Earthquake Vibration Research Articles

Vulnerability Of The Garut District Region In Tarogong Kalam, Tarogong Kidul, Garut Kota, And Karang Pawitan Sub-District Based On Microtremor Measurement

The Tasikmalaya M 7.3 earthquake on September 2, 2009 had an impact on Garut, damaged infrastructure and claimed many lives. From the search results there were five areas that were severely damaged by tectonic earthquake shocks, which included Pemeungpeuk, Cisompet, Cikelet, Peundeuy and Banjarwangi Subdistricts, so that earthquake mitigation measures were needed. One of the mitigations that can research how the impact is if the potential for earthquake disasters occur below the southern surface of Java. The final objective of this research is to map disaster-prone zones in Tarogong Kaler, Tarogong Kidul, Garut City, and Karang Pawitan, Garut Subdistrict, based on dominant frequency values, Vs30, seismic vulnerability indexes, and GSS (Ground Shear Strains) so that they can know the land movement that is. Retrieval of data in this study by measuring geophysicaly methods in the field. Processing data using HVSR (Horizontal to Vertical Spectra Ratio) method, then mapped with ArcGis to interpret the zoning of the study area. Based on the research, we known that the dominant frequency distribution value is between 1-5.2 Hz. The seismic vulnerability index values calculated the study area are between 3 – 45, GSS values in the study area between 3 ×10-4 - 42×10-4. By looking at the spatial distribution of the values of f0, Kg and GSS the areas of Karangmulya, Jatiasih, Sidanggalih and Godog villages are types of young volcanic sediments classified as soft soils that are easily to wave amplification and earthquake vibrations, so that they are easily damaged during large earthquakes. in this region qualify as earthquake resistant buildings to minimize damage and losses, while Sukabakti, Kersamenak, Sukajaya, and Mekargalih villages in the west with the geological conditions of the surrounding area which is hard land so that it will be safer when an earthquake occurs.

Liquefaction Hazard Mapping Based on LPI (Liquefaction Potential Index) At Jepara, Indonesia

Liquefaction is a phenomenon of loss of strength of the soil layers caused by earthquake vibration. Liquefaction causes the soil to be in a liquid – like state, especially on sandy soil. Analysis of liquefaction potential was performed by using the semi-empirical method by calculating the Safety Factor (SF) based on Standard penetration Test (SPT) and Cone Penetration test (CPT) data. After the SF value was obtained, then the Liquefaction Potential Index (LPI) was calculated to determine the level of potential liquefaction in the study area to further produce a liquefaction potential map based on the liquefaction potential index. Based on the results of the calculation of the LPI, the level of liquefaction potential in the study area was very low when the earthquake magnitude is 5 Mw because the Liquefaction Potential Index (LPI) = 0. When the earthquake magnitude is 6 Mw, 7 Mw, 8 Mw, and 9 Mw, most of the investigation area has low potential level and there are some points that a high potential level.

Identification of earthquake types based on seismogram data

Indonesia is one country that has many active volcanoes, and it can have a high potential for earthquakes due to volcanic activity. Central Java is an area that has an active volcano, the Mount Slamet. Various kinds of earthquake signals, earthquake strength, and frequency are recorded using a seismogram. The process of recognizing seismic signal patterns using short-wave transformations has a higher chance of success. Several types of earthquakes that have occurred on the Mount Slamet. There are three types of earthquake data tested, Shallow Volcanic Earthquakes (VB), Gust, and Tremors. This study aims to identify the type of earthquake vibration signals recorded on the seismograph. Earthquake image processing system consists of several parts. The image is normalized to get the image in the time domain. Then the image is processed with two processes to determine the characteristics of the earthquake. The Fast Fourier Transform process is used to determine the strength of earthquake signals based on the frequency. The quantization process is used to take samples of each data in the time domain. In this study, the method used for identification is pattern recognition and decision trees. The identification system can recognize signals that are approached using the Root Mean Square, Average Power Spectrum, and statistical features. The results of tests carried out obtain 100% accuracy of each method.

Earthquake and Tsunami Alert Through GSM Network

The earthquake and tsunami are dangerous natural disasters that are unpredictable, which causes damage to lives and property. It happens all of a sudden, but we can alert from it. In this modern world, many modern technologies can easily analyze the small vibrations and knock so that we can take the necessary precautions. The usage of accelerometer ADXL335 paves the way to sense the earthquake vibrations and tsunami seismic waves in all three axes. This project setup includes the LoRa and GSM module in addition to the accelerometer. Hence, it acts as a perfect shield because it gives a warning, vibration graph on the computer and spread the warning via messages.

Investigating the seismic impact made by the underground large-scale blast on the secure facilities of Kyshtym GOK when caving the floor pillar

Introduction. Within the mining claim boundaries of Kyshtym GOK the underground large-scale blast was made to cave in the floor pillar with the maximum explosive weight of 963 kg at the spacing stage. The Institute of Mining UB RAS has received a task to study the seismic impact of the underground large-scale blast on the secure facilities of Kyshtym underground mine industrial site located in the close proximity to the sites of blast works. Research aim is to determine the seismic stability of grounds at the sites of the secure facilities and the permissible values of vibration velocities for Kyshtym GOK buildings. It is also necessary to determine the permissible distances from the blast to the secure facilities for 5 engineering-geological elements on the basis of physical and mechanical properties of rock. Research methodology. On the basis of the initial data, according to the method of IM UB RAS, ground seismic stability calculations have been made at the sites of the facilities to determine the permissible values of vibration velocities for Kyshtym GOK buildings. A multivariate calculation of permissible distances from the blast to the secure facilities for 5 engineering-geological elements (EGE) has also been made depending on the explosive weight at the spacing stage, the coefficient of ground conditions and the permissible velocity of seismic vibrations. Results. The actual velocities of earthquake vibrations were determined by the results of experimental measurements using Minimate Plus and URAN seismic recorders, the values of which did not exceed the permissible velocities of ground motion in the base of buildings. Summary. As a result of comparing calculated values and experimental measurements, the recommendations have been given to establish the limitation of the explosive weight at the spacing stage to the level of minimum hazardous values during the large-scale blasts in the underground mine.

Study on Application of Vibration Response Control System on a Teaching Hospital Foundation Structure that Subjected to Earthquake Excitation

Strong earthquake affects buildings to response in huge dynamic oscillating motion. In a teaching hospital that full of patients, medical personnel and medical treatment facilities as well as many modern advanced equipment may be in very dangerous situation due to this building response. To reduce the human victims, equipments and infrastructure damages, a kind of base isolation is added to the foundation of the hospital building. Inspite of oscillation motion as a vertical cantilever, this foundation base isolation of the hospital building is applied and designed to give the response of the earthquake vibration waves in lateral motion. To find out the optimum properties of the base isolation, some calculations of the response from vibration parameters are observed. The Keq value is 415,120,000 N/m and the total massive Mass of the hospital is 148,057,364 kg as well as the highest vibration force is 108,136,030.2 N. This study work deals with simplified modelling using FEA in ANSYS software. The aim is to see the simulation based on the calculation of the analysis and whether the response is as expected.

A Self-Powered Magnetostrictive Sensor for Long-Term Earthquake Monitoring

A self-powered magnetostrictive sensor (SMS) for long-term earthquake monitoring is proposed in this article. A piece of magnetostrictive material was bonded on the upside surface of a stainless steel plate to form the proposed sensor. A force was applied on the free end of the sensor to mimic an earthquake vibration. The applied stress led to a varied permeability of the magnetostrictive material according to the Villari effect. Then, the varied permeability produced a varied magnetic field. The varied magnetic field was captured by a coil to generate electric power for an earthquake alarm. A theoretical analysis was investigated in this article. After the fabrication of a sensor prototype, the vibration characteristics and voltage output ability were measured. The maximum vibration amplitude and maximum output trust voltage were tested to be 25 mm and 0.38 V (peak to peak) under an applied force of 2 N. The proposed SMS exhibits merits of simple structure, small size, easy fabrication, and long-term working ability.

Numerical investigation on vibration-induced two-phase distribution in a vertical annular channel

Earthquake vibrations have great impacts on two-phase flow in the reactor core. In this paper, numerical simulations were conducted to identify the air-water two-phase distribution in a vertical upward annular channel under horizontal vibration condition. The inner and outer diameter of the annular channel are 19.1 mm and 38.1 mm. The simulations were performed based on the two-fluid Euler-Euler modeling framework. Benchmark simulations for bubbly flow under stationary condition were firstly conducted to validate the up-to-date interfacial force models. Applicability of the interfacial force models were evaluated and a set of Ishii-Zuber drag force model, Tomiyama lift force model, Frank wall lubrication force model and Burns turbulent dispersion force model was found to provide the best agreement with experimental results. Based on this work, two-phase flow distributions under vibration condition were studied. Horizontal vibration of the annular channel was simulated by introducing simple harmonic motion. The vibration frequency and vibration amplitude were set to 1.97 Hz and 9.5 mm, respectively. Additional interfacial force caused by inertial effect was imposed on disperse bubbles under vibration condition, which promoted the lateral migration of bubbles. The numerical results showed that the distributions of local interfacial parameters varied periodically along the vibration direction. A maximum increase of about 32% was observed in the peak void fraction compared to that under stationary condition for case 3. But the distribution of local flow parameters remained unchanged in the direction perpendicular to the vibration. A good consistency between the simulation results and the experimental data was found. The comparison results indicate that the present modeling method is able to predict the two-phase distribution of bubbly flow under vibration condition. But an inhomogeneous model considering bubble interactions and grouping is suggested for two-phase flow beyond bubbly regime.

Study of the Seismic Performance of Composite Shear Walls with Embedded Steel Truss For Use in High-rise Buildings

Abstract The composite wall with encased steel braces (ESB wall) is a novel type of steel–concrete composite wall that consists of a steel braced frame embedded in reinforced concrete. This arrangement is supposed to enhance the seismic performance of the wall, as the steel columns encased in the boundary elements can increase the flexural strength of the wall and the steel braces encased in the web can increase the shear strength. ESB walls have seen use in super tall building structures constructed in regions of high seismicity. The ESB walls are commonly used on stories where the shear force demand is very high. Currently, no design guidelines exist for the design of ESB Walls in the Eurocode. More research is required before a distinct set of guidelines can be prescribed for the design of ESB Walls. The present research will investigate behavior of composite walls with encased steel braces (ESB walls). Time history analysis will be performed to examine the shear strength and stiffness of the ESB walls. In this study, two frames with three floors and five floors will be modeled in ABAQUS software. Then the X- shaped braces and inverted V brace is added to frames. Later, reinforced concrete shear wall will be added to braced frames, so the steel braces encased in the reinforced concrete shear wall. Time history analysis, on the braced frames will be done Compare and note with each other. The results of the study are in good agreement with those of previous studies. However, none of these studies examined the effect of using V- and X-shaped struts and shear walls simultaneously, nor did they examine which struts reinforce the structures more strongly against earthquake vibrations. This has led the study to examine the effect of these reinforcements under various earthquakes. In future studies, reinforced concrete structures can also be used in addition to steel structures, and the results can be compared. In addition, these braces can also be used in other parts of the building. To meet this objective, one can use the very important data provided in this thesis, and ultimately better and more accurate results can be extracted using this approach. The main aim of this thesis is to study the effect of increasing the number of floors on how to extend the stress on the building structure. To this end, the number of floors increased from three to five. Therefore, it can be concluded that an increase in the number of floors also more than 5 storey causes stress values, but these modes are quite consistent with the three- and five-storey buildings.

2D numerical simulation of urban dam break and its effect to building using lax scheme with numerical filter

Dam-break is one of the disasters that can occurred due to earthquake. The earthquake vibration may damage the dam construction and therefore causing a dam-break flow. The flow can cause severe destruction to the downstream urban area. Dam-break modeling offers a way to analyze its effect of buildings. In this study, a 2D model for analyzing dam break flow is developed based on the Saint Venant equations and solved using Lax Scheme. The initial condition of the modelling is a rectangular channel with obstacles at both sides of the channel and two similar columns in the middle of the channel. These obstacles are considered as buildings in an urban area. Numerical filter is used to increase the stability of the simulation. The developed model is able to perform well in simulating a case of urban dam-break based on a previous experiment. In addition, the applied numerical filter is able to handle shock, therefore maintaining the stability of the model while reducing the simulation time without the needs to use a higher order numerical scheme.

The role of viscoelastic damping on retrofitting seismic performance of asymmetric reinforced concrete structures

The primary purpose of this research is to improve the seismic response of a complex asymmetric tall structure using viscoelastic (VE) dampers. Asymmetric structures have detrimental effects on the seismic performance because such structures create abrupt changes in the stiffness or strength that may lead to undesirable stress concentrations at weak locations. Structural control devices are one of the effective ways to reduce seismic impacts, particularly in asymmetric structures. For passive vibration control of structures, VE dampers are considered among the most preferred devices for energy dissipation. Therefore, in this research, VE dampers are implemented at strategic locations in a realistic case study structure to increase the level of distributed damping without occupying significant architectural space and reducing earthquake vibrations in terms of story displacements (drifts) and other design forces. It has been concluded that the seismic response of the considered structure retrofitted with supplemental VE dampers corresponded well in controlling the displacement demands. Moreover, it has been demonstrated that seismic response in terms of interstory drifts was effectively mitigated with supplemental damping when added up to a certain level. Exceeding the supplemental damping from this level did not contribute to additional mitigation of the seismic response of the considered structure. In addition, it was found that the supplemental damping increased the total acceleration of the considered structure at all floor levels, which indicates that for irregular tall structures of this type, VE dampers were only a good retrofitting measure for earthquake induced interstory deformations and their use may not be suitable for acceleration sensitive structures. Overall, the research findings demonstrate how seismic hazards to these types of structures can be reduced by introducing additional damping into the structure.

Damage detection in concrete gravity dams using signal processing algorithms based on earthquake vibrations

In structural engineering, damage detection in concrete gravity dams (CGDS) is a practical problem. Dam destruction can have severe financial consequences and may even lead to fatalities. Therefore, structural health monitoring in advance is crucial. In this regard, a well-known CGD, namely the Pine Flat Dam, has been chosen for the Finite Element Modeling. In this paper, damage is induced in the dam neck through elasticity modulus reduction by 40 % and 80 %. In addition, after applying Northridge earthquake, the acceleration in structure nodes for intact and damaged cases are recorded in vector formats. Using various methods, such as Discrete-time Fourier Transform (DTFT), Wavelet transform and Wiener transform, the differences between these two signals are investigated. The standard deviation (S.D.) of variations is chosen as the performance metric and is applied to the signal amplitude between intact and damage observations/signals. The reason why several signal processing algorithms are used is finding an approach which shows more clearly the differences caused by the destruction. This is evaluated via S.D. values for different algorithms. The results confirm the superiority of DTFT over other given algorithms. DTFT has a negligible outperformance (approximately zero dB) with respect to the Wavelet transform in both the crest and the lower nodes of the dam. This rate for DTFT and Wavelet is 10dB higher than that of Wiener and 35 dB in comparison with the simple amplitude difference. Moreover, the detection thresholds for the given methods are compared, and it is verified that the DTFT and Wavelet indicate the best performance.

Use of Rubber and Soil Mixture as a Base Isolation Technique for Developing Countries: A Review

Seismic Isolation technique has been in a developing phase for more than a century. For developing countries like Nepal, this technique ought to be viewed on the basis of its significance in terms of reducing Earthquake vibrations, while contiguously taking cost-effectiveness as an indispensable factor. To account for this, Rubber Soil Mixture (RSM) has been proposed as a suitable isolation mechanism. Furthermore, using rubber in this technique helps in significantly reducing the environmental effect caused by stockpiling of waste tire scraps. Addition of rubber on soil to form RSM mixture in the foundation layer shows that the mixture influences geotechnical properties of the soil, thereby, reducing the effect of ground excitation to the superstructure. Moreover, the structural responses in terms of base shear, base moment, inter-story drift, and acceleration gets reduced ensuring safety of the structure.

Dynamic behaviour of a 13-story reinforced concrete building under ambient vibration, forced vibration, and earthquake excitation

This paper presents a unique study of dynamic behaviour of a full-scale 13-story reinforced concrete building under forced vibration, ambient vibration, and distal earthquake-induced excitation. Initially, an eccentric mass shaker located on the upper floor of the building was used to excite the building while instrumented with eight accelerometers. Then, ambient vibrations induced by traffic and wind were recorded over a period of two weeks, utilizing over 40 tri-axial accelerometers. During the sampling period, the building was excited by a M6.5 earthquake and high-quality vibration data sets were recorded. Modal parameters of the building were identified with a range of frequency and time domain system identification (SI) methods, and the influence of excitation force characteristics on performance of various techniques was also investigated. A finite element model of the building was developed using SAP2000 to compare modal properties to the identified counterparts from experiments. Results showed a strong correlation between modal parameters identified by different SI methods, and all techniques provided accurate estimation of modal parameters when used with output-only data. Modal parameters determined from ambient vibrations were comparable to their forced vibration counterparts, providing evidence that ambient vibration testing can be as effective as forced vibration testing in determining modal parameters for similar size structures. The near stationary vibration data can produce accurate estimation of modal parameters. However, further study is required to facilitate application of output-only SI techniques with non-stationary data. There was a good match between peak displacement amplitudes obtained by the numerical model and those experimentally measured at different excitation frequencies. This match demonstrated the accuracy of the finite element model to predict realistic dynamic behaviour of the building under various harmonic excitation forces.

Analisis Kestabilan Lereng di Bukit Tui Section S0° 28’ 50.23” E100° 24’ 16.89”- S0° 28’ 49.19” E100° 24’ 17.07” Kecamatan Padang Panjang Barat Kota Padang Panjang

Tui Hill is a limestone hill lined south of Padang Panjang, located between Rao-Rao Village to Tanah Hitam. The results of research at Tui Hill at the location S0° 28’ 50.23” E100° 24’ 16.89”- S0° 28’ 49.19” E100° 24’ 17.07” located in Tanah Hitam Village has a covered dolomite rock slope. Based on the Indonesian earthquake zoning map, the city of Padang Panjang is classified as a high earthquake vibration zone, ranging from 0.8-0.9 g. The potential for landslides on the slopes of the study can lead to the closure of the access road to dolomite mining so that it can hamper road user traffic and disrupt mining production as well as potential material losses and fatalities This study aims to determine the Safety Factors on earthquake slope research and recommendations to increase the value of Safety Factors (FK). Based on the results of the analysis by simulating earthquake vibration values the maximum earthquake vibration values that can be held by slopes in a safe condition is 0.2 g or equivalent to 6.4-6.6 on the Richter Scale, namely with FK of 1,281. Then, the author issued for the slope by changing the slope of the slope from 53˚ to 25˚ increases can obtain a slope FK value of 1.438, according to Joseph E. Bowles (1984) the slope is in accordance with the safe conditions.

Experimental on the Residential Building of Earthquake Prone Areas using Shake Table Test

This paper highlights the experimental analysis on the Shake Table Test. The Shake Table is an equipment by which real earthquake conditions, forces and vibrations on any structure can be experimented, recorded and studied. When an earthquake occurs over an area it leads to the pause of the normal day to day life, havoc damages, loosing of human lives and failure of the structures. In this study the model is mounted is on the shake table and the vibrations are recorded. The Limit State Design criteria is considered from IS 456:2000 and for Seismic analysis the Load Combination is considered from IS 1893(PART-I):2002.

Neural network control for earthquake structural vibration reduction using MRD

Structural safety of building particularly that are intended for exposure to strong earthquake loads are designed and equipped with high technologies of control to ensure as possible as its protection against this brutal load. One of these technologies used in the protection of structures is the semi-active control using a Magneto Rheological Damper device. But this device need an adequate controller with a robust algorithm of current or tension adjustment to operate which is further discussed in the following of this paper. In this study, a neural network controller is proposed to control the MR damper to eliminate vibrations of 3-story scaled structure exposed to Tōhoku 2011 and Boumerdes 2003 earthquakes. The proposed controller is derived from a linear quadratic controller designed to control an MR damper installed in the first floor of the structure. Equipped with a feedback law the proposed control is coupled to a clipped optimal algorithm to adapt the current tension required to the MR damper adjustment. To evaluate the performance control of the proposed design controller, two numerical simulations of the controlled structure and uncontrolled structure are illustrated and compared.

Adaptive sliding mode vibrations control for civil engineering earthquake excited structures

In recent years, the semi-active control of structural vibrations has interested several researchers. It has been demonstrated that semi-active control strategies are economical solutions for the safety of structure against earthquake or wind excitations. In this study, a semi active device which utilizes the Magneto-Rheological fluid characteristics to dissipate the earthquake excitation energy is proposed. The Magneto-Rheological damper is adopted to control the undesired vibrations of an earthquake-excited structure. Furthermore, a sliding mode controller coupled to the Clipped optimal algorithm is proposed to control this semi-active device. Otherwise, the sliding mode controller is reinforced by an adaptive gain law and the effectiveness of the new proposed adaptive controller to control the structural earthquake vibrations is proved by the compared numerical simulation results of the controlled and uncontrolled structure. Thus, the improvement of the sliding mode controller through the adaptive gain law is proved by the evaluation indices of an excited three-story scaled structure. Hence, a comparison between the results of the proposed adaptive sliding mode controller and the uncontrolled structure under the El Centro 1940 and the Boumerdes 2003 earthquakes excitations are discussed.

Seismic Performance of High Voltage Composite Insulator Circuit Breaker

Dynamic seismic force causes damage to electrical equipment and structures resulting in loss of human and animal life. High voltage substation equipment are highly vulnerable to earthquake event compared to low voltage distribution network. Vulnerability to seismic event increases with increase in voltage rating of substation due to taller and slender porcelain structures. Porcelain insulators used in substation equipment have high compressive strength but weak tensile strength. Hence ceramic insulators are the weakest part in the substation equipment in the event of earthquake. Earthquake with 0.1g zero period acceleration can cause massive damage to high voltage substation equipment. Substation equipment with composite insulator are comparatively less vulnerable to seismic loading. Central Power Research Institute (CPRI) is equipped with state-of-the-art tri-axial shake table facility for simulating tri-axial earthquake vibration. Seismic qualification methods, codal provisions and seismic performance of 145 kV three pole operated composite insulator SF6 circuit breaker by shake table method are discussed in this paper. The seismic strain at critical locations, response acceleration on circuit breaker are presented along with relative displacement at the terminal of circuit breaker.

ANALISIS POTENSI LONGSOR LERENG BUKIT TUI KELURAHAN TANAH HITAM KOTA PADANG PANJANG SUMATERA BARAT MENGGUNAKAN APLIKASI SLIDE V6.0

Tui Hill is a limestone hill lined south of Padang Panjang. It is located between Rao-Rao Village and Tanah Hitam. Based on the results of investigations of researchers on the slopes of Bukit Tui limestone in the coordinates S0 ° 28'21.3 "E100 ° 24'00.4ʺ which are in the Tanah Hitam Village, there are many weak fields such as burly, steep slope geometry, influence on earthquake vibrations, and rainfall the high can lead to landslides on slopes, potential for landslides on the slopes of research can endanger road users and community settlements on slope locations. This study aims to analyze the potential of landslides based on the physical and mechanical properties of intact rocks, using the boundary equilibrium method. Then make reinforcement recommendations so that slope conditions are safe / stable. Based on the results of analysis and calculations in saturated conditions with the influence of earthquake factors 0,7 - 0,9g the values ​​of FK 1,461, 1,295, and 1,144 were obtained. From the results of the analysis, the slope is unsafe / unstable. In the original condition with 0.9g earthquake factor, FK 1.364 is obtained. Based on the results of analysis and calculations, the slope reinforcement recommendation used is the wire mesh installation method (wiremesh) in slope face.