Hybrid

 

Glass and Steel Construction:
Glass with a density comparable to reinforced concrete presents modulus of elasticity almost equal to that of aluminium. Glass is several times weaker in tension than in compression. The fracture pattern of glass is highly dependent on residual stress. Annealed float glass breaks into large fragments whereas fully tempered glass presents high fragmentation and breaks into small pieces which does not affect post-breakage strength.

Metal enforced glass beams:

Comparing the load-bearing capacity of different glass beams in four configurations of glass strips: layered laminated, laminated segmented and laminated reinforced glass, Veer  has proved that even small amount of steel bonded to tensile side of a glass beam improves the post-breakage performance of the beam significantly.

Carbon and glass fibre reinforced glass beams:

A carbon fibre strip was bonded to the bottom edge of a glass beam with a structural adhesive. The main role of the solution was to tie all glass sheets together and strengthen the beam by decreasing the value of tensile stress acting on the glass beam by moving down the neutral axis.

Hybrid steel-glass beams:

The cross-section of the beam consisted of a glass web adhesively bonded to steel angles screwed to steel rectangular flanges . The prefabricated 3600 mm long I-shaped hybrid beam was build and examined in a four-point bending test. Studies presented before confirm an increase of load-bearing capacity of glass beams with steel flanges bonded by linear adhesive connections. This concept can be applied particularly in a design of glass fins, girders and columns where the lateral torsional buckling resistance is crucial.

Hybrid concrete-glass beams:

A research on glass-concrete composite beams was

performed by Freytag at Graz University of Technology. Freytag presented structural behaviour and detailed theoretical failure mechanism of a hybrid concrete-glass beam. A 7800 mm long beam consisted of a glass web and two flanges made of ultra-high-performance concrete. The web was composed of three 8 mm panes made of fully tempered glass resin laminated together. The direct connection between glass and concrete was made by placing the web into the form before pouring fresh concrete. To ensure proper joint the glass was specially pretreated by roughening the surfaces. The experiments proved the high load-bearing capacity of glass-concrete beams. However, the concept demands complicated manufacturing process and special treatment of a glass surface before pouring the fresh concrete into formwork. In the project fully toughened glass has been used.

 

Hybrid timber-glass beams:

Timber-glass composite beams were researched by Hamm at École Polytechnique Fédérale de Lausanne. Eight 4000 mm long and 250 mm high beams with various cross-sections of timber flanges were built and tested. The web of all the specimens was 10 mm thick and made of annealed float glass. The laminated timber flanges were glued to the web by a polyurethane adhesive. To make sure that the forces are applied directly to the timber flanges instead of the glass web wooden blocks were placed under the jacks. All the specimens showed a similar behaviour. First cracks started to form long before the failure of the beam. After each crack occurrence a small reduction of stiffness was noticed.

Akshay