Using Glass as a Building Material

Glass is a hard substance which may be transparent or translucent and brittle in nature. It is manufactured by fusion process. In this process sand is fused with lime, soda and some other admixtures and then cooled rapidly. Glass is used in construction purpose and architectural purpose in engineering. Glass is one of the most desirable building materials in use today. However, wanting to use it is the easy part. Actually installing and incorporating glass into construction projects is a little more complex.

Traditional Form And Function
Sparkling, transparent, delicate, bullet proof, brittle, insulating, illustrative, recyclable. All are descriptions of glass as one of the most interesting and useful building materials in use today, with more applications and installation techniques constantly in development. Consequently the methods used to install these products in construction projects varies with the exact form and type of glass being used.

Probably the most familiar forms are fiberglass products, used for insulation and translucent panels, transparent blocks, and window glass. Glass insulation is typically installed in prefabricated bats or as loose particles blown into cavities and ceilings using specialized equipment. Translucent fiberglass panels are installed using support framing where light but not visibility is desired. The familiar glass block is usually installed as a “brick and mortar" system. And of course transparent glass windows are usually glazed into framing and installed as a prefabricated building element.

History of glass
Archaeological evidence has been found of man-made glass dating back to 4000 BC in the form of decorative glazes. In prehistoric times, weapons were made using obsidian and fulgurite, naturally occurring glasses found in volcanic regions and after lightning strikes respectively. Around 1500 BC glass was first used as a material for making hollow containers.

In prehistoric times, Obsidian (Naturally occurring glass found near volcanic regions) and fulgurite (glass formed naturally after lightning strikes sand) were used to make weapons. Manmade glass was used as a luxury material was used in decorations, jewelry, vessels and crockery.

Glass blowing was discovered in the 1st century in Europe, this revolutionized the glass making industry. The technique spread throughout the Roman Empire. Production of Clear glass, by introduction of manganese dioxide, saw glass being used for architectural purposes. Cast glass windows began to appear in the most important buildings and villas in Rome and Pompeii. Over the next 1,000 years glass making spread through all of Europe and Middle East. In 7th century Anglo Saxon glass was used in churches and cathedrals

By 11th century sheet glass was made by the crown glass process. In this process, the glassblower would spin molten glass at the end of a rod until it flattened into a disk. The disk would then be cut into panes. By 13th century, this technique was perfected in Venice. Stain glass windows were used in gothic renaissance and baroque architecture from the 11th to the 18th century. The examples of stunning patterns created by using colorful glass are immortalized by great artists all over the world.The Crown glass process was used up to the mid-19th century. in the 19th century, flat / sheet glass windows were used in making windows. These were completely flat and did not have any optical distortions.

But glass was still an item of luxury as it took large resources, brilliant skill and immense energy to be produced. In 1958 Pilkington and Bickerstaff introduced the revolutionary float glass process to the world. This method gave the sheet uniform thickness and very flat surfaces. Modern windows are made from float glass. 

Applications Advancement
More advanced glass construction products, however, require more advanced installation methods. Prefabricated structural fiberglass panels use pre-molded interlocks and adhesives to achieve engineering performance approaching that of traditional steel and wood elements. These can also incorporate foam insulation as a composite element for a complete building system, especially useful for structures requiring RF transparency, high corrosion and/or weathering resistance, and lightweight building applications. Glass in its solid, float manufactured state is where it really shines in construction. Technological advances in strengthening and improving resistance to shattering have resulted in many more applications than just windows. Some of these techniques such as annealing, tempering, and laminating produce glasses with structural properties similar to that of aluminum alloys, without the ductile and malleable properties, of course.

Consequently installation methods have improved as well. Frameless glazing utilizes specialized adhesives to hold glass panels in place against structural supports without exposed framework. This lends a smooth, continuous, uninterrupted effect to building exteriors, floors, and facades. Point supported glazing holds the glass in place at discrete locations as opposed to the perimeter edges, and has been used in building facades to dramatic effect. This requires engineered framing, mounting pads, and posts modeled to reduce shock and excessive stress distributions throughout the glass element.

The Transparent Future
In some of the most extreme forms of recent construction techniques, glass has been used as supporting columns and beams. Glass not only looks dramatic when substituted for these traditional metal or wood elements, but it also has an attractive compressive strength to weight ratio.

Like concrete, glass achieves its greatest strength when loaded in compression; it tends to fail catastrophically in tension. And again like concrete, post-tensioning techniques are being used to ensure these glass structural elements bear only compressive loads. Laminated vertical glass columns have also been installed with some success, as these elements are typically loaded compressively as constructed. In all of these advanced techniques, however, the basic uncertainty of brittle glass failure has led to no small amount of debate on their use in structural applications. Accordingly there are as yet no codified structural construction guides for use of these elements.

The success of any attempted construction utilizing non-traditional materials and techniques will of course depend on comprehensive testing and evaluation of the system in question, and structural glass applications will probably not be an exception for some time to come. However improved materials and construction techniques may one day allow us to peer through an entire structure made of glass…brightly!

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