Upgrading the Seismic Capacity of PileSupported Wharfs Using SemiActive Liquid Column Gas Damper

One of the most important structures in the ports is the wharf. The most common one is the pilesupported wharf. This type of wharf is consisted of a number of piles and one deck which placed on the piles. In addition to the conventional loads that this structure should withstand, in seismic areas, pilesupported wharfs should have the necessary capacity and strength against seismic excitations. There are some approaches to increase the seismic capacity of the berth. One of these methods is to control the vibrations of the pilesupported wharf against earthquake loads using a damper. In this research, for the first time, a new semiactive damper called the semi active liquid column gas damper (SALCGD), was used to reduce the response of pile supported wharf under seismic loads. In the first step by applying different records of the earthquake, the most important parameter of this damper the optimal opening ratio of the horizontal column was obtained for this particular structure. In the following, the performances of this damper and its comparison with the tuned liquid column gas damper (TLCGD) were discussed. This study showed that the use of this semiactive damper (SALCGD) reduces the displacement of the pilesupported wharf by 35% and reduces the acceleration of the structure by 50% on average. In contrast, the passive damper (TLCGD) reduces the displacement of about 20 percent and the acceleration of about 30 percent. Therefore, it was observed that the semiactivation of the damper (SALCGD) had a significant improvement in its performance in controlling the vibrations of pilesupported wharf.