Hankin Distinghuished Lecture

PENN STATE, November 14th, 2006

Prof. Dr.-Ing. Peer Haller

Institut für Stahl- und HolzbauTechnische Universität Dresden

New Technologies in Wood Construction - Examples from Practice and Research

Pedestrian Bridge in the Botanical Garden at Tharandt

- Realization From a Student‘s Competition in Architecture

A New Solid Timber Studio Building in Dresden / Hellerau

Production of Panels from Sawn Wood

Vacuum-Pressure

CNC Manufacturing Robot (Merck Holzbau)

Traglast (kN)

3200

1900

2400

House Am Klosterteichplatz 1 at Leubnitz / Dresden

Reasearch in Wood Construction at Dresden

- Wood Forming and Textile Reinforcements

U. Grubenmann

Sawing + Glueing + Computing

Schaffhausen RW Bridge Spruce Goose Expo Roof

+ Analysis + ?

Technological Basis and Methods

Design Development

H. Hugues J. Natterer,T. HerzogBrown

1950 2000 205018501750

?

Strength Classes of Structural Materials

0 100 200 300 400 500

Tension [N/mm²]100200300400500800 1500 2000

Compression [N/mm²]

Steel

Concrete

Sawn WoodGlue Laminated Timber

Composites

20 3010

Reactive Powder Concrete

Prestressed Steels

Fine Grain Steels

Timber-Textile-Composites

Timber Concrete

Steel and Prestressed Concrete

Wood + WBM

Grading

Densified Wood (Spruce)

J. Sell, 1997

Density of Wood and Wood based Materials

Manufacturing Process

50

100

150

200

250

300

0 1000 2000 3000 4000 Time [s]

Pres

sure

[bar

]

Tem

p [°

C]

10

20

30

40

50

Dis

tanc

e [m

m]

Pressure

Distance

Temperature

Manufacturing Process

Cross Section Spruce 0% and 50% densified

- Temperature: 140 to 160°C- Pressure: 10 to 15 N / mm2

- Pressure time: 1 min / mm - Material: Spruce

Multiple Daylight Hot Press

Densified Wood

Oil-Heat Treated Densified Wood

a) densified, OHT, glued b) densified, OHT

Comparison of Strength

85

58

3 4

50

163

6

88

25

6968

28

73

183

110

11

51

108

53

152

0

40

80

120

160

200

Embedding Bending Compression Compression Tensile

Stre

ngth

[M

Pa]

untreated Oil-heat-treated densified densified+OHT

Haller, Rapp, 2001

II II

Oil-Heat-treated densified Spruce

Sich selbst zur sparsamen Verwendung von Materialien zu zwingen, ist eine Art von Beschränkung, die das Schöpferische freisetzt.

Pablo Picasso

Yield and Cross Section‘s Efficiency

Thirty spokes surround the hub:

In their nothingness consists the carriage‘s effectiveness.

One hollows the clay and shapes it into pots:

In ist nothingness consists the pot‘s effectiveness.

One cuts out doors and windows to make the chamber:

In their nothingness consists the chamber‘s effectiveness.

Therefore: what exists serves for possession.

What does not exist serves for effectiveness.

Lao Tzu, Tao Te Ching, 11

Full Pipe Rectangle I - Profile

100 % 375 % 550 % 740 %

A = const

Comparison - Moment of Inertia

l3

Δ l1

l2

l1

Δ l2

Compression

Tension

1

1

llΔ

100⋅

2

21

lll Δ−Δ

100⋅=90,tε=90,cε %50≈ %100≈

Direction of densification

Manufacturing Principle

1. Charge 2. Closure 3. Pressure

a) uniaxial compression b) biaxial compression

Examples of Textile Structures – SFB 528

Failure Mechanisms of Dowel Type Fasteners

Shear Splitting Tension Embedding

Tailored Textile Structures

Flat knitting machine

2 x 1200 texGlass

Stitch bonded machine, variable oriented fiber placement

Multiaxial stitch bonded machine

Roving: 1200 texMaterial: GlassTextile surface density: 1302 g/m²

1200 tex Glass (10 threads)800 tex Carbon (10 threads)300 tex Aramid (20 threads)

Spruce Reinforced Reinf. + Dens.

Embedding Strength of Tailor Made Textiles

Wood unreinforced

Fan-like loop

Unsupported oval

Supported ovalGlass bonded fabric

Crossed loop

Parallel loop

StarSpiral

Flachgestricke

20

25

30

35

40

45

50

55

60

65

f h[N

/mm

2 ]

Embedding strength(Stitch bonded structures)Embedding strength (Knitted fabric)

Test setupIncrease in embedding strength fh by textile reinforcement

Biaxial reinforced knitted fabrics

Embedding Strength – η : Tailor-made Index f h

[N/m

m2 ]

μ [kg/m2m]

Embedding Strength According to EN 383

0

20

40

60

80

100

120

140

300 400 500 600 700 800 900 1000 1100 1200

ρ [kg/m3]

f h[N

/mm

2 ]

sprucespruce + non-woven fabric, multiaxialspruce + woven fabric, 2 layer 204gspruce densifiedspruce densified + non-woven fabric, multiaxialspruce + non-woven, 4 layer 300goakoak + woven fabric, 2 layer 204gsolid wood

densified

denisified, reinforced

reinforced

Solid Round Gluelam Joint Wooden Tube

3D-Knitted Textile

w [mm]

F[k

N]

Load Displacement Curve – 4 pt Bending

Wooden Tube

Wooden Tube

Wooden Tube

Solid Joint 3D-Knitted Textile

Poplar Oak Platane

Foto: Shigo

Digital Assessment of GeometryConnection Digital Model

Connection + gauges 3D Coordinates Solid Model FEM Model

Digital Assessment

Experimental Set up Failure 1 Failure 2

Experimental Study

baumarbeiten

master of science2nd master

(joint degree)

target group:

architects and engineers

Thank you for your attention.