large
Spans” is given by Professors Reyolando Manoel Lopes
Rebello da Fonseca Brasil and Ruy Marcelo de Oliveira
Pauletti, and is offered, with slight adaptations, to graduate

3. Session T3J
San Juan, PR July 23 – 28, 2006
9th
International Conference on Engineering Education
T3J-6
students of Civil Engineering of Polytechnic School and
Architecture of the Faculty of Architecture and Urbanism,
both of the University of São Paulo, Brazil.
The course covers theoretical elements, design details,
materials and constructive methods of light structural systems
for covering large spans, such as the tensile structures. Tensile
structures (membranes, cable nets, tensegrities, etc) are a very
modern and hi-tech way for covering very large spans of
sports fields (Georgia Dome, for example), exposition halls
(Rayleigh Arena, for example), airport halls (Denver and
Jedah, for example).
The course is divided in theoretical classes, practical
classes, seminaries and written tests.
II. Initial Classes
The initial classes of the courses serve as a motivation to the
study of tensile structures. Besides giving the general
theoretical basis necessary to the analysis of this kind of
systems, a show of the historical aspects and the most recent
present day examples is displayed with extensive use of
iconographic material, such as photographic slides and
drawings.
Although the main goal is to present large span roof
structures using membranes and cable networks, a complete
presentation is also made of structural systems for suspended
and stayed bridges. The courses always try to develop a
qualitative feeling of the behavior of these structures, never
forgetting the underlying theory.
The main presentation topics are the necessary tools to
design, analyze and construct tensile structures. First, the
students are introduced to basic usual shapes, the
characteristics of the materials, as shown in Figure 1.a), the
concept of shape finding and patterning, the importance of
model building, as in Figure 1.b), among other ideas.
(A) (B)
FIGURE 1
(A) COMPONENTS OF STRUCTURAL FABRIC; (B) PAPER MODEL AND NUMERICAL ANALYSIS.
Next, the process of computer aided analysis is presented,
using Finite Element Method programs [4]. Computer analysis
is a powerful design tool, providing great easiness in obtaining
different shapes and choosing among them, as in Figure 2.
Further, if makes possible to analyze stresses and strains
besides allowing a convenient form and cutting pattern
definition procedure (Figure 3).
FIGURE 2
SOME POSSIBLE SHAPES.

4. Session T3J
San Juan, PR July 23 – 28, 2006
9th
International Conference on Engineering Education
T3J-7
(A) (B)
FIGURE 3
(A) WIND EXCITED DISPLACEMENTS; (B) CUTTING PATTERNS.
In this phases of the course, the students are also informed
of important manufacturing details, such as the necessity of
great accuracy in the cutting and welding of the material
peaces, as displayed in Figure 4.a, the correct use of
connection devices (Figure 4.b), the importance of applying
the prescribed traction to the cables so to obtain the sought for
final form, as shown in Figures 5.a and 5.b.
(A) (B)
FIGURE 4
(A) STRCTURAL FRABIC WELDING; (B) IN SITE MEMBRANE DEPLOYMENT.
(A) (B)
FIGURE 5
(A) MEMBRANE FIXED TO THE STEEL SUPPORTS; (B) COMPLETED TENSILE STRUCTURE.
III. Practical classes
After those initial classes, the students are invited to take the
main role in the course, as several practical activities are
assigned to them in order to apply the fundamental concepts
already displayed.
The first assignment is to build a 1:50 scaled model of a
large real tensile structure (Figure 5). It is a 3,000 square
meters roof structure for the Central Presbyterian Church of
Fortaleza, Ceara, Brazil, designed by the first two authors [5].
The material is regular printing paper instead of the real fabric
and cotton wires instead of the steel cables. The cutting pattern
used in the real membrane is printed in the paper, cut using

5. Session T3J
San Juan, PR July 23 – 28, 2006
9th
International Conference on Engineering Education
T3J-8
scissors and “welded” with stick glue, reinforced, if needed,
with tape. The model is mounted on a wood base. Figures 6.a
and 6.b show a group of students at work.
This first assignment is important to develop a close
feeling for usual tensile structures geometry and to observe the
great care that must be exercised in cutting and joining the
patterns to avoid wrinkling. Further, this activity encourages
integration among the participants and helps to develop
organization abilities such as goals setting and team work.
(A) (B)
FIGURE 6
(A) PAPER MODEL READY; (B) PAPER MODEL UNDER CONSTRUCTION BY STUDENTS.
The second assignment is the construction of a 1:10 PVC
prototype of the same tensile structure. In this particular case,
the Professors provide all the material necessary to the task,
including the welded plastic material. The student’s task is to
deploy the prototype structure as designed. This assignment
gives a strong notion of most difficulties and possible pitfalls
in erecting this kind of structure. The job is performed
outdoors in the open areas of the Paula Souza Hall where the
Civil Engineering undergraduate and graduate courses of the
Polytechnic School of the University of São Paulo, Brazil, are
held.
FIGURE 7
ERECTING THE 1:10 SCALE PROTOTYPE (FIRST TWO FROM RIGHT TO LEFT IN THE PICTURE ARE PROF. BRASIL AND PROF. PAULETTI)
Next, the students are given their most demanding task.
They are put in charge of the complete construction of scaled
down prototype of another really built tensile structure. It is
the 800 square meters People’s Memorial of Belém of Pará,
Brazil, also designed by the two professors [6]. A lot more
team work and discipline is needed as materials must be
procured, cutting and welding made (Figure 8), besides
erecting in the University’s grounds.
Costs of materials are rated between the students. The
cutting is made according to the original full size project.

6. Session T3J
San Juan, PR July 23 – 28, 2006
9th
International Conference on Engineering Education
T3J-9
FIGURE 8
CUTTING PATTERNS.
After cutting the material by the students, the pieces are
sent to a professional seamstress to be joined in a single
membrane. As this is not a usual task for a seamstress, she
must be closely watched in her procedures to avoid wrinkling
of the final surface. Afterwards, a date is fixed for the
erecting procedures in the University’s grounds, usually in the
same place where the previous prototype was mounted. The
steel fixtures are carefully placed in the ground and the steel
cables introduced in the membrane to put it in tension. Figure
9, displays those activities by the graduate students.
FIGURE 9
ERECTING A PROTOTYPE OF THE PEOPLE’S MEMORIAL OF BELÉM OF PARÁ, BRAZIL.
Finally, the steel cables are pulled, introducing traction
stresses into the membrane in order to make it reach its final
shape (Figure 10). At this point, it becomes clear to the
students that the objectives of the course were completely
fulfilled, that is, their learning the theoretical and practical
aspects of tensile structures. This is quite different of what
happens in other engineering courses that give too much value
to purely mathematical analysis.

7. Session T3J
San Juan, PR July 23 – 28, 2006
9th
International Conference on Engineering Education
T3J-10
FIGURA 10
FINAL STAGES OF THE ERECTING PROCEDURE.
IV. Gradings
To compute final grades for the students, the professors rely
both on their performance in the assigned tasks and on a final
individual seminary presentation. Each one, together with the
professors, selects a theme related to the subject, usually some
recently built large span roof, to conduct an in depth research
and prepare a presentation.
SUMMARY
We presented a successful pedagogic experience in graduate
courses of Civil Engineering and Architecture in the
University of São Paulo, Brazil. The courses “Light Structural
Systems for Covering Large Spans” are considered by former
students very motivating. The success of the courses may be
attributed to practical aspects that allow for the participants to
build their own knowledge by connecting theory to practice.
The several prototype structures that are built and collected
every semester form a rich set of examples for future editions
of the courses.
ACKNOWLEDGMENT
The authors acknowledge financial support by CAPES, CNPq
and FAPESP, all Brazilian research support agencies.
REFERENCES
[1] PINHEIRO, P. C. C. “Desenvolvimento de protótipos: instrumento de
motivação e ligação das disciplinas do curso de engenharia”. In:
COBENGE, 2000, Ouro Preto-MG.
[2] AMARAL, D. C.; ZANCUL, E. S.; ROZENFELD, H.; “Cenário de
engenharia integrada: ampliando e avaliando uma aplicação na
educação”. (in www.numa.org.br).
[3] MASETTO, M. T. “Competência pedagógica do professor
universitário”. São Paulo: Summus, 2003.
[4] PAULETTI, R. M. O., BRASIL, Reyolando M L R F. “Design and
analysis of tension structures using general purpose finite element
programs”. In: International Conference on Textile Composites and
Inflatable Structures, 2003, Barcelona. Textile and Inflatable Structures.
Barcelona: CIMNE, 2003.
[5] PAULETTI, R. M. O., BRASIL, Reyolando M L R F, ALVIM, Rosana
de Albuquerque Arléo. “A large membrane roof for the Baptist Church
of Fortaleza: from models to realization”. In: IASS 2004 Symposium -
Shell and Spatial Structures: from Models to Realization, 2004,
Montpellier. Shell and Spatial Structures. Montpellier: Editions de
l'Espérou, collection Formes-Forces, 2004.
[6] PAULETTI, R.M.O., BRASIL, R.M.L.R.F. “A Simple Geometric
Procedure to Obtain Cutting Patterns of Membrane Tensile Structures”.
In: II Simposio Latinoamericano de Tenso-Estructuras. Caracas, 2005.
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