scholarly journals ANALISIS PERIODA BANGUNAN DINDING GESER DENGAN BASE ISOLATOR AKIBAT GAYA GEMPA

Teras Jurnal ◽  
2018 ◽  
Vol 7 (2) ◽  
pp. 263
Author(s):  
Mul Muliadi Adi ◽  
M. Kabir Kabir Ihsan

Bangunan yang hancur oleh gempa dapat dicegah dengan memperkuat struktur bangunan terhadap gaya gempa yang bekerja padanya. Perkuatan bangunan dapat dilakukan dengan memperkaku bangunan dalam arah lateral yaitu <em>moment resisting frame</em> (<em>rigid frame</em>), <em>braced frame</em> dan <em>shear wall</em>. Bangunan dinding geser merupakan salah satu jenis <em>bangunan</em> tahan gempa gedung beton bertulang menggunakan sistem rangka struktur yang dikombinasikan. Kinerja gedung akan bertambah dan menjadi optimal jika pola penempatan <em>dinding geser</em> serta metode analisanya tepat. Sistem lainnya dalam mengurangi kerusakan bangunan akibat gempa dengan <em>performance based seismic design</em> yaitu dengan menggunakan <em>base isolator.</em>, yang memanfaatkan teknik analisa non-linear berbasis komputer untuk menganalisa perilaku inelastis struktur dari berbagai macam intensitas gerakan tanah (<em>gempa</em>), sehingga dapat diketahui kinerjanya pada kondisi kritis. Tujuan penelitian ini dilakukan untuk mengetahui perioda dalam penggunaan <em>base isolator </em>dengan yang tanpa menggunakan <em>base isolator,</em> pada bangunan sistem ganda, lantai 10 tingkat, bentuk beraturan pada bangunan dinding geser. Analisis data yang dilakukan dengan menggunakan bantuan <em>software </em>komputer <em>SAP2000</em>. Pembebanan pada gedung didasarkan pada peraturan bangunan gedung beton bertulang dan analisa dinamik <em>Time History Modal Analysi</em>s struktur dalam Tata Cara Perencanaan Ketahanan Gempa Untuk Struktur Bangunan Gedung Dan Non Gedung (SNI 1726:2012). Dari hasil penelitian ini dapat diketahui bahwa penggunaan <em>base isolator</em> memperbesar perioda alami. Nilai perioda pada dinding geser dan dinding geser <em>base isolator</em> besarnya berturut-turut 0.988 detik dan 2.465 detik. Hal ini menyebabkan gaya gempa yang bekerja menjadi lebih kecil.

2019 ◽  
Vol 15 (8) ◽  
pp. 155014771985756 ◽  
Author(s):  
Mehdi Firoozbakht ◽  
Hamidreza Vosoughifar ◽  
Alireza Ghari Ghoran

The coverage intensity of sensors is the most important issue on structural health monitoring technique. The geometric configuration of sensors must be optimized based on coverage intensity with proper objectives. In this article, a novel algorithm for optimal sensor placement in various steel frames was evaluated. These frames including moment-resisting frame, moment-resisting frame with base isolation, and moment-resisting frame with base isolation with steel shear wall were selected for case studies. This approach was proposed based on combination of common optimal sensor placement algorithm and nonlinear time history analysis. A new method called transformed time history to frequency domain approach was evaluated to transform nonlinear time history analysis results to frequency domain and then the effective frequencies according the maximum range of Fourier amplitude were selected. The modified type of modal assurance criterion values can be achieved from modal assurance criterion with the exact seismic displacement. All of novel optimal sensor placement processes were done through FEM-MAC-TTFD code modeled and developed in MATLAB by authors of this article. The results show that there is good relative correlation between the sensors number and coverage intensity obtained with modal and modified modal assurance criterion approaches for moment-resisting frame system, but for integrated frame such as moment-resisting frame with base isolation and moment-resisting frame with base isolation with steel shear wall, the modified modal assurance criterion approach is better approach. There is no significant difference between coverage intensity of sensors for top joints between modal assurance criterion and modified modal assurance criterion approaches for moment-resisting frame, moment-resisting frame with base isolation, and moment-resisting frame with base isolation with steel shear wall systems ( R2 = 0.994, 0.986, and 0.724, respectively). It was found that if reference point is located in center of frame, there is significant difference between modal assurance criterion and modified modal assurance criterion approaches, and modified modal assurance criterion generated slightly better results.


Author(s):  
Prof. Pallavi K. Pasnur

In past two decades earthquake disasters in the world have shown that significant damage occurred even when the buildings were designed as per the conventional earthquake-resistant design philosophy (force-based approach) exposing the inability of the codes to ensure minimum performance of the structures under design earthquake. The performance based seismic design (PBSD), evaluates how the buildings are likely to perform under a design earthquake. As compared to force-based approach, PBSD provides a methodology for assessing the seismic performance of a building, ensuring life safety and minimum economic losses. The non-linear static procedures also known as time history analysis are used to analyze the performance of structure . Plastic hinge formation patterns, plastic rotation, drift ratio and other parameters are selected as performance criterias to define different performance level. In this paper, a five-storey RC building is modelled and designed as per IS 456:2000 and analyzed for lmmediate occupancy performance level in ETABS2015 softwere. Analysis is carried out as per FEMA P58 PART 1 & 2. Plastic hinges as per FEMA273. From the analysis, it is checked that the performance level of the building is as per the assumption


2018 ◽  
Vol 2 (01) ◽  
pp. 13
Author(s):  
Reza Kurniawan ◽  
Dwi Nurtanto ◽  
Gati Annisa Hayu

Eccentrically Braced Frame (EBF) is one of several types of braces that can be used in steel building. EBF has a good stiffness and ductility to withstand earthquake load. In EBF itself there are 3 types of links, namely: Long Link, Intermediate Link, and Short Link. Meanwhile, MRF of Moment resisting Frame is a structural system where the beams and columns are connected rigidly. MRF has a good ductility in accepting load even it has no lateral braces installed. In this research the Dafam Lotus Jember hotel consisting of 10 floors with total height of 33,6 m is modeled as a MRF system structure and steel structure equipped with EBF short link. The objective of this research is to compare the effectiveness of EBF and MRF in terms of displacement, axial force, shear force, and moment occurring in buildings. The modeling results show that EBF with short link has smaller displacement value compared to MRF. The difference between the two is 86,99%. In terms of axial force, shear force, and moment, EBF has smaller values than MRF. The differences are 79,76%, 53,91%, and 10,48% respectively. These results indicate that EBF has better capacity compared to MRF. Indonesia merupakan negara yang memiliki tingkat intensitas kegempaan yang tinggi. Ini menjadikan Indonesia tidak terhindarkan dari dampak negatif yang akan ditimbulkan oleh gempa bumi, yaitu menyebabkan kerusakan insfrastruktur fisik. Peraturan gempa SNI 03-1726-2012 membahas mengenai bresing sebagai salah satu alternatif yang dapat digunakan untuk menangani masalah gempa. Eccentrically Braced Frame (EBF) adalah salah satu jenis bresing yang memiliki kekakuan dan daktilitas yang baik jika dibandingkan dengan Concentrically Braced Frame (CBF) yang hanya memiliki kekakuan yang baik. Selain itu terdapat pula Moment Resisting Frame (MRF) yaitu salah satu sistem struktur yang memiliki sifat daktail. Melihat permasalahan yang ada, maka pembahasan ini bertujuan untuk membandingkan efektivitas dari EBF menggunakan short link dengan MRF apabila diaplikasikan pada bangunan Hotel Dafam Lotus Jember 10 lantai yang memiliki tinggi 33,6 m. Adapun efektivitas yang dibadingkan disini adalah nilai story displacement dan gaya dalam (momen, gaya geser, dan gaya aksial) yang terjadi. Hasil analisa dengan bantuan program analisa struktur menunjukkan bahwa EBF menggunakan short link memiliki nilai yang lebih kecil dibandingkan dengan MRF dalam menerima beban yang bekerja. Dari segi story displacement, selisih prosentasenya adalah 86,99% sedangkan untuk gaya dalam yang meliputi momen, gaya geser, dan gaya aksial, selisihnya secara berturut-urut adalah 79,76%, 53,91% dan 10,48%. Hal ini menunjukkan bahwa EBF menggunakan short link lebih efektif jika dibandingkan dengan MRF.


2009 ◽  
Vol 25 (3) ◽  
pp. 583-605 ◽  
Author(s):  
Wei Chiang Pang ◽  
David V. Rosowsky

This paper presents a direct displacement design (DDD) procedure that can be used for seismic design of multistory wood-framed structures. The proposed procedure is applicable to any pure shear deforming system. The design procedure is a promising design tool for performance-based seismic design since it allows consideration of multiple performance objectives (e.g., damage limitation, safety requirements) without requiring the engineer to perform a complex finite element or nonlinear time-history analysis of the complete structure. A simple procedure based on normalized modal analysis is used to convert the code-specified acceleration response spectrum into a set of interstory drift spectra. These spectra can be used to determine the minimum stiffness required for each floor based on the drift limit requirements. Specific shear walls can then be directly selected from a database of backbone curves. The procedure is illustrated on the design of two three-story ATC-63 archetype buildings, and the results are validated using nonlinear time-history analysis.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Rui Zhang ◽  
Dong-sheng Wang ◽  
Xiao-yu Chen ◽  
Hong-nan Li

In recent studies, spectral matching is the most commonly proposed method for selecting earthquake records for time-history analysis of structures. However, until now, there have been no serious investigations of the effects of coordinate values on the scaling of ground motions. This paper investigated the influence of using arithmetic and logarithmic values of response spectra in spectral matching procedures (i.e., ASM and LSM methods) on the results of nonlinear structural time-history analysis. Steel moment resisting frame structures of the 3-, 9-, and 20-stories, which represent low-, medium-, and high-rise buildings, respectively, were used as examples. Structural benchmark responses were determined by calculating the arithmetic mean and median of peak interstory drift ratio (PIDR) demands based on the three record sets developed by the American SAC Steel Project. The three record sets represent seismic hazard levels with 50%, 10%, and 2% probabilities exceeded in 50 years, and their average acceleration spectra were also taken as the target spectrum. Moreover, another 40 record components for selection were scaled both by ASM and LSM methods. The seven components whose spectra were best compatible with the target spectra were selected for the structural time-history analysis. The scale factors obtained by the LSM method are nearly larger than that of the ASM method, and their ranking and selection of records are different. The estimation accuracies of structural mean (median) responses by both methods can be controlled within an engineering acceptable range (±20%), but the LSM method may cause larger structural responses than the ASM method. The LSM method has a better capacity for reducing the variability of structural responses than the ASM method, and this advantage is more significant for longer-period structures (e.g., 20-story structure) with more severe nonlinear responses.


2014 ◽  
Vol 30 (4) ◽  
pp. 1683-1709 ◽  
Author(s):  
Edgar Tapia-Hernández ◽  
Arturo Tena-Colunga

In order to help improve the seismic design of regular steel buildings structured with ductile moment-resisting concentrically braced frames (MRCBFs) using the general design methodology of Mexico's Federal District Code (MFDC-04), suitable design parameters were first assessed using the results of pushover analyses of 13 regular MRCBFs. In order to insure collapse mechanisms consistent with the assumptions implicit in a code-based design (strong-column/weak-beam/weaker-brace), it is proposed to relate the minimum strength ratio for the resisting columns of the moment frames and the bracing system. Improved equations are proposed for a more realistic assessment of ductility and overstrength factors. In a second stage, the effectiveness of the improved methodology was assessed with the design of six regular steel buildings with MRCBFs. Buildings were evaluated by performing both pushover and nonlinear time-history analyses under ten selected artificial ground motions related to the corresponding design spectrum.


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