Earthquake Resisting Elements and Techniques in High Rise Buildings

Abstract

An earthquake resisting elements are the components that are introduced in a structure to improve its seismic resistance and method of application of these elements are said as techniques. Though structures are designed and detailed as per code provision there remains some possibility of damage or failure in strong earthquake. Performance of buildings may be improved using earthquake resistant elements and techniques. An earthquake produces seismic waves on earth surface of earth due to releases of large energy from lithosphere which produces waves in earth surface causing disturbance in structures resulting failure of seismically weak structures. Seismic waves then travels in horizontal and vertical direction. It causes horizontal and vertical ground movement or vibration. These seismic waves cause disturbances in in buildings. The disturbance caused depends on position of building with respect to the center of disturbance called as epicenter. Intensity of these seismic waves is maximum at center and goes on reducing away from epicenter. Generally horizontal waves are of stronger than vertical so buildings are designed to horizontal seismic forces. These valves travel in any direction but from design purpose it is resolved in two orthogonal directions. Few constructional precautions may help to avoid or minimize damage in buildings. Earthquake resistance of building may be improved with proper design and construction of structures. Some earthquake resisting elements like shear wall, moment resisting frame or innovative techniques like base isolation, or energy dissipation system are used in many high rise buildings to avoid or minimize damage and hence loss of lives and properties. Shear walls are RC member generally introduced in a structure during construction in symmetrical manner. Base isolators in the form bearings are placed between sub and super structure to reduce stiffness of structures. Structures are braced with seismic dampers in energy dissipation system. Composites are used by mixing in concrete or as a warp. All these techniques are reviewed herewith with special attention on shear walls.