Seismic Response of Building Due to Simultaneous Action of Horizontal and Torsional Components of Earthquake Ground Motion

Ideally, we do not know that when and where earthquake will occur so that many stations are instrumented to record the ground motion. Many more records have been obtained in regions where moderate ground shaking occurred. Earthquake is a natural phenomenon which occurs anytime there are regions where the earthquake occurs frequently. When an earthquake ground motion occurs, it consists of three translational and three rotational components of motion. We need to safeguard the buildings from earthquake for that we must do a thorough study about torsional and rocking components so that humans and lifeline structures are safe against earthquake. We have three translational components which can be studied by an instrument. Accelograms are meant to study the earthquake ground motion. Accelerograph is the instrument to record the three translational components of ground shaking. Transducer is the basic element of an accelograph. However there are no instruments developed to record torsional ground motion.in the present study after a critical review of the various method a simple method has been identified for generation of torsional response spectra from the response spectra of the recorded translational accelerograms for use in practical engineering application. The application of the identified method has been illustrated for recorded translational accelerograms in Himalayan region. A normalized standard spectrum is developed for the torsional ground acceleration in the region.