PERBANDINGAN RESPONS SPEKTRUM TANAH HIPOTESA DENGAN RESPON SPEKTRUM RSNI 03-1726-201X KOTA SEMARANG
(1) Jurusan Teknik Sipil, Fakultas Teknik, Universitas Negeri Semarang (UNNES)
Abstract
Nonlinear response analysis of soil in Semarang city is needed currently. There is change in earthquake map in Indonesian Building code from Earthquake with 500 years return period to 2500 years return period. The earthquake records in Indonesia are rare. In this paper Taft earthquake record is used. The calculation of nonlinear response of soil properties was done by finite difference analysis. Viscoelastic, elastoplastic constitutive relations are introduced and the need for using hyperbolic models are mentioned here, nonlinearity is treated by selecting strain compatible soil properties such as shear stiffness and viscous coefficient. Stepwise material properties are taken as the instantaneous slope and assumed to be constant within the given time interval. Case study is hypothesized site in Erdik (1982). The nonlinear analysis is compared with RSNI 03-1726-201X response spectrum for Semarang city. From graphic shown that for period less than 1 sec the response is below of the RSNI 03-1726-201X but for period more than 1 sec the response is more than of RSNI 03-1726-201X.
Analisis respon nonlinear tanah pada kota Semarang saat ini sangat diperlukan. Perubahan peta gempa di peraturan bangunan Indonesia dari peta gempa dengan kala ulang 500 tahun menjadi 2500 tahun mengakibatkan terjadi perubahan pada bentuk respon spektrum. Data rekaman gempa bumi di Indonesia sangat sulit didapatkan. Pada tulisan ini dipakai rekaman dari gempa bumi Taft.Perhitungan respon dinamis nonlinier tanah ditunjukkan dengan menggunakan formulasi beda hingga. Viskoelastik, hubungan konstitutif elastoplastic diperkenalkan dan penggunaan model hiperbolik disebutkan di sini, nonlinier diperlakukan dengan memilih sifat regangan tanah yang kompatibel seperti kekakuan geser dan koefisien kekentalan. Sifat material tahap demi tahap diambil sebagai kemiringan seketika dan diasumsikan konstan dalam interval waktu tertentu. Untuk studi kasus ini parameter tanah menggunakan data dari Erdik (1982). Hasil dari analisis nonlinear tanah dibandingkan dengan respon spectrum dari RSNI 03-1726-201X untuk kota Semarang. Pada grafik terlihat bahwa respon spectrum analisis terletak dibawah dari grafik respon spectrum RSNI 03-1726-201X. Tetapi pada periode lebih besar dari 1 detik terletak diatas respon spectrum RSNI 03-1726-201X.
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Departemen Permukiman dan Prasarana Wilayah, Standar Perencanaan Ketahanan Gempa untuk Struktur Bangunan Gedung dan Nongedung, RSNI 03-1726-201x
Tumilar, Steffie Prosedur Analisis Struktur Beton Akibat Gempa Menurut RSNI 03 - 1726-201X, Shortcourse HAKI, 11-12 November 2011, Semarang, Indonesia
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