Download or read book Dynamic response of footings bearing on saturated sand written by Lawrence G. Cartwright and published by . This book was released on 1987 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Saturation on Dynamic Response of Footings in Sand written by Jack K. Poplin and published by . This book was released on 1970 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: This investigation was undertaken to determine the effect of saturation of dense sand on the response of square footings to nuclear blast-type loading. Tests were conducted with footings on the surface and at a depth of burial equal to the footing width with a water table coincident with the plane of the footing. The results of these tests were compared with data from similar tests on dry sand from a preceding study. Saturation of dense sand had the effect of reducing maximum displacement. The displacements of surface footings were only about 30 percent of the displacement of footings on dry sand with equivalent soil density and loading condition, and the displacement of shallow buried footings was reduced by 50 percent. Empirical load-displacement curves developed from previous studies on dry sand were shown to be conservative when used to predict the response of footings on saturated dense sand. The primary difference in response occurred after peak reaction. The footings on saturated dense sand came to rest immediately, while footings on dry sand continued to displace for some short distance. This behavior was attributed to the development of transient negative pore pressures resulting from dilation of the sand. A similar laboratory investigation on a medium-density sand is recommended in order to determine whether or not any tendency toward liquefaction may occur at the lower end of the range of densities of interest for protective structure foundations. (Author).

Download or read book Effects of Relative Density and Pulse Duration on Dynamic Response of Footings Buried in Sand written by Jack K. Poplin and published by . This book was released on 1969 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Computer Program for Dynamic Response of Layered Saturated Sands written by Mahantesh S. Hiremath and published by . This book was released on 1984 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Engineering Approach to dynamic response analysis of saturated sand deposits is investigated. The logic on which the methodology is based is described and implemented in a computer program. Application of the procedure to obtain dynamic response of a saturated sand layer, including pore pressure, shear stress, and acceleration variations under two different ground excitation histories given. Two alternative numerical procedures are investigated. The results are compared with those reported by Finn. Limitations of the approach are discussed. Originator-supplied keywords: Computer Simulation, Dynamic Response, Explosion Effects, Finite Difference Method, Layered Sands, Seepage, Liquefaction, and Seismic Response.

Download or read book Dynamic Response of Rectangular Footings in Clay and Sand written by Hugh M. Taylor and published by . This book was released on 1972 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Model Study of Dynamically Loaded Square Footings on Dry Sand written by Jack K. Poplin and published by . This book was released on 1969 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation reported herein was undertaken to develop an approach to modeling displacements of surface and shallow-buried footings on dry sand subject to high-intensity, single-pulse loads. A hypothetical shallow-bured structure with an isolated footing loaded by airblast overpressure produced by detonation of a nuclear weapon was assumed for design of load pulses on nine model footings used: footing widths of 4.5, 6.0, and 7.5 in. and depth-of-burial to footing width ratios of 0, 0.5, and 1.0. The principles of similitude were used to scale length, force, and time in the models. The models were placed in mobile test bins of uniform, fine, dry sand (90 percent relative density) and subjected to dynamic and static loading. Nondimensional load-displacement relations dependent only on depth-of-burial ratio were developed relating maximum displacement to peak dynamic load, footing width, and soil shear strength gradient. When the dynamic response of the footings in the form of reaction-displacement curves was compared with static response, an increase in initial stiffness and ultimate strength was observed for dynamic loading. However, these dynamic increases were greatest when the static shear strength was lowest, i.e. footings on the surface, and were least for footings buried at a depth equal to its width where the static overburden produced a substantial increase in shear strength. (Author).

Download or read book Experimental Studies of Dynamically Loaded Footings on Sand written by Walter E. Fisher and published by . This book was released on 1962 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: DENTIFIERS: Footings. An investigation of the strength and behavior of spread footings subjected to dynamic forces is reported. To this end a single-degree-of freedom model representing the spread footing and its supporting medium was developed. The supporting medium was restricted to either a cohesive or cohesionless soil. Tests were conducted to aid in the correlation of the model components with the anticipated response behavior of spread footings. A correlation between the analytical model and the experimental results could not justifiably be carried out as the container affected the test medium. Results showed a finite increase in the dynamic bearing capacity of spread footings over their static capacity. Within the limited instrumentation, the dynamic settlement of the test plates is due to the establishment of failure surfaces. For se tlements equal to the maximum dynamic settlement, the applied dynamic load varied from 1.20 to 2.28 times the equivalent static load. (Author).

Download or read book Static and Dynamic Bearing Tests on a Strip Footing in Saturated Sand written by Charles Reed White and published by . This book was released on 1967 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report describes the static and dynamic loading of a 12-inch-wide by 18-inch-deep by 6-foot-long rigid footing, representing the strip footing of a subsurface shelter. Boundary conditions simulated those of a torsionally restrained footing of a flexible arch structure with simulated overburden of 20 feet at one side of the footing. Saturated and partially saturated sand was the test soil. Several soil void ratios were employed, and the effect on the relationship between load and displacement of the footing caused by soil saturation at void ratios higher than the critical void ratio was desmonstrated. (Author).

Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 411 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1 957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 32 (thesis year 1987) a total of 12,483 theses titles from 22 Canadian and 176 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 32 reports theses submitted in 1987, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.

Download or read book Effects of Relative Density and Pulse Duration on Dynamic Response of Footings Buried in Sand written by and published by . This book was released on 1969 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of dynamic tests on square footings buried in sand was conducted to determine the effect of varying relative density. It was found that a 60 percent increase in the stiffness of the load-displacement relation resulted from increasing relative density from 70 to 90 percent. In addition, it was determined that a dimensionless maximum load parameter-maximum displacement parameter relation developed in an earlier study involving tests at a single relative density was valid for the 70 to 90 percent relative density range. A second series of dynamic tests on square footings buried in sand was conducted to determine the influence of the duration of the dynamic load pulse. From this series of tests it was concluded that for peak dynamic loads of about one-half the static bearing capacity, pulse duration has a negligible influence on response. However, for loads slightly in excess of static bearing capacity, maximum displacement and the time to its occurrence increase with pulse duration. For each dynamic test in the relative density study, plots of computed column load, load column acceleration, footing load or reaction, and footing displacement versus time were drawn and are presented as an appendix. (Author).

Download or read book Dynamic Bearing Capacity of Soils written by Jack K. Poplin and published by . This book was released on 1967 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Bearing Capacity of Soils Field Test written by Robert W. Cunny and published by . This book was released on 1963 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Study of Dynamic Bearing Capacity of Footings on Sand written by Aleksandar Sedmak Vesić and published by . This book was released on 1965 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of the Dynamic Bearing Capacity of Footings on Sand written by John Marvin Woodard and published by . This book was released on 1964 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bearing Capacity and Settlement Behaviour of Footings Subjected to Static and Seismic Loading Conditions in Unsaturated Sandy Soils written by Fathi Mohamed Omar Mohamed and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several studies were undertaken by various investigators during the last five decades to better understand the engineering behaviour of unsaturated soils. These studies are justified as more than 33% of soils worldwide are found in either arid or semi-arid regions with evaporation losses exceeding water infiltration. Due to this reason, the natural ground water table in these regions is typically at a greater depth and the soil above it is in a state of unsaturated conditions. Foundations of structures such as the housing subdivisions, multi-storey buildings, bridges, retaining walls, silos, and other infrastructure constructed in these regions in sandy soils are usually built within the unsaturated zone (i.e., vadose zone). Limited studies are reported in the literature to understand the influence of capillary stresses (i.e., matric suction) on the bearing capacity, settlement and liquefaction potential of unsaturated sands. The influence of matric suction in the unsaturated zone of the sandy soils is ignored while estimating or evaluating bearing capacity, settlement and liquefaction resistance in conventional engineering practice. The focus of the research presented in the thesis has been directed towards better understanding of these aspects and providing rational and yet simple tools for the design of shallow foundations (i.e., footings) in sands under both static and dynamic loading conditions. Terzaghi (1943) or Meyerhof (1951) equations for bearing capacity and Schmertmann et al. (1978) equation for settlement are routinely used by practicing engineers for sandy soils based on saturated soil properties. The assumption of saturated conditions leads to conservative estimates for bearing capacity; however, neglecting the influence of capillary stresses contributes to unreliable estimates of settlement or differential settlement of footings in unsaturated sands. There are no studies reported in the literature on how capillary stresses influence liquefaction, bearing capacity and settlement behavior in earthquake prone regions under dynamic loading conditions. An extensive experimental program has been undertaken to study these parameters using several specially designed and constructed equipment at the University of Ottawa. The influence of matric suction, confinement and dilation on the bearing capacity of model footings in unsaturated sand was determined using the University of Ottawa Bearing Capacity Equipment (UOBCE-2011). Several series of plate load tests (PLTs) were carried out on a sandy soil both under saturated and unsaturated conditions. Based on these studies, a semi-empirical equation has been proposed for estimating the variation of bearing capacity with respect to matric suction. The saturated shear strength parameters and the soil water characteristic curve (SWCC) are required for using the proposed equation. This equation is consistent with the bearing capacity equation originally proposed by Terzaghi (1943) and later extended by Meyerhof (1951) for saturated soils. Chapter 2 provides the details of these studies. The cone penetration test (CPT) is conventionally used for estimating the bearing capacity of foundations because it is simple and quick, while providing continuous records with depth. In this research program, a cone penetrometer was specially designed to investigate the influence of matric suction on the cone resistance in a controlled laboratory environment. Several series of CPTs were conducted in sand under both saturated and unsaturated conditions. Simple correlations were proposed from CPTs data to relate the bearing capacity of shallow foundations to cone resistance in saturated and unsaturated sands. The details of these studies are presented and summarized in Chapter 3. Standard penetration tests (SPTs) and PLTs were conducted in-situ sand deposit at Carp region in Ottawa under both saturated and unsaturated conditions. The test results from the SPTs and PLTs at Carp were used along with other data from the literature for developing correlations for estimating the bearing capacity of both saturated and unsaturated sands. The proposed SPT-CPT-based technique is simple and reliable for estimation of the bearing capacity of footings in sands. Chapter 4 summarizes the details of these investigations. Empirical relationships were proposed using the CPTs data to estimate the modulus of elasticity of sands for settlement estimation of footings in both saturated and unsaturated sands. This was achieved by modifying the Schmertmann et al. (1978) equation, which is conventionally used for settlement estimations in practice. Comparisons are provided between the three CPT-based methods that are commonly used for settlement estimations in practice and the proposed method for seven large scale footings in sandy soils. The results of the comparisons show that the proposed method provides better estimations for both saturated and unsaturated sands. Chapter 5 summarizes the details of these studies. A Flexible Laminar Shear Box (FLSB of 800-mm3 in size) was specially designed and constructed to simulate and better understand the behaviour of model surface footing under seismic loads taking account of the influence of matric suction in an unsaturated sandy soil. The main purpose of using the FLSB is to simulate realistic in-situ soils behaviour during earthquake ground shaking. The FLSB test setup with model footing was placed on unidirectional 1-g shake table (aluminum platform of 1000-mm2 in size) during testing. The resistance of unsaturated sand to deformations and liquefaction under seismic loads was investigated. The results of the study show that matric suction offers significant resistance to liquefaction and settlement of footings in sand. Details of the equipment setup, test procedure and results of this study are presented in Chapter 6. Simple techniques are provided in this thesis for estimating the bearing capacity and settlement behaviour of sandy soils taking account of the influence of capillary stresses (i.e., matric suction). These techniques are consistent with the methods used in conventional geotechnical engineering practice. The studies show that even low values of capillary stresses (i.e., 0 to 5 kPa) increases the bearing capacity by two to four folds, and the settlement of footings not only decreases significantly but also offers resistance to liquefaction in sands. These studies are promising and encouraging to use ground improvement techniques; such as capillary barrier techniques to maintain capillary stresses within the zone of influence below shallow foundations. Such techniques, not only contribute to the increase of bearing capacity, they reduce settlement and alleviate problems associated with earthquake effects in sandy soils.

Download or read book Dynamic Bearing Capacity of Soils written by and published by . This book was released on 1962 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rapid Penetration into Granular Media written by Magued Iskander and published by Elsevier. This book was released on 2015-07-10 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid Penetration into Granular Media: Visualizing the Fundamental Physics of Rapid Penetration introduces readers to the variety of methods developed to visualize, observe, and model the rapid penetration of natural and man-made projectiles into earth materials while providing seasoned practitioners with a standard reference that showcases the topic's most recent developments in research and application. There has been a flurry of recently funded research both in the U.S. and Europe on studying the behavior of projectiles in granular media. This book compiles the findings of recent research on the subject and outlines the fundamental physics of rapid earth penetration, and assembles a comprehensive collection of experimental and numerical techniques to study the problem. Presents a comprehensive interdisciplinary review of the latest research developments in the response of granular media to impact and impulsive loading Combines the experience of prominent researchers from different disciplines focusing on the challenges presented by impact loading of granular media Introduces recently developed methods for visualizing the fundamental physics of rapid penetration into granular media