timber roof by digital fabrication

Timber Roof by Digital FabricationA Research of the complex-form timber construction

Name: Shi BoyuanStudent Number: 4329368

Email： [email protected]

Architectural Engineering Graduation Studio

Tutor1st: Architecture: Annebregje Snijders

2nd: Building Technology:Maarten Meijs3rd: Technical Research: Martijn Stellingwerff

Abstract

Nowadays (Post-modernism) architectural theory and practice have been devot-ed to the indetermination, randomness,arbitrariness,complexity and contradition.

The morphological reflection of this exploration is the --curvy, non-stan-dard,non-regular--free form. Materializing these complex forms by digital para-metrical design workflow (from design to construction) has been a hot topic in recent 20 years Wood, as a construction material, has been developed and studied for almost thousand years. Due to the advantage in the digital materialization workflow and the sustainable chaaraceristics, timber became the ideal material for the complex from materialization.

In this research paper , the workflow of materializing the timber complex form is studied and researched by designing a new wood roof for the vacant factory hall--Van Gendt Hallen. By research and design, the roof construction type, structure pattern and assembled/disassembled joint/detail are studied and researched.

The findings and recommended principles in designing the free-form roof acts as the tool box for the development and application in this rennovation project. With the combination of the climate and space design in further process, this project will explore how the wood ,as the material, improves the spatial quality and shows the technical power at the same time.

CONTENT

1.INTRODUCTION

2.BACKGROUND RESEARCH

2.1 The Importance Of The New Roof In This Renovation2.2 The Wood As The Architectural Material2.3 Materializatin Of Timber Digital Fabrication

3.1 The On-site Constructing System

3.2 The On-site Assembly System

3.3 Comparison And Conclusion

4.1 The Timber-lath System

5.1 Wood Joint Study

5.1 Wood Joint Exploration

4.2 The Timber Lattice System4.3 The Timber Subsurface System4.4 Comparison And Conclusion

3.FREE-FORM WOOD CONSTRUCTION SYSTEMS

4. FREE-FORM WOOD STRUCTURE SYSTEM

5. WOOD-JOINT STUDY AND EXPLORATION

6. WOOD ROOF DESIGN BY RESEARCH

6.1 Climate Aspect

6.2 Architectural Aspect

7. COCLUSION AND DISCUSSION

8. BIBLIOGRAPHY

01

02

03

05

08

09

10

12

12

12

13

18

22

28

32

35

37

1.INTRODUCTION

Research of the wood construction for complex form Research by the design

Other fascinations

Wood has been applied in the buildings as the construction material since the very beginning of the architecture. So timber, as the worldwide main construction material in the history, has been stud-ied from different perspectives for thousand years.In the last centu-ry, concrete and steel gradually replaced the wood in the artifically built environment. The study of the complex form in architecture and the development of the digital fabrication bring the wood back into the sight of public due to the its easy-manufacturing character-istics. Coupled with the potential of sustainbility in the lifecycle of timber, it’s not surprising that the digital wood construction will be a hot topic in nowadays architecture realm. Although,recenty, the research about the timber constrution for free form is quite adundant, most of the researchs are focusing on the temporary utility such as fast-built pavilion, temporary exhibition space, interior installation, etc. When talking about the permanent complex-form wood construction, there are not so many mature systems or principles that could combine the advantage of easy-as-sembly and easy-manufacturing together. In this research paper, I would like to explore the possibility of wood construction in complex form by the study of the references and the analysis of the different possibilities aiming at find a proper system for permanent construction for further recycling and reuse.

In order to reseach the digital design and materializing workflow in complex-form timber construction. The methodology of research by design is applied.The vacant factory hall,the monumental building -Van Gent hallen, in Amsterdam had played an important role in the ship/train manufacturing history of Netherlands. But due to the uncomfortable indoor climate and the inconvenient transportation, the factory halls are now under bad maintenance and only used for temporary activites such as short-time exhibition and dance party. By introducing a new wood roof into this context for the building, a new system controlling the daylight, wind and rain,etc integrally is created which could make the indoor climate fittable for the multi-functional purposes in the further development and renovation.At the same time, the new roof could give a new identity to the vacant factory halls and creat intriguing space by the discourse with the existing structure. All of these effects could assist the exsiting context forming a new, dynamic order. Taking all the above into account, we could define the design question as how to renovate the Van Gendt Hallen into a multi-functional complex (mainly by making a new roof)？

A delicate renovation/design should take the technical and architectural design in consideration together. Addition to the structure construction analysis and study, the following design will also touch upon the effect of climate and the diversity of space in the potential of timber construction. In a another word, how wood, as a contruction material, could formulate a better living environment in an architectur-al way?

1

2.BACKGROUND RESEARCH2.1 The importance of the new roof

A.the problem of Van Gendt Hallen

B. Effect of the factory halls’ roofs

CLIMATE PROBLEM

CLIMATE:Because of the existing large glass panels on the roof, this large space receives overmuch light in summer which leads to the overglazing and overheating problems and the natural ventilation makes negligible melioration to this situation because of this large span space(160m x 80m). So in summer, it’s very hot in this halls. While in winter, the high glass/wall ratio leads to the apparent emission from inside to outside which makes this space quite cold if it’s a cloudy day(quite common in winter).

In my opinion, there are mainly twofold of problems the Van Gendt Hallen facing: climate and utility .

UTILITY PROBLEM

UTILITY: The Van Gendt Hallen now only rent for the temporary exhibitions and parties. There is no permanent functions located in these factory halls which is not quite helpful for the long-term development for the building and site.

SUMMER WINTER

NEED SOME STRATEGIES FOR BETTER INDOOR CLIMATE

NEED SOME STRATEGY FOR NEW FUNCTIONS AND PRGRAMMESVACANT FACTORY HALLS

UNCOMFORTABLE INDOOR CLIMATE

Fig 2.1 Illustration of the climate problem Source: Drawn by author

Fig 2.2 Illustration of the utility problem Source: Drawn by author

Fig 2.2 Comparison of the facade’s area and the roof’s area. Source: Drawn by author

EMPTY auditorium?office?

hotel?

education?

dwelling? party?exhibition? market?

sports?

BIG AREA:The roof is an important envolope of the building, especially the factory hall. As my calculation, the area of four facades of the building is (1197+2643)*2=7680m2. The area of roof is 100*160=16000m2(As twice as the area of facade).

7680m2

16000m2

Facade

Roof

2

Fig 2.3 How the roof affect the interior climate Source: Drawn by author

Fig 2.4 How the roof affect the surrounding environment.Source: Drawn by author

Fig 2.5 How the roof improve the indoor space quality.Source: Drawn by author

INFLUENCE TO THE INDOOR CLIMATE:The roof could also has a remarkable influence to the indoor cliamte of the factory due to its key role for the natural ventilation and the sunlight which will change the indoor climate dramatically.

2.BACKGROUND RESEARCH2.1 The importance of the new roof

heat

light

heatexisting situation

existing situation

natural ventilation hole for heat exchange

transparent part for sunlight control

B. Effect of the factory halls’ roofs

C. Advantege of a new roof

EXISTING SITUATION

EXISTING SITUATION

EXISTING SPACE EXISTING SPACE

SPACE QUALITY

NEW ROOF/ NOW GESTURE

IMPRESSION TO SURROUNDINGS: Besides the technical factor, the roof of the factory hall should contribute as an icon/gesture to the surrounding urban component and should act as a attractor to the residential area nearby. The architectural meaning of the building should also be considered as an important aspect in the characteriscs of the roof.

IMPROVEMENT OF THE SPACE QUALITY: If we add a new roof to the Van Gent Hallen, we could put a kind of new space quality into the building.--the space between the new roof and the existing construction could be quite interesting and utilized for some extra functions.

NEW SPACE

2

2.BACKGROUND RESEARCH2.2 The wood as the architectural material

Wood As The Arhictural Material Has Hits Own Charecteristics That Are Summariesd Into Five Categories Below.

Wood is one of the most large-utilized, long-history and wide-spread material in architecture domain(both interior and exterior). There are piles of successful architectural examples existing , no matter in the document or around us, numerous wood construction being built and there are lots of educational or industrial institution exploring the modern potential of this histotic material leading the application of this common material to other climax throughout the whole history.

A.Wide-spread Material/common Reconginition Material

Fig 2.6 Handmade Wooden Octagon Chairs/ Indoor Fig 2.7 Metropol Parasol/ Outdoor

Source: http://www.1001chinesefurniture.com/ Source: http://www.yatzer.com/MetropolParasol

Wood is quite a sustainable material if we could balance the consumption of wood with the amount of the growth of the trees.（ideal situation）We should know that the construction industry occupies quite large part of the whole exhaust of CO2 in the world. and as we all know that the before the wood becoming the construction material, the tree could absorb lots of CO2 and give out large amount of O2 which is crucial for the living organism. By using wood, we could countervail some CO2 emission in this meaning.

B.Sustainability

Fig 2.8 Managed Forest in Michigan. US Fig 2.9 Energy Consumption Diagram

Fig 2.11 Total energy use

Source:http://csis.msu.edu/ Source: ruth slavid /2005/woodarchitecture

Source:http://www.woodsolutions.com.au/Blog/House-the-world-and-save-the-environment

Moisture is one of the biggiest enemy of wood construction: Wet weather will lead to the decay of the wood mechanical properties. The intrinsic of the natural wood: there are always knots in the natural wood material which would reduce the applicability of wood construction. Long term shortening: the weather condition will affect the volume of the wood, and the wood will shorten during the life span of the building. All these factors will affect the design and construction process when we deal with the wood material and we should take care of the charateristics and find a way to reduce these negative impacts.

C.Limitation Of Wood Material

Fig 2.10 swiss sound box

Source: 000 expo swiss pavillion /peter zumthor

3

2.BACKGROUND RESEARCH2.2 The wood as the architectural material

The substaintial of the biological organism and physical structure in the wood material determinate that the wood has the potential for easy-manufacturing. No matter in the most traditional way - hand-making skill created by carpenters or the most advanced way-industrialized standard manufacture and the digital fabrication. The wood has showed its capability for easy-cutting , cheap-gluing and flexible-bending. For this reason, we could see lots of elegant wood construction created by those pioneer.

Some architects work with because of the structural characteriscs or the environmental-friendly. But there is also the issue of appearance-The architectural feeling of the wood material: The pattern on the wood and the natural textile born with the wood. Beside, Timber is warm, it gives a human scale, it’s a material that most peole would be happy with,would touch, would smell even. This is also a main reason why wood could be so popular during the the long constrction history-people like it, so people will use it and study it. It’s just like the building: people like one building so they will renovate and reconstruct it. It’s all about the sense of beauty .

D.Easy Manufacturing

E.Architectural Atmosphere

Fig 2.12 Handmade TOU-KUNG Joints Fig 2.13 The Ripple Wall

Fig 2.15 chesa futura apartment buildingFig 2.14 parliament building

Source: Foster and Partners 2004Source: Stein Halvorsen and Christian A. Sundby 2000

Source:http://www.arch.mcgill.ca/prof/sijpkes/arch374/winter2001/jqiu/evolution.html

Source: Christopher Beorkrem P35 Material Strategy in digital fabrication

4

2.BACKGROUND RESEARCH2.3 Materialization Of Timber Digital Fabrication

A. The advantage of CNC-Milling System

In Nowadays Digital Fabrication, The Cnc Milling System Has Become One Of The Most Common Systems In The Subtractive Way Of Manufacturing Especially Dealing With The Wood. In This Chapter, I Will Show A.Some Basic Information About The Cnc-milling System And B.The Choice Of Wood Product For Digital Fabrication.

ACCURACY:This CNC machine is controlled by the G-script in computer.And this subtractive fabrication by the drill-bit on machein is much more steady and efficient than the hand work obviously. This high accuracy method of the fabrcation makes the constructing and assembling the complex surface much easier and faster.

LOW-COST:Because of the way CNC-milling working（controlled by the computer and digital programme）, this CNC-milling method could make the unique construction elements almost in the same cost compared to the mass-customized.

MULTIPLE CHOICES: There are many kinds of CNC router and mills available now according to the movement of drill-bit and the sizes of the operation platform. There are CNC 3-axis router, 5-axis router and 7-axis router in the market which are able to finish almost all the substractive work we can imagine. About the operation size, for most CNC router, the 3000mm(length) x 1500mm(width) x 200mm(thickness) is the maximum scale it can cut efficiently and economically. Of course, we also have really huge CNC router machine in industrial realm which could create quite impressive dimension shape at once.

UNDERSTANDING CNC ROUTERS

18

Traditional Method

CNC

Equal Cost

Batch Size

Unit

Cost

Photos courtesy of FDM and CabinetMaker magazines

As seen in the next table, a batch size of one can be made for a much lower unit cost using CNC technology compared to traditional methods.

CNC in the Media

There is no doubt that as CNC technology gets more established in the woodworking market, it should also get more coverage in the media. The fact is that this technology is changing so rapidly that it provides an endless supply of material that deserves to be put in print.

Source:http://www.elecprint.ch/downloads/modelaplayer4e.pdf

Fig 2.16 Different Drilling Bits Fig 2.17 Comparison Of The Cost

Source: Alain Albert FPInnovations Understanding CNC routers P18

Source:http://www.wired.com/design/2012/06/cnc-mill-that-will-build-a-house/

http://northwoodmachine.com/photos/5-axis-machinery-photos

http://procnc.com/resourcesFig 2.18 12.5m X 4m X 150m Hsm-model Fig 2.19 3-axis Machine Fig 2.20 5-axis Machine

5

2.BACKGROUND RESEARCH2.3 Materialization Of Timber Digital Fabrication

B. Choice Of Wood Production

Due to the long term development of the technique about wood manufabracatio, there are quite a lot of wood production we could chose for the construction.

Actually, all the wood production can be separated into two groups: solid sawn timbers and engineered wood products. Solid sawn timbers contain products of softwood and hardwood, which come from sawing of logs. Engineered wood production are developed to overcome the limitations of solid timber in size and quality. The main kinds of the engineered wood production for architecture construction are: Glued Laminated timber(glulam), plywood, Laminated veneer lumber(LVL), solid wood panel(SWP), oriented strand board(OSB), medium density fiber board(MDF).

The laminated wood is preferred to solid wood because of warping. The characteristics of solid timber is influenced by its gain,knot; however , plywood (a kind of laminated wood product) which is made by banding together and pressing a number of thin layers of veneer, has an even properties and strength in each direction, so its structural perfomance depend mainly on the number of layers and the thickness of each layer. The homogeneity of laminated wood products as well as their producing sizes makes it a suitable choice for digital fabrication timber structure. Plywood has different kinds of products in several grades,such as structural plywood.

In my opinion. the plywood is one kind of ideal wood production for the CNC router system. Because of its dimension is alway 2400mm x 1200mm or 2440mm x 1220mm in X Y axis and it has lots of different dimension in Z axis according to different construction necessity from 4mm to 50mm.

Fig 2.21 Standard different panel thickness

Source: P4-5 Finnforest Plywood

Fig 2.22 Cross-lamination in plywood as a result of alternating the veneer grain

Source: P23 Structural Plywood &LVL Design Manual

6


If studying the timber construction comprehensivly, according to the construction progress in real project, the timber roof/shelter could be sorted into two main categories: On-site Construction System Or The On-site Assembly System

The on-site construction system means that the shelter/roof need be constructed on site, we need shape the form of the shelter on-site. And on-site assembly system means that we prefabricate every element off-site and assembel them on-site.Each system has its own characteristics and will be discussed in this chapter.

Large roof or (shelter) or (shed) as an important architectural element has been discussed and developed since the appearance of architecture. Due to the combination of architectural meaning(social meaning) and technical meaning(scientific meaning), the shelter is still a hot topic in nowadays architecture realm under the circumstance of the developing advanced technique. As a result, the potential of free-form timber shelter construction has been explored in many different aspects.

7


3.1 The On-site construction system

The on-site construction system is called gridshell-system in timber construction process. The principle of this system is using the deformable capability of the wood strip and the good performance in bearing the axial force of the wood strip. When the wood strips are connected as a grid system and the boundar-ies of the form are rigidly constrianed, this kind of structure could be very strong and quite light.

Downland Gridshell 2002 UKBuro Happold, The Green Oak Carpentry Company, E A Chiverton,Boxall Sayer

This project is the first permanent construction made applying this system in UK.We could see the workflow of the on-site construction very clear from the first set of illustration images. Firstly, creating a elevating platform for the wood shelfter and connecting all the wood strips as a grid system for further deform.Secondly, using the platform to shape the final form of the shelter/roof by lifting the platforms into different heights then fixing all the nodes of the system. Thirdly, completing the gridshell construction by constraining the boundaries and adding the secondary structure system. Fianlly, finishing the construction by installing the cladding system and additional skins

A successful node and a sucessful system are two key factors for any successful timber construction system, especially for the grdishell system. The node should be capable for the transforming of the wood gridshell system in first/ second phases and strong enough to fasten the whole system as the permanent construction.In this case, this node is consisted by three layers of steel panel and combined by four steel sticks/screws through the wood strips.

Fig 3.1 Construction _Process

Fig 3.2 Detail DesignSource: http://parametricsemiology.com/2013/10/18/grp_01_active_gridshell/

Source:http://www.cullinanstudio.com/project/downland-gridshell

Fig 3.3 Construction DetailSource:http://www.cullinanstudio.com/project/downland-gridshell

1.constrution the roof on site 2.Lift the roof and form the shape

3.finish the structure construction 4.finish the cladding layer

8


3.2 The On-site Assembly system

Fig 3.4 On-site assembly _Process

Fig 3.5 Easy-assembly Fig 3.6 Steel-Joints Fig 3.7 Indoor Perspective

Fig 3.8 Lattice System Illustration

Source:Archidaily Peoples Meeting Dome / Kristoffer Tejlgaard & Benny Jepsen

Source:Archidaily Peoples Meeting Dome / Kristoffer Tejlgaard & Benny Jepsen

Source: Drawn by author

Peoples Meeting Dome /2012 DenmarkArchitect: Kristoffer Tejlgaard & Benny Jepsen

The on-site assembly system is a kind wide-spread and fast-develop-ing construction system not only being applied in the timber construc-tion. There are lots of different kinds of manifestation in this system but the principle are almost the same: prefabricating all the elements off-site and conastructing these components on-site by the easy-as-sembly.

This project is located in Allinge,Bornholm in Denmark and was a temparary construction providing a place for residents who live around to meet each other and have some extra social activities.(now it beomes a permanent project for its high quality). From first image, we could see the workflow of the on-site assemly system.Carrying all the prefabricated elements to the site and only need several worker aseembling all the skeleton.The equipment is quite simple: a lifting trunk and some scaffolds. In this case, the steel joints are printed nodes that laser cutted and robot welded, meeting the high precision requirements of the structure of complex form.In the second image, all the steel nodes are prefabricated and piled for further assemling.

The node of the on-site system seems not so “smart”, but actually they need be well-designed as well. For instance, in this design the nodes are designed as steel shoes that are open in one dimension and two inches in the other, so they can accommodate the family of standard rafters.

9

3.FREE-FORM WOOD CONSTRUCTION SYSTEMS3.3 Comparison And Conclusion

A. Comparison of the two construction system

As analysed above, the key advantage of the gridshell system is: first, the continuity of the form; second, the light weight of the construction. The disadvantage of this gridshell system is : first, the complicated constructing process; second, the need of the rigid boundaries.

The advantage of the on-site assenbly system is: first, high-completition of the form; second, easy manufacturing process.The disadvantage of this gridshell system is : first, the self-weight is heavy compared to the gridshell; second, joints should be much stronger than the gridshell system.

On site construction

Stability Weight Complexity of Process Feasibility

On site assembly

category

aspect

+ +

+

-

+0

0 +

+ +

According to the introduction and analysis before. We could find that 1.The stability and the constructing complexity of the both ways (constructing and assembly) are almost the same. (Each way has the real project built)2.The self-weight of the structure are different and gridshell system(on site construction) has a better result(less weight)3.The Feasibility is quite crucial in my case (a heritage renovation): The gridshell system forms the shape on site by lifting or falling the control points on the roof and this characteristic makes it almost impossible to use this way to build the roof just above a heritage factory hall.

Conclusion: Though the gridshell system has a plus point in the selft-weight but the feasibility makes me choose the on site assembly system for the roof construction in this renovation assignment.

10

Fig 3.8 Gridshell System : From flat to curvedSource: http://shells.princeton.edu/Mann1.html Source: http://shells.princeton.edu/Mann1.html

Fig 3.9 Gridshell System : System Illustration


Fig 3.10 OnSite Assembly System : System Illustration


Table 3.11 Comparison and Conclusion

4. FREE-FORM WOOD STRUCTURE SYSTEM

In last chapter, we discuss the different constructing systems: the on-site constructing system and on-site assembly system. After the analysis, the second construction system is suitable for the renovation and chosen for further development.

In this chapter, we will continue discuss the different structure systems within the on-site assembly system. This timber shelter/roof system is consisted of four different structural principles: 1. Timber-Lath System; 2. Timber-Lattice System; 3. Timber-Sunsurface System.In this chapter, we will analyse these three systems by example study and some force analysis programs(such as grasshopper+karamba in Rhino). Finally, the decision will be made that which structure system is most appropiate for my design.

11

4. FREE-FORM WOOD STRUCTURE SYSTEM 4.1 The Timber-lath System

4.2 The Timber Lattice System

4.3 The Timber Subsurface System

Fig 4.1 Overall shape Fig 4.2 Wood Component Fig 4.3 Steel Joints

Fig 4.1 Overall shape Fig 4.2 Wood Connection Fig 4.3 Detail Drawing

Fig 4.4 Overall shape Fig 4.5Wood Connection Fig 4.6 Wood Detail

Source: DETAIL 2010 10

Source: http://www.archdaily.com.br/br/01-27417/metropol-parasol-jurgen-mayer-h-architects

Source: http://www.dezeen.com/2011/10/31/icditke-research-pavilion-at-the-university-of-stuttgart/

Center Pompidou Metz --Curvy Lath NetWork SystemShigeru Ban

The Characteristic of this structure: 1. Perfect representation of free form. 2. Prefabricated and on-site assembled 3. Complicate manufacture process (such as twisting the wood beam)and the consequential high-cost.

Metropol Parasol Seville, Spain 2011Jürgen Mayer H.

The Characteristic of this structure: 1. High representation of free form. 2. Prefabricated and on-site assembled 3. The freedom in making the node or manufacturing the wood element.

Temporary bionic research pavilion made of wood(2011)ICD/ITKE University of Stuttgart

The Characteristic of this structure: 1. Good representation of free form. 2. Prefabricated and on-site assembled 3. The detail to connecting the edge of each subface is crucial to this system.

12

4. FREE-FORM WOOD STRUCTURE SYSTEM 4.4 Comparison And Conclusion

4.4 Comparison And Conclusion

A. Comparison of three systems in constructiona. diagram analysis

b. choice and conclusion

Fig 4.7 Illustration of the three systemsSource: Drawn by author

Table 4.8 Comparison of the these three systemsSource: Drawn by author

X

Y

x

x

y

y

14

7

8

9

5

6

2

3

X

Y

X

Y

1

1 22 3

34

4

5

5

6

6

7

7

8

8

9

9

10

10

1

1

1

1

1’

1’

1’

1’

2

2

2

22

2’

2’

2’

2’

3

3

3

33

3’

3’

3’3’

4

4

4

44

4’

4’

4’4’

5

5

55

5

5’

5’

5’5’

6’

6’

6’6’

Timber Lath Structure Timber Lattice Structure Timber Subface Structure

1

1

11

1’

1’ 22’

2

Fabrication

Pre-Assembly

On-Site Assembly

Lath Stick

Fabrication

On-Site Assembly

Fabrication

On-Site Assembly

Panel

Timber Lath System

Timber Lattice System

Timber Panel System

name

Summary

++ -

+ +

++

0

+

+

Practicability

According to the analysis and summary of these three different structure system, I prefer the last two structure system for the further research because we could use the simple CNC-milling for manufacture the elements and they all easy-assembly systems.

From the diagram right, we could see the construction process of these three systems clearly: The timber lath system: (1) fabrication of the wood lath (2) the pre-assembly of construction elements (3) bring the fragment to the site and final on-site assembly

The timber lattie system: (1) fabrication of the wood lattice and the joints elements.(2)bring all the construction elements to the site and assemble on-site.

The Subsurface system :(1) fabrication of the wood panel and the connection elements. (2) bring all the construction elements to the site and assemble on-site.

Form-Performance Prefabrication-Difficulty Assembly-Difficulty

++

++

0

13

Fig 4.9 Force Analysis of the Lattice System by Karamba


4. FREE-FORM WOOD STRUCTURE SYSTEM 4.4 Comparison And ConclusionB. Force analysis of lattice/subsurface system a. Lattice System force analysis

Displacement Illustration

Utility Illustration

Some basic information of the test model and the analysis result:Scale of the cross-section of the wood lattice: Height,40cm/Width, 10cm. The weight of the roof: 45,463 KG； The analysis parameter : Area load, 1.5kN/m2；Max-Displacement of the roof: 0.007m；Max-Material Utilization: 153.8%

disp[cm]-1.33e-088.31e-021.66e-012.49e-013.32e-014.15e-014.99e-015.82e-016.65e-017.48e-018.31e-019.14e-019.97e-011.08e+001.16e+001.25e+001.33e+00

utilization-153.8%-135.7%-117.6%-99.4%-81.3%-63.1%-45.0%-26.9%-8.7%9.4%27.6%45.7%63.8%82.0%100.1%118.3%136.4%

14

Support Point

Roof Body

Connection

Joint Detail

Displacement Illustration

Utility Illustration

4. FREE-FORM WOOD STRUCTURE SYSTEM 4.4 Comparison And ConclusionB. Force analysis of lattice/subsurface system b. Subsurface System force analysis

utilization2.2%42.8%83.5%124.2%164.8%205.5%246.1%286.8%327.4%368.1%408.7%449.4%490.0%530.7%571.3%612.0%652.7%

disp.[com]-7.20e-094.50e-029.00e-021.35e-01

1.80e-012.25e-01

2.70e-013.15e-013.60e-014.05e-014.50e-014.95e-015.40e-015.85e-016.30e-016.75e-01

7.20e-01

Some basic information of the test model and the analysis result:Scale of the cross-section of the wood panel: Shell Height, 5cm. The weight of the roof: 166,842 KG ;The analysis parameter : Area load, 1.5kN/m2;Max-Displacement of the roof: 0.006mThe max-material utilization: 652.7%

15

Fig 4.10 Force Analysis of the Lattice System by Karamba


Support Point

Roof Body

Connection

Joint Detail

4. FREE-FORM WOOD STRUCTURE SYSTEM 4.4 Comparison And ConclusionC. Choice And Conclusion

From the analysis above we could make a comparison easily:

From this table we could see that the reasonable choice in my case is the Lattice Timber System. It has the light self-weight, acceptable displacment and good material utility. The short board of this system is the force distribution. This part should be improved further.

Lattice System

SubSurface System

name

analysisSelf-mass Max-Displacement Max-Material-Utility Force-Distribution

45,463 kg

166,842kg 0.006m 652% +

0.007m 153% o

16

Table 4.11 Comparison of the lattice and subsurface system



In last chapter, we have discussed the three different kinds structure systems: (1) The timber lath system, (2) The timber lattice system (3) The timber Subsurface system. After the analysis and comparison, the timber lattice system has been chosen for the further development.

In this chapter, we will continue studying the timber lattice system by analysing different types of nodes and exploring different possibilities.

The nodes of the lattice system play an important role in keeping the shelter/roof stable and presenting the complexity of the whole construction system.

Example study diagrams, software programs force analyzing and phsical model testing are used in this chapter for the joint development.

17

5000mm

3000mm

5000mm

3000mm

Direct Connection

Wood Beam

Wood Joints

Wood Beam

5000mm

3000mm

5000mm3000m

m

Lattice without node

Lattice with node

name

analysisSelf-mass Max-Displacement Material-Utility

2052 kg

2555 kg 0.002m

0.009m 24.3%

Beam

Mesh

10%

60%

According to the table, we could see that when the cross-section is same, the lattice system with node has more weight than the normal one(2555kg to 2052kg) and has less max-displacement than the normal one.(2mm to 9mm). From the material utility, we could find that the nodes share lots of load distribution and much more important than the stick when talking about the loading capacity and stability. We could see lots of research and exploration about the node in the real buildings.

5. WOOD-JOINT STUDY AND EXPLORATION5.1 Wood Joint StudyA. The Importance Of The Joint

The normal timber lattice systemSome basic information and parameters:Wood lattice CrossSection: 60cm x 5cmMass: 2052 kgMax-displacement: 0.009mLoad: Selft Weight

The timber lattice system with node:Some baisc information and parameters:Wood lattice CrossSection: 60cm x 5cmNode-MeshHeight: 15cmMass: 2555kgMax-displacement: 0.002mLoad: Self-Weight

18

Fig 5.1 Analysis of the wood Joints by Karamba


Table 5.2 Importance of the node in Lattice System


1.Serpentine Gallery Pavillion/2005 U.KArchitect: Alvaro Siza/Eduardo Soute de Moura/Cecil BalmondEngineers: ARUP

This construction is based on the square-pattern. Using the inter-lock tecnique and simple steel stick to fix all the timber lattice together. The improvement of this joint system is the changing the four-direction connection into the two-direction connection.

This construction is based on the hexogan-pattern. The strategy is replacing all the three elements joints to two elements joints by the displacement of the wood sticks.This system applies the half-cut wood locks and the steel screws connecting all the lattice together.

2. KREOD pavillion/2012 U.Karchitect: Chun Qing Li location: Greenwish Peninsula, London, UKEngineer: Ramboll

5. WOOD-JOINT STUDY AND EXPLORATION5.1 Wood Joint StudyB. Example Study of the Wood Joints

19

Fig 5.3 Illustration of the Wood Joint Source: Drawn by author

Fig 5.5 Serpentine Gallery Pavillion/SizaSource:http://inhabitat.com/timber-and-polycarbonate-pavilion-at-londons-serpentine-galle

ry-illuminated-by-solar-paneling/alvaro-sizavieira-serpentine-pavilion3

Fig 5.6 Development of construction system

Fig 5.8 Development of construction system



Fig 5.7 KREOD pavilionSource:http://www.istructe.org/structuralawards/20

13/categories/small-projects/2013/kreod-pavilion

Fig 5.4 Illustration of the Wood Joint Source: Drawn by author

5.1 Wood Joint StudyB. Example Study of the Wood Joints


Construction

Roof

Roof

installation

Ornament

Pavilion

Pavilion

A

B

C

D

E

F

Permanent

Permanent

Test

Temporary

Permanent

Temporary

Wood

Wood

Wood

Wood

Wood

Wood

Steel

Steel

Wood

Wood

Steel

Wood

Exterior

Exterior

Interior

Exterior

Interior

Exterior

Utility MaterialNodeCondition

The timber construction is quite di�erent from the metal construction, in metal construction, the joints of the metal elements are usually made by welding to get sti�. In timber construction, especially in a 3D structure, it is not a durable solution to join several timber elements together at the same location by wood-wood connection, which will make the wood joints too complicated that a single fabrication tool could not achieve, even weaken-ing the connection due to the wood cutting.

So there are basic two practical ways to make better nodes in timber lattice:

(1)Connecting the timber elements by metal nodes.

(2)Staggering the connection position changing the complex, several elements connection into the simple, two elements connection

20

Table 5.8 Comparison of the material and utility Source: Drawn by author

Table 5.9 Different Joint StudyImage Source: Internet source

Illustration Source: Drawn by author

BOLT STICK NODEPANEL

NAME

STABILITY

DURABILITY

MANUFACTORY

ASSEMBLY

FLEXIBILITY

CONCLUSION

ANALYSIS

0 ++

++

+

++

++ +++

+

+

+

+

+

0

+ + +++

- -++ +

5.1 Wood Joint StudyC. Summary Of Metal Connection

From the example studies of the wood joints. We could find that the timber constructions for permanent utility always have steel connections(for strong stability and qualified durability, especially in exterior).The metal connections are sorted into four categories as my analysis: (1)metal bolts (2) metal sticks (3) metal panels (4) metal nodes according to the complexity of the metal connection.

(1) (3) are 2-D connections which means they have limits in connecting direction: the elements connected should be in the same plane. (2) is 1-D connection which only could connect the parallel elements.(4) is 3-D connection which is most flexible in connect-ing elements from different directions(1)(2) are two-element connections.(3)(4) are multi-element connections.(1)(2) are always applied into temporary construction.(3)(4) are always applied into permanent construction.


21

Table 5.10 Metal Joints SummarySource: Drawn by author

The Single-Stick Lattice System Some basic information and parameters:CrossSection: 50cm x 4cmMass: 1703 kgLoad： 1.5KN/m2Max-displacement: 0.007m

5000mm

3000mm

The Double-Stick Lattice SystemSome basic information and parameters:CrossSection: 50cm x 2cmMass: 1530 kgLoad： 1.5KN/m2Max-displacement: 0.006m

From the right-table, we could find that when the load-force increases, the double-stick system performs better than the single-stick system in the stablility.

5000mm

3000mm

Wood Joint

Single Wood Beam

Wood Joints

Double Wood Beam

Single Stick System

Double Stick System

Max-Displacement

Load0

5mm 6mm 7.5mm 8.7mm 9.9mm

9.8mm 12.9mm 16.0mm7mm4mm

1.5kn/m2 3.0kn/m2 4.5kn/m2 6.0kn/m2

5. WOOD-JOINT STUDY AND EXPLORATION5.2 Wood Joint Exploration

22

Fig 5.11 Analysis of different Lattice SystemsSource: Drawn by author

Fig 5.1 Analysis of the Lattice System by Karamba


A Timber Lattice System are combined by two parts: the node and the lattices. After example study and summary, we could find that the wood joints ,especially these that applied in the real permanent roof construction seems having been well-designed and there are not so much rest space for improvement. So I change my focus from the joints to the wood sticks. This is the explorating part of the study about the wood joint.

Timber Beam

Net Node Timber Beam

Net Node

Timber Box

Net Node


23

Fig 5.12 Development of the Double-Lattice SystemSource: Drawn by author


24

Fig 5.13 Physical Model Test Source: Drawn by author


1000mm

500mm

2.5D WOOD CNC MILLING

2D METAL CNC MILLING

2.Easy assembly and disassembly for furter recycling.

1.Simple manufacture technique

Technique Applied

3.Strong Connection for perma-nent condstruction

SCREW/NAILING

A. Development of the TImber Roof

25

Fig 5.14 Detail IllustrationSource: Drawn by author


The advantage of this system is that it could be easily manufac-tured and it also could be developed further: adding the cladding layer and hanging the structure underneath the timber roof construction.

26

Fig 5.15 Construction Illustration

Cladding Possibility

Stability Possibility


6.WOOD ROOF DESIGN BY RESEARCH

In chapter 3/4/5, we have analysed and explored the possibilities in wood lattice system and preliminarily established the construction principle of the wood roof.In this chapter, the application of this wood roof will be discussed. As I have mentioned in /2.1 the importance of the new roof/, this new roof mainly act in two aspect: the climate aspect and the space aspect. By controlling the sunshine/ the wind/ the rain,etc. integally, the indoor climate could be well intervened.By adding a new structure/system onto the existing building/order. The new space will be created and new activitis will be added into the new atmosphere.

27


6.1 Climate Aspect

A. Climate aspect case studyExisting Building New Roof DoubleCurved Roof

A.sun B.rain

C.wind

The main problem of the existing building is the uncomfortable indoor climate. By adding a new roof, we could improve the indoor climate integrally and control the environment at the same time. The climate aspect of the new roof contains three parts: A. The SunShading System B. The Natural Ventilation System C. The RainHarvesting System.

Diagram I: have the same vault-type roof but their roof transmittances range from 0.05, 0.1, 0.3, 0.5, and 0.7 respectively. If the reference case was included, the roof transmittances would be chronologically arranged as, cases 8, 9, reference, 10, 11, and 12. The respective mean indoor temperatures of these cases are 27.1 C, 27.4 C, 28.0 C, 28.5 C, 29.6 C, and 30.5 C respectively,

Diagram II: 12, 16 and 17, which have a roof transmittance of 0.7, show different results, though they are similar to the reference case and cases 14 and 15, respec-tively with the exception of roof transmit-tance. The mean indoor temperature of case 16 with a 50%-opening is 31.1 C, which is an increase of +0.8 C compared to that of case 12, which has a 100% open-ing. For case 17, which is fully closed, the mean indoor temperature is 32.5 C, an increase of +2.0 C compared to that of case 12.

Two key factor that influence the cliamte under-neath the roof: Primary, transmittance; Second, cladding opening

28

Fig 6.2 Relationship between the roof transmittance and opening rateSource: Article: “Survey and numerical effect analyses of the market structure and arcade form on the indoor environment of enclosed-arcade markets during summer”Department of Architectural Engineering, Yonsei University, Seoul

Fig 6.1 Roof integrally controlling the climate Source: Drawn by author

B. SunShading System

Esplanade Theatre in SingaporeDP Architects/ Michael Wilford &Partners2002

a.Mechanic Solar Shading

b.Metarial Solar Shading

Palazzo Lombardia Pei Cobb Freed & Partners/Henry N. Cobb2010

Design is made in 1994 and critics also accused that the design would have created a greenhouse in the tropical climate of Singapore,so a cladding of aluminium sunshades was added to the final design. Hence, the building is colloquially known to locals as "the durians"The design consists of two rounded space frames fitted with triangulated glass elements and sunshades, which balance outward views with solar shading.

Palazzo Lombardia was designed in 2004 and compelted in 2010.An important corollary benefit of the curvilinear building concept is the resultant array of interconnected open spaces that invite public passage and public gathering at street level. The largest of these spaces—Piazza Città di Lombardia—is sheltered by a roof composed of transparent pillows of ETFE film.

6.1 Climate Aspect


29

Fig 6.3 Esplanade Theatre in Singapore

Source:https://www.flickr.com/photos/adforce1/6089884013/in/photostream/

Fig 6.4 Metal Sunshading element

Source:http://commons.wikimedia.org/wiki/File:Esplanade_theatre_dome.JPG

Fig 6.5 Palazzo LombardiaSource:http://www.vector-foiltec.com/en/projects

/pages/it-milan-altra-sede-regione-lomb.html

Fig 6.6 Opacity SunshadingSource:http://www.vector-foiltec.com/en/project

s/pages/it-milan-altra-sede-regione-lomb.html

C. Natural Ventilation

Neutral plane is influenced by: Stack-effect/buoyancy Chim-ney height Temperature differ-ence Zone of the lowest pressure Effect of wind on the façade and above the roof Oper-able windows (generally negative effect)

An atrium can make use of the thermal buoyancy for naturalventilation (Fig. 5.1). Warm air from the adjacent rooms escapes to the high atrium space where the stack effect occurs and the continuous airflow is generated. The infiltration takes place locally in the façades of the rooms. The effect can be enhanced with heat gain from solarradiation by making an atrium with a glass façade or an extended glass cover on the roof. (Holford & Hunt, 2003).

6.1 Climate Aspect


30

Fig 6.7 Stack Effect PrincipleSource: Naturally and hybrid ventilated buildings

The state of the art and options for the future. TUDelft Peter van den Engel

Fig 6.8 Atrium/Buoyancy-driven techniquesSource: Natural ventilation based

bioclimatic redevelopmentBart Macquoy /TUDelft/

C. Natural Ventilation6.1 Climate Aspect


31

Fig 6.9 Natural Ventilation DiagramSource: Drawn by author

1.WOOD ROOF

Technical

Architectural

3.WOOD STALL2.WOOD CONSTRUCTION

PARTY ACTIVITIES restaurant office hotel Shopping education auditorium museum Market

Day Time

Day

NightTime

Night

Space Scale L SSS LLMMM

Yes

Could

No

CONCLUSION



A. Programs Concept

Function Analysis

What happens in the existing factory halls? After investigation, I found that this building is full of dynamic temporary activities. Such as : Laser Dancing Party, Exhibition, Open Market and fashion show, etc. These activities make this area more lively and will attract people gather-ing. So I want to remain a part of these activies for the diversity and add more permanent functions into Van Gendt Hallen.

The permanent functions suitable for the situation are restaurant, office, shops, museum, market.In the daytime, Van Gendt Hallen is the museum + office / market + restaurantIn the night, the museum and auditorium will keep closed and the market + restau-rant will become the party center + bar.

The other fashion shows and the exhibi-tion could locate into the museum space.

This strategy could divide the large span space into functional space and keep the advantage of the large span at the same time.

32

Fig 6.10 Overall Design DiagramSource: Drawn by author

Table 6.11 Function AnalysisSource: Drawn by author


6.2 Architectural AspectB. Programs Concept

The new roof could create new space on the top of the building and at the same time , it could create a new structure order: a hang-ing-system. I image that all the circulation system in this renovation should be suspend-ed onto this timber roof structure. The timber construction for the grogram space(new floors/new columns) is another construction system.

33

Fig 6.11 Concept Section DiagramSource: Drawn by author



34

?3.New Construction/Old Cinstruction

1.Roof Opening / Ventilation

A.Demolition/Remaining B.New Roof SystemI.Roof form / Existing Situation

II.New space/ New Roof

2.Roof Transmittance / Sunshading

4.New Construction/Foundation34

35

7. CONCLUSION AND DISCUSSION

BACKGROUND KNOWLEDGE

TECHNICAL RESEARCH PART

ROOF ANALYSIS AND DESIGN PROPOSAL

Wood as a suitable choice to materialize the architecture wiith complex form with the benefit of digital fabrication. There are a great many of practical works by digtal fabriacation in wood. These works as well as the related literature provide lots of inspiration in the research process.

Different wood products have different properties. For CNC cutting, laminated wood production are more suitable for the structural utility.

For any timber construction, certain treatment and maintenance to resist the moisture and insects is necessary, such as coating.

In new complex structure system, rather than define the main structure system, to give the full play of the small element can be an effient way. (including the efficient CNC milling)

In this design, the timber roof acts the crucial role in the both climatic and architectur-al issue. In the climate aspect, the opening and the transmittance of the roof are two fundamen-tal characters for the natural ventilation and the illumination of the area underneath the roof.

In the architectural aspect, the discourse of the new construction and the existing situation should be carefully designed.

TImber lattice system is a flexible structure system for architecture in different complex forms. To design a a timber lattice system, the construction details and patterns are important aspects. Structural Calculation and analysis should be conduct-ed.

With the benefit of the digital frabrication, the wood-wood joint comes back to timber structure as an economic and architonic of new timber joints. Of course, the steel joints also should be applied in the timber construction for the permanent utility.

36

7. CONCLUSION AND DISCUSSION

Fig 7.1 Connection Principle

Fig 7.3 Body Connection Detail Fig 7.4 Boundary Connection Detail

Fig 7.2 Element name system

37

8. BIBLIOGRAPHY

Branko Kolarevic, 2003. Architecture in the digital age· Design and manufacturing. New York: Spon Press.Christopher Beorkrem, 2013. Material strategies in digital fabrication. Routledge.Christoph Schindler, Information- Tool- Technology: Contemporary digital fabrication as part of a continuous development of process technology as illustrated wit the example of timber construction. <http:// www. caad. arch. ethz.ch/wiki/uploads/ Organisation/2007_Schindler_Information-tool-tech-nology.pdf> Jack Porteous, Abdy Kermani, 2011. Structural Timber Design to Eurocode 5, 2nd ed. John Wiley& Sons.Klaus Zwerger, 2012. Wood and Wood Joints: Building Traditions of Europe, Japan and China. Walter de Gruyter.Martin Bechthold, Daniel L. Schodek, 2007. Structures. Prentice Hall PTR.Tomoko Sakamoto, Albert(ed.). Ferre, 2008. From Control to Design: Parametric /Algorithmic Architecture, Actar Birkhauser Distribution.Hani Buri, Yves Weinand, ORIGAMI- Folded Plate Structures, Architecture. <http:// www.ewpa.com/archive/2008/june/paper_286.pdf.>Hani Buri, Yves Weinand, 2010. Origami with Laminated Cross-Boarded Wood Sheeting. Detail, 10, pp. 1066-1068Hani Buri, Yves Weinand, 2009. INNOVATIVE TIMBER CONSTRUCTION. JOURNAL OF THE INTERNATIONAL ASSOCIATION FOR SHELL AND SPATIAL STRUCTURES: J. IASS, No.50, pp.111-120.Oliver Neumann, CNC timber framing-innovative applications of digital wood fabrication technology. [pdf] http://cumincades. scix. net/data/works/att/ sigradi2006_e151c.content.pdf.Kenji Kanasaki, Hiroya Tanaka, Traditional wood joint system in digital fabrication, [pdf]. http:// cumincad. architexturez. net/system/ files/ pdf/ ecaade2013_247 . content. pdfAndrew Borgart, Tuba KOCATURA, 2007. FREE FORM DESIGN AS THE DIGITAL “ZEITGEIST”. JOURNAL OF THE INTERNATIONAL ASSOCIATION FOR SHELL AND SPATIAL STRUCTURES: J. IASS, No. 48, pp. 3-9Engineered wood products Association of Australasia, Structural plywood & LVL design manual, [pdf]. http:// www. ewp.asn. au/library/down-loads/ewpaa_ply_and lvl_design.pdf.Simon Van Engmond, 2011. Medium Rise timber buildings in the Netherlands. Master. Delft University of Technology.Smith, P, 2005. Architecture in a Climate of Change : A guide to sustainable design. Oxford: Architectural Press. Michela Turrin, 2014. Performance Assessment Strategies: A computational framework for conceptual design of large roofs. Delft University of Technology, Faculty of Architecture and The Built Environment, Architectural Engineering + Technology department

timber roof by digital fabrication

Documents