Effects Of Local Soil Conditions Research Articles

Study of soil structure interaction on basement wall with variants in distance and depth of the basement on soil class SE

The function of the basement is to carry the weight of the upper structure into the soil and to resist lateral loads around the basement wall. One aspect of geotechnical engineering that often a problem in basement wall planning is the determination of lateral ground pressure in the basement wall due to earthquake which must be held by the basement wall. In this study, an analysis of the effects of local soil conditions due to dynamic loads is done through analysis of soil-structure interaction. The analysis is done by modeling the local soil with variations in basement depth and the adjacent basement distance to get the lateral pressure distribution due to dynamic load. The analyzed soil conditions are considered homogeneous at land sites SE (soft soil) with the dynamic load input from earthquake loads uses a 10% probability of exceedance in 50 years (500 years). The most influential parameter for soil displacement is the distance of the basement and then the depth of the basement. The most influential parameter on lateral forces is the depth of the basement followed by the distance of the basement.

Soil and transport factors in potential distribution systems for biofertilisers derived from palm oil mill residues in Malaysia

Oil palm provides an important source of edible oils and fats, accounting for >30% of total global production and >55% of the international trade in these foodstuffs. The palms produce fresh fruit bunches, comprising several hundreds of small fruitlets, which are compressed and steamed to extract the oil. Soil nutrients in oil palm estates become depleted after decades of heavy harvesting and require fertilisers. Liquid palm oil mill effluent, solid empty fruit bunches and other residues can have deleterious environmental impacts and require careful management.The problems of residue disposal and soil nutrient impoverishment can be linked and managed by composting the oil palm mill residues and distributing the biofertiliser produced back to the plantation. Using case studies from West Malaysia we present an early stage practical tool for the planning of the distribution component of such a cycle. The computer-based tool uses multiple field-based and remote sensing data sources to integrate the effects of local soil conditions, transport distances, environmental protection and management priorities and then models customised distribution plans. The tool operates at plantation level and can be augmented with detailed local data, but the approach is extensible and potentially applicable to regional or national planning.

The Effect of Soil Type and Different In-situ Test Results on Soil Amplification Analysis

The effect of local soil conditions is taken into consideration in the evaluation of ground motion properties in seismic design of structures. One of the most important effects on the ground surface due to strong ground motion is soil amplification resulted in the structural damage. Soil amplification can be determined both by dynamic analyses performed according to analytical methods based on local site conditions and obtained with investigations based on the results of in-situ testing methods. Therefore, the effects of local site conditions are considered to evaluate the properties of ground motion for seismic design of structure. In this study, soil properties of İnönü district are evaluated based on Standard Penetration Test (SPT) and Multi-Channel Analysis of Surface Wave (MASW) method which is one of the geophysical methods. İnönü is located at the west of Eskişehir surrounded with numerous active fault systems and subjected to very intensive tectonic activities in geological history. The studies related to seismic activity have been made on the basis of probabilistic seismic hazard analyses. Soil amplification analyses are performed with Shake2000 software comparatively by taking into considerations data from in-situ testing methods.

On the realization of seismic microzonation of Almaty (Kazakhstan) in ground accelerations based on the “continual” approach

Seismic microzonation for Almaty city for the first time use probabilistic approach and hazard is expressed in terms of not only macroseismic intensity, but also Peak Ground Acceleration (PGA). To account for the effects of local soil conditions, the continual approach proposed by A.S. Aleshin [1, 2] was used, in which soil coefficients are a function of the continuously changing seismic rigidity. Soil coefficients were calculated using the new data of geological and geophysical surveys and findings of previous geotechnical studies. The used approach made it possible to avoid using soil categories and a jump change in characteristics of soil conditions and seismic impact. The developed seismic microzonation maps are prepared for further introduction into the normative documents of the Republic of Kazakhstan.

Influences of Local Soil Conditions for Ground Response in Kolkata City During Earthquakes

Ground motion while travelling from the bedrock to the ground surface, causing a change in amplitude and frequency of the seismic waves, and leading to amplification of ground motion have been seen in Kolkata in eastern India. One dimensional equivalent linear ground response analyses for some typical soil sites in Kolkata city of India have been implemented using SHAKE2000 for studying the effects of local soil conditions on the ground motions taking five different input motions having a wide variation in ground motion parameters. It is observed that the maximum horizontal acceleration at the ground surface is amplified by 4.1 times for 2001 Bhuj motion while the Fourier amplification factor and spectral acceleration at 5 % damping is observed to be 10.15 and 3.84 g, respectively at Rajarhat area due to 2011 Sikkim motion. The response spectrum curves obtained are useful for designers for evaluating the safety in designing infrastructures against earthquake forces in Kolkata city, especially in the absence of site specific data.

Effect of local soil conditions on dynamic ground response in the southern coast of Izmir Bay, Turkey

The city of Izmir, located at the western end of Turkey, has experienced many strong earthquakes throughout its history. The southern coast of Izmir Bay, one of the most densely populated areas of Izmir, is located on deep alluvial sediments. It is important to determine the effect of local soil conditions on dynamic ground response in the study area, where thick loose water-saturated alluvial sediments exist. A database including geotechnical and geological information on the study area is constructed. Majority of the site is classified as D and E according to NEHRP provisions. Dynamic site response analyses are performed with EERA by utilizing the field and laboratory test results and earthquake time histories of moderate-scale earthquakes such as 1977 Izmir (ML=5.3), 2003 Urla (Md=5.6), and 2005 Uzunkuyu-Urla (ML=5.9), which occurred in and nearby Izmir. In addition, a scenario ground motion generated by the Izmir Fault with a magnitude of 6.5, having an average distance of 10km to the study area, is also considered. The output data obtained from the dynamic site response analyses are evaluated, and maps displaying variation in dynamic parameters on ground surface are prepared for the southern coast of Izmir Bay, Turkey. Consequently, the dynamic analyses performed with the soil models constituted for the study area verified the damage occurred in a close distance event of 1977 Izmir earthquake. The scenario earthquake resulted in peak ground accelerations more than 0.6g at the eastern and western ends of the study area. However, long distance events resulted in spectral amplifications by up to 5 times. With this study, it is emphasized that local soil conditions should be evaluated individually in the area of interest. Generation of a site-specific design spectrum is recommended for the areas located on deep alluvial sediments.

An Overview of Soil Models for Earthquake Response Analysis

Earthquakes can damage thousands of buildings and infrastructure as well as cause the loss of thousands of lives. During an earthquake, the damage to buildings is mostly caused by the effect of local soil conditions. Depending on the soil type, the earthquake waves propagating from the epicenter to the ground surface will result in various behaviors of the soil. Several studies have been conducted to accurately obtain the soil response during an earthquake. The soil model used must be able to characterize the stress-strain behavior of the soil during the earthquake. This paper compares equivalent linear and nonlinear soil model responses. Analysis was performed on two soil types, Site Class D and Site Class E. An equivalent linear soil model leads to a constant value of shear modulus, while in a nonlinear soil model, the shear modulus changes constantly,depending on the stress level, and shows inelastic behavior. The results from a comparison of both soil models are displayed in the form of maximum acceleration profiles and stress-strain curves.

Site response zones and short-period earthquake ground motion projections for the Las Vegas Basin

A deterministic seismic hazard analysis was conducted to address the effect of local soil conditions on earthquake-induced strong ground motion in the Las Vegas Basin, Nevada (US). Using a large geological and geotechnical database, two response units were defined: a fine-grained unit, predominantly clay; and a coarse-grained unit, predominantly gravel. A moderate number of high-quality shallow shear wave velocity measurements were collected from which characteristic shear wave velocity profiles were developed for each response unit. An equivalent-linear one-dimensional site response model was used. The model was calibrated using a basin-wide, small-strain ground motion database. Calibration tests showed that ground motion projections become increasingly conservative with increasing ground-motion amplitude. Projections were overconservative for the coarse-grained response unit, likely due to the sparseness of the velocity database. For the earthquake response analyses, historical ground motions were used to model characteristic ‘bedrock’ motion for earthquakes on 10 faults judged to be critical. Response spectral envelopes were generated for each unit through Monte-Carlo simulations. For the fine-grained response unit, 95th percentile peak ground acceleration, peak spectral acceleration and predominant period were 310 cm/s2, 1100 cm/s2, and 0.29 s, respectively. With respect to codified design spectra, projections are lower at short periods and higher at long periods. Projections of peak spectral accelerations for the coarse-grained response unit, were more than double that of codified spectra; however, they are believed to be overconservative. Near-fault effects and basin-edge effects, though potentially important, were not considered in these analyses.

Analytical calculation of blast-induced strains to buried pipelines

The aim of this paper is to introduce a robust methodology for the analytical calculation of strains in flexible buried pipelines due to surface point-source blasts. Following a brief bibliographic overview regarding the characteristics of ground waves produced by surface explosions, a method used to model wave propagation with radial attenuation and spherical front is presented. Strains due to P- and Rayleigh waves, which dominate the waveform generated by an explosion, are accordingly calculated by modeling the pipeline as a three-dimensional (3-D) cylindrical thin shell and ignoring soil–structure interaction. To simplify the design procedure, a set of easy-to-use relations for the calculation of maximum strains and their position along the pipeline axis is supplied. The derived expressions are evaluated through comparison against 3-D dynamic numerical analyses, field strain measurements in flexible pipelines due to a series of full scale blasts, and state-of-practice design methods. Comparisons show that the proposed methodology provides improved accuracy at no major expense of simplicity, as well as the advantage of properly accounting for the effect of local soil conditions.

Microzonation of Zeytinburnu region with respect to soil amplification: A case study

A microzonation study is performed as a part of the Zeytinburnu Pilot Project within the framework of the Earthquake Master Plan for Istanbul to determine the effects of local soil conditions on the earthquake forces that will act on structures. For this purpose, detailed geological and geotechnical studies are conducted at the site, a geological map which demonstrates the local geological features of the site is prepared, and the site is classified with respect to the dynamic behaviour based on the data gathered from the soil borings. In order to investigate the effects of local soil conditions on the dynamic behaviour, site response analyses are performed with the computer code EERA by utilizing the findings of field and laboratory investigations. The behaviour of the region during a probable earthquake is investigated through one dimensional response analyses and microzonation maps are prepared with respect to ground shaking intensity in accordance with the new microzonation manual [Ansal, A., Laue, J., Buchheister, J., Erdik, M., Springman, S., Studer, J., and Koksal, D., 2004. “Site characterization and site amplification for a seismic microzonation study in Turkey” 11th Int. Conference on Soil Dynamics and Earthquake Engineering and 3rd Earthquake Geotechnical Engineering, San Francisco; Studer, J. and Ansal, A., 2004. Belediyeler için Sismik Mikrobölgeleme El Kitabı, Araştırma Raporu, Afet İşleri Genel Müdürlüğü, Bayındırlık ve İskan Bakanlığı, Afet Risk Yönetimi Dünya Enstitüsü].

Site Response and Earthquake Design Spectra for Central Khartoum, Sudan

Khartoum, the capital of Sudan, is located at the confluence of White and Blue Niles. The city is heavily populated. Central Khartoum with its high-rise buildings is the center of governmental and business activities and is located on a strip adjacent to the Blue Nile. Geological and geotechnical data indicate that the subsoil conditions at Central Khartoum are characterized by alluvial deposits underlain by Nubian Sandstone at a depth of 25 m. The alluvial deposits, locally known as Gezira formations, consist of clays grading into silt and sand with depth. Macro seismic zonation of Sudan and its vicinities, developed by the authors, gave the ground acceleration at the bedrock surface. The effect of alluvial deposits in Central Khartoum on propagation of seismic motion parameters to the ground surface is investigated in this study. Correlations are proposed for pertinent cyclic soil properties such as shear modulus, damping, and shear wave velocity. The Equivalent-Linear Earthquake Response Analyses (EERA) Model was used to study the effect of local soil conditions on ground-motion parameters. In the absence of strong-motion records in Khartoum, available worldwide strong-motion records are used. Plots showing the time histories of ground motion parameters at the ground surface are obtained. The results indicate amplification of ground motion of up to 4.93. The predicted fundamental period of soils is about 0.5 s which is typical for these types of soils. The maximum spectral acceleration varied from 0.76 to 0.95 g. For design purposes, a response spectrum curve is proposed.

Engineering geological approach to the evaluation of seismic risk in metropolitan regions: case study of Patras, Greece

The city of Patras in western Greece has experienced several destructive earthquakes during the past centuries. The engineering geological conditions of the area have been analyzed and described using a relational geotechnical database management system including geotechnical and geological information obtained from exploratory boreholes, cone penetration tests and cross hole seismic prospecting. The foundation soils of the city were grouped into individual geotechnical units and several engineering geological maps and geotechnical cross sections were compiled. Criteria are proposed for the approximate evaluation of the effect of local soil conditions on ground motion, especially on the distribution of amplification features.

Effects of Local Soil Conditions on the Topographic Aggravation of Seismic Motion: Parametric Investigation and Recorded Field Evidence from the 1999 Athens Earthquake

During the 1999 Athens earthquake, the town of Adames, located on the eastern side of the Kifissos river canyon, experienced unexpectedly heavy damage. Despite the particular geometry of the slope that caused significant motion amplification, topography effects alone cannot explain the uneven damage distribution within a 300-m zone parallel to the canyon’s crest, which is characterized by a rather uniform structural quality. In this article, we illustrate the important role of soil stratigraphy and material heterogeneity on the topographic aggravation of surface ground motion. For this purpose, we first conduct an extensive time-domain parametric study using idealized stratified profiles and Gaussian stochastic fields to characterize the spatial distribution of soil properties, and using Ricker wavelets to describe the seismic input motion; the results show that both topography and local soil conditions significantly affect the spatial variability of seismic motion. We next perform elastic two-dimensional wave propagation analyses based on available local geotechnical and seismological data and validate our results by comparison with aftershock recordings.

Evaluation of dynamic response and local soil effects of the Evripos cable-stayed bridge using multi-sensor monitoring systems

The acquisition of response data from large structures and surrounding sites during earthquakes is essential to determine the effect of local soil conditions on seismic ground motion and consequently on the structure's response. This paper studies the local soil effects on the ground motion based on recordings from a permanent accelerometer array installed on the cable-stayed bridge of the Evripos channel in Greece. Furthermore, the dynamic characteristics of the bridge using analytical and experimental methods, which include geodetic monitoring techniques, are investigated in order to provide a more realistic modelling of the bridge. This can result in reliable predictions of the bridge response in future earthquake excitations.

Spatial variability effects of ground motions on cable-stayed bridges

In this paper, stochastic analysis of a cable-stayed bridge subjected to spatially varying ground motions is performed. While the ground motion is described by power spectral density (PSD) function, the spatial variability of ground motions is taken into account with the incoherence and the wave-passage effects. The incoherence effect is examined by taking into account two extensively used models. As the effect of the wave-passage effect is investigated by using various wave velocities, the effect of local soil conditions where the bridge supports are constructed is outlined by using homogeneous firm, medium and soft soil conditions. Solutions obtained for the spatially varying ground motions are compared with those of the specialised cases of the ground motion model. Stationary as well as the transient response analyses are performed for the considered bridge model. It is concluded that spatial variability and propagation effects of ground motions have important effects on the dynamic behaviour of the bridge and the variability of the ground motions should be included in the stochastic analysis of cable-stayed bridges.

Numerical study on the frequency-dependent viscous damping in dynamic response analyses of ground

The effects of local soil conditions on ground motion are commonly evaluated by performing either frequency or time domain analyses. Time domain analyses usually incorporate in the equations of motion viscous damping which is generally assumed to be of the Rayleigh type, i.e. stiffness- and massproportional, or in a simplified form, only stiffness-proportional. These two formulations result in a different dependency of damping from frequency. In order to evaluate the impact of the viscous damping formulations on site response, several linear analyses were conducted for an idealised soil deposit with different computer codes. The results of the analyses show that the use of the simplified Rayleigh damping formulation can significantly underestimate the response, especially for deep deposits and high frequency motion.

Ground motion amplification factors for the proposed 2005 edition of the National Building Code of Canada

Foundation factors are used in seismic codes to capture the amplification effects of local soil conditions on ground motions and, hence, on seismic design forces. Recent developments in categorizing site conditions for seismic codes and assigning intensity- and frequency-dependent amplification factors to the various site classes are presented to provide a basis for understanding the new foundation factors proposed for the 2005 edition of the National Building Code of Canada.Key words: design spectra, site characterization, amplification factors.

The Mexico Earthquake of September 19, 1985—Relationships between Soil Conditions and Earthquake Ground Motions

Comparisons are presented between the characteristics of ground motions at five sites underlain by clay at which ground motions were recorded in Mexico City in the earthquake of September 16, 1985 and for which analyses of ground response have been made, based on the measured properties of soils and the motions recorded on hard formations at the National University of Mexico. It is shown that the ground response in areas of Mexico City underlain by clay is extremely sensitive to small changes in the shear wave velocity of the clay and it is suggested that a probabilistic approach which allows for uncertainties in shear wave velocity measurements and in the characteristics of the motions on the hard formations is desirable to assess these effects. Based on the results of such an approach it is concluded that simple ground response analyses can provide very useful data for engineering assessments of the effects of local soil conditions on the characteristics of ground motions likely to develop at sites underlain by soft clays, and that the use of these procedures also provides a useful basis for estimating the general nature of the ground motions in the extensive heavy damage zone of Mexico City in the 1985 earthquake.

Fundamentals of Earthquake Engineering: Book Review

In the introduction to Funckrll7entrrl.s of Eurtl7qunlce Engineel.i~ig, Professors Newmark and Rosenblueth express their hope that this book will serve as a guide to those who must cope with the effects of earthquakes, will supplement the education of other engineers, and will help open avenues of research. It appears that each of these objectives has been admirably met in the three general parts making up this reference and graduate text: Dynamics (progressing from simple linear systems to nonlinear systems and hydrodynamics, with an outline of the numerical methods employed); Earthquake Motions and Structural Responses (including the behavior of materials and structural components under earthquake loading, and emphasizing a probabilistic framework to describe tlleoretical seismology and earthquake characteristics); and, Design (concepts in earthquake-resistant design). While the title indicates that fundamentals are being considered, some preparation and revision will be required on the part of most readers. This is particularly the case in the second and third parts when state-of-the-art material is often presented. Fortunately, a series of examples and problems with answers is provided in the first part that will assist in establishing the required background for what follows. The specific topics of inost interest to geotechnical engineers would include: hydrodynamics (particularly the discussion on tsunamis); characteristics of earthquakes; seismicity; probability distributions of response spectral ordinates (including the effect of local soil conditions); behavior of soils (detailed section 012 liquefaction); and all of the third part on design. Each topic is provided with a survey of the literature so the reader can obtain more detail as required. Problems that require further research are indicated where appropriate. This book should be in the reference library of anyone interested in earthquake engineering or structural dynamics, and should find wide acceptance as a text for graduate courses in earthquake engineering.

Modification of seismograph records for effects of local soil conditions

abstract A procedure for modifying the time histories of seismic records for the effect of local soil conditions is presented. The method is based on a conventional one-dimensional wave-propagation approach with equivalent linear soil properties, extended to practical use for transient motions through the Fast Fourier technique. The validity of the approach is tested against the motions recorded at four soil sites and one rock site during the 1957 San Francisco earthquake. The good agreement between the computed and recorded values indicates that rock motions can be computed from motions recorded on soil deposits, and that the computed rock motions in turn can be used to predict the motion that would have been recorded under different soil and geological conditions. The method is also used to evaluate the probable rock motions in the vicinity of El Centro in the earthquake of 1940 and the ground surface motions that could have been developed on various soil conditions in the same general area.