Statement of the Problem

In the context of the growing rainfalls and other natural calamities like tsunami, sustainable two-storey buildings have been used and will continue to be used for providing shelters, safety and conform to its lodgers. However, the building design is an important consideration that affects the ability of the building to isolate the waste and protect the environment.

Purpose of the study

The main purpose of this study is to evaluate the sustainable two-storey building design, the choice of materials ( recycles, reusable), environmental impact, adaptability / flexibility of the design and the choice of construction methods ( single connection , elements easy to dismantle). Dissertation Literature Review

Objectives and scope

The overall objective of this research is to gain a better understanding of the materials used and the design of a sustainable for life two-storey building. For this purpose, this research focuses on the behavior of buildings designed with the criteria of the philosophy of Capacity Design, i.e., buildings are capable of developing plastic mechanisms in the response to the maximum considered earthquake.

In the design practice a variety of structural systems are used. However it is not realistic to attempt finding patterns of behavior for each one of these structural systems, in the limited time available for this research. Thus, the research is restricted to study the behavior of framed buildings. Simplified framed buildings are adopted to study this type of structural system.

Within this context, the following specific objectives are pursued herein:

· Description of the mathematical model of a one story and a multi story prototype buildings.

· Design of a two-story prototype buildings.

· Search for patterns of behavior of buildings responding in a torsional mode.

· Perform parametric studies of the one-story and the three-story buildings.

· Establish the conclusions of this research.

CHAPTER II: REVIEW OF THE LITERATURE

Introduction

The life cycle of concrete buildings is usually 40 to 90 years. However, during this life cycle, buildings will often meet some circumstances, such as disasters, changing functions, city reconstruction, or higher demand for the residence etc.; all of these circumstances will lead to demolition or reconstruction of buildings. Moreover, many of Reinforced Concrete (RC) buildings in Asia or Europe built after World War II have been used for about 50 years or more. It is obvious that such buildings, if built with low quality material, lacking proper construction design or unsuitable geographical location are prone to deterioration and as a result need demolition. Dissertation Literature Review

Reinforced Concrete Building Frames

There are different conduction approaches applied while designing and constructing a building. In general, reinforced concrete structures are designed to be durable, serviceable, and attractive. Structural elements composing a reinforced concrete system may be broadly classified into floor slabs, beams, columns, walls, and foundations.

Building design

Earthquake Engineering is a body of knowledge that has been in continuous development during a long period of time. This progress has been an evolutionary process, most of the time, with occasional revolutionary jumps ahead, and sometimes backwards.

The occurrence of some catastrophic seismic events around the world were the source of most of the new knowledge, and a strong motivation to work on the problem. Structural solutions used by the practicing engineers (designers), are tested by Nature during their occurrence. Afterward, it appears that some ideas seemingly very good, turned out to be bad solutions. Thus, academics and researchers have contributed to the body of knowledge by reviewing the behavior of the solutions used by the engineers, learning from the good behavior, but much more from the bad behavior and failures of some of these structures.

So, it has been cycles were designers have tried new structural solutions without having a complete knowledge of their future behavior, and later researchers helped to understand why their solutions failed or behaved in unexpected ways. This way, the original solutions have been repeatedly amended, improved or abandoned as a result of these cycles. Each cycle that, besides the personal worries and interests of engineers, academics and researchers, has had a high cost in terms of lives and economic loses around the globe. Dissertation Literature Review

One revolutionary event in the history of the Earthquake Engineering was the proposal by Park and Paulay (1975) of a systematic method of design, based on the accumulated observations of the behavior, during strong seismic events, of many structures around the world. Some of these structures surprised engineers and researchers due to their capacity to resist unexpected extreme seismic events. These structures showed extensive damage in non structural elements and localized plasticization, despite this, the structures survived these events.

From these accumulated knowledge by the engineering community, emerges the systematic proposal by Park and Paulay. They called their design approach as the philosophy of Capacity Design. With the publication of their book in 1975, this philosophy started to spread out. De Buen (2004) tells that the Mexico City building code was modified to include in its published 1976 edition, recommendations and procedures to provide structures with the capacity to dissipate energy by developing non linear behavior. That was the first time these recommendations appeared.

In this context, it becomes clear why many works published before the 1970's focused on the elastic behavior of buildings, and after that time, the research community shifted their interests to study the non linear behavior of structures.

Another milestone is marked by the introduction of computer machines to the practice and research of Earthquake Engineering. In their early times, the computation power provided by these machines was relatively small, but during the last 50 years, the computer power has increased steadily. Wilson (2007) presents a short table describing how the relative speed of different computer systems has changed with time.

The scope of the research made during this long period has been strongly influenced by the available computer machines. This way, many early researches focused on one degree of freedom structures, or one story buildings. Adopting hypothesis of linear behavior and using single seismic records, applied to the models in only one direction. The available computer power was a severe limitation.

In more recent times, published works reporting studies of multi story buildings have emerged, considering non linear behavior of the material and using multiple seismic records. This widening in scope occurred hand on hand with the increase in computer power. Dissertation Literature Review

About the first half of the XX century, it was very common to have more partitions and facade mansory walls in buildings. Also, most of the buildings were relatively short in height. In those times, the torsional response was not an issue, as it is nowadays. The "non structural" walls provided a large torsional strength and stiffness to those buildings.

In the last 50 years, the new buildings have had fewer non structural walls and/or new materials have substituted the masonry walls by light and fragile materials, like the gypsum panel boards attached to wood or metallic studs. Also, first story walls (facing the street side) have disappeared to give way to the wide windows required by modern commercial buildings.

All these changes have had the effect of changing radically the actual lateral strength, stiffness, and energy dissipation capacity of the modern buildings. More important, these changes opened the window to conditions that amplified the problem of the torsional response of buildings, turning this phenomenon into the big problem that has been observed in recent strong seismic events. This way, the engineers, pushed by the necessities and demands of the contemporary world, have contributed to unleash a structural problem.

For the purposes of this research, the topics investigated by the researchers interested in the problem of torsional response of buildings were reviewed. From the perspective of the present time, it is easy to underestimate the importance of the work done by the first researchers. However, it is unfair to judge their achievements based on the current knowledge. Dissertation Literature Review