Seismic Behaviour of Reinforced Concrete Bridge under Significance of Fluctuating Frequency

Earthquake is the result of sudden release of energy in the earths crust that generates seismic waves. Ground shaking and rupture are the major effects generated by earthquakes. It has social as well as economic consequences such as causing death and injury of living things especially human beings and damages the built and natural environment. In order to take precaution for the loss of life and damage of structures due to the ground motion, it is important to understand the characteristics of the ground motion. The most important dynamic characteristics of earthquake are peak ground acceleration (PGA), frequency content, and duration. These characteristics play predominant role in studying the behavior of structures under seismic loads. The strength of ground motion is measured based on the PGA, frequency content and how long the shaking continues. Ground motion has different frequency contents such as low, intermediate, and high. Present work deals with study of frequency content of ground motion on reinforced concrete bridges. Linear time history analysis is performed in structural analysis and design (ANSYSIS) software. The proposed method is to study the response of small, medium, and long span reinforced concrete bridges under low, intermediate, and high-frequency contents ground motions having equal duration and peak ground acceleration. The response of the bridges due to the ground motions in terms of displacement, velocity, acceleration and base shear can also be find out. The results got from the three types of bridges are compared and find out the most suitable span for bridges built in seismic prone area.