What to see when visiting Princeton, USA: Guastavino Vaulting

The famous Princeton Reunions are coming up this weekend and many guests will reminisce and celebrate their student years with us .  But few of these guests will know about the Gaustavino vaults hidden between the neo-gothic architecture, typical of our Campus.

Much has been written about how Rafael Guastavino introduced this original Catalan Vaulting technique to the United States of America at the end of the 19th century [1].  The technique goes back to the 14th century in the city of Valencia. The Spanish king Pedro IV encouraged his masons to travel from Madrid to Valencia to learn this new technique to constructs vaults that were “Very profitable, very lightweight, and very low cost work of plaster and brick”[2]. The concept of this construction technique is to interlock tiles with layers of fast-setting mortar to make a thin skin.  Many centuries later the Spanish architect Rafael Guastavino (1842-1908) would bring this technique to North- America.

Figure 1: 1910 Patent for a Guastavino Vault Structure (left) , and Rafael Guastavino (right)

When trying to understand Guastavino’s decision to migrate from Spain to the United States of America, it is important to assess the impact that the socio-economic context of the time had in it. It is important to note that Guastavino was a respected architect in Barcelona. Spain in the 19th century experienced tumultuous period. During these years, the political situation was never stable. The change from the Ancient Regime to the liberalism was not easy. King Alfonso XII ascended to the throne in 1875. He was a popular king and was able to qualify the monarchy again. Being a male was enough to calm down the Carlists, who had been fighting against his mother, Queen Isabel II, for the last 40 years. However, the situation in the country forced many people to emigrate to America. The period between 1882 and 1930 was marked by a deep depression. Around four million Spaniards emigrated to America between 1882 and 1930. Usually, before a period of recession starts, there are some years in which economy stabilizes and does not grow. Guastavino’s family moved before the actual depression started, but they were showing the path to many Spaniards that will move later.

In the United States, the situation was completely the opposite. East coast cities were starting to develop and overpass the European metropolis. Guastavino saw in the new development a great chance to export his technique of tile vaulting. A new era of industrialization was taking place around these cities. The country was being expanded rapidly towards the West Coast as well so, new cities would be created.

One can say that Guastavino made a brave decision when choosing a country with such a different culture and language, which he did not speak at the moment of his arrival, when he could have chosen any other Spanish speaking country such as Argentina or Uruguay where many Spanish emigrants moved to. Guastavino put his career ahead of his personal comfort. He was able to evaluate the different possibilities and choose the most appropriate to develop his job.

For your visit to the Princeton Campus, we have identified no less than three Guastavino Vaults.mapPrinceton

Figure 2: Campus Map showing the location of Gaustavino Vaults

Class of 1879 Gateway

The Class of 1879 Hall was designed by the architect Benjamin Wistar Morris Jr when the President of the University was Mr. Woodrow Wilson, who would become later the President of the United States. Guastavino’s main contribution was the tiling of main arched pathway under the tower. The vaults are built with bricks, and completed with stone ribs to provide stability.

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Figure 3: Princeton University Class of 1879 Guastavino Vault

Princeton University Chapel

Princeton University Chapel was built in response to the fire that destroyed the previous Chapel, Marquand Chapel, in 1920. The president of the University at that time was Mr. John Grier Hibbe. The design was based in 14th Century English Gothic style. The University appointed Ralph Adam Cram as the architect for this project, the leading Gothic revival architect of the early 20th Century. The building was completed in 1928 and it costed $2 million, which was a significant amount of money in that time.  Even though the main vault was not designed by the Guastavino Company, some auxiliary vaults, not open to the public, were built by them. The main vault is built, according to the plans, out of cohesive tile. It is reinforced with ribs that meet in the center point of each individual bay. These ribs help the vault to stay stable.

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Figure 4: Princeton University Chapel Vaults (image credit Princeton University)

Patton Hall Entrance 

We have little information about the construction history of the Vault in Patton Hall.  The Hall  was first occupied in 1906, so it was built probably between 1900 and 1905. When visiting, one sees the thickness of some tiles and the mortar between two rows of tiles, the typical shape of the Gaustavino Vaultand as well as the arches between the two vaults. This arrangement of arches can also be found in the Boston Public Library, for example. Finally, the artistic pattern in which the tiles are placed is characteristic for the work of  Guastavino.

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Figure 5: Azul tiling in a herringbone pattern at Patton Hall.  This pattern can also be found in the Guastavino Vaults at the Grand Central Oyster Bar in NYC.

References:

[1] J. Ochsendorf. Gaustavino vaulting: the art of the structural tile. Princeton Architectural Press, 1st edition, 2010.

[2] P. Araguas. Butlleti de le Reial Academia Catalan de Belles Arts de Sant Jordi, 1998. Extract from “Rey Pedro IV de Aragon a Merino de Zaragoza el 20 Junio de 1382”, from Archivo de la Corona de Aragon.

Author: Lazaro Luis Vallelado

Editor: Sigrid Adriaenssens

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Sun, Water and Shapes

“Water is essential for life, health and human dignity” World Health Organization

In a previous post Dream Big: Engineering our world, we showed a video of our students designing and constructing a water supply system in Peru with Engineers without Borders.  In our CEE 546 Form Finding of Structural Surfaces Course, teams of engineering and architecture students were challenged to develop the shape of a membrane so that it channels rainwater into a 2 or more storage shipping containers.  The membrane water harvester is meant to double up as a shading canopy for a small community.

Figure 1: Inverted conoid membranes with interesting seam layout pattern. (project Laura Salazar, Ryan Roark and Annie Levine)

The entire design would preferably be demountable and fit within the container (to be transported and deployed elsewhere). Such a deployable low-cost system, would aid temporary or permanent recovery efforts in disaster struck areas, cut-off clean water supply.

Figure 2: An assymetric membrane conoid configuration with a ring hoop connection at the top of the mast to reduce stresses in the membrane. Sun and rain shading studies for one and a coupled module (project Veronica Boyce, Emma Benintende and Dorit Aviv)

For this project the students experimented with physical form finding techniques using a flexible fabric such as lycra as well as a numerical form finding technique based on the force density method to arrive at and fine tune their shapes.

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Figure 3: Spline stressed arch supported membranes with an elegant solution to ensure the stability of the  boundary arches.  Active bent arch spans in the order of 25m and is stabilised from buckling by the pre-stressed membrane. Cross-ventilation envisaged (project Devin Dobrowolski, Andrew Percival and Andrew Rock)

The generated shapes drew upon the 4 archetypal membrane forms: the saddle, the ridge and valley, the conoid and the arch supported membrane system.  The students steered their forms to have sufficient anticlastic curvature for stiffness and rainwater flow.  They also paid attention to appropriate membrane and edge cable pre-stress levels and connection detailing.

Figure 4: Ridge and valley system poses a great challenge to achieve anticlastic curvature in the membrane.  This curvature is achieved here by positioning the supports close together and having a substantial height difference between the low an high points. (project John Cooper and Vivek Kumar)

Figure 5:  A variation on the saddle shape. (project Peter Wang, Miles McCaulay, Jedi Lau and Ji Shi)

Author: Sigrid Adriaenssens

 

Exhibition: Creativity in Cuban Thin Shell Structures

After the revolution, Fidel Castro ordered the National Art Schools to be built on the site of a country club, a move to enrage wealthy capitalists.  The post-embargo material shortage resulted in the curved thin shell brick shell of the School of Modern Dance, designed by Ricardo Porro.  This shell reflected the sensuality Castro thought to be unique to the Cuban spirit.

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School of Modern Dance image credit: Paolo Gasparini

While four other schools were planned, the School of Modern Dance was the only one to come close to completion when Castro pulled funding from the entire project in 1965.  The movie “Unfinished Spaces”  draws attention the restoration movement of this shell.

The shells of the National Ballet School and the National Dramatic Art School are two of the six thin shell project highlighted in the exhibition “Creativity in Cuban Thin Shell Structures”, currently on display in the Friend’s Library at Princeton University.

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The National Ballet School by Vittorio Garatti (image credit archdaily.com.br)
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Plan view of the National Ballet School image credit images.adsttc

The models presented in this exhibition were made by students in the course CEE 463 A Social and Multi-dimensional Exploration of Structures.  By focusing on the Cuban shell designs (National Ballet School, National Dramatic Art School, Parque Jose Marti Stadium, Nunez-Galvez tomb , Arcos de Cristal and Tropicana entrance Canopy) the students made engineering analyses and examined the socio-political context in which the shells were realised.  In one of our next posts, we will show how that Cuban shell zeitgeist influenced one of the most iconic thin shell structures in the United States of America.

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Arcos de Cristal Image credit monsternet.com

Author: Sigrid Adriaenssens

DREAM BIG: Engineering our world

In the next decade, the USA will have to add 250 000 civil engineers to its workforce in addition to replacing those who will retire. However, only 12.2% of the current USA civil engineers are female. These statistics indicate the need to encourage young people, especially from underrepresented groups in civil engineering, to pursue engineering opportunities in their education. I am delighted to see the efforts of the American Society of Civil Engineers to inspire enthusiastic young innovative minds to enter into the profession with their project DREAM BIG.  This movie is narrated by the Academy Award Winning actor Jeff Bridges. In particular I was super excited to see a large number of our female undergrad CEE Princeton students feature in the Dream Big video Water Wishes for those in need (required watching and enjoy :-)).

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Author: Sigrid Adriaenssens

Reflecting on the Future of Design at the IABSE conference

On Saturday, April 29, the IABSE Future of Design 2017 conference was held in New York City. The Form Finding Lab was well represented, with Victor Charpentier in the organization, Professor Adriaenssens as a speaker and alumnus Professor Ted Segal (Hofstra University) leading a design workshop. Demi Fang ’17 summarized the main ideas of the speakers and panelists:

The Future of Design NYC conference kicked off with a vibrant set of “10 + 10 Talks,” in which structural engineers paired up with professionals in a field slightly different from their own. Each pair gave a joint presentation on their thoughts on the “future of design.”

Throughout the five presentations and the Q&A that followed, several recurring themes unfolded.

Technology can be leveraged as a tool to enhance, rather than compete with, the creative human process of design.

Glenn Bell (SGH) and Antonio Rodriguez (LERA) began with a presentation titled “Disruptive Influences as Opportunities, Not Threats.” Rodriguez gave a personal anecdote of a mentor who once warned him against entering the engineering field with the argument that computers would soon take over engineers’ work. Rodriguez explained how he has found that some engineering decisions do, and always will, require human judgment. That’s not to say that technology should be considered a competitor; rather, technology can play a key role in enhancing those creative processes that are best executed by humans.

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Antonio Rodriguez of LERA on distinguishing the roles of technology and humans in the future of design.

Bell quoted Chris Wise of Expedition Engineering from a talk at the 2015 IStructE conference in Singapore: “Which bits of the engineer’s life are really human and which should we let go to machines?” Many presenters touched on the importance of this distinction, especially with the rise of digital drawing tools that easily allow for technology to “take over” the design process. Rodriguez made the distinction by identifying the processes at which computers do best, such as repetitive tasks and optimum searches. The use of these technologies “free designers to do what they do best: solving human problems.” He went on to conclude that the “future of design depends on how technology is used to enhance people’s skills, facilitate collaboration, and improve relationships.”

This approach was whole-heartedly echoed in the following presentations. Eric Long (SOM) cited Frei Otto’s scientific explorations of soap film as an example of how “technology inspires design.” As a firsthand example, he cited SOM’s partnership with Altair in topology optimization; fittingly, his presentation partner was Luca Frattari of Altair, who emphasized the fundamental role of these technologies as tools, or “a complicated pencil.” Sigrid Adriaenssens (Princeton University) presented some of her engineering projects such as Dutch Maritime Museum courtyard roof and the Verviers Passerelle from her practicing days in the Belgian structural engineering firm Ney and Partners. With a nod to David Billington’s principles on structural art, she used these examples to note how “using optimization tools efficiently can allow for efficient, economic, and elegant systems.” Her presentation partner, Bill Washabaugh (Hypersonic), also shared stunning sculptures that utilized engineering technology to not overshadow but recreate motions of nature, such as the rippling reflection of a tree over water, the murmuring of a sea anemone, or the flight of a flock of birds.

With increased levels of collaboration in the design process, broadness and diversity in education can help prepare engineers well for future challenges.

Bell pointed out that the drive towards resource efficiency and sustainability has led to the necessity of interdisciplinary collaboration in the design process. He described his perception of the structural engineer as a T-section, with the “flange representing a broadness in education, and the stem representing a fundamental expertise in structures.” As one of the few educators presenting, Adriaenssens answered one of the last questions squeezed into the end of the Q&A session: what educational approaches should be taken to prepare the next generation for the future challenges of design, which differ greatly to the challenges of the older generation? Adriaenssens shared her conviction in bringing students with different backgrounds into the field of engineering in order to supply a diverse workforce to face these interdisciplinary challenges. “Many of the students I advise are excellent in other fields – they are superb athletes, musicians, or dancers. Asking an 18-year-old to focus on one particular field limits their potential.” She mentions courses at Princeton that bridge engineering with other fields such as the arts, explaining that “aside from the traditional engineering courses, we also need courses that focus on interdisciplinary training,” supporting Bell’s previous statements.

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Bill Washabaugh (left) and Sigrid Adriaenssens present their projects that utilize technology as an advanced tool for imitating and perpetuating the systems and aesthetics of nature.

Guy Nordenson (Princeton University) reinforced his colleague’s comments with statements on a more specific type of diversity: “I think Sigrid is a manifestation of where we’ve come and where we’re going,” not just with her more creative and innovative approach to engineering, but also her presence as a female in the field. “Looking out at the audience, it’s great to see that there are a lot more women in the field than when Glenn and I were students. We can do a lot to improve diversity in education starting as early as high school.” Continue reading “Reflecting on the Future of Design at the IABSE conference”

HIGROW – Hygroscopic proprieties of wood used as programmable matter in lightweight construction

Luigi Olivieri, who is visiting the Form Finding Lab this week from the University of Tre (Rome, Italy) with Professor Stefano Gabriele, presents his master’s thesis work:

The project explores the possibilities of using the hygroscopic proprieties of wood as a programmable material. The aim of the research is to explore the possibilities of a temporary structure through a new method of design by studying a shell through the physical behavior of its construction material: wood. The design process is driven by a set of physical tests on the material to come up with an idea for a new pavilion.

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View of the exterior space of MAXXI, High humidity – open condition, Rome. [Copyright Luigi Olivieri]
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View of the exterior space of MAXXI, Low humidity – close condition, Rome. [Copyright Luigi Olivieri]
The process is divided in two parts, a local and global one. The local part concerns the fabrication process of the structure assembling the local parts taking in consideration the proprieties of wood. The second -global- part concerns the morphology of the pavilion according to the constructive biomimetic principles of a seashell.

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Diagram of the design space. [Copyright Luigi Olivieri]
Biomimetic implies the consciousness of understanding natural structures and their process through principles that can be adapted to procedure and technology in the design process. The genome of the project is given by a code that can be adapted to different contexts and through parameters that can acquire multiple variations.

From the study of the seashell, four main principles arise that bring stiffness to the overall shape. The form of seashells is curved in two directions, stiffening the body and distributing the weight efficiently. The distortion of the line in the shell furthermore modifies the distribution of the forces, preventing the shell from breaking.

Experimenting with paper models gives the possibilities to observe how the crease activated by a kinematic movement augments the resistance of a simple sheet of paper.  Transferring the physical system of folding paper into a digital environment, the range expands drastically by using a code that simulates the act of folding.

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Study model of paper folding experiment. [Copyright Luigi Olivieri]
By changing the shape of the folding, the result is different every time which allows to create a catalog. The result of this catalog also brings to light the possibilities of using these modules as a self-supporting structure and the ability to develop the surface in a planar sheet.

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Diagram for fabrication of modules with positive and negative Gaussian curvature. [Copyright Luigi Olivieri]

The system is already self-supporting, but by adding additional force and bending in the modules, the stiffness increases exponentially. Using the biomimetic principle, behavior similar to that of a pine cone is observed: due to humidity changes an automatic mechanism is triggered generating movement.

The fabrication of the morphological system demonstrates that such a system prototype is feasible. Simple tests inside a humidified control room show that it is indeed possible to measure the curvature of different samples at different percentages of humidity.

The developed fabrication process uses a simple mechanism of absorption and resistance of forces thanks to a special bilayer of plywood. The lamination process takes into consideration how the fibers are layered in the pinecone petal to activate the kinematic mechanism due to the variation of humidity. The evolution of the test reveals that it is possible to control and reverse this mechanism. A joint is also developed in order to merge the components, to allow flexibility of the structure and to simplify the assembly process.

The functional prototype successfully demonstrated that the kinematic structure is capable of rearranging its microscopic cell organization by adapting its shape to various climatic conditions.

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Paper model of the global geometry. [Copyright Luigi Olivieri]
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Functional prototype of assembled modules in humidified control room. [Copyright Luigi Olivieri]
The output of the project is divided in three levels. First, the hygroscopic mechanism of wood cells and how it can be programmed to achieve different results. Second, the joint that allows the modules to connect together and guarantee mechanical strength. Third, the morphology and the architectural function of the shape.

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Micro, Meso and Macro structure hierarchy of the system. [Copyright Luigi Olivieri]

Author: Luigi Olivier. Edited by Tim Michiels.

[thesis work advised by Stefano Gabriele, Luciano Teresi and Stefano Converso]

Luigi Olivieri is an architect and computational designer. He attended “La Sapienza” University in Rome, Italy where he received his bachelor degree in Architecture and Science of the City. During the course of his Master program at the University of “Roma Tre”, Luigi spent his second year at the University of Stuttgart working at the ITECH Master program for the duration of the entire year. He completed his Master’s in Rome with a presentation on material programming as his final thesis. Luigi moved on to work in different international firms from Tomas Saraceno to Fuksas Architecture and Rimond, participating in projects of different scale.

Luigi is currently interested in emergent technology, computational design, and architectural fabrication. He believes that studying emergent structure and natural principles can help architects find a better way of using technology and material to program efficient structures for the future of tomorrow.

What is the value of critique in structural design?

Practicing chefs in the kitchen can revise and refine a recipe to their own satisfaction, yet their progress need not be limited by their own opinion. What might result from allowing a fellow chef or a mentor to taste their recipe? Each taster might give his/her own personal feedback – too salty, not crisp enough – and the aspiring chef, filtering through the responses, may modify and further improve the recipe to a level otherwise unattainable without outside feedback. We find this occurrence in countless other fields; why else might athletes have coaches, and musicians have private instructors? One may be able to accomplish much through individual work, but a trained eye (or ear) observing from the outside can potentially coax an even better performance out of an individual.

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Image credit: arch20

It is no different in design. Some design principles that we espouse to our students (such as constraints as drivers of design, drawing as a means of clarifying thoughts, the usefulness of studying precedents, and the iterative nature of the design process) primarily concern the designer as an individual. However, like the chef or the athlete or the musician, designers can only improve on their own to a certain degree. No matter how experienced the designer, outside feedback can add another dimension of considerations that enhance the design.

In structural design, the feedback of a more experienced engineer can be especially important in verifying the suitability and feasibility of the structure. However, that’s not to say that critique from a less experienced engineer is not useful; anyone who has not labored over the design process already has the advantage of seeing the design with fresh eyes and may perceive problems or solutions with greater ease. The act of critiquing is also a valuable exercise for the aspiring engineer, revealing the opportunity to jump into another’s design process and explore the different design decisions that were or were not made.

We emphasize that critique is an opportunity to improve a design; rather than shy away from a critique that may bash on the flaws in a design, designers would benefit from embracing the critique as a way of learning and improving from both peers and mentors.

The Happy Pontist blog discusses in detail the challenges of critiquing works of structural engineering and how to circumvent them. Read more about them here.

The secret of egg tapping boiled down: outsmart your peers on Greek Easter

Once a year, engineers can put shell theory into practice in a less conventional way: by winning their family’s egg cracking competition (also known as egg knocking or egg tapping). On Easter Sunday, it is a tradition for Greek and Armenian families to gather and play a game of egg tapping. Similar traditions exist in many different places such as in Cajun communities in Louisiana or for other occasions, like the Persian New Year Nowruz (celebrated at the beginning of spring).

“As geometric stiffness is inversely proportional to the radius of curvature, the curvier the egg, the better it will perform.”

Here’s how the game works: everyone picks one hard-boiled egg from a basket, and the battle begins. In a knock-out tournament, several players hit their eggs against each other, first bottom-to-bottom, then when bottoms are broken – top to top. When a player’s egg is cracked on both sides, he or she is eliminated. The game continues until one player remains with an intact side of their egg, and he or she is proclaimed the winner.

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Egg tapping, red won [By Superbass – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=3767798%5D
Several approaches on how to outsmart your opponents in this game exist. Certain crafty rascals suggest manufacturing eggs from cement mortar or wood. Others resort to the less labor-intensive freezing of eggs. These cheats, however, will likely get you caught and we recommend you steer clear of them. Other strategists advise without any rationale, picking the largest egg or eggs from free range hens as their shells are allegedly thicker. We doubt the scientific basis for any of these suggestions and recommend you instead follow the guide below.

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Local egg shell failure due to impact load.

But first some structural mechanics. The mechanical behavior of shells is predominantly determined by the overall shell shape. When observing the failure mechanism of the egg shells, you will see a relatively small depression with some cracks (as shown on egg B above). This failure mode in shells is called local buckling, and is caused by the sudden excessive deformation of the super thin shell due to the impact of the other shell. But why did shell B break, rather than the egg used to break it?

How much a shell deflects can be predicted through what engineers call the shell’s stiffness. Stiffness depends on two factors: material properties (material stiffness) and geometry (geometric stiffness). For egg shells, geometric stiffness dominates the behavior, especially as the material of all eggs is basically identical. Thus, the secret of winning the egg challenge can be boiled down to the (local) shape of the egg. As geometric stiffness is inversely proportional to the radius of curvature, the curvier the egg, the better it will perform: geometric stiffness   ̴   1/radius.

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Top of the left egg shell has significantly lower radius of curvature than top of the right egg shell and so the left egg will be much stiffer (2D-simplification).

 

That gets us to strategy:

Step 1:  Pick the pointiest egg in the basket. The importance of this step cannot be stressed enough. Only the top part of the egg matters. Size and thickness are of very little importance. Curvature is key, but make sure the egg has no pre-existing cracks (like egg D). For example,  if  you were to consider the eggs pictured below, egg C would be the best choice.

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Egg C has the most curved top. It’s bottom is also less flat than for example B’s bottom. Egg D is almost as curved as C at the top (although this is less visible in the 2 D picture), but has very small cracks that have been highlighted in black.

Step 2: Polish your egg. The buckling phenomenon described above is dominated by curvature. However, local buckling can be facilitated though small imperfections (like small bumps) on your egg. Try to remove as many as possible. Also, it it is nicer to win with a clean, shiny egg.

Step 3: Start hitting. Typically, you will first use the bottom of your egg, this part of the game is relatively unimportant. Consider playing strategically: try to steer the game so you can make the first hit when you get to attack the top of the egg of your opponent (see step 4).

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Egg B breaks by hitting it with the most curvy part of egg C

Step 4: all bottoms of the eggs are broken, time to step up your game and get cracking with your pointy top. Make sure you hold your egg in a grip so that it can only be hit at the curviest spot on the top. Buttress the sides with the palm of your hand for extra support.

However, imagine someone picked egg C before you, and you ended up with the less desirable egg D. If you plotted well and are the hitter, you can still win: aim for the flatter area on egg C next to the top (see red arrow below). It does not matter how hard you hit the egg (remember Newton’s 3rd law of action-reaction), the location is much more important.

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Egg C can still be broken by hitting it on a flatter section.

Good luck in your next egg face-off.

Author: Tim Michiels

P.S.: The secret to a delicious egg salad is a splash of vinegar!

You are invited to celebrate our 1st anniversary with us!

We are delighted to be celebrating the first anniversary of the Form Finding Lab blog with you. You have been an amazing audience and we would like to thank you by sharing our highlights with you.

ENGINEERING AND ARTS: We pride ourselves at exploring the intersection of engineering and the arts. We believe that this is important for three reasons. First of all engineering works that elicit an emotional response from the public through elegance of design, increase people’s quality of life and their productivity. No better example than “The refreshing tandem: the works of the engineer Laurent Ney perceived by the visual artist Toshio Shibata”.

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Esch-sur-Alzette Footbrodge, LUX(C) Toshio Shibata for Laurent Ney, Design (c) Laurent Ney

Second, innovations that will solve 21st century societal challenges, need to be firmly based on engineering principles, but also must be seamlessly interwoven with art and design. Our rammed earth wall spiral embodied the use of engineered earthen construction combined with an esthetic design intent. The engineering and design were intended to engage and enthuse the local community about zero-carbon structures.

Rammed earth spiral seating sculpture, designed and built in 2016 by the Form Finding Lab

And finally in our work we draw on approaches in art and craft to develop transformative structural designs. The physical and numerical exploration of the Costa Surface, a not well-known minimal surface, allowed us to walk that fine line between material-efficient structure and sculpture.

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Numerical form finding of the Costa Surfcea, prior to its contruction

STRUCTURAL DESIGN: Infrastructure is designed to last between 100 and 200 years. Therefore, their long lifespan makes the aesthetic quality of structures also important to society. Some might doubt that aesthetic quality in structures actually exists, but its existence is proven by the number of visitors to the Brooklyn Bridge (New York City, USA, 1883) and the Eiffel Tower (Paris, France, 1887). For several iconic structures, we have interviewed their world renowned designers about how structures achieve a good degree of fit in terms of social, political and historical context, their program, technical quality, cost and context‐sensitivity. We are very proud to have a collection of exclusive interviews with many of the world leading structural, architectural and product designers including Bill Baker, Maria Blaisse, Thorsten Helbig, Marc Mimram, Mister Mourao, Eric Hines, Knut Stockhusen, Doris Kim Sung and Jane Wernick. Through these interviews we hope that our readers recognize good design and hopefully become an advocate for it.

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Our visionary cohort of interviewees: Bill, Maria, Thorsten, Marc, Mourao, Eric, Knut, Doris and Jane.

FORMS and ALGORITHMS: Our research blog contributions have discussed form‐finding algorithms and design methodologies that enable unique large span bridge and building forms for a resilient and sustainable built environment. These forms are dictated by the flow of forces. Therefore, the forms can be very thin, cost‐effective, and have low carbon footprint while maintaining strength, stability, and be aesthetically pleasing and comfortable for users. You might have liked reading A structural designer’s new toolbox, Form Finding Flashback: Basento Bridge and Assessing the stability of masonry structures.

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The form found shape of the Basento bridge has been compared to a nun’s headdress.

But most of all we are very grateful for you, our more than 10 000 readers who have come from all over the world to spend time with us on subjects that really matter to us. We look forward to the continuing this conversation in 2017.

The Form Finding Lab Team

PS:  and don’t forget to watch and like our videos on Our Idea Worth Spreading (Tedx talk, Prof. A.), our rammed earth installation Spiraling Dirt,  and Bamboo Structures (Senior Theses Project Lu Lu and Russell Archer) and stay updated by liking our Facebook Page.

Assessing the Stability of Masonry Structures (part 2): Numerical and Physical Modeling

This post is second in a series covering different assessment methods for stability of masonry structures. Part 1 covered classical and equilibrium methods; this post covers suitable numerical modeling techniques as well as different examples of physical modeling for masonry stability.

4. Numerical modeling

Several methods of numerical modeling for masonry structures exist, as demonstrated by the flowchart in Fig. 10.

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Figure 10: Overview of numerical modeling methods for masonry structures, adapted from [41] with [8]
As the first level of Fig. 10 suggests, numerical modeling of masonry structures can be divided into four main categories: macro-modeling, homogenized modeling, simplified micro-modeling, and detailed micro-modeling. Asteris et al. [41] provide discussions, summarized below with some additions where noted, on the differences between these modeling approaches. Fig. 11 also depicts the different numerical modeling approaches. In this section, macro-modeling and simplified micro-modeling are the focus.

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Figure 11: Illustration of different strategies for modeling true masonry sample (a): (b) one-phase macro-modeling, (c) two-phase micro-modeling, and (d) three-phase micro-modeling [41]

4.1 Macro-modeling: masonry as a one-phase material

The macro-modeling approach models both bricks and mortar (or all bricks, in the case of dry masonry) as a homogeneous continuum as in Fig. 11(b). As the subsets under macro-modeling in Fig. 10 suggest, these numerical models are typically finite element models.

Continue reading “Assessing the Stability of Masonry Structures (part 2): Numerical and Physical Modeling”