Reinforced glass beams lecture for Verre 2006 Dr.ir. F.A. Veer

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.

Cathedral of Notre dame , Paris

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

Crystal palace, London , 1851 19th century greenhouse, Madrid, Spain

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.

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

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 ?

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

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

ING office, Budapest

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

Apple store, New York , use of Sentry glass

Wolfson building of the medical faculty of the university of Glasgow

IHK building , Munich

Carbon fibre reinforced glass roof beams for the loggia di vicari

Stainless steel reinforced glass beam after testing TU Delft all glass paviljon 2004

Failure behaviour stress Monolithic glass PVB laminated glass Reinforced glass PC laminated glass strain

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.

1997 Glass polycarbonate beam

2001

2002

2002

Glass box section reinforced beam, 2003

2003 Glass T-section post-tensioned beam

2004

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 :

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

Ease of manufacture

Required volume of reinforcement thickness

Reinforcement configuration

Adhesive type Stainless steel reinforced glass bonded using GB 368 adhesive Stainless steel reinforced glass Bonded using araldite 2013 adhesive

configuration for the glass

configuration for the glass

maximum length

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

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