## 1 Introduction
Four electromagnetic coils were provided on the top and bottom of MRE samples to generate the magnetic flux. The coils were covered with two steel caps along with steel cores. The overall dimensions of VSDI are 128 mm \(\times\) 64 mm \(\times\) 110 mm. The number of turns in a single-coil is 800, and the power required for each device is 234.2W at a 4 A current. A maximum stiffness increase of 57% was reported in shear mode. However, the main drawback of this design of the isolator for civil structures is the limited loading capacity in the vertical direction. [PERSON] et al. [55; 56] put forward, for the first time, a laminated MRE base isolator containing 47 sheets of MR elastomer each 2 mm thick with a diameter of 140 mm. Every MRE layer is accompanied by a 1-mm-thick steel sheet of the same diameter with a total of 46 steel sheets. This configuration makes the laminated structure 140 mm high. An electromagnetic coil was positioned outside the laminations. An enclosed magnetic path is formed with the steel plates at the top and bottom; the hollow steel yoke, the cylindrical steel block, and the laminated structure also form the core of the electromagnetic coil. The benefits of the laminated design are greater vertical loading capacity of the isolator and an improved magnetic conductivity of the structure and the widely practiced design of the MRE base isolator as shown in Figure 1. This device can take a maximum load of 370 kg in compression for its weakest state, i.e., 0 magnetic flux, and at a maximum design displacement of 26 mm. An even greater vertical loading capacity is expected under the application of a magnetic field. This loading capacity furnishes the minimum requirements for its use in the seismic isolation of civil structures. Experimental tests on a shake table demonstrated an effective stiffness increase of 37% and of 45% of force under a designed maximum current of 5A. The uniform magnetic field of 0.3 T is estimated to energize all of the MR elastomer layers in the device. Furthermore, an MR elastomer of a highly adjustable nature with a laminated structure was developed and experimentally tested by [PERSON] et al. [5] using a soft MRE. The device contains 25 sheets of MR elastomer, each 1 mm thick with diameters of 120 mm. The MR elastomer used in the new device can produce a force increase of 1479% and a stiffness increase of 1630% when the magnetic field varied from 0T to 0.44T. [PERSON] al. [57] conducted a study on the design and experimental testing of a novel MRE-based isolator with a hybrid magnetic system. A negative stiffness change in the isolator has been reported due to the incorporated hybrid magnetic system. The stiffness of the isolator can be increased or decreased based on the direction of current in the proposed isolator design. The current trend on studies of MRE-based seismic isolation is focused on the development of isolation devices, their mathematical models, and subsequent necessary improvements/modifications in them for their effective implementation in large civil structures. No explicit research for MRE base isolation, however, has been conducted to gauge its effectiveness for near-fault and far-fault earthquakes. Since its performance for near-fault and far-fault earthquakes is a major drawback for passive base isolation systems, it is pretty much indispensable to obtain a comparison of the structural responses for both the systems, i.e., passive base isolation and MRE-based seismic isolation and to gauge how much response improvement is possible by employing MRE base isolation techniques for the case of both near-fault and far-fault earthquakes. This study is focused on the investigation of the structural response of magnetorheological elastomers (MRE)-based multi-degree-of-freedom (MDOF) isolated structures under historic earthquake loadings. The effectiveness of MRE base isolation has been analyzed for near- and far-fault earthquakes individually first, and a comparison has been drawn afterward.