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Reinforced glass beamslecture for Verre 2006

Dr.ir. F.A. Veer

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Glass in architecture

• Glass has played an important role in architecture as the material that opens up a building to light.

• An important example are the great rose windows of the medieval cathedrals.

3Cathedral of Notre dame , Paris

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Glass in architecture

• Although these windows are very dramatic they need extensive supporting masonry as they weaken the structure.

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Crystal palace, London , 1851

19th century greenhouse, Madrid, Spain

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Glass in architecture

• Although glass appeared to take a leading role it was still only a material that separated the interior and exterior.

• It was only some twenty years ago that glass started to be used in a limited structural role.

7Grand Serres of cite des sciences et de l’industrie at la Villette

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Glass in architecture

• This marks a transition from non-structural to limited structural use of glass.

• This also raised the important question:

How far can we go in using

glass as a structural material ?

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Glass as a structural material

• It also raises the question of what loads we can put on glass in :– Tension– Bending– Compression

Bending will be the focus of this presentation

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Glass beams

• Monolithic annealed float glass

• Tempered float glass• PVB laminated

tempered float glass• Sentry glass

laminated tempered float glass

• Cast resin laminated tempered glass

• Polycarbonate laminated glass

• Carbon fibre reinforced glass

• Stainless steel reinforced glass

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ING office, Budapest

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Glass museum, Kings Wingford, England, PVB laminated roof beams

13Apple store, New York , use of Sentry glass

14Wolfson building of the medical faculty of the university of Glasgow

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IHK building , Munich

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Carbon fibre reinforced glass roof beams for the loggia di vicari

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Stainless steel reinforced glass beam after testing

TU Delft all glass paviljon 2004

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Failure behaviour

stress

strain

Monolithic glass

PVB laminated glass

PC laminated glass

Reinforced glass

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Stainless steel reinforcement

• In 1995 the ZAPPI research program started.

• Goals was to develop safe transparent components for a transparent building of 20×20×20 meters.

• This means beams of large span, column’s etc. as well as the technology to put it together.

200 1 2 3 4 5 6 7 8

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

d i s p l a c e m e n t ( m m )

Force (N)

s e g m e n t e d g l a s s _ _ _ t e s t 1 . . . t e s t 2 - - - t e s t 3

f i r s t l o a d i n gGlass polycarbonate beam

1997

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Glass

Polycarbonate

Stainless steel

2001

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2002

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2002

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Glass box section reinforced beam, 2003

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2003

Glass T-section post-tensioned beam

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2004

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Further improvement

• Although the 2004 result showed large and safe beams can be made research is continuing in several directions.

• This with the following aims :

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Further improvement

- how to increase the ease of manufacture- what is the required volume of reinforcement– what is the optimum configuration for the

reinforcement- what is the optimum configuration for the

glass – What is the best adhesive for the

reinforcement– What is the maximum length that can be

attained

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Ease of manufacture

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Required volume of reinforcement

thickness

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Reinforcement configuration

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Adhesive type

Stainless steel reinforced glass bonded using GB 368 adhesive

Stainless steel reinforced glassBonded using araldite 2013adhesive

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configuration for the glass

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configuration for the glass

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maximum length

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Conclusions

The results so far show that reinforced glass beams :

– can exceed the 6 meter length limitation imposed by the standard glass panel size

– can have a build in structural safety mechanism which shows considerable deformation after initial cracking and thus cannot collapse spontaneously

– can in theory be used as structural member of the main load bearing construction

– have a length limit of about 20 m – can result in innovative architectural solutions

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Conclusions

The main obstacles to introduction of reinforced glass beams are:

– the lack of an adequate knowledge base on which to design the components

– the problem in joining the glass components together– the lack of knowledge about these components at the

architecture and engineering level– the lack of clearly applicable building codes for the

regulatory body– the need for specialised staff and expertise for the

contractor