A limited gap between closely spaced structural parts may induce internal pounding in seismically isolated structures, because of notable displacement at the level of the isolation system under severe earthquakes. A gap between a fixed-base elevator shaft and the surrounding building is presented here with reference to a reinforced concrete building located in the Sicilian town of Augusta. The building, comprising a basement and three storeys above the ground level, is seismically isolated at the top of rigid columns in the basement with a hybrid isolation system including elastomeric and sliding bearings, while a steel framed elevator shaft crosses the isolation level. Despite the gap, internal pounding may occur at all levels of the superstructure when the elevator with maximum load stops at the upper floors. To reduce structural pounding effects, a magnetic damped link (MDL) between adjacent corners of the elevator and the surrounding building is proposed. This is obtained as an in parallel combination of an eddy current damped link (ECDL) and an elastic helicoidal spring, and occupies less space than traditional passive dampers and transmits considerably less forces compared to a rigid link configuration. Specifically, an ECDL consists of an outer cylindrical copper tube, as conductor, and an inner tube, equipped with an array of axially magnetized and ring-shaped permanent magnets separated by iron pole pieces, as mover. The relative motion between conductor and magnets, during seismic loading, induces an eddy current producing electromagnetic damping. Given that viscoelastic linear behaviour can be hypothesized for the MDL, a simplified iterative design procedure of the ECDL is proposed, with optimization of the thickness and radius of the magnets, thereby enhancing magnetic flux and energy dissipation. The directionality of the near-fault ground motions is investigated through nonlinear seismic analysis, comparing no connection with four configurations of the interconnection: i.e., flexible and rigid elastic links, viscous and magnetic damped links.

由于在严重地震下隔离系统水平上的明显位移，因此紧密间隔的结构部件之间的有限间隙可能会在地震隔离结构中引起内部撞击。此处参考位于西西里奥古斯塔镇的钢筋混凝土建筑，介绍了固定式电梯井道与周围建筑之间的缝隙。该建筑物包括一个地下室和一个位于地面以上三层的建筑物，在地下室的刚性柱顶部通过包括弹性体和滑动轴承的混合隔离系统进行了地震隔离，而钢制的电梯井道则穿过隔离层。尽管存在间隙，但当最大负荷的电梯停在较高楼层时，内部冲击可能会在上层建筑的所有楼层发生。为了减少结构的撞击作用，提出了在电梯的相邻拐角与周围建筑物之间的磁阻尼链（MDL）。这是通过涡流阻尼连杆（ECDL）和弹性螺旋弹簧的并联组合而获得的，与传统的被动阻尼器相比，其占据的空间较小，并且与刚性连杆结构相比，传递的力要小得多。具体地，ECDL由作为导体的圆柱状外部铜管和由作为动子的由铁极片隔开的轴向磁化的环状永久磁铁构成的内管构成。在地震荷载作用下，导体和磁体之间的相对运动会引起产生电磁阻尼的涡流。假设可以针对MDL假设粘弹性线性行为，提出了简化的ECDL迭代设计程序，并优化了磁体的厚度和半径，从而提高了磁通量和能量耗散。通过非线性地震分析研究了近断层地震动的方向性，将无连接与互连的四种配置进行了比较：即柔性和刚性弹性连杆，粘性和磁阻尼连杆。