Hugo Gasnier

Eddie Jones

Philip Weddle

Philipp Neher

Rick Joy

Contemporary Earth Architecture in the vast American Desert. les architectures contemporaines en terre dans l'immensité du désert americain

The Delano and Aldrich/

Since 1930, the American Institute of Architects has awarded a fellowship for travel and study in the United States to a French architect. The architect is selected by members of the French Academy of Architecture and is welcomed and assisted in the United States by a three-member committee of AIA members architects in New York. The fellowship is supported by the interest income of an endowment fund established for this sole purpose.

Depuis 1930, «the Americain Institute of Architects (AIA) attribue à un jeune architecte français, une bourse de voyage et d'étude aux États Unis. L'architecte est sélectionné par les membres de l'académie française d'architecture et est accueilli aux États Unis par un comité de trois architectes, membres de l'AIA. La bourse est financée par un fond de dons établie à cet effet.

The Delano and Aldrich/Emerson Fellowship desert dream // Contemporary Earth Architecture in the vast American Desert. les architectures contemporaines en terre dans l'immensité du désert americain.

Hugo Gasnier

The Delano and Aldrich/Emerson Fellowship This work entitled "desert dream" is the result of a three month long study trip financed by the Delano-Aldrich and Emerson Foundation. Ever since the end of my studies, I dreamt of crossing the usa Territory to visit the contemporary earth architecture there. This desire forced me to drive trough Arizona, Utah, New Mexico, California to meet with architects and craftsmen working with earth as a material (this type of construction being very present in this area of the United States). The purpose of this trip was to uncover and understand the architectural thinking specific to western USA and its dry territory. How and why would the persons I meet make American desert rime with earth architecture renewal? As an architect expert on earth architecture (CRAterre), I thought using earth would become a way to built a contemporary architecture connected with mankind, landscape, space, light… Somewhere along this trip I realized it was actually way more than that. This kind of construction is the pride of those designing it, building it, living within it. This architecture talks about its context, its territory, it's long forgotten history and it's inhabitants.

Rencontres:

Projetcs:

A light breeze rose clearing the sky above the desert. While the clouds went away by the mountains, a star filled sky appeared. It lighted up the white clouds as paper lanterns, bringing a light glow on the pale sand. It seemed like it starting to vibrate. The sand shimmered, amongst these billions of sand bead some refleced the stars' light. I fell asleep feeling surrounded by a comforting veil.

Hugo Gasnier est un jeune architecte diplômé de l'école d'architecture de Grenoble. Il poursuit sa formation au laboratoire CRAterre où il travail sur la construction en pisé. Il a mené des recherches sur le pisé au travers de plusieurs prototypes. L'utilisation de la terre dans nos bâtiments constitue aujourd'hui une piste afin de construire une architecture contemporaine détenant son propre langage architectural, en lien avec le contexte, le paysage, l'espace et la lumière. Nombreux sont les pays où la seul ressource disponible pour construire est la terre du sol. For the traveler, western USA offers sequences of landscapes each more magnificent than the other.

To experiment and reflect on these places has you realizing the interaction between humans and this soil that shapes the landscape. It is a great lesson on earth as a material. It creates the landscapes, shapes the mountains, fashions shadows, floods the red earth into a lighted skyline. Topography, color, texture. In these desertique lands, the soil is the place's identity. It builds the landscape's limits and its nature. It causes surprises and contemplation. Each landscape has its own dynamiques according to its very specifique raw material. Sometimes sand dunes, isolated rocks, steep cliff or even great canyons. They move with the wind, and get shaped by a river or even by the rain. To understand these material dynamiques allows a new reading of the landscape and territory's extreme beauty. « Il semble que la perfection soit atteinte non quand il n'y a plus rien à ajouter, mais quand il n'y a plus rien à retrancher » Antoine de Saint-Exupéry Terre des hommes ch. III, 1939 Etre simple ne veut pas dire être simple d'esprit, la simplicité s'accompagne de lucidité de connaissance et de savoirs. Traversé ces paysages américains permet de comprendre que la construction en terre est un geste simple. Prendre ce que l'on à autour de nous, sous nos pieds. Utiliser ce mélange de sable, de graviers, de cailloux, d'argile. Transformer ce mélange de grains en murs, briques, matière, texture, espace. Ainsi la mise en oeuvre d'un bâtiment en terre nécessite un savoir faire de la matière basé sur les connaissances de l'expérience, ou de la science. Une simplicité du temps qui passe : Construire en terre c'est respecter ce cycle naturel qui fait les paysages de Grand Canyon, Monument Valley, Brice Canyon. Les roches se sont élevées pour construire ces paysages, puis avec le temps qui passe, ils retournent progressivement au sol. Construire en terre c'est accepter cette vérité, que toute construction que l'homme fait finira par le même cycle que ces falaises millénaires. La construction en terre détient de manière intrinsèque cette logique dans le matériau terre.

« it seams perfection is reached not when there is nothing more to add but when there is nothing more to remove." Antoine de Saint-Exupéry Terre des hommes ch.III, 1939 . To be simple does not mean to be simple-minded. Simplicity comes with lucidity and knowledge. Crossing the American territory allows you to understand that building in earth is a simple gesture. Take what's around you, under your feet and use this mix of gravel, sand, rocks and, clay. Transform it shape it into walls, into bricks, into building material, textur, space. The implementation of an earth building needs the knowledge of the material based on experience or on science. The simplicity of time going by: building in earth means respecting the natural cycle that shaped the gran canyon, monument valley, brice canyon… The soil is erected, then, with time going by, it returns back down. When building in earth, you have to accept this truth, that every thing humans build enters the same cycle as the ancient cliffs.

Earth material from simplicity.

La terre matériau de la simplicité.

The Adobe Alliance, Inc.

Presidio, Texas

We teach the ancient Babylonian engineering methods of crafting roofs by hand with blocks made from the earth beneath our feet, with no need for supporting material, without centering whether steel or wood. We provide the solution for structurally sound housing in desert climates for the growing multitudes of families in need -emigres, refugees, untouchables, or the perennial poor of their region. As Hassan Fathy, our mentor, said, "We design and build with our clients who live outside the cash economy."

Through bi-annual workshops at our center in the Chihuahuan desert on the Texas-Mexico border, laborers and architects become familiar with handling earth as a building material, as mortar, or mud as a protective plaster, especially when mixed with local natural binding agents such as cactus juice, lime, or whatever the environment yields.

In areas where rainfall would damage adobe roofs we plan to experiment with coverings, also low cost, in the form of metal fish-scales for domes, and corrugated tin roofs over vaults bolted to wood bond beams. For such protection we will raise funds for research from charitable organizations. Simone Swan 9/5/2012 swan@adobealliance.org student of Hassan Fathy « I got the first permit in the history of pheonix for an alternative buiding material can you believe that, and i got the first permit in scottsdalle for a ramed earth house and the first permit of paradise valley for doing a ramed earth house and now you know the flod gates are open, there are just a lot of ramed earth structures that are beeing builed beatifully. They've improved over my walls so much and i loved my walls, my earlly walls but now the cruise are capable of doing them so perfectly i think something's lost You know they are that good it's kind of like it's not honest you know Ramed earth doen't need to be perfect, not that perfect, any more than the face of grand canyon you know it as a lot of imperfection too but that why it the grand canyon!" Philip Weddle est un jeune architecte qui travaile à Phoenix. Son agence, déjà conséquente, réalise des projets qui ont pour identité ce désert du sud de l' Arizona. Il n'a peut être pas réalisé les plus gros projets en pisé, mais on perçoit dans son travail une réelle finesse dans l'approche du site et la compréhension du contexte. L'intégration paysagère ainsi qu'une poétique du désert transparait dans ces merveilleux bâtiments qui semblent comme sortir de terre, tel un mouvement de terrain soulevant des toitures d'acier, créant un subtil jeu d'ombre, de lumière et de cadrage paysagé.

Extrait de l'entretien du 09/08/12

H: what made you fall in love with rammed earth? P: I've always been very interested in architecture that connects with it's place. So, from that perspective, if I'm doing architecture in the desert I'm very interested in architecture that connects with that desert place. I think rammed earth is one of those materials that has that kind of strong connection. Especially if you're using soil that comes from that site, the color, the texture, the grain of the soil… It feels, it looks like it's from that place. Particularly in the desert, I mean if you look at your photographs, the soil and the earth is what you see. It's not the case everywhere you know. There are many places where what you see is green covering everything in the desert environment in particular the soil and the surface of the earth is very much more prominent that in other places. And it feels to me that it has a nice connection to the place if you use that material.

H: Did you study earth architecture at school? (Arizona state university) P: Not so much actually. It was really something that as I started my professional career I became much more interested in. I've always been very interested in architecture that has a very strong environment emphasis to it. We've also done project that are built in straw bale walls that are very energy efficient and I've always been interested in architecture that is kind of pushing for passing solar, solar rays and capturing rain water… So in a lot of ways rammed earth is just a part of that. I mean obviously not all of our buildings are earth architecture but we try to make all of our project feel like they are connected to place and feel like they are making a bigger environmental statement. Rammed earth is just one piece of that. Soucieux de la qualité du produit qu'ils proposent la société Rammed Earth Works réalise une étude approfondie de la matière puis une série d'échantillon avec la terre du site pour montrer les différents rendus possibles.

Philip

La société a aussi beaucoup travaillé sur les outils pour améliorer les rendements du pisé. Ils utilisent des tapis pour amener la terre dans les banches et des fouloirs pneumatiques modifiés pour pisé de l'extérieur du coffrage.

Extrait de l'entretient du 24 09 2012:

In addition of rammed earth we have shot earth. I call it "PISE" (Pneumatically Impacted Stabilized Earth) and I've been doing this since 20 years and so we shoot it out of a spray gun. "PISE" when I came up with that idea in 1988. It was so difficult. No one though I could do it. The first fiew times we had all kinds of problems and most people would have given up because it just didn't looked like it was gonna work. But I knew! Find the tweaking formula and air pressure, till we could solv, same thing with rammed earth when I started it. Now this bloc I have just got this idea one year ago. You can involve other people to do this, as masons. Q: Je les ai planté hier mais je crois que ça n'a pas marché, il fait définitivement trop chaud ici. Je récupère l'eau de pluie des toitures de mes trois voisins pour faire pousser tout cela.

Nous continuons notre traversée du jardin. Puis nous arrivons sur un gros tas de fumier. Q: Tu sais Oracle comme une bonne partie des villes du sud de l' Arizona est située sur un sol granitique, non seulement il n'y a pas d'eau mais en plus on ne trouve pas de terre végétale, voilà pourquoi nous sommes dans un désert. Le sol résulte de l'érosion du granite, donc ce ne sont que des silts, sables, graviers. Cette terre est donc bonne pour construire mais pas pour cultiver. J'ai créé mon propre sol avec le crottin de cheval que je vais récupérer chez mes voisins, je le laisse 6 mois je le mélange avec les fientes de mes poules puis je plante dedans.

Il prend une pelle, marche jusqu'au tas de terre. Il m'explique que cette terre est celle qu'il utilise pour construire en pisé elle vient d'une carrière tout proche. La carrière vend des agrégats pour réaliser les revêtements de sol concassé. Lui il récupère les déchets, fraction la plus fine qui n'est pas utilisée. Il ajoute ensuite entre 2,5 et 8 % de ciment portland pour le stabiliser. Le ciment fonctionne très bien avec cette terre car elle ne contient pas d'argile. "Every year we give architecture students the chance to design and build a sustainable home on the Navajo reservation. In doing so, we don't just create a home for a family in need. We create better, more compassionate architects for the betterment of our entire community." Design Build Bluff DBB est une expérience d'apprentissage par la pratique. Cette association à but non lucratif se donne pour objectif d'impliquer des étudiants des universités d'Utha et de Colorado dans la conception et sur le chantier. Ceci afin de trouver des solutions et offrir des logements décents aux populations des réserves Navajos.

Extrait de l'interview :

Cette approche par "le faire" permet une interaction entre les participants pour les inciter à prendre des décisions ensemble. Outre l'apprentissage de l'aspect constructif, cela leur fait prendre conscience du contexte qu'est la réserve Navajo .Il s'agit là d'une véritable avancée pour ces universitaires, puisque cela leur donne une ouverture d'esprit (que j'ai pu constater par moi-même). Donc, c'est avant tout une expérience à but pédagogique, qui donne priorité à l'apprentissage des étudiants. Cette forme d'apprentissage est inspirée de Rural Studio.

Hank Louis, le fondateur de DBB, est un personnage très sympathique. Je l'ai rencontré à Parc City (à côté de Saltlake city) dans son bureau avant de me rendre à Bluff pour partager le temps du chantier avec les étudiants.

Extrait de l'interview :

HG: how do you choose the materials of your projects? HL: The students choose it;, they choose what they want to work with. I keep trying to point them towards earth because that's what the resource there is; earth. There is nothing more than earth and sun. The local material would be those two things. I can just explain that to the students but sometime they don't quite get it. They want to use straw bale or things like that. But they usually use earth i've got to say 80% of the time there's some earth in, even in the house last year, little water, there was earth. For a while we were trying more prefabricated ideas so that we could build it on our propriety and move them out. We were thinking in terms, like you, of how can we house the most people. Rather than just building one unique house every year shouldn't we be thinking more on terms of can we make ten every year? But that didn't work either cause the transportation was way too expensive.

HG: what are your criteria to choose the family? HL: The first one I suppose is at least they have a site.

Each year the students make there one criteria. Each year they were interviewing the families with there own criteria. They would usually choose somebody they could communicate with, wish is unfortunate, i mean a lot of those who would need our houses, they don't get them because they cannot speak English, in their cultures they don't speak much, they are very reserved. If we could break that barrier, break that wall down maybe we could get to the neediest people. But now we found it took too much time to do that cause we only have a semester to design a semester to build. Now we are finding families through the Navajo system they give us names of the families.

Thank you so much to Hank Louis, Atsushi, Cindy, Hiroko, Cortland and all the students for the warmest welcome.

Hank Louis, Design Build Bluff, Bluff, UT Depuis des millénaires l'homme a utilisé la terre afin de cultiver pour se nourrir, creuser pour s'abriter, construire pour habiter. Avant même que l'homme découvre d'autres matériaux comme le métal, le tissu, il a eu cette relation de simplicité avec la terre, qu'il prend du sol pour en façonner des poteries, des murs, des paysages. La terre ce lieu où l'homme s'est établit, ce lieu où il a planté ses racines et sa culture, nous appartient à tous. Lorsque l'on parcoure le monde on perçoit ces différentes formes, couleurs, textures, mais elle est l'environnement de l'homme. Cet aspect est encore plus marqué aux Etats Unis l'espace des maisons que j'ai pu voir dans les plaines s'étend jusqu'aux falaises qui la bordent. Nous avons ainsi une sensation de proximité avec ce matériau naturel et bienfaisant, proche de notre histoire, proche de nos origines. For century's humans have used earth to cultivate to feed, dig to shelter, build to live in. Even before mankind discovered any other material such as metal, fabrics, they entertained a really simple relationship with dirt taken from soil and shaped into piece of pottery, walls and landscape. The earth, this land where mankind established, where he grew his roots, his culture, belongs to us all. As we travel around the world, we notice its different shapes, colors textures but It our environment. It feels even stronger in the USA. The space in the house I got to visite in the vast plain reaches beyond to the faraway cliffs. This natural material feels close, close to our history, close to our origin.

Universality.

La terre une ressource universelle.

Programme :

Ce projet est une porte pour un trail dans le désert proche de Phoenix. Il inclut une salle de réunion, un bureau d'accueil, et des sanitaires.

Principe architectural :

Le bâtiment est un espace de passage, point de départ pour une aventure paysagère. Il déploie une grande toiture supportée par des piles de pisé. Il se ferme sur l'espace de parking pour ouvrir sur le paysage du trail.

Le rôle du pisé :

Le pisé joue son rôle d'intégration dans ce paysage aride. Il sert de protection et de signale sur l'arrivée des promeneurs. Il apporte, par les piles, un caractère monumental au bâtiment.

Program :

This project is a trail gate in the desert near Phoenix. It includes a meeting room, a reception desk and restrooms.

Architectural principal :

The building is a passageway, starting point of a landscaping adventure. It extends a large roof supported by two piles in rammed earth. It 's closed on the parking side to open to the trail's landscape.

Rammed earth fonction:

Rammed earth here acts as an integrator in the dry landscape. It protects and signals the arriving of trailers. The Piles gives it its monumental look. Looking for the truth of an architecture that would be definitely contemporary consist in searching in every direction to make sure not to forget anything. It would be an architecture opened to the human scale considering his knowledge, opened to the landscape scale by its color, texture and material, open to the territory scale with its resources and its functioning. In this chapter it's a matter of presenting the things I learned through meetings and talks and visits during this trip. Understand the essence and the evolution of this architecture.

Rechercher la vérité d'une architecture qui serait définitivement contemporaine c'est regarder dans toutes les directions pour ne rien oublier. Ce serait une architecture qui s'ouvre sur l'échelle de l'homme en prenant en compte son savoir, sur l'échelle du paysage par sa couleur, sa texture, sa matérialité; enfin sur l'échelle du territoire par ces ressources et son fonctionnement. Dans cette partie il s'agira de mettre en valeur les apprentissages fait au travers de rencontres, discutions et visites lors de se voyage. Comprendre l'essence et l'évolution de cette architecture.

Toward an Earth Architecture :

Vers une architecture en terre :

Western USA holds remarkable patrimonies related to pueblos civilizations and Honokan's. Thoses buildings used the only existing resource: dirt. The style was untimely linked with it's constructive logic.

Casa Grande, Arizona.

Casa grande was built by the Honokans between 1300 and 1400 after Jesus Christ. This tribe had developed irrigation canals since 300 after J.C to be able to cultivate in the desert. Their first housing were simple hut made of branches plastered with dirt. Around 1300 AJC, at their apogee, they built walls in cob stabilized with natural lime. Casa Grande was built with this technic.

TAOS Pueblo, New Mexico.

Taos pueblo is considered the oldest inhabited community in the USA. It's supposed to be 1000 years old. It was classified a world heritage site by UNESCO in 1992. It's a remarkable group of adobe construction (uncooked brick of dirt, dried in the sun).

The beauty of these constructions lies into the intelligence and the meaning between style and construction logic. This logic depends on the resources and on the knowledge of implementation. L'ouest américain détient des patrimoines remarquables liés aux civilisations pueblos et Honokan, les constructions réalisées utilisaient la seul ressource présente, la terre. Le style était intimement lié avec la logique constructive.

Casa Grande, Arizona.

Casa Grande fut bâti par les Honokan entre 1300 et 1400 ap.J-C, cette tribu avait développé des canaux d'irrigation dès 300 ap.J-C pour pouvoir cultiver dans le désert. Leurs premiers habitats étaient de simples huttes de branches enduites de terre, mais à leur apogée vers 1300 ils ont construit des murs de bauges stabilisées avec une chaux naturelle. La Casa Grande est construite avec cette technique.

TAOS Pueblo, Nouveau Mexique.

Le pueblo TAOS est considéré comme la plus ancienne communauté habitée aux USA. Il est supposé être vieux de plus de 1000 ans. Classé en 1992 au patrimoine mondial de l'UNESCO, il s'agit d'un ensemble remarquable de constructions en adobe (briques de terre crue, séchée au soleil).

La beauté de ces constructions réside dans l'intelligence et le sens donné entre style et logique de construction. Une logique de construction liée aux ressources et à des connaissances de construction.

Patrimony : Patrimoine :

Santa Fake ! « Le style n'a pas d'importance… » Ce conseil, quelque peu provocateur, dispensé par Simone Swan lors d'une de nos discussion a pris son sens lors de ma visite de Santa Fe. Lors du cheminement dans Santa Fe j'ai pu observer des constructions dites de style Adobe. Cependant l'ossature bois recouvertes de mousse pour donner une forme arrondie dans les angles a remplacé les adobes, Les enduits en ciments (couleur terre) ont remplacés les enduits en terre. En tant que visiteur je me suis posé ces questions : d'où proviens ce bois ? Est ce confortable en été ? Pourquoi donner l'apparence d'une construction terre a un édifice en bois ? Le style Adobe ne tire du nom que l'aspect, on perd l'importance de la logique constructive adapté au climat et aux ressources locales. Santa Fake! « Style doesn't matter… » This advise, somewhat provocative, Simone Swan gave me during one of our discussions took a whole new meaning when I visited Santa Fe. As I drove around Santa Fe I noticed buildings of said Adobe style. However wood structures covered with foam to round the angles stands for adobe and maroon cement plasters stand for earth plaster. As a visitor I asked myself, where does this wood come from? Is it comfortable in summer? Why would they give a wood structure an earthbuilding look? The adobe style is only a matter of look and loses the importance of constructive logic adapted to climate and local resources.

Lors de se voyage il semblait que la pensée de chacun se développait de manière parallèle sur des thématiques parfois éloignées. Mais lorsqu'il m'a été possible de les lires ensemble et de les confronter j'ai pu comprend le sens commun qu'elles donnaient. Il s'agit en fait là de l'évolution des questionnements et l'interprétation que donne l'architecte à la vision d'un habitat dans le désert allant vers la seul ressource disponible, la terre.

During this trip it seemed to me that each one's thought evolved in a paralleled way on sometimes very different themes. But as I was able to link them together and to confront them I realized the common sense they had. It was a matter of how the questioning the architect had, on housing in the desert, evolved and his (or her) interpretation leading toward the only resource available : dirt.

Earth construction and desert architecture developement.

Evolution de l'essence d'une architecture du désert et de la construction terre.

Flw as he created Taliesin west went toward a scattered architecture, opened to the landscape and holding its place into the great territory. It adapts to the topography and uses vasts roofs to shield from the sun. Its large walls create spaces and its grand openings cool down the house and give the opportunity to see the beautiful desert.

Paolo Soleri wishes to give an other proposition for the building of a town in the desert. It's dense, energy-efficient, self-sufficient, in a spirit of community. He calls it "arcology" a meeting between architecture and ecology. It is density and communitarianism that he adds to FLW's thought.

Simone Swan learned from Hassan Fathy. She uses a simpl architecture that keeps the full potential of a traditional adobe construction and adds contemporary quality spaces. This vision for architecture places back human in the center of the building process using a material of human scale.

Quentin Branch first stands out using rammed earth technique as an evolution of the adobe tradition existing in western USA. To improve the implementation efficiency in earth building, he focused on constructing solar housing well adapted to the climate in the desert. This logic is adapting a local constructive tradition to obtain a contemporary architecture.

These architects in phoenix area developed an architecture inspired from and identifying itself to the Arizona's landscape. These buildings melt in and magnify the desert in a poetic manner. « Architecture, is politic » Ronald Rael is an architect teaching in Berkeley University. He wrote "earth architecture" and the blog which is it's continuum. He is a provocateur. His idea is to question what we know, and create new paradigm confronting ideas somewhat opposed. His books confronts hearth architecture and contemporanity. His agency works on other themes like earth architecture and new technologies.

Érosion.

Ce n'est plus tout à fait une montagne, mais ce n'est pas encore une dune de sable. Un instant. Plusieurs milliers d'années… Paysage instantané, entre ce moment et le suivant, qui fait de Bryce canyon un monument d'une beauté sans pareille.

Les pluies, le vent ont creusé et sculpté ce paysage, qui à cet instant, joue de ses reliefs et de la lumière. Une lumière qui change minute par minute, qui modifie ce que l'on ressent. Une lumière qui amène les ombres, qui révèlent ou gomme les imperfections. Entre lumière et temps passé. Entre ombre infinie et temps qui nous dépasse.

Le pisé (non stabilisé) s'enrichit de cette expérience du temps qui passe. Entre mur trop lisse et ruine de terre. Il exprime lui aussi cette dimension de la vie qui s'écoule, tranquillement. Il subit les pluies et les tempêtes. Il est beau parce qu'il n'est pas figé… il continue à se transformer, dévoile ses reliefs ses textures et ses jeux de lumières. En tant qu'architecte, si je peux dire : je l'ai construit, mais il n'est plus... C'est que j'ai bien fait mon travail! Hugo GASNIER

Erosion.

It's not a montain no more but not yet a sand dune eather. A moment, several thousdands of years… Instant landscape, between this moment and the next, this is what makes Bryce canyon a monument which beauty stands no comparaison.

Rains, winds dug and shaped this landscape, which at this moment, reveals it's charm between relief and light. A light that changes every minute, modifying our feelings. A light that brings shadows, revealing or hiding imperfections. A landscape between light and time passing by, between infinite shadows and eternity..

  kiosk built in earth. 5/ Opening af an earth annalysis laboratory in China.+ workshop organisation in collaboration with Mu Jun 6/ Rammed earth expertise for the Qualiforsol building, archi: Letiec & Misse 7/ Rammed earth expertise and building process supervisation for the BathHouse project, archi: Brussels cooperation 8/ Teaching first year project, light -space -material -architectural language

J

  'ai eu la chance de rencontrer Simone Swan chez elle à Santa Fe. Simone Swan est une personne charmante, sa réflexion et ses actes concernant l'architecture en terre ont conservé une réelle sincérité et authenticité héritées de son apprentissage avec Hassan Fathy. Simone Swan a créé Adobe Alliance dans les années 90. Le but de cette association est de construire et de former des individus sur la question du logement économique. Elle installe Adobe Alliance à Presidio dans le Texas à la frontière avec le Mexique. Ce choix est lié au contexte économique, social et climatique de la région. Extrait de l'entretien du 17/08/12 « Donc ce que j'enseigne, c'est plutôt ce que j'ai appris de Hassan Fathy, et la raison pour la quelle je veux partager la technique que j'ai apprise, c'est de permettre aux clients, aux gens, de construire de façon à ce qu'ils ne dépensent pas d'argent ou très peu. Ça c'est le principe. Il se trouve que les voutes et les coupoles sont ce qu'il y a de moins cher à construire si on connait « the engeniering » et que la beauté qui en découle est un cadeau ! Je n'enseigne pas la beauté, mais que l'architecture de Hassan Fathy que vous connaissez est structurellement solide et donc sied au climat du désert, je n'enseigne vraiment rien d'autre. … Nous enseignons vraiment l'architecture du désert. » « S : Nous commençons avec un concept de base de confort et de solidité et comme de par hasard nos maisons sont magnifiques. Elles sont belles. Mais ce n'est pas le but, grande différence! Ce n'est pas le but ! Le but c'est d'être très simple solide et d'abriter pour peu d'argent et puis avec ces voutes et coupoles c'est magnifique ! H : C'est parce qu'il y a la logique même du matériau dans le bâtiment. C'est cela qui donne l'esthétique et l'aspect « beau » du bâtiment. S : « It just happens ! » (rires)» À propos des adobes aux états unis : « H : Richard (New Mexico Earth Adobes) produit en grande quantité ? S : Oui ! Puis beaucoup de clients veulent des adobes stabilisés au bitume ou au ciment. Nous ne faisons pas ça, puis ce dont je m'occupe moi, c'est d'aider ceux qui ont très peu de ressources et qui ne peuvent pas se permettre d'acheter du ciment. Donc nous sommes très « basic ». H : C'est justement par la simplicité que nous pouvons fournir un habitat à tout le monde… S : Oui… Ceux qui comprennent sont très enthousiastes !» Simone Swan, The Adobe Alliance, One Casa Piedra Road, Presidio, Texas 79845 Swan House Presidio Texas Credit: Simone Sawn Parmi les architectes de Phoenix qui construisent en pisé, Eddie se démarque par ses magnifiques projets. Il a réalisé 5 projets en pisé dont deux sont en cours de finition. Il m'explique au cours de notre rencontre que sa démarche d'architecte l'a amené à travailler sur le pisé pour trois raisons: l'aspect structurel du pisé qui permet de construire des murs massifs, son inertie qui lui donne des propriétés thermiques tout à fait adaptées au climat chaud de Phoenix, et enfin son aspect esthétique entre architecture et paysage. Ce matériau s'intègre parfaitement dans les étendues désertiques. Cette conscience du matériau lui permettant de traiter à la fois l'aspect sensible d'une architecture proche des paysages de la région tout en faisant attention au sur-coût que l'utilisation du pisé génère. Eddie Jones, Jones Studio inc, 4450 n 12st s104 Phoenix, az 85014 Extrait de l'entretien du 30/07/12

  Weddle, Weddle Guilmor Black Rock Studio, 6916 east fifth avenue scottsdale AZ 85251 Liste des projets: -The Gateway to the McDowell Sonoran Preserve: entrée de Sonoran Preserve -Lost Dog Wash Trailhead: entrée du trail -Crossroads Center at Prescott College: Collège -Lives at The Phoenix Zoo: traitement paysagé du Zoo de phoenix a pisé 2/ palette de ciment portland 3/ mélange de la terre au malaxeur planetaire 4/ chargement de la banche au tapis 5/ compactage au fouloir pneumatique à partir de l'exterieur de la banche 6/ compresseur David Easton a commencé dans sa société par la construction en pisé. Le developpement de cette activité est venu comme une réponse aux constructions en adobes et une alternative écologique à la construction en blocs de ciments. Par la suite il a diversifié les techniques proposées avec du pisé projeté et des blocs de terre, dans un souci d'améliorer les rendements.

  Because you are here for a client or an architect they want a rammed earth wall and you have no way of knowing why they want it. Rammed earth when you seen Martin Rauch, rick joy , James Cutler stuff, each one is very different from another. How thick are the lift line, different colors. You have to gate them to understand that there is all this different ways how it can look. I had problems in the past with people been disappointed because they were expecting something different. Now we are very, very careful to go throught this long preconstruction process and education process. To make sure they know what it's gona look like. HIghway Napa 94558 CA Rick Joy devient architecte après avoir travaillé pendant douze ans comme " charpentier de détail" et comme musicien. Il est certainement le plus connu des architectes construisant en terre crue. Son architecture se fond réellement dans le paysage. Ses maisons sont remarquables par leur toiture légère supportée par des murs massifs, des espaces qui semblent connectés avec le contexte du désert de l' Arizona. Il en résulte une architecture qui joue, de manière très poétique , avec le contraste entre les murs massifs des espaces et l'élégance du paysage.Lors de mon entretien avec le bureau Rick Joy studio nous avons pu aborder une question très intéressante avec Philipp Neher. Il s'agit du "design processus" qu'utilise l'agence pour concevoir ses projets. Ce "design process" constitue un engagement total pour la mise en oeuvre de la construction et de son design. Il définit très précisément les étapes à franchir lors des tout premiers pas de la conception d'un projet, pour que celui ci soit en tout point intégré au contexte.Les points traités.Territoire et inspirationsDans un premier temps, ils réalisent un état des lieux des activités à proximité permettant de comprendre, les enjeux et l'impact que le projet pourra avoir sur cet équilibre local.Puis suite à une visite du site, une série de clichés est prise, afin de comprendre l'ambiance présente sur le site. Il peut s'agir d'habitations, de végétations, ou de roches . Ces clichés doivent révéler à la fois les lumières, couleurs et textures présentes sur le site. Climatique et confort Dés le début les données climatiques sont intégrées : soleil, vent et températures pour définir l'orientation du projet, la direction des ouvertures. Aucune esquisse n'est encore faite, mais cela permet de se concerter sur l'essence même de ces données, de les intégrer comme axe directeur du projet. Vues, cadrages Une fois les éléments climatiques rassemblés, un travail sur la définition des vues et du cadrage est réalisé. Deux panoramiques complets, des vues sud et nord sont disposés et les cadrages sont définis dessus. Programme Enfin, vient le temps des premières esquisses et du projet. Il intègre alors toutes les composantes développées dans les étapes précédentes. « Pour créer une architecture profonde et séduisante, la position de R JOY est très claire, il faut créer le silence, le calme, la concentration afin de pouvoir éprouver la beauté du monde et de la vie autour de nous. » Desert works Philipp Neher, Rick joy Studio, 400 rubio avenue, Tucson, AZ Contexte: Suite à notre rencontre sur son chantier du Zoo, Julie Szekely la compagne de Quentin m'invite chez eux pour passer un weekend. Ils me récupèrent devant un café de Tucson, puis m'emmènent jusqu'à leur maison située à Oracle, une ville proche de Tucson situé dans le désert du sud de l' Arizona. Nous arrivons vers 10h devant une grande maison en pisé, baignée de lumière, sous une chaleur écrasante. Quentin me fait alors visiter son jardin, une oasis de verdure au milieu des cactus et des arbres brunis par le soleil. Il décrit les plantes qu'il cultive, citronnelle, basilic, roquette, cresson, radis, patates, patates douces, des noyers, des pêchers. Il m'explique qu'il vend une partie de sa récolte à des restaurants et puis le reste aux habitants d'Oracle. Nous passons devant deux pieds de lavandes ratatinés.

Q

  : tu sais on est une bande de vieux qui fait du pisé (sourire). Moi j'ai 70 ans, mon chef d'équipe à 65 ans, et les autres gars on entre 45 et 60 ans. On est cinq sur le chantier et pourtant on fait 20 tonnes de pisé par jour. On commence la journée à 4h du matin on pise jusqu'à 11H30, 12h puis on fait une pause et le soir entre 16h et 19h on prépare les coffrages pour le lendemain. Quentin Branch / Julie Szekely, Rammed Earth Solar Homes INC, P.O. Box 654 Oracle, AZ 85623 1/ terre a pisé 2/ palette de ciment portland 3/ mélange de la terre au chargeur compact 4/ chargement de la banche au manuscopique 5legé permet une manutention plus facile et une plus grande rapidité de coffrage. earth in the form.

  Gateway to the McDowell Sonoran Preserve 1 / Parking. 2 / Trail entrance, this is the border betwin the city and the wild area of the desert. 3 / Place to observe the begining of the trail. 4 / Trail inside the desert.

  of the rammed earth piles, on the covered hall. 2 / View from the trail. 3 / The rammed earth wall is use as a protection from the parking and a signal for the trail.

/

  Duality landscape architecture. / A cozy interior space, made of wood. / Rammed earth integrate the house into the landscape.

  concret base comes under the opening. 2 / intermediar space betwin the street and the residence. 3 / the rammed earth wall incude only small opennings.

  specifique architecture made of vault create the identity of the house.

  south face catch the sun and the wind. 2 / On the north face the rammed eart is use as a protection and as an inertia wall. 3 / the rammed earth lines fit in the landscape.

  1 / 2 / Taliesin West, design by Frank LloydWright, 1937. 3/ Arcosanti, design by Paolo Soleri, 1970. 3 / Swan residence, 1990. 4 / Branch résidence.1// Une première approche d'une architecture du désert : L'enseignement de Taliesin West (FLW 1937). FLW lors de la création de Taliesin West s'est orienté sur une architecture étendue, ouverte sur le paysage qui prend place dans le vaste territoire, elle s'adapte au terrain et joue de ses grandes toitures pour se protéger du soleil, de ses murs épais pour créer les espaces et de ses grandes ouvertures pour ventiler et offrir a l'homme le plaisir de la vue sur le désert. 2// Une ville dans le désert : Arcosanti (Paolo Soleri 1970). Paolo Soleri cherche à apporter une autre réponse pour la construction d'une ville dans le désert. Elle s'exprime de manière dense, économe en énergie, autosuffisante, se développant dans un esprit de communauté. C'est ce qu'il appel l' « Arcologie » rencontre entre l' Architecture et l'Ecologie, c'est donc par la densité et l'esprit communautaire qu'il ajoute une dimension à la pensée de FLW. 3// Construire pour l'être humain : Adobe Alliance (Simone Swan 1990). Simone Swan a fait son apprentissage au près de Hassan Fathy, elle part d'une architecture simple qui tire le meilleur parti de la construction traditionnelle en Adobe, en intégrant une conception de l'espace contemporain. Cette vision de l'architecture replace l'être humain au centre de la construction par l'utilisation d'un matériau à l'échelle de l'homme. 4// De l'Adobe traditionnel au Pisé contemporain : Rammed Earth Solar INC (Quentin Branch). Quentin Branch c'est d'abord positionné en utilisant la technique du pisé comme une évolution de la tradition de l'adobe présente dans l'ouest américain. La raison première était d'améliorer l'efficacité lors de la mise en oeuvre d'une construction en terre. Il c'est consacré a la construction d'habitats solaires adaptés au climat du désert. Cette logique vient donc d'une adaptation de la tradition constructive locale aboutissant à une esthétique contemporaine. 5// Du Pisé dans le paysage : Les architectes de l'Arizona (Rick joy, Philip Weddle, Eddie Jones). Ces architectes de la région de Phoenix ont développé une architecture qui s'inspire et s'identifie au caractère des paysages de l' Arizona. Les constructions s'intègrent et magnifient le paysage du désert de manière poétique. 6// Provoquer de nouveaux paradigmes : Rael San Fratello (Ronald Rael). "L'architecture est politique" Ronald Rael architecte enseignant de l'université de Berkeley auteur du livre Earth Architecture et du blog qui est son prolongement est un provocateur. Son idée est de questionner ce que l'on sait, et de créer de nouveaux paradigme en confrontant des idées parfois paradoxales. Ainsi son livre confronte l'idée : Architecture en terre / contemporanéité. Avec son agence il travail sur d'autres thématiques comme architecture en terre / technologies numériques. L'intégration de ces nouveaux questionnements fait évoluer la vision de ce que l'on a d'une architecture en terre.

  Dog Wash Trailhead, design by weddel & Guilmor. 8 / Prada shop on the mexican border, design by rael-sanfratello. 9 / emerging objects, 3D printing objects rael-sanfratello.

  Rammed earth enriches of this experience of passing time. Between an over smooth wall and an earth ruin. It speaks about life going by smoothly. It undergoes rainfalls and storms. It's beautifull because it's alive... It continues to transforme itself, reveals its reliefs and textures and its light shows. As an architecte, if i can say "i built it but it's no more... It's a job well done." Hugo GASNIER the beauty of time passing by De la beauté du temps qui passe.

19

* Utah, sur le chemin de mesa verde

Principe architectural :

L'habitation est conçue comme un espace découpé et fragmenté qui s'étend sur le terrain. Les espaces de vie sont réalisés dans des boites de bois posées à différents niveaux sur la topographie et sont entourés par des murs en pisé.

Le rôle du pisé :

Le pisé est localisé au mur extérieur de la maison. Il permet de jouer sur cette dualité façade de terre et noyau de bois. Il donne a la maison un espace recentré sur lui-même qui s'ouvre de manière dirigée sur le paysage..

Architectural principal :

The building is conceived as a fragmented space that spreads on the site. The living areas are made in wood structure disposed on different levels of the topography. They are surrounded by rammed earth walls.

Rammed earth fonction:

Rammed earth is reserved for the exterior walls of the house. This disposition brings duality between earth façade and wood core. It gives the house a space centered on itself allowing controlled views on the landscape.

3// Lost Dog Wash Trailhead

Principe architectural :

Le bâtiment se place en travers du chemin, il développe une toiture élancée qui passe au dessus de l'entrée du trail. Il n'existe pas vraiment de façade principale, on a le sentiment de rentrer par le côté du bâtiment et d'en ressortir par l'autre. Sur la partie haute le porte à faux est suspendu aux quartes colonnes de pisé.

Le rôle du pisé :

La structure est simple deux murs parallèles enserrent l'espace des sanitaires, le pisé associé à la pente de la toiture crée la dynamique du bâtiment.

Program :

This project is a trail gate near Taliesin West. The building includes a display board , restrooms and a technical room.

Architectural principal :

The building is placed across the path, it's slender roof goes above the trail's entry. There isn't really any main façade, it feels like you enter form the side of the building. The overhanged roof is suspended to the four rammed earth columns.

Rammed earth fonction:

The structure is simple. Two paralleled walls enclose the restrooms, The rammed earth creates with the slope of the roof the dynamique of this building.

Principe architectural :

Les trois studios sont pensés comme des blocs monolithiques en pisé en trapèze. Ils sont agencés en quinconce pour dégager des espaces entre chaque volume. Pour chaque studio, la toiture est en pente ce qui permet de réaliser un planché qui sert de chambre sur la moitié du studio.

Le rôle du pisé :

La totalité des murs sont réalisés en pisé et disposent d'une ouverture par pièce. Ce design est caractéristique au travail de Rick Joy qui met en valeur l'aspect monolithique du pisé en choisissant les cadrages sur le paysage.

Program :

This project is a group of three studios built on a tight parcel. It's the only project i visited in a dense urban context.

Architectural principal :

The studios are three monolithic blocs built in rammed earth. They are placed in staggered rows in order to free the spaces in between them. Each studio's roof is sloped which allows a second floor on half of the volume for the bedroom.

Rammed earth fonction:

The walls are made of rammed earth and each room has one window. This design is characteristic of Rick Joy's work. He emphasizes the monolithic aspect of the rammed earth walls selecting specific views on the landscape.

Principe architectural :

L'intelligence de ce projet réside dans le mariage subtile entre la technique millénaire de la voute nubienne et une conception spatiale et architecturale contemporaine. Le plan en forme de H permet de générer des pièces à vivre indépendantes et deux espace de cour.

Le rôle du matériau terre :

Les briques d'adobe permettent de créer des voutes qui déterminent la trame du projet. La largeur de la voute détermine la taille de la pièce par la limite physique de la portée. Cette architecture à l'échelle humaine de par la contrainte du matériau est tout a fait adaptée à une habitation.

Program :

This house is Simone Swan's personal residence. It's made of adobe.

Architectural principal :

This project's cleverness is to subtly combine millenary technique of Nubian's volt and a contemporary architectural and space design. Its H shaped design creates independents parts and two courtyards.

Rammed earth fonction:

The adobe bricks create volt determining the weft of the project. The length of the volt determines the sizes of the rooms because of the range's physical limits. This human scaled architecture is very well adapted to housing due to its material's stress.

Le rôle du pisé :

Un dispositif de tour des vents est mis au centre de la maison les murs au nord sont en pisé et permettent de stocker la fraicheur apportée par la tour des vents.

Architectural principal :

It's designed to adapt to the Navajo culture and to the climate of the Navajo reserve. This house respects the Navajo's traditional typology with few windows and a central fireplace.

Rammed earth fonction:

A wind tower device is placed at the center of the house. The northern walls are made of rammed earth storing the cool brought by the wind tower.

Rammed earth fonction:

In this house, the rammed earth wall separates the project in two from the inside is role is to maintain a thermal comfort inside. The general aspect of the project isn't one of a rammed earth project. * Utah, Brice Canyon


François Brillet

Armand Maul

Marie-José Durand

Gerald Thouand

From laboratory to environmental conditions: a new approach for chemical's biodegradability assessment

Keywords: Biodegradability assessment, Probability of biodegradation, OECD screening tests

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

According to the American database CHEMCATS, millions of chemicals are commercially available and ubiquitous in our lives. Minimizing the impact of potential pollution is a necessity for environmental protection agencies, researchers, industry, and society as a whole. In Europe, for example, REgistration, Authorization and restriction of CHemicals (REACH) regulations require a biodegradability evaluation of high-production-volume organic chemicals [START_REF] Ue | European Parliament and of the Council of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH)[END_REF]. The stakes are high; in addition to the substance-specific properties, the fate of each chemical in the environment differs according to its terms of use and mode of discharge [START_REF] Bartholomew | Influence of spatial and temporal variations on organic pollutant biodegradation rates in an estuarine environment[END_REF][START_REF] Federle | Extrapolating mineralization rates from the ready CO 2 screening test to activated sludge, river water, and soil[END_REF][START_REF] Vink | Pesticide biotransformation in surface waters : multivariate analyses of environmental factors at field sites[END_REF]. In silico models have been developed [START_REF] Raymond | A review of structure-based biodegradation estimation methods[END_REF] and are available under REACH regulations [START_REF] Pizzo | In silico models for predicting ready biodegradability under REACH: a comparative study[END_REF]), but the prediction of overall persistence with multimedia fate models remains limited to existing data and may be not adapted to assess environmental persistence as a function of both chemical intrinsic properties and environmental conditions [START_REF] Howard | Predictive model for aerobic biodegradability developed from a file of evaluated biodegradation data[END_REF][START_REF] Fenner | Prediction of overall persistence and long-range transport potential with multimedia fate models: robustness and sensitivity of results[END_REF][START_REF] Aronson | Estimating biodegradation half-lives for use in chemical screening[END_REF]. Indeed, the various environmental microbial communities, which are potentially involved in the biodegradation of chemicals, are different from each other [START_REF] Forney | Structure of microbial communities in activated sludge: potential implications for assessing the biodegradability of chemicals[END_REF][START_REF] Martiny | Microbial biogeography: putting microorganisms on the map[END_REF] and are also subject to the variation of environmental parameters associated with the conditions of in situ life [START_REF] Zogg | Compositional and functional shifts in microbial communities due to soil warming[END_REF][START_REF] Ranjard | Turnover of soil bacterial diversity driven by wide-scale environmental heterogeneity[END_REF]. Faced with the impossibility to assess biodegradability From laboratory to environmental conditions: a new approach for chemical's biodegradability assessment Brillet François 1 & Maul Armand 2 & Durand Marie-José 1 & Gérald Thouand 1 in real conditions [START_REF] Mackay | Environmental persistence of chemicals[END_REF], microbial communities are taken from a selected environment and used in vitro under laboratory conditions [START_REF] Nyholm | The European system of standardized legal tests for assessing the biodegradability of chemicals[END_REF]. In REACH, Ready Biodegradation Tests (RBT) (OECD 1992) are at the basis of the integrated testing strategy on biodegradation (ECHA 2011;[START_REF] Echa | Guidance on information requirements and chemical safety assessment chapter R.7b: endpoint specific guidance[END_REF]. Dedicated to the screening stage, they are individually designed to cope with the physicochemical properties of tested substances (e.g., poorly soluble or volatile). They are cheap and easy to use but give point data limited to one specific type of environment, which leads to a variable and restricted view of biodegradation [START_REF] Thouand | Bacterial inoculum density and probability of para-nitrophenol biodegradability test response[END_REF][START_REF] Van Ginkel | Influence of the size and source of the inoculum on biodegradation curves in closedbottle tests[END_REF][START_REF] Vazquez-Rodriguez | Toward a standardization of the microbial inoculum for ready biodegradability testing of chemicals[END_REF][START_REF] Goodhead | Standard inocula preparations reduce the bacterial diversity and reliability of regulatory biodegradation tests[END_REF]. Despite this uncertainty, a positive RBT result can be used to classify the tested substance as readily biodegradable [START_REF] Ahtiainen | Biodegradation of chemicals in a standardized test and in environmental conditions[END_REF][START_REF] Echa | Guidance on information requirements and chemical safety assessment chapter R.7b: endpoint specific guidance[END_REF]. Simulation tests (e.g., OECD 314 (OECD 2008)) are designed to evaluate the long-term chemical behavior in the environment. However, these tests are expensive, technically sophisticated, and time-consuming (e.g., use of several different tests and the use of 14 C-labeled chemicals) [START_REF] Nyholm | A comparative study of test methods for assessment of the biodegradability of chemicals in seawater-screening tests and simulation tests[END_REF][START_REF] Ericson | Evaluation of the OECD 314B activated sludge dieaway test for assessing the biodegradation of pharmaceuticals[END_REF], limiting the tests' use to a very small number of substances. There is, therefore, a gap between ease of use and biodegradability assessment, hence the necessity for the community of environmental stakeholders to strike a balance to assess biodegradation between Ready Biodegradation Tests and simulation.

This problem has been recurrent for 60 years; assessing chemical persistence in the environment is not straightforward and better screening tests are needed [START_REF] Boethling | Environmental persistence of organic pollutants: guidance for development and review of POP risk profiles[END_REF]. In all test classes, the substance-specific properties are known, which provide indications of potential environmental behavior (e.g., solubility, volatility). What is unknown is the number of microorganisms that are potentially present in the environment and competent to degrade the released molecules under in situ conditions. If the growth of a group of bacterial species with the tested substance as the only carbon source is the very principle of biodegradability assessment, the environmental fate of the molecule would be linked to the likelihood to be in contact with these specific bacterial communities. With this in mind, we suggest performing biodegradability assessment for soluble substances following a stochastic approach. This new concept, which is denoted by ProbaBio, for Probability of Biodegradation, connects the likelihood to inoculate specific microbial degraders from different environments in a given biodegradation test with the probability for a chemical to be biodegraded. Thus, according to the ProbaBio approach [START_REF] Thouand | New concepts in the evaluation of biodegradation/persistence of chemical substances using a microbial inoculum[END_REF], persistence is not regarded as a simple intrinsic substance property, but as the capability of various environmental samples to degrade a substance under realistic exposure scenarios and conditions (e.g., regional and local wastewater treatment plants (WWTPs), soil and water types, climate changes). Using a screening platform and a probabilistic approach, ProbaBio provides probability profiles of microbial degradation that are obtained under more realistic environmental conditions relative to cell density and temperature.

Materials and methods

An overview of the strategy used to provide the ProbaBio proof of concept is presented in Fig. 1.

Sampling collection and inoculum preparation

The environmental samples were selected to be representative of the many natural compartments in which chemicals can be discharged (see supplementary data Fig. 1). Activated sludge, freshwater, soils, and seawater were sampled using sterile equipment and were stored at 4 °C during transportation to the laboratory. An aliquot of each sample was stored at 4 °C, and all samples were immediately prepared. Activated sludge was first filtered through 500-μm nylon cloth, sonicated three times (0.400 kJ), and filtered through 5-μm nylon cloth. Freshwater and seawater were centrifuged (6400g, 10 min, 4 °C) to concentrate microorganisms. Pellets were resuspended in sterile mineral medium and were filtered through 5-μm nylon cloth. Soils were incubated in sterile phosphatebuffered saline (PBS) solution (v/v) under agitation for 2 h at 4 °C. The mixture was then filtered through 500-μm nylon cloth, sonicated three times (0.400 kJ), and filtered through 5-μm nylon cloth. Then, all inocula were washed, centrifuged, and resuspended in sterile mineral solution (MgSO 4 , 10 -2 M) three times.

Total cell count

The concentrations of living cells in the environmental and concentrated samples were measured by LIVE/DEAD BacLight Bacterial Viability Kit for microscopy under an epifluorescence microscope with a ×400 objective according to the manufacturer's instructions (Invitrogen, France).

Chemical preparation

Solutions 521) were prepared in the culture medium for biodegradation assessment described in the OECD 301B guidelines at a final concentration of 10 mg of carbon per liter.

High-throughput and miniaturized system for biodegradability assessment

The platform developed in our laboratory for biodegradation screening tests was used [START_REF] Cregut | High throughput and miniaturised systems for biodegradability assessments[END_REF]). The platform is based on non-invasive sensors for dissolved oxygen monitoring in 24-well plates (PreSens, Ge) filled with 2.5 ml of chemical stock solutions. Inoculum samples were diluted and added at both the environmental concentration and 10 times the environmental concentration for a maximum concentration of 10 8 cells ml -1 . Environmental samples with a cell concentration higher than 10 8 cells ml -1 were diluted. All samples were inoculated in duplicate. A control inoculum used to assess the endogenic consumption of O 2 (mineral culture medium + microorganisms) was included for each condition and environment. Microplates were sealed and incubated at 12 and 25 °C. The evolution of dissolved oxygen was measured online for 28 days. A positive biodegradation result was validated when (i) O 2 consumption in the inoculum control was inferior to 0.5 mg l -1 and (ii) O 2 consumption of the assay was greater than 10 times the maximal value observed in the negative control at any time point. An example is given in Fig. 2. Note that a positive biodegradation result does not necessarily mean that an ultimate biotransformation of tested substances has occurred. With this high-throughput system, distinction between primary and ultimate biodegradation is not possible. Consequently, positive results and models discussed in this work are based on the observation of an event of biodegradation and are not necessarily linked to a complete mineralization of chemicals introduced in the assays.

Statistical methods

The proportions of positive results, which were observed under different experimental conditions, were compared using either the chi-squared or the likelihood ratio test, according to the requirements for performing each of these statistical methods. The Mann-Whitney-Wilcoxon test was used to test the effect of the number of cells inoculated on the outcome of each biodegradation test. Logistic regression analysis was performed on the binary outcomes of the biodegradation tests to examine the effects of the explanatory variables on the biodegradability. To this end, the probability of observing a positive result for a biodegradation test was expressed as a logistic ). The consumption of oxygen in the assays (carbon source (4-NP) + bacterial inoculum + mineral culture medium) from A4, C4, and D4 is more than 10 times the negative control and can be attributed to the biodegradation of 4-NP (validated by the color loss in these same wells). The consumption of oxygen in the assay B4 is equal to the inoculum control and cannot be considered as positive (validated by the yellow color in these same wells). pH has been checked at the end of each experiment and is equal to 7.4

function of both the temperature and the cell density of each sample, including an interaction term between these two variables. Three-dimensional surface plots of the fitted logistic regression models were used to profile the potential environmental persistence of a chemical in terms of the probability of biodegradation expressed as a function of the temperature and the cell density. The volume under each surface was used as a risk indicator of potential persistence in environmental conditions. This volume is expressed as a number called the ProbaBio Index (PBI), which can be used as an index characterizing the biodegradability of a given molecule. Moreover, calculating the variance of the estimator of the probability of biodegradation allowed us to construct lower and upper confidence 3D surface plots and subsequently compute confidence limits at a predetermined probability level of the PBI which is associated with the chemical considered. All of the computations were performed using the statistical package R (version 2.12.2; Bell Laboratories, Lucent Technologies; http://www.r-project.org).

Results and discussion

Thousands of biodegradation tests were performed with five compounds, in different environments throughout a year, at different biomass concentrations and incubation temperatures, providing a matrix of 4244 tests.

Sampling network and data set presentation

From November 2012 to October 2013, samples from 10 environments (3 WWTPs, 3 soils, 3 freshwater, and 1 seawater; see supplementary data Fig. 1) were collected each month. Temperatures and the numbers of cells were subject to very large variations with differences observed intraand inter-environments (Fig. 3). For all of these environments, throughout the year, the average temperature measured was 13.7 °C with a maximum at 24 °C (month of June in a WWTP) and a minimum of 0 °C (month of December in a soil). The number of cells also evolved throughout the year but was mainly different from one environment to another, with a difference in the annual average of 10 3 cells ml -1 between the most concentrated activated sludge (WWTP Nantes 2.35 × 10 9 ± 1.88 × 10 9 cells ml -1 ) and river water (Yon 1.04 × 10 6 ± 7.18 × 10 5 cells ml -1 ). Biodegradation of BNA, 4-NP, DEG, TCP, and ATZ was assessed in these environments in different conditions using a 1 (chemical tested in duplicate) × 10 (environments separately) × 12 (months) × 4 (variations of in vitro parameters) factorial experimental design (see BMaterials and methods^section and Fig. 1). For each molecule, more than 840 biodegradation tests were analyzed (of a total of 960 tests, approximately 12 % were uninterpretable due to carbon contamination in the inoculum control). Among these five molecules (Table 1), two are described as readily biodegradable (BNA and DEG) by the European Chemical Agency (ECHA). Our results are consistent with ECHA for BNA (100 % of the tests are positive). For DEG, biodegradation activity was observed in only 60.88 % of the tests performed. 4-NP is described as inherently biodegradable and well known to fail RB tests, which is consistent with an observed variable biodegradation activity depending on the condition tested (79.02 % of the tests were positive). Regarding ATZ and TCP, which are characterized as persistent by ECHA, they were biodegradable in 4.72 and 0 % of the cases for ATZ and TCP, respectively. As shown by these results, the biodegradation test outcomes for certain molecules may not always be positive (DEG, 4-NP, and ATZ) when tested in several environments under microbial realistic exposure scenarios and conditions.

Influence of exposure scenarios and conditions

For the three molecules showing variable biodegradation results, 4-nitrophenol, diethylene glycol, and atrazine, the

b a

Fig. 3 Environmental variability of the sampled sites from November 2012 to October 2013. a In situ temperature (°C) from coldest (4 °C, green) to hottest (24 °C, red) and b average bacterial concentration (cells ml -1 ) in environments sampled sampling location of the bacterial inoculum has a significant impact on the success or failure of the test (Fig. 4a). Positive test percentages are highly dependent on the inoculum sampling location for 4-NP (P < 0.001) with some environments being more efficient in degrading this compound (freshwater Yon 95.83 %, WWTP Roche sur Yon 92.68 %, urban soil 91.66 %). These observations are the same for DEG (P < 0.001) and ATZ (P < 0.001), although the most effective environments are different (DEG WWTP Roche sur Yon and freshwaters; ATZ WWTP Roche sur Yon and river Yon). We also show (Fig. 4b) for 4-NP and ATZ that the season in which the inoculum was sampled has a significant impact on the success or failure of a test. This impact is only slightly significant for 4-NP (P = 0.035), with a maximum of positive tests observed in winter and spring, whereas ATZ was mostly biodegraded in May and August (P < 0.001), with very low percentages in other months.

Influence of temperature and cell density

The probability of the biodegradation of DEG, 4-NP, and ATZ is related not only to the intrinsic chemical properties but also to the environmental variables such as the geographical conditions (e.g., in situ cell density and temperature). In an attempt to study the effect of environmental variation on the outcome of the biodegradation tests for these molecules, the influence of cell concentration and incubation temperature was evaluated in the laboratory (Fig. 4c). A statistically significant increase of positive results was observed between the tests performed at 12 and 25 °C for each of the three molecules (P < 0.001). Concretely, 9.66, 1.39, and 2.85 times more positive results were observed at 25 °C than at 12 °C for, respectively, ATZ, 4-NP, and DEG. The number of cells inoculated at the beginning of the tests also had a statistically significant effect on biodegradation. The higher the cell concentration is, the higher the probability of biodegradation is (ATZ P = 0.003, 4-NP P < 0.001, DEG P < 0.001). Moreover, the number of positive results observed with enhanced concentration of the inoculums is estimated to be 1.7, 1.17, and 1.28 times the corresponding number at the environmental concentration, for ATZ, 4-NP, and DEG, respectively.

It is then clear that the strategies (RBT, simulation) of the evaluation of the biodegradation process, which is a significant part of the environmental persistence assessment, cannot be based on the outcome of a laboratory test that does not take into account changes in terms of bacterial diversity, quantity, and climatic conditions. Indeed, these parameters naturally evolve over time and space and directly impact the communities of microorganisms that are potentially degrading chemical compounds.

Modeling biodegradability

The probability of biodegradation has been expressed as a logistic function of the temperature and the cell density, including an interaction term between these two variables. Thus, the reduced fitted logistic model for the probability of biodegradation, which was computed from more than 840 tests with binary outcomes, is shown in Fig. 4d for each molecule examined. These three-dimensional surfaces plots model the probability to obtain a positive biodegradation test as a function of the inoculated quantity of cells from 10 different sites (effect of quantity and diversity) and the temperature (climatic conditions). From left to the right, the surfaces shown in Fig. 4d evolve from top to bottom according to the global probability of obtaining a positive test for each of the chemicals. According to the probabilities obtained from the fitted model, BNA (used as positive control in several biodegradation test guidelines) tests are positive under any experimental conditions, i.e., within the range of values considered for the temperature and the cell density. The probabilities of biodegradation corresponding to DEG, 4-NP, and ATZ are shown to depend on the values of the explanatory variables. In other words, for these three chemicals, the outcome of a biodegradability test is dependent on both the bacterial inoculum and the temperature, with the highest probabilities at high temperature and high cell quantity. Moreover, the two explanatory variables do not have the same impact in terms of the probability of biodegradation according to the chemical tested. For DEG, a 1 log variation of the cell concentration has the same effect on biodegradability as a variation of 3.5 °C. Similarly, for 4-NP and ATZ, a 1 log variation of cell concentration is equivalent to 7.5 and 4 °C, respectively. For TCP, which had no positive tests, the estimated probability of biodegradation is uniformly equal to zero.

Surfaces and ProbaBio index to profile biodegradation under environmental conditions

According to the fitted logistic regression models, the probability of biodegradation calculated from various environmental samples and values of the temperature can be extended to define a profile of microbial degradation in the environment. For example, the potential risk for BNA to be persistent when released in the environment is expected to be very low because the corresponding model predicts that all of the results of the biodegradation tests are positive. This, however, is not the case for DEG and 4-NP because the positive test predictions are low outside of the most favorable conditions (no biodegradation activity predicted in 28 days). Hence, the microbial degradation profiles of these two molecules point toward potential environmental persistence. This is especially true for ATZ. With very few conditions that result in positive tests, the environmental fate of this compound may exhibit persistence in certain conditions. A high risk of persistence in certain environmental compartments is expected. With a downward flat surface, the profile of the microbial degradation of TCP is the lowest, which means that this compound could be highly persistent. Based on the decrease of the probability to obtain a positive biodegradation test and consequently the lowering of surfaces, microbial degradation profiles can be ranked. A risk indicator of potential persistence in environmental conditions has been determined by calculating the volume under each surface. This volume is expressed as a number called the PBI and can be used as an index characterizing the biodegradability of a given molecule. This number, which can be calculated with 95 % confidence limits, ranges from 1 to 0, according to whether the molecule considered is potentially highly biodegradable (low environmental persistence expected) to potentially poorly biodegradable (high environmental persistence expected), respectively (Fig. 4e). Thus, the estimated PBI is equal to 1 for BNA, 0.44 (0.38, 0.50) for 4-NP, 0.38 (0.32, 0.44) for DEG, 0.03 (0.01, 0.06) for ATZ, and 0 for TCP. This allows a ranking of the chemicals, in terms of their biodegradability, from readily biodegradable to not biodegradable in the environment, BNA > 4-NP > DEG > ATZ > TCP.

From the proof of concept to a reduced experimental designed tool to profile biodegradability in the environment

The high number of biodegradation tests, which were performed to establish the ProbaBio concept (more than 800 per chemical), was used to perform a global study of the effects and interactions of the environmental variables and to ensure the reliability of the fitted regression models. Nevertheless, this number was too high for current laboratory applications. Therefore, to make it accessible to industry, scientific community, and environmental agencies, a reduction of the experimental design was examined. To this end, we decided to profile the biodegradation of DEG, as an example, by means of only 40 tests, which were performed in duplicate (n = 80). Thus, during the month of September 2014, the same 10 environments were sampled to inoculate four microplates of the high-throughput and miniaturized system for biodegradability assessment at 2 cell concentrations and 2 incubation temperatures. Here, it is worth pointing out that similar analyses could also have been carried out by randomly selecting n = 80 out of the full set of test results. Indeed, Bin silico^analyses may offer a convenient way to demonstrate how reducing the number of tests would affect the results and their associated uncertainties. The results are shown in Fig. 5a. With n = 80, the percentage of positive tests was 58.75 %. This result is in close agreement and is not statistically significantly different from the first study with n = 844 (positive tests = 60.88 % (chi-squared test, P = 0.93)). Moreover, the coefficient of determination calculated between the corresponding results, which were obtained from the logistic regression models with n = 80 and n = 844, is equal to 0.97. Consequently, the surface used to profile the biodegradation of DEG with n = 80 is similar to the first surface, thus showing the same influence of the variable temperature and cell concentration on the probability of biodegradation (Fig. 5b). Here, a 1 log variation of the cell concentration is equivalent to 3.2 °C in terms of ProbaBio (3.5 °C with n = 844). The ProbaBio Index with 95 % confidence is PBI = 0.32 (0.18, 0.48) and PBI = 0.38 (0.32, 0.44) for n = 40 and n = 854, respectively. Both the environmental biodegradation profiles and the PBI of the DEG, established from 80 or more than 800 tests, describe the same risk of potential persistence under certain environmental conditions. Seen another way, it may be possible to achieve a reliable ProbaBio approach with only 40 tests, performed in duplicate. This means that a lab-scale application of ProbaBio could be performed in a lightweight form. ProbaBio: case study with glyphosate Glyphosate [N-(phosphomethyl) glycine] is the active ingredient of the world's biggest selling herbicide. Studies and reviews on its environmental fate have been numerous in the last 30 years, and bibliographic findings often describe the same difficulties to assess glyphosate biodegradation due to geographic and climatic influences, among other influences, on the environmental fate of this molecule [START_REF] Carlisle | Glyphosate in the environment[END_REF][START_REF] Giesy | Ecotoxicological risk assessment for roundup® herbicide[END_REF][START_REF] Annett | Impact of glyphosate and glyphosate-based herbicides on the freshwater environment[END_REF]. In view of these conclusions, we performed a lab-scale application of ProbaBio on glyphosate with the same reduced experimental design as DEG above. Of a total of 80 tests, 11.25 % were positive (mostly, 44 %, with an inoculum from a farm wastewater treatment plant; other inocula were from a freshwater sample and soils). According to the estimated probability of positive biodegradation tests calculated by means of the fitted logistic regression model (Fig. 6), the maximum probability was 0.48 at 30 °C and 10 8 cells ml -1 . Apart from these favorable conditions (i.e., high temperatures and high concentrations of microorganisms), the glyphosate biodegradation probabilities are low. Indeed, the biodegradation profile, as given by the three-dimensional surface plot, highlights a potential hazardous biodegradation profile in the environment, which is highly dependent on in situ conditions. The probability of the Biodegradation Index with 95 % confidence limits is estimated at 0.036 (0.005, 0.15), which suggest that glyphosate has the same hazardous profile as atrazine. Our conclusions are in full agreement with those of other scientific reviews and articles on the same subject; glyphosate can be considered biodegradable [START_REF] Imfeld | Transport and attenuation of dissolved glyphosate and AMPA in a stormwater wetland[END_REF], but its biodegradation profile can quickly change depending on the geographical [START_REF] Borggaard | Fate of glyphosate in soil and the possibility of leaching to ground and surface waters: a review[END_REF] and climatic [START_REF] Helander | Glyphosate in northern ecosystems[END_REF] variations and can present the risk of persistence.

Advantages, contributions, and limits of the ProbaBio concept For biodegradation tests realized according to OECD standard procedures from the guidelines 301, assays are incubated at only one temperature level (commonly 22 ± 2 °C) and are inoculated with only one quantity of cells (between 10 4 and 10 8 cells ml -1 ) sampled generally from a single environment. When tested under these conditions, the probability for DEG to be biodegraded varies from 0.22 (10 4 cells ml -1 ) to 0.96 (10 8 cells ml -1 ), whereas the probability for glyphosate to be biodegraded increases from 0 to 0.26. However, with tests allowing higher initial cell concentrations, both DEG and glyphosate could be considered biodegradable in some environments. Therefore, what would not have been measured with standard tests clearly appeared with ProbaBio; the environmental profiles of these two chemicals are not constant. Moreover, the estimated surfaces are not always at the top, as was the case for BNA. Indeed, the environmental profiles change in time and space, and the risks of persistence may appear, according to the very low probabilities of the positive biodegradation tests, which can be observed when either the temperature and/or the cell density decrease. However, such low levels of temperature and cell density are realistic environmental conditions for widespread chemicals. It must be emphasized that what is possible to observe from compiling several scientific studies may be highlighted in less than 1 month of testing with ProbaBio. Moreover, this technically simple concept is not static and can be significantly improved. In this regard, it must be pointed out that extrapolating beyond the tested values is model dependent and may thus be questionable in terms of the accuracy of the predictions made. Indeed, the choice of a logistic function to model biodegradation, with values ranging from 0 to 1 as the bounds corresponding to low and high values, respectively, of both the temperature and the cell density, is liable to restrict the shape of the fitted model considerably. In particular, potential abrupt changes in microbial community structure and activity (e.g., depending to low and very low temperatures) cannot be accounted for with the present approach. Still, one should keep in mind that our approach is just a first attempt to model biodegradation, in the sense that it is essentially an exploratory research work, which is intended to be improved, namely, for use in the context of a more systematic (screening) application. Indeed and as said before, the number of biodegradation tests which was used in the present study is too high for current laboratory and/or industrial purposes. Thus, reducing the number of these tests (e.g., n = 40) may advantageously allow to optimize the standard experimental design for further applications. This can be attained for instance by increasing the number of levels and, subsequently, the range of the values which are tested (e.g., increasing the levels of incubation temperature to achieve greater accuracy). Other variables can also be integrated into the model according to the chemical behavior and mode or conditions of use (e.g., focus on specific geographical area). The biological degradation processes in environmental conditions are multifactorial and are subsequently very complex phenomena because other influencing variables are additionally present in natural compartments. Furthermore, the concentrations of some chemical molecules may be low, and they are often mixed with organic material or other chemicals or metabolized by co-metabolism. These additional variables are not yet included in ProbaBio. Finally, ProbaBio still retains many of the technical limitations common to ready biodegradability standardized procedures (e.g., testing of poorly soluble chemicals, biotransformation of microbial communities during inoculum pre-treatment processes; [START_REF] Goodhead | Standard inocula preparations reduce the bacterial diversity and reliability of regulatory biodegradation tests[END_REF]. Consequently, ProbaBio has not been designed to replace OECD guidelines but provide a complementary approach for chemical biodegradability assessment using different sources of microbial inocula and temperature regimes. Probes integrated in a high-throughput system to quantify and qualify ultimate biodegradation have also to be designed and tested in ProbaBio conditions. With a system allowing an estimation of the half-life, a combination of our concept with existing quantitative structure-activity relationship (QSAR)/quantitative structure-biodegradation relationship (QSBR) would improve, through the generation of data, the prediction of environmental fate. Testing this concept with more chemicals could help better define the limits and conceivable solutions to increase the reliability of this tool.

Conclusions

Predicting the behavior and the environmental fate of newly synthesized chemicals remains a priority for the community of environmental stakeholders. Thus, the management of the ever-increasing flow of chemicals requires appropriate concepts to assess the chemicals' risk during the screening stages. Regarding the behavior and the evaluation of intrinsic persistence, there are many tools available for laboratories to establish the potential for biodegradation. However, predicting the probability of biodegradation by assuming given environmental conditions is not a simple task. Ready Biodegradation Tests are not adapted to addressing the quantity and complexity of environmental variables. To our knowledge, this is the first time a strategy in biodegradation assessment bridges the gap between experimental ease of use and probabilistic approach of biological persistence. The ProbaBio approach presented in this study is a new concept that allows stakeholders to perform biodegradation tests under environmentally more realistic conditions. As a concept, ProbaBio combines the exposure scenario and probabilities of biodegradation using a miniaturized high-throughput system and logistic regression analysis. As a result, ProbaBio profiles microbial degradation, in the sense that it both indicates the potential risk of environmental persistence and allows the quantification of this risk, as shown for the tested molecule glyphosate after only 1 month of testing. Furthermore, including this strategy in the decision tree of environmental persistence assessment for new molecules could help industrial, scientific, and environmental agencies to better understand and hence manage the risk of environmental persistence.

Fig. 1

 1 Fig. 1 Global overview of the ProbaBio strategy. Ten environments are sampled. Bacteria are extracted, pretreated, and inoculated at two different concentrations separately in duplicate in 24-well

Fig. 2

 2 Fig.2High-throughput and miniaturized system for biodegradability assessment. a Twenty-four-well microplates with non-invasive sensors for dissolved oxygen monitoring (Ω) were filled with 2.5 ml of chemical stock solution plus inocula (Φ). b 4-NP can be considered as biodegradable in only three of four cases (4-NP is yellow at 10 mg of carbon per liter and pH = 7.4 and is clear when biodegraded). c Concentration of dissolved oxygen for 28 days for 4-NP. The negative control (bacterial inoculum + mineral culture medium) consumption of

Fig. 4

 4 Fig. 4 ProbaBio proof of concept. a, b Influence of the origin of the inocula (wastewater treatment plans (WWTPs)) and period of sampling on the percentage of positive biodegradation tests over all other varying parameters. c Influence of the incubation temperature (12 or 25 °C) and cell density (environmental (EnV) test inoculated depending on the in situ environmental concentration, enhanced (EnH) test inoculated at 10 times environmental concentration for a maximum of 10 8 cells ml -1 ) on the percentage of positive biodegradation tests. d Three-dimensional surfaces

5

  Optimized ProbaBio concept applied to diethylene glycol. a Three-dimensional surface plot of the fitted logistic regression model (n = 80) to profile the potential environmental persistence of DEG in terms of the probability of biodegradation expressed as a function of the temperature (between 4 and 30 °C) and the cell density (between 10 2 and 10 8 cells ml -1 ). b Comparison of the three-dimensional surface plots characterizing the environmental profiles of DEG with n = 80 (blue surface) and n = 844 (yellow surface)

Fig. 6

 6 Fig. 6 Microbial biodegradation profile of glyphosate according to the optimized ProbaBio concept (n = 80)

from January to December Cells.ml -1

		1,00E+10
	WWTPs	1,00E+09
		1,00E+08
		1,00E+07
	Fresh	1,00E+06
	water	1,00E+05
		1,00E+04
		1,00E+03
	Soils	1,00E+02
		1,00E+01
	Sea
	12 months	WWTPs	Fresh water	Soils	Sea

Table 1

 1 Summary of the chemicals used in the proof of concept of ProbaBio with n = ∼850 tests or with n = 80 tests Chemicals (CAS no.) Tonnage band per annum (ECHA database) Biodegradability according to ECHA database Percent of positive tests

	Sodium benzoate (532-32-1)	10,000 to 100,000	Readily biodegradable	100 (n = 854)
	Diethylene glycol (111-46-6) 100,000 to 1,000,000	Readily biodegradable	60.88 (n = 844)
	4-Nitrophenol (100-02-7)	Intermediate use only	Inherently biodegradable	79.02 (n = 854)
	Atrazine (1912-24-9)	Intermediate use only	Not biodegradable	4.72 (n = 846)
	2,4,5 trichlorophenol (95-95-4) Intermediate use only	Not biodegradable	0 (n = 846)
	Diethylene glycol (111-46-6) 100,000 to 1,000,000	Readily biodegradable	58.75 (n = 80)
	Glyphosate (1071-83-6)	No data available	No data available	11.25 (n = 80)