Reducing the lateral displacement of lead rubber bearing isolators under the near field earthquakes by crosswise dissipaters connected to rigid support structure

The purpose of base isolation is to absorb earthquake energy, prolong the life of the structure, and enable the structure to be similar to a rigid body. However, since resonance can occur due to the closeness of the period of structures to the long period and large velocity pulses of the near field earthquakes, the stability of these buildings greatly reduces, and with the large displacement above isolation level, sometimes, tendency of overturning is created in isolators leading to their destruction. The main objective of this study is to significantly reduce the lateral displacement of base isolation subjected to near field earthquakes. In this research, seismic response calculation has been carried out for five steel moment frame structure with the 3, 5, 8, 11, and 14 stories in two states of with and without stiff core structure and energy dissipaters. The analyses has been done under fourteen scaled records of seven near-source and seven far-source earthquakes. It has been shown that the lateral displacement of base isolation system can be reduced by 87% for low-rise buildings, and 77% for high-rise buildings.

Optimum Location Analysis of Story Isolation System on High Rise Building

Various studies have been carried out to evaluate the feasibility and effectiveness of the story isolation system. The results obtained are also quite impressive, where the story isolation system gave a better story drift reduction than the base isolation system. However, these studies only focused on low-rise buildings, even though the story isolation system will be more engaging if it could also be compatible with high-rise buildings. In this study, a numerical analysis will be carried out on 30-, 40-, 50-, and 60-story buildings to evaluate the story isolator’s location, so that the system gives an optimum reduction of story drift and story shear. Then a general solution is sought to become a reference for buildings with different plans and heights. Keywords: Story isolation system, story isolator optimum location, high-rise building. Abstract Berbagai penelitian telah dilakukan untuk mengevaluasi kelayakan dan efektivitas sistem isolasi tingkat. Hasil yang diperoleh juga cukup mengesankan, dimana sistem isolasi tingkat memberikan reduksi simpangan antar tingkat yang lebih baik dibandingkan dengan sistem isolasi dasar. Namun, studi tersebut hanya berfokus pada bangunan bertingkat rendah, padahal sistem isolasi lantai akan lebih menarik jika dapat juga digunakan pada bangunan bertingkat tinggi. Dalam studi ini, analisis numerik akan dilakukan pada bangunan berlantai 30, 40, 50, dan 60 untuk mengevaluasi lokasi isolator tingkat yang memberikan reduksi simpangan tingkat dan geser tingkat terbesar. Kemudian dicari solusi umum untuk menjadi acuan untuk bangunan dengan denah dan ketinggian yang berbeda. Kata kunci: Sistem isolasi tingkat, lokasi optimum isolator tingkat, bangunan bertingkat tinggi.

Analytical and Experimental Overview of Fiber Reinforced Elastomeric Isolator

There has been many researches in order to further improve the Base Isolation system by trying various combinations and alternative materials. In that fiber reinforced isometric isolators are emerged as a viable solution, because for the low cost and effective response to seismic waves as compared to the conventional isolators. Studies further shows that it provides high vertical stiffness and low horizontal stiffness, also having effective damping over the conventional one. Developing countries who doesn’t have proper seismic protection solutions have found this convenient as they are comparatively less in cost and doesn’t require complex installation. Studies also shows Un-bonded FREI has lower horizontal stiffness and considerably lower stress demand on rubber material as compared to the B-FREI and hence significantly higher seismic isolation efficiency.