TWO-SIDED STRUCTURAL GLAZING SYSTEMTwo opposite glass edges arebonded to the load bearingframework. The two other edgesare fixed mechanically bysecuring profiles. The bondingcan occur vertically as well ashorizontally. The dynamic loadswill be absorbed from theStructural Glazing Siliconewhereas the dead load will betransferred to the securingprofiles.
FOUR-SIDED STRUCTURAL GLAZING SYSTEMAll four sides of the glasselements are bonded to a framewhich will be subsequentlyattached to the substructure onsite. Depending on theconstruction the dead load willbe transferred eithermechanically or through theStructural Glazing Silicone. Witha four-sided Structural Glazingsystem, no mounting will bevisible from the outside. Theresult is an aesthetically pleasingall-glass facade.
GLAZING SYSTEM• In butt-joint glazing, the head and sill of the glass sheets are supported conventionally in metal frames, but the vertical joints between sheets of glass being made by the injection of a clear silicone sealant.• In structural silicone flush glazing, the metal mullions are entirely inside the glass, with the glass adhered to the mullions by silicone sealant.• The outside skin of the building is therefore completely flush, unbroken by protruding mullions.
Horizontal strip windowsthat need to appearmullionless only from theexterior can be created byadhering the glass tointerior mullions withstructural silicone sealant.The sill and head areconventionally glazed,using snap-on aluminumcovers to hold the interiorglazing gaskets. Eithersingle glazing, as shown ordouble glazing can be usedwith this type of system.
Steps in the assembly of a mullion for a four-sidestructural silicone exterior flush glazing system. Thissystem is used to construct multistory glass walls with nometal exposed on the exterior of the building. Theadhesive action of structural silicone sealant is the solemeans by which the glass is held in place.
Structural spacer glazing is apatented system of flushglazing that provides a morepositive attachment of thedouble glazing unit to thebuilding. The glass is fastenedto the mullion with analuminum pressure plate thatengages a slot in the spacerstrip between the sheets ofglass. The dessicant requiredto remove residual moisturefrom the airspace is mixedwith the butyl sealantmaterial in this system.
Glass beam are simply that structural beams made of glass.These members are usually simply BEAM supported or cantilevered.The span of glass beams is limited to the length that a single piece of glass and 3.9m for toughened glass. Glass beams and fins should be designed to sustain minimal tensile stress.Tensile stress promotes the gradual propagation of cracks due to microcopic flaws.Most glass beams are designed with substantial redundancy, or are designed so that steel cables carry the tensile loads putting the glass only in compression.Tensile loads imposed on the structure usually result from short duration wind gusts,vibration,or deflection.Any material imperfection dramatically reduces the beam’s capacity to endure tensile loads. BEAM Like most design considerations for glass, shear strength is highly undocument.Finite elementSTRENGTH analysis has become extremely popular to calculate max stress.Maual calculation using the strut and tie analogy or Mohr’s stress circle is adequate for design. It necessary to consider mid span and support regions.Because glass beams must be designed for low levels of stress, deflection is rarely problematic.The glass is often designed to act in compression, while steel members endure the high stresses and potential deflection.It is more likely that vibration will govern the design.Dynamic excitation resulting from pedestrian cadence or wind gusting can dominate a structure and consequently should be considered, The rule of thumb for controlling vibration is.
All thin structural members can become unstable if not adequately braced.For example, a glass façade provides some rigidity and rotational for the glass fins affixed to it.This relaionship makes instability failure less probable.Rotational restraint is essential to prevent buckling of many columns,fins,and beams.A finite element analysis is preferable for the design of glass wall supported by glass fins.Local buckling should be investigated in addition to the buckling of the free edge.A basic check of local buckling derived from the study conducted by Yoxon (1987) ELASTIC considers: STABILITY Where Mmax is the max unfactored destabilizing bending moment in the fin.This expression usually determines the buckling limit, and has been confirmed by full sized testing and non linear finite element analysis. YURAKU-CHO STATION CANOPY, TOKYO, JAPAN Project architect, Rafael Vinoly Architects PC, working for the Tokyo Metropolitan Government, designed the glass canopy for Tokyo’s most important subway station. The critical element of the design would be the considerations given to the vast amount of pedestrian traffic at this critical stop in the transportation system. Over 100, 00 people enter this station every day, and much consideration was given to curved spaces and natural light.CASE STUDY The canopy’s beams were created by laminated glass and acrylic blades that decrease in number from 4 blades at the base of the cantiliver beam to 1 blade at the tip. 40mm diameter stainless steel pins attach the blades to T-shaped brackets, making up the supports for the glass p a horizontal beam running the full width of the canopy panels. The end result is the canopy roof, connected at the base by V-shaped stainless steel brackets, which connect each cantiliver to a horizontal beam running the full width of the canopy.
• architect and owner dislike column because they obscure view and interrupt spaceCOLUMN • go to great length to make column out of glass creates an interesting visual feature almost scuptural that doest intrude on the openness of a great space. • Glass perform best under compression • reason for the scarcity of glass compression is the fear of sudden brittle failure • stricture must have a robust design that can tolerate the loss of glass or column or wall with out collapse and should be protected from accidental damage. • The general design principle for glass column similar unreinforced piers or walls. • must carefully distributed into the glass column in a way they localized areas of BEAMSTRENGTH concentrated stress do not develop and trigger a brittle failure . • edgers of the glass panel have have to be ground with chamfers avoid stress concentrations at edges that would cause premature failure of the glass column . • steel shoes should be used to support the glass • injection mortar used to fill the gap edges and the shoe. • is important to minimize exposure of a coloumn to undue impact or abrasion by locating it in a sheltered location
• Glass column are most likely to fail due to lack of stability includes column buckling • The factor of safety is up to the discretion of the engineer accounting for special circumstances and environmental concern • If conditions for comlumn buckling are satisefied, then the limit for compressive Elastic stresses also most likely satisfied. stability • Columns can be designed to withstand shear and bending forces in addition to axial loads • column dimension not subjected Elastic Elastic stability stabilityOf column Of column
1. Wall have evolved to allow building occupants to visually connect with the environment on the other side. 2. Taking in the cityscape from the top of floor of a high rise. 3. admiring a courtyard garden. 4. experiencing sae-life at aquarium. 5. Glass walls essentially behave like very wide glass columns. To sustain loads, walls must have substantial thickness and consequently multiple plies.Glass Wall 6. Designers must be careful that load transfer doesn’t generate undue concentrated stresses. 7. Glass could fracture and fall out of the pane causing harm to people and property below, or it could allow someone to fall out of the building itself. 8. To meet safety standards, the glass must be able to stay in place for a minimum of 15 minutes after breakage with no applied load. This should permit adequate time to evacuate people from dangerous areas. 9. In geographic regions that experience severe weather, such as hurricanes, the criteria are far more stringent. 1. Most engineers almost immediately associate glass curtain walls with spider connections. 2. The metallic fingers that are supporting todays curtain walls allow the designer to Point increase transparency and translucency by minimizing the structural framing. Supported 3. Toughened glass is a requirement to accommodate the stress concentrations resulting from bolting directly to glass façade plates. Planar fittings support the dead Glass weight of the glass by direct bearing on the bolts.
The synthesis of metal and glass structures immediately of domed structures. Domes proliferated over markets and train stations in the 19th century. The earliest notable example is London’sGlass Dome Crystal Palace built in 1851. The glass panels were not structural and were fixed onto a lightweight metal frame