The Importance Of Seismic Design

The backbone of structural engineering practice is for a structure to perform well. The objective of designing a structure is to provide safety to life and property, keeping the design economical. Guidelines provided in design codes fulfil this objective. But, the need for seismic design is necessary. The current design codes specify guidelines which provide simple seismic design procedures, through empirical factors and simple equations. However the behaviour of the structure is complex and depends on various factors and hence the sufficiency of these designs based on simple equations cannot be predicted.
In addition to gravity loads, a structure has to be designed for anticipated lateral loads. The lateral loads subjected to a structure can be due to wind or earthquake. A structural engineer needs to develop an effective lateral load resisting system, which would prevent collapse and damage to life and property.
In the event of an earthquake, the structure is subjected to lateral forces which are generated by the structure’s inertia resisting motion. These forces can be very high in magnitude. To design a structure to remain elastic during earthquake would be impractical and uneconomical.
A number of techniques and

Moment-resisting frames are rectilinear assemblages of beams and columns, with the beams rigidly connected to the columns. Resistance to lateral forces is provided primarily by rigid frame action-that is, by the development of bending moment and shear force in the frame members and joints. By virtue of the rigid beam-column connections, a moment frame cannot displace laterally without bending the beams or columns depending on the geometry of the connection. The bending rigidity and strength of the frame members is therefore the primary source of lateral stiffness and strength for the entire