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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.

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Previous studies have shown that most link-to-column connections fail before achieving the required plastic link rotation capacity. To avoid such connection failures, a semi-rigid connection is proposed for use as a long link-to-column connection. A top and seat bolted angle connection with a web angle is a desirable candidate for a semi-rigid connection since no welding is needed. Experimental tests and finite-element simulations were conducted in this study. The accuracy of the finite-element model predictions was verified using the results of the experimental testing conducted by the authors and good agreement was achieved. The effects of angle thickness and bolt diameter were also numerically studied. The results showed desirable behaviour of the proposed connection in eccentrically braced frames with a long link connected to column.