Showing papers on "Embedment published in 1972"

Vertical Vibration of Embedded Footings

Abstract: The theory makes it possible to consider soil as an elastic half-space or a stratum. In the latter case, embedment becomes particularly important because the omission of embedment leads to unrealistic overestimation of amplitudes, while the omission of layering can result in considerable underestimation of the response. The approximate analytical solution compares favorably with the finite element solution and can be easily applied in design of footings or structures supported by embedded foundations. A further advantage is that the same approach can be used to predict the response in any vibration mode including coupled modes. The field experiments were conducted with concrete blocks having square and rectangular bases. There was a reasonable agreement between the theoretical and experimental relative variations of the resonant amplitudes and of the resonant frequencies with embedment in the case of the undisturbed soil.

The strength of thin composites of finite width, with brittle matrices and random discontinuous reinforcing fibres

Abstract: A new theory is proposed for the estimation of the tensile strength of a two-dimensional composite with a brittle matrix and randomly orientated discontinuous elastic fibrous reinforcement. The estimate is made by integrating the strengths of all fibres that cross a transverse crack. It is necessary to know the relationship between the length of embedment of a fibre and the force needed to break it or pull it out. No assumptions are made about the shape of the cross section of the fibre or about the magnitude or distribution of bond stresses. An important feature is the allowance made for the loss of effectiveness of fibres cut by the edges of a tensile specimen of finite width.

Coupled Sliding and Rocking of Embedded Foundations

Abstract: Wide ranges of soil properties, foundation dimensions, and depths of embedment are considered, and typical results are presented for the maximum amplitudes of the sliding and rocking oscillations and the frequencies at which these maximum amplitudes occur. The natural frequencies of the system with and without radiation damping are dependent on the shear wave velocity and Poisson's ratio of the half-space material, the geometric proportions of the foundation, and the depth of embedment, and they increase substantially as the depth of embedment increases. The total peak amplitude of vibration for the coupled motion is expressed in terms of a linear function whose coefficients are dependent on Poisson's ratio, the foundation dimensions, and the depth of embedment depth, and graphical relationships are presented to facilitate the determination of these coefficients. The results obtained clearly illustrate that embedment of the foundation significantly decreases its total peak amplitude for a given exciting force.

Effect of foundation embedment on the dynamic behaviour of the foundation-soil system

Abstract: Foundation embedment is one of the factors not considered in the analysis of foundations subjected to dynamic loads either by elastic half space theory or by a lumped parameter system. Model tests ...

Direct embedment anchor holding capacity

Abstract: : Techniques for predicting the maximum uplift forces which may be applied to direct embedment anchors without causing the anchor to pull out are provided. This holding capacity problem is subdivided into three categories: immediate breakout, long-term static load, and long-term repeated load. Holding capacities under long-term repeated and long-term static loading conditions are poorly understood at present. It was therefore necessary to combine work from other areas with a small amount of directly applicable work to yield approximate immediate use results. For each manner of loading considered, two general types of seafloors are considered: cohesionless and cohesive soil. Rock is not considered in this report. (Author)

Cell for measuring stresses in prestressed concrete

Abstract: A compact embedment device has been provided for determining changes of stress in prestressed concrete structures. Stress forces are applied to opposite sides of the cell whereby a deflection of an internal member is proportional to the stress. Any changes are detected by variations in the output of strain gages attached to the internal member. Temperature effects are nullified by using titanium as a material of construction, and periodic drift checks may be made with an internal pneumatic ram actuated from an external air pressure source.

Wave Propagation in Anisotropic Rocks

Abstract: : The report summarizes progress on the analytical and experimental aspects of the investigation concerned with wave propagation resulting from impact on a Yule marble block and an investigation of its mechanical properties. The system was modeled as a transversely isotropic halfspace with the elastic symmetry axis lying in the free surface, loaded by a concentrated normal force of arbitrary time variation. The analysis for the displacements, strains and stresses in the interior is complete and numerical results have been obtained by integral transform methods. A corresponding finite element program has also been completed. Transducer packages for the measurement of stresses in the interior of a Yule marble block have been developed, calibrated and tested. Drilling and embedment techniques for the testing of the Yule marble blocks under actual impact conditions have been evolved. Static and dynamic tests in tension and compression for various orientations of samples have been completed as well as cyclic loading, creep and some fracture tests.

Earth anchors - stress distribution analysis and design

Abstract: THE THEORETICAL SOLUTION OBTAINED BY SALAS AND BELZUNCE FOR A SERIES OF POINT LOADS ALONG A LINE OF PILES IN THE INTERIOR OF AN IDEAL, ELASTIC HALFSPACE IS FOUND TO BE APPLICABLE TO THE EARTH ANCHOR PROBLEM. THE EXPERIMENTAL VERIFICATION OBTAINED BY A PHOTOELASTIC MODEL SHOWS EXCELLENT AGREEMENT WITH THE THEORETICAL STRESS DISTRIBUTION, ESPECIALLY IN THE ANCHOR RANGE 0.2 TO 0.9. AN ANALYSIS OF THE ANCHOR'S CAPACITY AT FAILURE IS ALSO PRESENTED, EXPRESSING THE ULTIMATE LOAD AS A FUNCTION OF THE ANCHOR DIAMETER, THE EMBEDMENT LENGTH AND THE SHEAR RESISTANCE OF THE SURROUNDING SOIL. /TRRL/

Investigation of the opening of construction joints in an experimental section of the Andizhansk dam (Uzbek SSR)

Abstract: 1. In the rock zone the opening of the joints agrees with the calculated value of the temperature deformations of adjacent blocks only during the initial period. Subsequently, the opening of the joints is greatly affected by the embedment of the blocks in the foundation and by the temperature regimen of the latter. Thus, for the period of maximum joint opening, the coefficient which takes into consideration the embedment in the foundation and its temperature regimen was equal to 0.42, while for the entire cooling period it was equal to 0.34. 2. The initiation of joint openings between the sections coincides with the time of disappearance of compressible stresses in them. 3. Opening of the joints takes place uniformly in the horizontal sections (with an accuracy of up to 10%), independently of the temperature drop in the structures which make up the joint. 4. The presence of friction forces in the horizontal areas of stepped joints causes some reduction of the opening of such joints between the vertical faces (up to 10%), as compared with a plane joint, as well as cracking of the steps on the side of the head blocks and on the side of the buttress blocks.