CHAPTER I
INTRODUCTION

Background of the Study
Structural materials can be categorized in many ways in many different ways. One of the most common is by the nature of their failure. Materials, such as steel, after reaching their elastic limit, deform plastically before failing. Such materials, where reasonably large plastic strains are observed, are broadly categorized as ductile. On the other hand, those materials that exhibit little or no plasticity are in contrast termed brittle. In structural design, ductile materials are usually preferred, because failure is rarely sudden and catastrophic. Once the material has yielded, large observable strains will occur before total collapse of a structure. Steel, the most common primary structural building material, generally behaves in a ductile fashion. However, during the World War II, over 200 steel ships suffered serious brittle fracture, often at relatively low stress levels. It was observed that brittle behavior, in normally ductile materials, almost always occurs in regions of elastic stress concentration, where some constraint exists to prevent plastic stress redistribution (McGuire, 1968)
Following these experiences, designers realized that brittle fracture in steel could be avoided by sensible detailing.
This is also true of reinforced concrete. Concrete itself, is a brittle composite, but with the addition of reinforcements concrete it behaves in a ductile fashion. In an earthquake-prone areas, where designing for ductility is paramount, reinforced concrete beam-column joints are highly reinforced to avoid the possibility of brittle behavior. Structural engineers, being concern mainly with design in these two materials, have come to understand brittle fracture in structural elements to be unnecessary and avoidable, as expressed by Nethercott (1991).

Statement of the problem 1. Why anyone would wish to design structural elements in glass? 2. How much more daring to remove the steel altogether. 3. Make a wall totally transparent by bracing with glass fins? 4. How to account for it in a stress-based design 5. How will the glass behave under long term loading?
Objectives of the study 1. To review current design methods, with reference to their application to common structural building materials. 2. To discuss the nature of glass and brittle fracture. 3. To examine the strengths and weaknesses of a glass. 4. To review of glass strength information currently available to design engineers. 5. To describe the properties of glass in details.

Significance of the Study This thesis is about the structural use of glass. A specific design issue relating to glass beams is examined. The strength distribution found for single beams. Aims to take a rational look at why glass designer almost always use multiply beams. Cited the need for a statistical approach to applying factors of safety in multi-ply construction as an important area for further research and design development. Briefly discuss the appropriateness and validity of stress-based design methods for glass.
Scope and Limitation of the Study This study focus on the scope of glass strengths and weaknesses and the information regarding to the topic will be provided with critical thinking and analysis. Some ideas are coverage from internet and assume data.
Definition of Terms 1. Ductile – capable of being drawn out into wire or thread. Being bent or pulled in different shapes. 2. Plasticity – The quality or state of being elastic and being adaptable. The capability of a strained body to recover its size and shape after deformation. 3. Brittle – easily broken, crack, or snapped. Easily disrupted, overthrown or damage. 4. Fracture – The result of breaking something. The act or process of breaking or the state of being broken. 5. Construction – The act or process of building or making something.