Effects of strong ground motions of near source earthquakes on response of thin-walled L-shaped steel bridge piers

Near source earthquakes can be characterized not only by strong horizontal but also by<br />strong vertical ground motions with broad range of dominant frequencies. The inelastic horizontal<br />response of thin-walled L-shaped steel bridge piers, which are popularly used as highway bridge supports,<br />subjected to simultaneous horizontal and vertical ground excitations of near source earthquakes is<br />investigated. A comprehensive damage index and an evolutionary-degrading hysteretic model are applied.<br />Numerical analysis reveals that the strong vertical excitation of a near source earthquake exerts<br />considerable influences on the damage development and horizontal response of thin-walled L-shaped steel<br />bridge piers.