Learning from Local Wisdom: Friction Damper in Traditional Building

Indonesia is situated in the so called “Ring of Fire” where earthquake are very frequent. Despite of all the engineering effort, due to the March 28, 2005 strong earthquake (8.7 on Richter scale) a lot of modern buildings in Nias collapsed, while the traditional Northern Nias house (omohada) survived without any damage. Undoubtedly many other traditional buildings in other area in Indonesia have survived similar earthquake. Something in common of the traditional building are the columns which usually are not fixed on the ground, but rest on top of flat stones. In this paper some traditional building are subjected to non linear time history analysis to artificial earthquake equivalent to 500 years return period earthquake. This study shows that apparently the columns which rest on top of flat stone acts as friction damper or base isolation. The presence of sliding at the friction type support significantly reduces the internal forces in the structure

Application of Modified-Partial Capacity Design Method on 6- and 15-story Square Buildings with Variation in number of Elastic Columns

Modified-Partial Capacity Design (M-PCD) is proposed as one alternative of structural design methods. In M-PCD, the partial side sway mechanism where beams and some columns may develop plastic hinges. This method uses two structural models during the design process. The models are used to simulate undamaged and damaged structures when subjected to design earthquake (R=8.0) and larger target earthquake (R=1.6) respectively. In this study, 6- and 15- story square buildings with 30% and 50% elastic column are designed using M-PCD. Performances of the buildings are investigated by using non-linear time history analysis. Results show that the buildings� performances are still unsatisfactory, especially for the 15-story buildings. However, it should be noted that the levels of earthquakes used for the analysis were larger than that used for the design. A more accurate prediction of the required strength should be developed further to improve M-PCD

Seismic Performance of a Three-Story Reinforced Concrete Building with Masonry Infill Walls and Friction Base Support

The stiffness of masonry infill walls is commonly neglected in design practice of Reinforced Concrete (RC) structures. In fact, the stiffness of masonry infill wall may significantly influence seismic performance and dynamic behavior of RC buildings. In this research, influence of masonry infill walls to the structural performance of a three-story RC frame is investigated. In addition, possible application of friction-based support is also studied. Full 3D non-linear time history analysis is conducted to observe the behavior of the structure under two-directional ground motion. In the analysis, any failed elements are removed subsequently from the model to avoid numerical analysis problem. The result shows that the masonry infill walls can significantly influence the structural behavior of RC structure. Inappropriate placement of masonry wall may lead the building undergo soft-story mechanism. It is also found that the use of friction-based support can effectively improve the seismic performance of the building

Performance of Six- and Ten-story Reinforced Concrete Buildings Designed by using Modified Partial Capacity Design (M-PCD) Method with 70% Shear Force Ratio

One design alternative of earthquake resistant building is Partial Capacity Design (PCD) method. Unlike the commonly used capacity design method, PCD allows a safe failure mechanism which is called partial sidesway mechanism. In this mechanism, all beams and some columns are allowed to experience plastic damages while some selected columns are designed to remain elastic (called elastic columns). A new approach to predict the required strengths needed to design each structural member, called modified-PCD (M-PCD) is proposed. In this research six�and ten-story reinforced concrete buildings were designed using M-PCD, and their seismic performances are investigated. The base shear force resisted by the elastic columns was set to approximately 70% of the total base shear. Both nonlinear static procedure (NSP) and nonlinear dynamic procedure (NDP) are used to analyze the structures. The results show that the expected partial side sway mechanism is observed, and the drifts of the buildings are acceptable

Local wisdom to a sustainable non-engineered brick building

With the increase of wealth, people tend to modernize their houses by replacing the traditional wooden house to brick building, unfortunately most of these “modern non-engineered building” collapsed during earthquake, while the traditional buildings remain undamaged. In previous studies, the Authors have shown that the strength of the traditional building was in the construction of the columns which were not fixed to the ground but rested on top of flat stones, hence simulating friction base dampers. In this study a typical non-engineered brick building is used as a prototype, it is also assumed that this building is built properly. Two types of building are considered, the first one has its tie beams anchored to the foundation. While in the second one, the tie beams are not anchored to the foundation, allowing the building to slide thus simulating friction damper. Both non-engineered brick buildings are subjected to spectrum consistent earthquake excitations with several return periods. The prototype building with anchors is treated as pinned on the anchor locations, while the one without anchor is treated as friction base isolation. A third building assuming no infilling brick wall is also analyzed as a comparison. The result shows that assuming there are no damages on the wall due to load perpendicular to the wall (face load), the two buildings can stand to earthquake with a return period of 500 and 2500 year, however the one with pinned base suffers some small damages. It is worth to note that the building with friction base attracts only 66% of the total base shear of the one with pinned base

Application of modified partial capacity design on six-story Lshaped reinforced concrete buildings with variations on elastic columns configurations

Modified Partial Capacity Design (M-PCD) is an alternative design method for seismic-resistant structures. M-PCD adopts the partial side sway mechanism for its failure mechanism where beams and some columns are allowed to develop plastic hinges. This method uses two models for design. The first model simulates a small earthquake occurrence and is used to design beams and plastic columns. The second model simulates a larger earthquake occurrence and damages on the structure. The elastic columns are designed based on the superposition of internal forces from the first and second models, provided that the effects from gravity loads are considered only once. This study focuses on the application of M-PCD on six-story L-shaped reinforced concrete buildings with variations on elastic columns configurations. Nonlinear time history analyses are used to determine the buildings’ performance on two earthquake levels (EDRS and MCER) and two earthquake directions (0° and 45° rotated earthquake). The results show that the partial side sway mechanism is observed in most of the analyzed structures and drifts are within set boundaries

Kritisi Desain Pseudo Elastis Pada Bangunan Beraturan 6- Dan 10-lantai Dengan Denah Persegi Panjang Di Wilayah 6 Peta Gempa Indonesia

Metode Pseudo Elastis merupakan sebuah metode desain alternatif yang dikembangkan untuk perencanaan bangunan yang didesain terhadap gempa selain metode Desain Kapasitas. Perencanaan Pseudo Elastis memperbolehkan terjadinya sendi-sendi plastis pada ujung atas dan bawah kolom interior, sedangkan kolom eksteriornya harus berperilaku elastis penuh, kecuali ujung bawah kolom lantai dasar. Pola keruntuhan yang diharapkan setelah terjadi gempa merupakan partial side sway mechanism. Untuk menjamin terjadinya distribusi gaya geser pada kolom eksterior, maka diperlukan pembesaran gaya dalam kolom elastis akibat gempa berupa Faktor Pengali (FP). Tujuan penelitian ini adalah menguji asumsi penyaluran gaya geser dasar pada desain Pseudo Elastis dan menguji terjadinya partial side sway mechanism pada bangunan beraturan 6- dan 10-lantai berdenah persegi panjang di wilayah 6 peta gempa Indonesia. Kinerja bangunan diperiksa dengan metode dynamic non-linear time history analysis. Hasil penelitian menunjukkan bahwa asumsi penyaluran gaya geser dasar pada desain Pseudo Elastis tidak selalu terjadi pada bangunan yang ditinjau.Untuk hasil kinerja bangunan, partial side sway mechanism terjadi pada bangunan 6-lantai untuk arah memanjang dan melintang, dan bangunan 10-lantai pada arah memanjang bangunan, sedangkan arah melintangnya tidak terjadi karena mengalami soft storey di lantai ke-2

Performance of Direct Displacement Based Design on Regular Concrete Building Against Indonesian Response Spectrum

The renewal of Indonesian seismic code from SNI 1726-2002 into SNI 1726-2012 brings significant change in the design spectrum. Focused on several regular plan concrete building which have been design using displacement based design method, the aim of this study is to verify their performance using nonlinear time history analysis based on parameters: drift, damage indices, and plastic mechanism determined by FEMA 356. The excitation is spectrum consistent accelerogram based on El-Centro 1940 N-S, to match with the new Indonesian response spectrum for soft soil in low- and high intensity area. It is found that the code-designed buildings are not suitable for the targeted design of level-2 with maximum drift of 2.5% due to major. This is caused by improper selection of SNI spectrum as the design major earthquake. In fact, it is only equivalent to small earthquake. Although buildings survive up to a very rare earthquake without collapse but they suffer excessive damage and rotation due to small- to major-earthquake. The capacity design procedure is able to maintain ductile mechanism, but some columns experience yielding at prohibited locations

Improving Seismic Performance of Structure with Semi-rigid floor using VSL-Gensui Damper

Seismic performance of structures can be improved using various methods. In this study, Vorspann System Losinger (VSL) Gensui Damper is used to improve the seismic performance of building with semi-rigid floors. Spectrum consistent ground accelerations is generated from El Centro May 19th, 1940 earthquake per SNI 1726:2012 for Mataram, Indonesia. Modified Simplified Sequential Search Algorithm (MSSSA) and Optimum Damper Allocation Method (ODAM) are used to efficiently place the dampers on the building to meet certain criteria. Uniform placement which is used as the first step of ODAM is used for comparison. The results show that both methods can effectively reduce structural drifts and damages. MSSSA shows slightly better performance since ODAM has a limitation that dampers can only be swapped among stories of the initially chosen frames. It is also noted that the dampers must be well distributed among frames in the same story, to take care the different drifts in building with semirigid floors

Kemungkinan Penggunaan Base Isolation Pada Bangunan Sederhana

Penelitian sebelumnya oleh Lumantarna dan Pudjisuryadi tentang friction damper pada rumah tradisional dengan hubungan kolom kayu yang terletak di atas batu, menunjukkan bahwa sistem friction base isolation menghasilkan performa yang baik terhadap beban gempa. Konsep yang dipakai adalah memanfaatkan friksi pada dasar kolom dan pondasi. Konsep base isolation ini terbukti dapat mengurangi gaya dalam yang terjadi pada struktur di atasnya. Konsep inilah yang menjadi landasan pada penelitian ini di mana objek bangunan adalah struktur bangunan sederhana yang terbuat dari beton. Penelitian ini membandingkan struktur bangunan sederhana yang hubungan kolom dan sloof ke pondasi diberi angker dan tanpa angker. Permodelan pondasi menggunakan friction isolator link pada SAP2000v11. Beban gempa yang digunakan berupa gempa El Centro modifikasi yang disesuaikan dengan SNI 03-1726-2012 untuk kota Palu. Kedua jenis struktur diuji dengan analisa riwayat waktu nonlinear. Hasil penelitian ini menunjukkan bahwa friction isolator link pada SAP2000v11 dapat digunakan untuk memodelkan sistem friction base isolation. Hasil secara keseluruhan menunjukkan bahwa besarnya gaya dalam akibat gempa berkurang pada saat struktur dalam keadaan slip