Microsoft Word - 05---B-.docNstterer-Dittrich Gmbh

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WORKING ADDRESS
Swiss Federal Institute of Technology in Lausanne IBOIS - Chair of Timber Construction GCH2 Ecublens 1015 Lausanne Switzerland Tel. +41-21 693 23 91 Fax +41-21 693 23 94
HOME ADDRESS
Route de la Gare 10 1163 Etoy Switzerland Tel. +41-21 808 75 30 Fax +41-21 808 78 30
PERSONAL DATA
Born: December 5, 1938 Place of birth: Haggn/Basse-Bavaria Nationality: German Marital status: Married (4 children) Languages: German mother tongue
Excellent knowledge’s in French and English CAREER
1965 Engineering diploma in Civil Engineering, Technical University of Munich 1965-1974 Assistant at the chair of construction, Technical University of Munich 1970 Founded an engineering office in D-Munich:
Research, construction and static calculation 1978 Nominated to the post of professor of the chair of timber construction
(IBOIS) at the Swiss Federal Institute of Technology in Lausanne 1980 Founded an engineering office in D-Munich: Planungsgesellschaft Natterer + Dittrich GmbH (PND)
1983 Founded an engineering office in CH-Etoy Bois Consult Natterer SA (BCN)
1987 Founded an engineering office in F-Les Lanches Ingénierie, Conception - Structures Bois (ICS)
1993 Founded an international centre of development concerning timber constructions (IEZ) in the Bavarian forest, D-94344 Wiesenfelden

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A way to Sustainable Architecture by new technologies for engineered timber structures
Julius NATTERER * Professor hon. EPFL



Abstract
Only the use of wood in the construction field can save
and renew the forests of the world and motivate people to
maintain and plant forests in a sustainable way.
Today, ecological concerns become more and more important and wood, under the double aspect of the energy necessary to its production and its aptitude to store CO2, could be the best-suited building material of XX1e century. However, if these ecological concerns take more amplitude and influence, there is another aspect, the economic concern. Thus each project must present not only one ecological or architectural value, but also an economical one.
Keywords: massive wood, nailed planks, mixed structures,
glued and spatial structures
1. Introduction
Today, ecological concerns become more and more important and wood, under the double aspect of the energy necessary to its production and its aptitude to store CO2, could be the best-suited building materials of XX1e century. However, if these ecological concerns take more amplitude and influence, there is another aspect, the economic concern. Thus each project must present not only one ecological or architectural value, but also an economical one.
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It is necessary to promote the different possibilities where wood as timber can be used. Besides the utilization of high quality wood for high-tech constructions of halls, wide span covers and bridges, one should further develop the possibilities of using medium to low quality for massive-timber construction for floors, walls and roofs, also in association with other materials like steel, concrete, glass or fiber glass.
2. Massive-timber constructions
Round, sawn timber constructions or nailed, screwed, doweled and glued massive plank systems today allow us to reach these objectives. The nailed, screwed, doweled and glued massive plank system consists of planks, aligned one next to the other, face to face and assembled with nails. Massif elements with a thickness that corresponds to the width of the planks are obtained. With these systems, a hypothetical defect in one plank will not lead to a failure of the whole structure. The stress is then taken over by the adjacent planks through the nailing pattern (fig. 1).
The advantages of these structures are multiple. They
allow reducing the necessary static height in comparison to the traditional joist and improve the acoustic protection as well as the thermal inertia. With this system, during summer, overheating of the buildings is limited and in winter, the solar heating is better distributed during the day. These structures may remain visible, coated or not, or recovered with plaster and wall paper. Different variants of sections can be obtained without high costs (fig.2).
For floors, higher spans can be obtained through the
1. Figure 1. System effect
No O12 MF/12.95
d = 6-18 cm
2. Figure 2. Variant of cross-section

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Tower de Sauvablin
Lausanne () 2003


use of mixed systems, where wood is in tension and concrete in compression. Materials are thus used to their best abilities. The connection between the two components is realized through grooves and pre-stressed bolts (fig. 4). Depending on the different loadings and the aesthetic requirements, the wood parts can have differing forms: From round wood for bridges or half-round wood for ceilings without any particular aesthetic demands, to nailed planks for normal buildings or even glue laminated beams in “T” section for high stressed floors. Comparing to a traditional concrete slab, the self-weight is heavily reduced (fig.3) and it is fire resistant from 60 to 90 min.
Tower de Sauvablin
Lausanne (CH) 2003
Tower high 36 m. Observation platform at 30 m. Diameter: 12 m at base, 6m at the platform. 24 poles half round are distributed around the spiral staircase made of 20x40 cm Douglas sections. The spiral builds two independent staircases one behind the other. The upper platform and the two intermediates one are made of nailed laminated timber
No O09 MF/12.95
A : Compression zone
60
tige filetée M12
résine époxyde (scellement)
tube plastique (protection)
collerette en acier
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72 VNP



cm

Houses of Residence, Arlesheim (CH), 1999
The grouped residence consists of 72 two-story houses. The floor is built from VNP elements. The double diaphragm separates and stabilizes as a solid element
between two houses. A layer of plaster panel also covers the visible facets for satisfying fire resistance criteria. Outside of the building, the VNP elements are in Douglas timber with a section of 30 mm x 30 mm which provides well the whether resistance without any chemical treatment. In order to optimize the construction cost, most of the elements are prefabricated.
Church, Schnerverdingen (D), 2000
The church consists of a free space with a height of 2-stories. The roof suspends a platform at the first floor. The casing of the building is erected by VNP element in Oak. The inside bearing structure is built by VNP elements in Pine. Two frames with longitudinal trusses and two transversal frames transmit the load from the platform and the church tower.

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VNP
VNP

wood-particle panel
Sport hall, Haukivuori (FIN), 1999
Sports hall of 24 x 30 m. The roof is composed of VNP modules between the primary bearing system. This consists of subtensioned beams with a Kerto web. The walls are also made of nailed planks recovered with plywood for stabilization. Due to its easy construction system, unemployed local people can be involved. Before the construction, several tests were made in order to determine the physical characteristic of the
nailed planks as well as their fire resistance. Finally, before putting them in place, the primary systems were tested with a load over 50t.
Schaanwald, 1995 Multi-Family House (CH)
The construction consists of five two-family houses. The roof and the floors are single span structures, which are spanning from one partywall to the other. The floors inside one apartment are VNP, visible on both sides. The inter- mediate floors between two apartments are made up of the TCC-system with soundproofing insulation and floating screed. The interior wind bracing walls are VNP, which are covered with wood-particle panels. Due to fire and phonetic related reasons the partywalls were filled with concrete.
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90
150 mm
Building of residence, Rieselfeld (D) 1999
A 4-story residence building, with vertical and horizontal bearing systems in wood-concrete mixed system. The wood-concrete diaphragm consists of two facets in VNP element with 80 mm of thickness and (a concrete layer with 150 mm thickness in-between due to the 90-minute fire resistance was required between apartments). An overhanging gangway is fixed on the front wall of the 4th floor, which continues to the facade of 3rd floor. Braces in compression support these two floors.

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,


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Heavy load bridge,
Le Sentier (CH), 1997
Principal purposes were the optimal use of the raw material of a forest municipality and the application of modern civil engineering. The wood concrete cross section consists of eight 13 m long round timber cross sections ( 48-72 cm). In order to achieve thereby a parallel limited carriageway slab, this was bilaterally cut in order to have a constant width and provided with discharge slots. The distribution of the wheel loads is made by reinforcement in the grooves of the concrete composite slab
Wimmis (CH) 1989
Pedestrian and cycle bridge over the "Simme". Main structural system of the bridge of two parallels and over three fields passing trusses with cross beams in the distance of 6.75 m. The horizontal stability of the bridge is obtained by a bracing composed of the lower chords of the truss, the transversal beams and crossing round steel diagonals. Center zone: 54 m, side fields: 27 m, width: 4.5 m
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3. Space structures
Besides a quantitative use, high-tech wood constructions like bridges, wide span covers require a detailed planning to obtain a "light" looking structure. Different criteria have to be respected to optimize the structure. First the choice of hyperstatical systems, which transfer the stresses toward higher quality elements, allow to make uniform the woods characteristics. Further, the adjunction of members in compression reduces the span of the primary bearing system and transfers the stresses from bending, which requests big sections, to normal stresses. If those members are spatially distributed, they allow stabilizing directly the structure. Finally, details are of particular importance because of their costs. It is therefore necessary to reduce their number or simplify them. For instance, compression members can be joined only by contact.
Space structures like shells, ribbed or suspended shells fulfill the first two criteria. They are highly hyperstatical and stressed mainly by axial stresses under permanent loads. However, the high number of nodes necessary for their realization has during a long time limited the construction of such structures. But these nodes, if they are numerous, can also be realized in a easier way. In the screwed plank shells, the joints are made only by planks alternately continued in each direction with filler elements in the other direction and screwed to obtain composed elements. All these techniques request a close and excellent collaboration between architects and engineers to best profit of the diversity of forms and texture that wood constructions can give.
Lüterkofen, Sports-Hall (CH) 1993
Only the lower entrance area is a truss grid (span: 16x16 m, grid: 2.3 x 2.3 m) with load distribution in 2 directions. The roof of the sports hall itself contains main- and secondary truss structures.

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30 x 100 4
30 25

16
Wien (A) 1981
Suspended roof shell of 170m diameter. The shape of the ribs has been developed to achieve symetrical loads in a state of tension. The covering layer of counter directionally aligned planks assume the shear resistance forces.
Open Air Stage, Altusried (D) 1998
The roof structure covers an area of 30 x 100 m.. The 4 highly stressed truss can-tilevers (cantilever 30 m) in a distance of 25 m are in selected round wood trunks. The suspended roof structure that spans between the truss is made up of nailed boards. The different slabs as well as the inclined terraces where made of mixed wood concrete construction. The wood parts made from round conical trunks (base 32cm top 16cm) thus allowing to follow the hemispherical form of the tribune.
Hall for Galley,
Morges (CH) 1995
The hall is a shell structure made of screwed planks; it was erected with the help of unskilled workers. The transverse loads due to wind action are supported by external timber trusses, The dimensions of the structure are: Length 60 m, width 20 m and height 12 m
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Sports Hall, Arlesheim (CH) 2000
Sports Stadium 35m X 54m. The roof consists of a barrel form structure supported on the posts. The laminated curves beams are arranged on the roof in order to transfer the horizontal force from the vault to the supporting points. The horizontal reactions are beared by the arched binding beams in laminated wood.
The arcs placed transversally take the asymmetrical force applying on the structure.
DOME SHELL
The following projects are built in grid structure - using the same technique described in the above barrel roofs. Here we have the same advantages and construction methods, with the only difference being the shape of the shell -now it is curved in two directions.

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Polydôme,
6.8

40 x 40 26



Ecublens (CH) 1991
The spherical dome structure made of screwed planks construction has the following dimensions: radius: 27.5 m on a ground surface of 25 x 25 m, ridge height: 6.8 m. In the intersection points planks are bolted to each other. The planking, screwed on the ribs in a diagonal direction, has the function of the bracing in the roof plane The whole structure needed 32 m3 of wood (planks).
Health Center Hall
Uzwil (CH) 2004
Kugelförmige Holzhalle als Umfeld für heilende Schwingungen. Die mit einem zylindrischen Anbau ummantelte Kuppelstruktur wurde mit einer Vertikalschalung verkleidet. Die sich kreuzenden Rippen bestehen jeweils aus sechs Lamellenlagen, die mittels Schrauben verbunden werden.
ExpoDach2000,
Hannover (D)
For the central meeting area of the EXPO 2000 a wide spaced roof construction of 10 square „umbrellas“ was constructed serving as the main event location. Each „umbrella“ covers an area of 40 m x 40 m and is about 26 m high. It consists of four double curved shell surfaces, having been constructed as partly glue-laminated timber ripped shells. The shells hang over about 26 m and hang on four cantilevers. In the middle of the „umbrella“ a big steel structure transfers the forces onto a tower construction. The
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„umbrellas“ are connected at the outer bending edges of the shells and the ends of the cantilevers. The structural components were mostly manufactured in the plant and in an exhibition hall near the site. Big cranes assembled the completely pre-manufactured construction parts step by step.
4. Conclusions
The ecological challenges cannot be taken up without respecting the economic value of the forest, allowing to cover their costs. The ancients have protected their forest not because of their altruistic spirit, but because the forest gave them more than just some logs to burn. The ability of the forest to resist to the natural elements as well as their protective functions must also be taken into account. But those rules are not bound with financial resources. Using wood for construction assists the chance to save the forests world-wide as it represents a noble use of their product and allows them to be maintained and replanted. Use of wood as an energy source cannot reach this objective.
The role of the forest of the future will have to play for mankind and environment cannot be assured only through

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environmental protection- as little as the role of future cities can be granted through the sole protection of monuments.
In the future, the rarefaction of fossil energies and raw materials will mean a growing role for the forest through wood production and CO2 regulation. It is therefore important to further develop the research on wood, in parallel to the teaching at the 2nd and 3rd cycle, to rapidly diffuse widely these results. The society must rediscover the privileged bonds it had with wood not only in a nostalgic way, by plagiarizing the traditional construction, but instead being inspired by their concepts. That means a perfect harmony between form and function and the right choice of the materials to be able to respond in a competitive way to the wishes of the modern architecture.
The use of wood is not a “proof ” for good architecture. It is, however, an important contribution to the environmental conservation, even if it needs more concentration in the planning phase
“We do not inherit the ground our parents, we borrow the ground of our children”
Antoine de Saint-Exupéry
“Perfection of means and confusion of goals seem to characterize our age”
Albert Einstein
5.reference
1992 : Natterer, J.; Herzog, Th.; Volz, M.: Holzbau Atlas Zwei. Institut für internationale Architektur-Dokumentation GmbH. D-8000 München (en japonais)
1998 : Natterer, J.; Herzog, Th; Volz, M,: Construire en bois 2. Presses Polytechniques Romandes. CH-1015 Lausanne (2ème édition augmentée)
1998 : Natterer, J.; Herzog, Th.; Volz, M.: Atalante del Legno. Unione Tipografico-Editrice Torinese. I-10125 Torino 1999 : Natterer, J. ; Sandoz, J.L. ; Rey, M. : Construction en bois. Matériau, technologie et dimensionnement. Traité de
Génie Civil de l’Ecole polytechnique fédérale de Lausanne. Volume 13. Presses Polytechniques Romandes. CH-1015 Lausanne
2003: Natterer, J.; Herzog, Th.; Winter, W.; Schweitzer, R.; Volz, M.: Holzbau Atlas Vierte Auflage neu bearbeitet - ISBN 3-7643-6984-1. Institut für internationale Architektur-Dokumentation GmbH. D-8000 München
2004: Natterer, J. ; Sandoz, J.L. ; Rey, M. : Construction en bois. Matériau, technologie et dimensionnement. Traité de Génie Civil de l’Ecole polytechnique fédérale de Lausanne. Volume 13 deuxième édition ISBN 2-88074-609-4 Presses Polytechniques Romandes. CH-1015 Lausanne
2004: Natterer, J.; Herzog, Th.; Winter, W.; Schweitzer, R.; Volz, M.: Timber Construction Manual – Translation of fourth revised German edition – ISBN 3-7643-7025-4 Birkhäuser – Publishers for Architecture Basel – Boston – Berlin Edition Detail Munich