Effect of near-fault earthquakes with forward directivity on telecommunication towers

Abstract

In this paper, the effect of pulse-type motions caused by forward directivity that can release huge amounts of energy in a short time period is studied on a telecommunication tower. Since telecommunication towers have longer periods, they are not as affected by seismic forces. Nevertheless, near source earthquakes characterized by high velocity and velocity pulses can change the behavior of these structures. For this reason, a telecommunication tower located near active faults was selected in this study. Considering the probable earthquake magnitude at the site and the distance of the tower from adjacent faults, nine simulated pulses and three near-fault earthquake records with forward directivity are selected and applied to a 3D fi nite element model of the tower. The results of nonlinear dynamic analysis, i.e., displacements and damage in the tower, indicate that the maximum displacement and drift ratio of the tower under the pulses are obviously affected by the ratio of the structure period to pulse period. When this ratio is decreased and close to 1.0, the maximum displacement and drift ratio are sharply increased and cause large displacements in the tower.

Effect of near-fault ground motion with pulse signal on dynamic response of dam-reservoir-foundation systems

“…The main characteristics of these impulse motions are the period and maximum velocity pulse amplitudes. The velocity pulse has specific characteristics of near-fault earthquakes that cannot be observed in far-field earthquakes [24].…”

“…The velocity waveforms were chosen to identify the pulse signals because it is easier to detect the pulse from the velocity [27,30]. Owing to these unique characteristics of near-fault ground motions, the seismic responses of civil engineering structures, such as buildings, tunnels, bridges, nuclear stations, dams, towers, viaducts, wind turbines, and tanks, under near-fault ground motions have received a great deal of attention over the last decades [5,7,11,24,28,30,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49].…”

Effect of Fling-Step on Seismic Response of Steel Eccentrically Braced Frame Structures

“…Since the amplitude of the fling-step is highly sensitive to the choice of baseline, and baseline correction has a negligible effect on elastic response spectra, records are typically filtered and added to an engineering database [6]. Previous studies showed that structural response due to near field earthquakes is more severe than that of far-field records, and significantly depends on the pulse period to structure period [7][8][9][10]. There are only a few studies on the effect of near-field earthquakes with the fling-step effect.…”