19 - Seismic Analysis of Piles

Abstract

This chapter begins by providing a general understanding on seismology. Due to the movement of the pile cap, piles are subjected to additional shear forces and bending moments. Earthquakes occur as a result of disturbances occurring inside the earth's crust. Earthquakes produce three main types of waves—primary waves, secondary waves, and surface waves. Faults are the fractures where a block of earth has moved relative to the other. They are a common occurrence in the earth. Peak ground acceleration is a very important parameter for geotechnical engineers. During an earthquake, soil particles accelerate. Acceleration of soil particles can be either horizontal or vertical. Earthquakes can cause additional bending moments and shear forces on piles. Earthquake-induced bending moments and shear forces can be categorized into three types: kinematic loads, inertial loads, and loads due to liquefaction. Seismic waves travel at different velocities in different soils. Because of these differences, piles are subjected to bending and shear forces. This bending is known as kinematic pile bending. The chapter describes pile design for each load.