Fluid - Structure - Soil Interaction of Cylindrical Liquid Storage Tank Subjected to Horizontal Earthquake Loading

Shallow founded tanks are strategic structures used to store a variety of kind of liquids. The fluid develops hydrodynamic effect on solid domain of container during an earthquake. This paper provides the theoretical background for numerical model on seismic response of fluid-structure-soil interaction. The Finite Element Method (FEM) was used for seismic response of shallow founded cylindrical container. The Fluid- Structure-Soil interaction of shallow founded tank was analysed according to theories of I. Limit States - the ultimate limit state (ULS) and II. Limit States - the serviceability limit state (SLS) pursuant to EN 1997-1. Summary of the results: the maximum rotation of foundation is growing with the reduction of the stiffness of the subsoil and the vertical and horizontal bearing capacity depends on the strength properties of the subsoil

METODE KESEIMBANGAN BATAS vs METODE ELEMEN HINGGA UNTUK ANALISIS PONDASI DANGKAL MENERUS PADA TANAH KOHESIF

The most common analysis methods on shallow foundation are Terzaghi, Meyerhof, and Vesic. All of them are based on limit equilibrium, when the foundation starting to failure by applying maximum load. One of disadvantages of this method is that deformation and displacement of foundation and soil are not being considered. This behavior is very important for determining ultimate bearing capacity. The subject of this research is to compare the bearing capacity of shallow foundation between limit equilibrium method and finite element method (FEM). The foundation is modeled as strip rigid footing, whereas soil media is cohessive material with Mohr-Coulomb material model. The variation of soil consistency are: very soft, soft, medium, stiff and very stiff. The result indicates that bearing capacity by using finite element approach is relatively different from limit equilibrium method. The first methods is larger than the last one. By using FEM, soil deformation around the foundation can also be determined. Keywords: finite element method, limiting equilibrium, Mohr-Coulomb material model, shallow foundatio

Pengaruh Bentuk dan Dimensi Tapak Pondasi terhadap Daya Dukung Pondasi Dangkal Akibat Beban Aksial pada Tanah Pasir

The load distribution of shallow foundation spread out along the width of the foundation. Ultimate bearing capacity is defined as the maximum load that can be supported by the footing. Some form of shallow foundation were square, rectangular and circular shapes were they made to analyze the influence of the foundation over the same area of the shallow foundation bearing capacity due to axial loads on sandy soil. Variations foundation area of 100 cm2, 150 cm2 and 200 cm2. In the same area, the square shape can withstand greater load than in rectangular and circular shapes. Addition area will make 50-100% in weight-bearing capacity increased from 102,016 to 157,661% for squares, 135,751 to 228,497% for the rectangle and circle 187,413 to 341.259%. There are differences in the results of observation and empirical formula. Shape factors of squares and circles according to Mayerhof, Vesic and Hansen are the same. So, Terzaghi`s formula was similiar phenomenom with this research

Increased temperature in urban ground as source of sustainable energy

This paper is part of the Proceedings of the 10th International Conference on Urban Regeneration and Sustainability (Sustainable City 2015). http://www.witconferences.comDensely urbanized areas are characterized by special microclimatic conditions with typically elevated temperatures in comparison with the rural surrounding. This phenomenon is known as the urban heat island (UHI) effect, but not restricted exclusively to the atmosphere. We also find significant warming of the urban subsurface and shallow groundwater bodies. Here, main sources of heat are elevated ground surface temperatures, direct thermal exploitation of aquifers and heat losses from buildings and other infrastructure. By measuring the shallow groundwater temperature in several European cities, we identify that heat sources and associated transport processes interact at multiple spatial and temporal scales. The intensity of a subsurface UHI can reach the values of above 4 K in city centres with hotspots featuring temperatures up to +20°C. In comparison with atmospheric UHIs, subsurface UHIs represent long-term accumulations of heat in a relatively sluggish environment. This potentially impairs urban groundwater quality and permanently influences subsurface ecosystems. From another point of view, however, these thermal anomalies can also be seen as hidden large-scale batteries that constitute a source of shallow geothermal energy. Based on our measurements, data surveys and estimated physical ground properties, it is possible to estimate the theoretical geothermal potential of the urban groundwater bodies beneath the studied cities. For instance, by decreasing the elevated temperature of the shallow aquifer in Cologne, Germany, by only 2 K, the obtained energy could supply the space-heating demand of the entire city for at least 2.5 years. In the city of Karlsruhe, it is estimated that about 30% of annual heating demand could be sustainably supplied by tapping the anthropogenic heat loss in the urban aquifer. These results reveal the attractive potential of heated urban ground as energy reservoir and storage, which is in place at many places worldwide but so far not integrated in any city energy plans.This work was supported by the Swiss National Science Foundation (SNSF) under grant number 200021L 144288, and the German Research Foundation (DFG), under grant number BL 1015/4-1

A record of fossil shallow-water whale falls from Italy

Twenty-five Neogene-Quaternary whales hosted in Italian museum collections and their associated fauna were analysed for evidence of whale-fall community development in shallow-water settings. The degree of bone articulation, completeness of the skeleton and lithology of the embedding sediments were used to gather information on relative water depth, water energy, sedimentation rate and overall environmental predictability around the bones. Shark teeth and hard-shelled invertebrates with a necrophagous diet in close association with the bones were used as evidence of scavenging. Fossil bone bioerosion, microbially mediated cementation and other mollusc shells in the proximity of the remains informed on past biological activity around the bones. The results are consistent with the hypothesis that shallow-water whale falls differ from their deep-water counterparts. Taphonomic pathways are more variable on the shelf and whale carcasses may not go through all steps of the ecological succession as recognised in the deep sea. Whilst the mobile scavenger and the enrichment opportunistic stages are well represented, chemosynthetic taxa typical of the sulphophilic stage were recovered only in one instance. The presence of a generalist fauna among the suspension feeding bivalves and carnivorous gastropods, and the extreme rarity of chemosynthetic taxa, suggest that predatory pressure rules out whale-fall specialists from shallow shelf settings as in analogous cold seep and vent shallow-water communities. © 2014 The Lethaia Foundation

The effects of foundation size on the seismic performance of buildings considering the soil-foundation-structure interaction

Copyright © 2016 Techno-Press, Ltd. Shallow footings are one of the most common types of foundations used to support mid-rise buildings in high risk seismic zones. Recent findings have revealed that the dynamic interaction between the soil, foundation, and the superstructure can influence the seismic response of the building during earthquakes. Accordingly, the properties of a foundation can alter the dynamic characteristics (natural frequency and damping) of the soil-foundation-structure system. In this paper the influence that shallow foundations have on the seismic response of a mid-rise moment resisting building is investigated. For this purpose, a fifteen storey moment resisting frame sitting on shallow footings with different sizes was simulated numerically using ABAQUS software. By adopting a direct calculation method, the numerical model can perform a fully nonlinear time history dynamic analysis to realistically simulate the dynamic behaviour of soil, foundation, and structure under seismic excitations. This three-dimensional numerical model accounts for the nonlinear behaviour of the soil medium and structural elements. Infinite boundary conditions were assigned to the numerical model to simulate free field boundaries, and appropriate contact elements capable of modelling sliding and separation between the foundation and soil elements are also considered. The influence of foundation size on the natural frequency of the system and structural response spectrum was also studied. The numerical results for cases of soil-foundation-structure systems with different sized foundations and fixed base conditions (excluding soil-foundation-structure interaction) in terms of lateral deformations, inter-storey drifts, rocking, and shear force distribution of the structure were then compared. Due to natural period lengthening, there was a significant reduction in the base shears when the size of the foundation was reduced. It was concluded that the size of a shallow foundation influences the dynamic characteristics and the seismic response of the building due to interaction between the soil, foundation, and structure, and therefore design engineer should carefully consider these parameters in order to ensure a safe and cost effective seismic design

Geochemistry and petrogenesis of volcanic rocks from Daimao Seamount (South China Sea) and their tectonic implications

The South China Sea (SCS) experienced three episodes of seafloor spreading and left three fossil spreading centers presently located at 18°N, 17°N and 15.5°N. Spreading ceased at these three locations during magnetic anomaly 10, 8, and 5c, respectively. Daimao Seamount (16.6. Ma) was formed 10. my after the cessation of the 17°N spreading center. Volcaniclastic rocks and shallow-water carbonate facies near the summit of Daimao Seamount provide key information on the seamount's geologic history. New major and trace element and Sr-Nd-Pb isotopic compositions of basaltic breccia clasts in the volcaniclastics suggest that Daimao and other SCS seamounts have typical ocean island basalt-like composition and possess a 'Dupal' isotopic signature. Our new analyses, combined with available data, indicate that the basaltic foundation of Daimao Seamount was formed through subaqueous explosive volcanic eruptions at 16.6. Ma. The seamount subsided rapidly (>. 0.12. mm/y) at first, allowing the deposition of shallow-water, coral-bearing carbonates around its summit and, then, at a slower rate (<. 0.12. mm/y). We propose that the parental magmas of SCS seamount lavas originated from the Hainan mantle plume. In contrast, lavas from contemporaneous seamounts in other marginal basins in the western Pacific are subduction-related