Papers by Keyword: Earthquake

Abstract: Thermal anomaly Detection prior to earthquake events has been widely confirmed by researchers over the past decade. In this paper, we use robust satellite technique approach (RST) on a collection of six years of MODIS satellite data, representing land surface temperature (LST) images to predict 21st May 2003 Boumerdès Algeria earthquake. The thermal anomalies results were compared with the ambient temperature variation measured in three meteorological stations of Algerian National Office of Meteorology (ONM) (DELLYS-AFIR, TIZI-OUZOU, and DAR-EL-BEIDA). The results confirm the importance of robust satellite technique as an approach highly effective for monitoring the earthquakes.

Abstract: Aseismic design of modern structures imposes a new requirement on structural engineers. Structural systems should withstand even very huge earthquakes. This goal cannot be achieved by standard design methods applying a linear elastic approach. An advanced aseismic design applies energy dissipating anti-seismic devices. During seismic event, these devices are exposed to a large plastic strain. The code EN 15129 is the standard on anti-seismic devices applicable in Europe. Mentioned standard defines a special material requirement imposed on devices working as energy absorbers. Material verification is possible only experimentally. In compliance with the instructions contained in the code EN15129, several cyclic tests of the materials S235 and DD11 have been used. Evaluation of the previous research and the current test results have proved that structural steel S235 is not applicable to the anti-seismic devices. As an alternative, steel DD11 has been suggested for this application. The test results have shown that the steel DD11 is applicable in specified range of target strain amplitudes.

Abstract: Current practice for seismic design of earth structures considers the use of displacement-based methods, which allow a quick and quantitative estimation of the movement of soil masses under earthquake loading. This type of procedures are aimed to establish a relationship between (i) the main earthquake parameters, (ii) the critical acceleration, and (iii) the corresponding permanent displacements of the soil structure. In this sense, based on the well-known Newmark’s sliding block method, several regression models intended for design purposes have been proposed during last decades. However, the selection of an appropriate method to predict the expected permanent displacements of a soil mass remains a difficult and somewhat arbitrary practice. In this paper, strong-motion records from four major Chilean earthquakes, grouped by soil conditions, are used to compare and evaluate the suitability of the reviewed methods for assessing the seismic performance of earth structures. From the results obtained, general conclusions and recommendations for practical applications on sites with similar characteristics to the Chilean subduction zone are elaborated.

Abstract: In reinforced concrete buildings in case of a possible earthquake, the buildings slamp as they lost their horizontal stability because of hinging of column ends. The assumptions for plastic hinge lengths are present during project stage of reinforced concrete buildings. According to Turkish Earthquake Regulations, although plastic hinge length is determined to be 0.5h, it's known that plastic hinge length is determined via various formulas in some other regulations all over the world. In reinforced concrete columns, it's necessary to indicate the effect of plastic hinge length on the column behavior. For this purpose, pushover analysis of 5 column samples having different plastic hinge lengths was performed with non-linear analysis program. As a result of pushover analysis, situations of plastic hinges formed in columns and their load-displacement curves were determined. The graphs and the data were compared and the results were discussed.

Abstract: Pacitan City, the capital of Pacitan Regency is located at the southern part of East Java Province. This area is facing directly to the earthquake source due to plates subduction between Indo-Australia and Eurasia plates. Southern part of this City is coastal resort area which is geologicaly consists of alluvial deposits that is still under compaction and some of the upper layers are consist of loose material. According to the condition, this area is vulnerable to the earthquake induced soil liquefaction. Five soil borings and 30 cone penetration tests were conducted in this study area to investigate soil properties for evaluating soil liquefaction. Severity of the potential surface damages due to liquefaction were identified by calculating Liquefaction Potential Index (LPI). The results show that study area is vulnerable to soil liquefaction, with potential damage severity vary from very low to very high. Medium to high severity of potential damage are distributed in almost area of the city, and only in the southern part close to the coast line have very high severity level.

Abstract: To account for the conflict sensitivity, one model is presented to fuse the high conflict risk evidences about earthquake-damaged underground structure. Following the nature ideology and model rule of Evidence Theory, the earthquake-damaged origin risk evidence is revised with Similarity Coefficients, and the identical intensity and conflict intensity is calculated for each risk evidence; the difference and conflict character is comparatively analyzed about the fusion rules respectively on Similarity Coefficient and Conflict Intensity; Under Standard DS Fusion Mode and Conflict Intensity Fusion Method, the four combination fusion model is presented as Model-AO, Model-RO, Model-AC and Model-RC, and the improved risk fusion operator is given for such earthquake-damaged underground structure evidences. Finally, case demonstrates the validity of the integrated model, which could overcome the high conflict lack in the risk fusion standard DS model.

Abstract: Structural vulnerability of buildings to damage needs to be identified during the time of earthquake for reliable seismic design. Conventional linear elastic design methods cease to predict seismic damages in buildings. Pushover analysis is a popular displacement-based nonlinear structural analysis procedure employed to predict the seismic behaviour of structures. Generally, buildings are designed based on the assumption that they are fixed at their base, without considering the foundation as well as soil. But in reality, when a structure is subjected to an earthquake excitation, it interacts with the soil, influencing the structural response. In this study, a multi-bay building with different heights are modelled and analysed, duly considering Soil-Structure Interaction (SSI). The study can form foundation for rigorous performance-based seismic design procedure, considering the effect of soil beneath the structure.

Abstract: In the areas prone to natural disasters, ability of lifeline systems from catastrophic damages is one of the most important challenges in civil engineering. One of the most important structures is elevated water tanks. Most of the damages observed to these structures under seismic events are due to the improper design and wrong selection of supporting system. This paper investigates the suitability of interlocking system for staging of an elevated water tank of higher capacity. As a preliminary study the performance of concrete interlock panelled tower under static condition is analyzed by considering the standard earth gravity under full and empty conditions. The study concludes that the new system can perform in a similar way as that of the conventional system.

Abstract: This paper presents the analysis of seismic ground response of Makassar, the capital city of South Sulawesi Province in Indonesia, by employing an equivalent linear approximation of non-linear response technique. In this way, in-situ geotechnical tests were undertaken to obtain soil mechanics properties and establish shear wave velocity profiles by using CPT and SPT based empirical correlation formulas. Acceleration time histories model, which is considered to be able to propagate similar maximum credible earthquake, was used for input motion in computing seismic ground response of typical deep sediment in Makassar. Our findings suggested that seismic wave travels from bedrock to surface would be amplified at range of 0.124g to 0.349g with amplification factor of 1.14 to 5.54. Response spectral acceleration is found at range of 0.315g to 1.501g with the frequency of 7.69 Hz to 20 Hz. The southern areas of the city would propagate a high seismic amplification, while the eastern areas would yield low amplification. This is due to typical deep sediment seated on the southern areas is a thick clay overlying stiff sand. This would create impedance contrast, leading to reverberating a trapped seismic wave in between those two layers, and then producing high resonance at surface level. Deep sediment with interbedded clay and sand or interbedded sand and clay above bedrock would yield a larger seismic amplification than deep sediment with only clay dominated or sand dominated soil.

Abstract: After the introduction of the ANCOLD Guidelines on the dam design to withstand earthquakes in 1998, many dams in Australia have been reviewed on their capacity to withstand earthquakes. As results, many of them have been upgraded in the last two decades to increase their resistance against seismic loading. This paper presents the current methods used in Australia to undertake seismic upgrade for earth dams. The paper firstly presents brief discussion on the current methods of seismic stability assessment of earth dams. It then discusses the advantages and limitations of the available methods for seismic rehabilitation. Finally, it presents one of the case histories of seismic upgrade in Victoria, Australia.