Earthquakes have plagued man for millennia. It is a destructive force, which was once upon a time declared to be wrath of God for infidelity of human beings. But today, we understand what causes earthquakes, and can design effective mechanisms to mitigate the effects of earthquakes.
Basically, there is the Conventional approach to achieving earthquake resistance, then there is the basic approach, and nowadays, there are Active Control Devices which can counteract the effects of earthquakes on buildings.
Design depends upon providing the building with strength, stiffness and inelastic deformation capacity which are great enough to withstand a given level of earthquake-generated force. This can be accomplished by selection of an appropriate structural configuration and careful detailing of structural members, such as beams and columns, and the connections between them.
Design depends upon underlying more advanced techniques for earthquake resistance is not to strengthen the building, but to reduce the earthquake generated forces acting upon it. This can be accomplished by de-coupling the structure from seismic ground motion it is possible to reduce the earthquake induced forces in it by three ways.
- Increase natural period of structures by Base Isolation.
- Increase damping of system by Energy Dissipation Devices.
- Mitigate earthquake effects completely by using Active Control Devices.