Papers by Keyword: Earthquake

Abstract: Indonesia, situated at the convergence of active tectonic plates and surrounded by active mountain ranges known as the Ring of Fire, enjoys advantages such as fertile land and a tropical climate. However, these benefits also pose threats when nature is not in its best state, rendering certain regions of Indonesia susceptible to natural disasters. The consequences not only entail material and human losses but also extend to the detriment of critical infrastructure, including communication networks. Communication disruptions in crucial conditions undoubtedly hinder rescue and recovery efforts. This study focuses on designing communication scenarios based on Mobile Ad-hoc Network (MANET) as a post-disaster communication solution, utilizing the NS-3 simulator with proactive routing protocols OLSR and DSDV, alongside an analysis of their performance in scenarios involving the addition of nodes. Performance metrics, including Packet Loss, Throughput, and Delay, are compared based on the TIPHON QoS standard. The experimental results demonstrate the superiority of OLSR routing performance over DSDV, with the best average throughput value at 2292.57 Kbps, a delay of 76.98 ms, and a packet loss of 0.12% for a scenario involving 150 nodes. This research aims to provide an alternative solution for developing post-disaster emergency communication networks and contribute to post-disaster rescue and recovery efforts.

Abstract: The earthquake caused by the Garsela Fault significantly damaged the infrastructure and home of residents around Pasirwangi District. This fault is in Garut Regency, West Java and is one of the primary sources of earthquakes in Garut. This study aims to calculate rate of surface deformation and interpret its causes by analyzing InSAR data from 2017 to 2021. LiCSBAS, a Python-based time-series deformation analysis program, processed InSAR data to determine fault movement attributes and sources. Geological mapping, analysis of fault kinematics and dynamics determine the characteristics and fault movement. The results of time series analysis show that the rate of surface deformation in the Pasirwangi and its surrounding areas ranges from -45 mm/year to 35 mm/year. The movement mechanism of normal and right-normal slip faults causes the dominant surface subsidence. The difference in maximum ground movement acceleration between the north and south areas is caused by force moments which distributed at building points, affected by the differences in building density in the research area.

Abstract: Fire produces unique effects on steel structures which can compromise the residual capacity and therefore the structural response if they impact jointly with other natural hazards, such as earthquakes. This work presents a procedure that allows for the extension of the analysis method introduced in the 1990s by Fajfar and Gaspersic and outlined in EC8 (referred to as the N2 method) for the case of Multi-Hazard (MH) analysis, specifically for hazard-chain scenarios involving earthquake and fire. The goal is to assess the structural performance at the end of the sequence of considered events. By appropriately modeling the structure considering elasto-plastic behaviour, it becomes possible to observe the structural response as the plasticization of structural elements progresses: in this context, accounting for material and geometric nonlinearities has proven essential, since the material and structure's behaviour under fire are governed by complex phenomena, due to the significant deformations and distortions involved. The hazard-chain scenario here discussed is characterised by the consecutiveness of main earthquake event and fire; the proposed procedure is then applied to a 2D steel structure. Results highlight that neglecting possible hazard interactions could lead to an erroneous evaluation of the residual structural capacity.

Abstract: Earthquakes cause deformations in structural elements which then lead to interstory drift and probability of collapse in building structures. Incremental Dynamic Analysis (IDA) will obtain a graph containing the Response Spectral Acceleration (RSA) value for the maximum interstory drift ratio, which will then be used to calculate the probability of collapse using the Fragility Curve. The structure is planned to be located in Biak city on hard soil conditions with a 16-story two-dimensional SRPMK building model. Various ground motions scaled to the design response spectrum of Biak city with 2 different methods were used. Based on the analysis conducted, the average interstory drift value for RSA scaling (T1) is 0.33 meters and RSA scaling (T1 = 0) is 0.2 meters, both of which occur on the first floor of the building structure. The largest RSA value obtained through IDA for the RSA scaling (T1) was 1.63 g and the RSA scaling (T1 = 0) was 1.89 g. Through the Fragility Curve, the probability of structural collapse at an RSA value of 1.63 g is 0.99 and at an RSA value of 1.89 g is 0.75.

Abstract: . The use of Ordinary Portland Cement (OPC) for building structures should be reduced because it can produce harmful CO₂ emissions. The use of environmentally friendly materials could be the solution. Liquid carbon dioxide (CO₂) is one of these material innovations. In this study, the liquid carbon dioxide was used as a substitute for OPC. The use of this material will affect the rigidity of the multi-story building structure. The effect of the stiffness variable value is tested by looking at the response of multy storey buildings during an earthquake. By using the finite difference method, the response of the multi-story building structure is analyzed through mode shape, structural displacement, and shear force.

Abstract: Ordinary Portland Cement (OPC) used in building structures has a negative impact. The presence of CO2 emissions produced becomes very dangerous. To reduce this impact, materials that are more environmentally friendly are used. Silica Fume and liquid carbon dioxide (CO2) are among them. In this study, silica fume and liquid carbon dioxide were used as a substitute for cement. The effect of the stiffness of the two materials and the earthquake lateral load was tested by looking at the response of the high-rise building. Through numerical simulations, we compare the mode shape, displacement of the structure, and the sheer force experienced by the structure.

Abstract: Masonry is used as a construction material since old age. It is a cheaper construction material compared to R.C.C. and also requires comparatively less construction skills. During an earthquake, the masonry wall constructed following the codal provisions shows preliminary behaviour in the in-plane direction of wall and it has lesser deformation in the out-of-plane direction of the wall. Although, the strength and stiffness of the Un-Reinforced Masonry (URM) walls were reduce due to sizes and positions of openings, the relationship between the seismic capacity of the walls and the position and size of opening in walls are not clear. Researchers in the past mostly explored the in-plane behaviour of solid masonry wall without opening. Considering the openings in these walls can significantly affect the strength of the masonry wall. Hence, in the present study, an attempt is made to understand the effect of varying opening sizes (4 different combinations of door and/or window openings) in unreinforced masonry wall using finite element software CATIA. From this software, URM walls were modeled and load based quasi-static analysis were done in in-plane direction. The collapse mechanisms of the masonry walls and crack patterns are studied from the analysis and a key output from this work is the characterization of the relationships between the sizes and positions of openings and the in-plane performance of masonry walls.

Abstract: Reinforced concrete buildings are normally designed and constructed with well-defined vertical column supports which are able to withstand both vertical and lateral loadings. In the case of high columns there is a risk of instability due to its slenderness caused by the higher apex ratio (measured by its height in relation to the width). This is compounded by having such buildings located at medium to high seismic risk zones, where lateral dynamic loadings can occur. This research paper focused on how such slender reinforced concrete columns will behave under earthquake loading conditions, and highlights some innovative ways to strengthen the column capacity to withstand both vertical and lateral loadings. Besides the conventional ways to provide diagonal or lateral bracings, the use of glass fibre reinforced polymer (GFRP) as an alternative material for retrofitting tall slender reinforced concrete columns are presented here. The new method includes spraying of the GFRP onto the external surfaces of the columns and also incorporate the GFRP bars as additional reinforcement into the concrete columns. Both methods proved to improve the durability and strengthen the tall reinforced concrete column. This study shows the ability of the new method of amelioration of the slender reinforced concrete columns to increase their stability during seismic activity.

Abstract: This paper presents the predicted results of nonlinear time history analysis of 11 storey (G+10) Reinforced Concrete (RC) residential building under the effects of a strong earthquake. The paper includes studying the effects of using Lead Rubber Bearings (LRB) as base isolators to improve the performance of RC building to sustain the impact of an earthquake. It also includes the effects of the infill panels on the overall dynamic response of both fixed base and base-isolated buildings subjected to a strong earthquake. The main results that are presented in this study include the variation of roof acceleration, roof displacement, base shear with time. The effects of using LRB and including the infill panels on the storey drift are also presented. Maximum reduction in the story drift was obtained when infill panels are included in the analysis of the base isolated building. The inclusion of the infill panels has only marginal effects on the variation of roof displacement with time when the building is isolated by LRB. The main important improvements that emerged from using LRB as well as the infill panels in the analysis are the reduction of inelastic energy and upgrading the elastic one that is summed up along the period of the earthquake.

Abstract: Steel structures are commonly used in seismic regions of the world because of its strength and ductility. However, these structures are still prone to damage during an earthquake. With this risk of seismic damage, the strengthening of steel structures is a major concern in order to resist the dynamic loads resulted from earthquakes. This report investigates the potential for the use of Carbon Fibre Reinforced Polymer (CFRP) to strengthen the rigid steel frame under a real earthquake load. This research will be undertaken using Strand7, a finite element (FE) analysis software. To validate the accuracy of this research, the finite analysis results have been compared to the available experimental study by the Authors. First, both FE models of a five-story bare steel frame and CFRP strengthened steel frame has been developed. Then the predicted numerical results of bare steel frame and CFRP strengthened steel frame under earthquake excitation are compared. The results indicated an increase in the seismic performance of the steel structure due to the strengthened with CFRP. The CFRP strengthened steel frame showed 15% less tip deflection compared to bare steel frame. Further analysis on the strengthening capabilities of higher thickness CFRP was performed to assess the effect of the thickness of CFRP and the higher thickness CFRP showed better seismic performance compare to normal thickness CFRP by reducing 34.38% of tip deflection.