Literature Review On Earthquake

2 CHAPTER 2- LITERATURE REVIEW
A state of the art literature review is carried out as part of the present study. This chapter presents a brief summary of the literature review. The literature review is divided into two parts. The first part deals with the seismic principles design and whereas the second part of this chapter discusses about seismic modern and vernacular building construction in Bhutan.
2.1 STUDY BACKGROUND
An earthquake or a tremor is a redesign of the earth’s crust caused by the vibratory movements of the tectonic plates of the planet and it spreads in all directions in waves. By themselves are natural phenomena that don’t affect too much the people. The movements of the earth’s surface causing an earthquake are not a risk,

The type of earthquake depends on the region where it occurs and the geological make-up of that region. The most common are tectonic earthquakes. The earthquake comes different in waves forms mainly either in body waves and surface waves. Body waves consist of p-waves(primary or compressional waves) which is like sound waves and s waves (secondary, shear, sideways or transverse waves) travels like ripples on waters. Surface waves resembling water waves containing Love waves move like a snake and a Rayleigh wave rolls along the ground just like a wave rolls across a lake or

The taller the building is, the lower its natural frequency -code of earthquake resistant.

2.2.2.7 Mass distribution and concentration
The distribution of the masses must be as uniform as possible, on each floor and height. It is desirable that the variation of the floor to floor mass accompanying the variation in stiffness. If the mass-stiffness varies sharply from one floor to another stress concentration occurs.
Avoid superfluous presence of masses, such as excessive fillers on terraces, garden terraces, etc. It is desirable to solve the water supply systems which avoid the construction of a voluminous water reserve the highest level of the building.
2.2.2.8 Density structure in plant

In old buildings, there is a large amount of walls with large structural function. It was also found that many of them have worked well for centuries in earthquakes zones taking the gravity and seismic loads to the ground by direct routes.
When we have the largest presence of structure on the ground floor the building is better able to withstand the shear force on the ground floor, the upper floors accumulated and accumulated gravity loads. Many modern projects away from this setting, and for aesthetic reasons the ground floor has a few elements. The most efficient seismic configuration is which has the largest number of vertical elements at the base, that’s where most