DUCTILITY DESIGN OF REINFORCED CONCRETE APARTMENT BUILDING

[attachment=18341]
ABSTRACT
Among the three basic need of human being shelter is one of the important features. The study of project deals with the effect of earthquake on the structures and their environment & also the method of reducing its effort.
A number of naturally occurring disasters as earthquake are capable of causing death injuries & damage of properties. These natural hazards causes tremendous the losses around the world in every year it can be designing the structures to resist vibration to with stand the damage caused by earthquake
The proposed Apartment building is in BHUJ city falls under the zone 5 region as per IS 1893-2002 (part 1). In this Apartment building consist of ground floor + 3 floors, hall, bedroom, dinning, kitchen, bath. Total Plinth area 297.4 sq.m



INTRODUCTION
1.1 GENERAL
Ductility can be defined as the “ability of material to undergo large deformations without rupture before failure”.The property of the material or a structure indicating the extent to which it can deform beyond the limit of yield deformation before failure.
The ratio of ultimate to yield deformation is defined as ductility. Ductile detailing is provided in structures so as to give them adequate toughness and ductility to resist severe earthquake shocks without collapse. Mild steel is an example of a ductile material that can be bent and twisted without rupture.
Structures are subjected to unexpected overloads, load reversals, impact and structural movements due to foundation settlement and volume changes. These items are generally ignored in the analysis and design. If a structure is ductile than taken care by the presence of some ductility in the structure.
Ductile detailing is provided in structures so as to give them adequate toughness and ductility to resist severe earthquake shocks without collapse. Mild steel is an example of a ductile material that can be bent and twisted without rupture.


Capacity Design Concept
Let us take two bars of same length and cross sectional area - one made of a ductile material and another of a brittle material. Now, pull these two bars until they break!! You will notice that the ductile bar elongates by a large amount before it breaks, while the brittle bar breaks suddenly on reaching its maximum strength at a relatively small elongation. (Shown in Fig 1.1) Amongst the materials used in building construction, steel is ductile, while masonry and concrete are brittle.


Earthquake-Resistant Design of Buildings
Gravity loading on building causes RC frame to bend resulting in stretching and shortening at various location. Tension is generated at surface that stretch and compression at those that shorten. Under gravity load, tension in the beam in the centre location and is at the top surface at the end. On the other hand, earthquake loading causes tension on beam and column face at location different from those under gravity loading the relative levels of this tension generated in member. The level of bending moment due to earthquake loading depends on severity of shaking and can exceed that due to gravity loading. (Shown in Fig 1.3) Thus under strong earthquake shaking, the beam ends can develop tension on either of the top and bottom face of beam. Since concrete cannot carry this tension, steel bars are required on both face of beam to resist reversals of bending moment. Similarly, steel bars are required on all face of column too.