Estimasi Sifat Fisika Untuk Tanah Dan Bangunan Pada Gedung Research Center Dan FMIPA Tower

Berliana, Ratri (2017) Estimasi Sifat Fisika Untuk Tanah Dan Bangunan Pada Gedung Research Center Dan FMIPA Tower. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Parameter yang menyebabkan kerusakan pada bangunan adalah karakteristik struktur bangunan dan efek gempa seperti frekuensi natural, rasio redaman, dan indeks kerentanan bangunan. Secara geologis, Surabaya khususnya di sekitar kawasan Kampus ITS Surabaya memiliki kondisi tanah alluvial. Selain itu, Surabaya juga terletak dekat dengan sesar aktif Watu Kosek dan Kendeng sehingga besar kemungkinan wilayah ini terjadi gempa bumi yang disebabkan oleh sesar aktif tersebut. Kampus ITS Surabaya, dahulunya hanya memiliki bangunan tertinggi Gedung Perpustakaan ITS yang dibangun hanya enam lantai, kini telah dibangun dua gedung baru yaitu Gedung FMIPA Tower dan Research Center yang memiliki sebelas lantai. Dengan adanya dua bangunan tinggi tersebut, diperlukan upaya untuk mengurangi resiko bencana gempa bumi utamanya pada kerusakan bangunan akibat gempa. Pengukuran mikrotremor dilakukan di gedung Research Center dan FMIPA Tower untuk mengetahui nilai frekuensi natural dari bangunan dan tanah di bawahnya. Juga menentukan tingkat resonansi bangunan terhadap gelombang gempa. Akuisi pengukuran dilakukan pada sepuluh titik pada setiap bangunan, yaitu lima titik pada lantai dua, dan lima titik lain pada lantai rooftop. Pengolahan data pada penelitian ini menggunakan metode analisis spectrum, analisis FRS (Floor Spectra Ratio) dan analisis RDM (Random Decrement Method). Kedua parameter ini kemudian dibandingkan dan diperkuat pula dengan metode HVSR sehingga dapat diketahui tingkat resonansi bangunan tersebut. Hasil penelitian menunjukkan bahwa nilai amplifikasi tanah T1 sebesar 27, 5394 sedangkan pada T2 sebesar 28.7669. Perbandingan hasil frekuensi natural dari metode FSR, RDM, dan analisis Spektrum menunjukkan grafik linier sehingga hubungan ketiga diantaranya adalah berbanding lurus. Nilai damping ratio pada lantai dua FMIPA Tower sebesar NS = 4.540933333, EW = 2.651033333, sedangkan pada lantai rooftop sebesar NS = 3.284557143; EW = 2.818914286. Pada Research Center lantai dua sebesar NS = 4.273054545; EW = 3.677609091, dan lantai rooftop sebesar NS = 1.668122222; EW = 2.1759. Didapatkan empat titik pada bangunan FMIPA Tower dengan tingkat resonansi sedang (FT2, FT6, FT8, FT9), dan enam titik dengan tingkat resonansi rendah (FT3, FT4, FT5, FT7, FT10, FT11). Dan seluruh titik pada bangunan Research Center dengan tingkat resonansi rendah. ===================================================================================== Several parameters caused damage to the building are structural building characteristics and earthquake effects such as natural frequencies, damping ratio, and building vulnerability index. Geologically, Surabaya, especially area around ITS Surabaya campus, has alluvial soil condition. Moreover, Surabaya is located close to active sesar Watu Kosek and Kendeng thus create high possibilities of earthquake in this region because of that active sesar. In the previous year, the tallest building in ITS Surabaya was the Library Tower who has only six floors. However, recently ITS have built two new high rise buildings which are FMIPA Tower and Research Center Tower that have completed its construction on Januari 2016. Those two buildings need high consideration to reduce the earthquake risk towards building breakage. Microtremor measurement was performed in the Research Center and FMIPA Tower to determine the value of natural frequency of a building and the soil beneath it. That measurement also used to determine the vulnerability level of buildings against earthquake waves. The acquisition measurement was performed at ten points of each building, where five points on the second floor, and five points on the rooftop. Data in this research being processed using Spectrum Analysis Method, FRS Analysis (Floor Spectral Ratio), and RDM Analysis (Random Decrement Method) to estimate the natural frequency and damping ratio. Both parameters were compared and reinforced with HVSR in the next step. Thus the resonance level of the building could be seen. The result of this research showed that the soil ampliphication value of T1 was 27, 5394 whereas at T2 was 28.7669. Ratio of natural frequency from these FSR, RDM, and Spectrum analysis method showed linier graph until the relation between those three directly proportional. Damping ratio value at second floor of FMIPA Tower was NS = 4.540933333, EW = 2.651033333, while at the rooftop was NS = 3.284557143; EW = 2.818914286. At second floor of Research Center building was NS = 4.273054545; EW = 3.677609091, and rooftop floor was NS = 1.668122222; EW = 2.1759. Four points founded at FMIPA Tower with middle resonance stage (FT2, FT6, FT8, FT9), and six points with low resonance stage (FT3, FT4, FT5, FT7, FT10, FT11) and all points at Research Center building with low stage of resonance.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: FSR; mikrotremor; RDM; resonansi tanah dan bangunan; Microtremor; Soil-building resonance
Subjects: Q Science > QC Physics
Q Science > QE Geology > QE601 Geology, Structural
Divisions: Faculty of Mathematics and Science > Physics > (S1) Undergraduate Theses
Depositing User: - RATRI BERLIANA
Date Deposited: 11 Apr 2017 01:43
Last Modified: 11 Apr 2017 01:43
URI: http://repository.its.ac.id/id/eprint/3493

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