Showing papers on "Embedment published in 1982"

The behaviour of anchor plates in sand

Abstract: This Paper describes a theoretical investigation into the behaviour of anchor plates in sand. Consideration is given to the effects of anchor embedment, friction angle, dilatancy, initial stress st...

The behaviour of anchor plates in clay

Abstract: The undrained behaviour of anchor plates with a vertical or horizontal axis, resting in a saturated clay, is examined. Theoretical consideration is given to the effects of anchor embedment, layer d...

Analytical model for concrete anchorages of reinforcing bars under generalized excitations

Abstract: This report presents an analytical model for predicting the behavior of single deformed reinforcing bars embedded in confirmed concrete and subjected to generalized excitations in the range of low cycle fatigue. The model is based on a general local bond stress-slip relationship, derived from the results of an extensive study performed at Berkeley, and on either a bilinear or a simple but sufficiently accurate nonlinear stress-strain relationship for the reinforcing steel bar. An efficient numerical scheme for the integration of the governing differential equation of bond along the embedment length of the bar is presented.

Influence of loading rate on bond behaviour of reinforcing steel and prestressing strands

Abstract: Pull-out tests with short embedment length were carried out within a wide range of loading rates. The highest loading rate which could be achieved on a Split-Hopkinson-bar equipment was about 500,000 times the loading rate in a static test. The test variables were the steel type, the concrete quality and the loading rates.

Bond characteristics of epoxy coated reinforcing bars

Abstract: The objective of this study was to evaluate the flexural bond characteristics of epoxy coated reinforcing bars in comparison to uncoated bars under static and fatigue loadings. Comparative tests were conducted between reinforcing bars with epoxy coated, normal mill scale and blast cleaned surface conditions. Both #6 and #11 bars were included. Forth flexural bond specimens of the beam end type were tested in static and fatigue loadings. Three embedment lengths were used in the tests. In addition, six slab specimens were tested to evaluate the effect of epoxy coating on concrete crack spacing and crack width. Behavior is assessed in terms of influence on crack spacing, crack width, bond strength and bond fatigue. Suggestions for design criteria modification are proposed. (FHWA)

Failure loads for model adhesive joints subjected to tension, compression or torsion

Abstract: The Griffith fracture criterion has been applied to model adhesive joints subjected to tension, compression or torsion. Two model joints are considered: a rigid cylinder partly embedded in and bonded to an elastic cylinder (termed “rod joint” here), and an elastic cylinder inserted partway into, and bonded to, a rigid tube (termed “sleeve joint” here). Both types of joint have been constructed, using vulcanized rubber cylinders bonded to aluminium rods and sleeves.Measurements have been made of the failure loads under tension, compression and torsional loading. They were found to be in satisfactory agreement with the theoretical predictions except, in some instances, for rod joints subjected to tension or torsional loading when the failure loads were as much as three times the predicted values. This discrepancy is attributed to friction between the partially-detached rubber cylinder and the embedded rod, enhanced to a great extent by the tendency of the rubber cylinder to shrink in radius on stretching or twisting. A theoretical analysis of the effect of friction is presented. It predicts increasingly large pull-out forces or torques, as the depth of embedment increases, until frictional seizure occurs. Experimentally, frictional effects were limited by applying an internal gas pressure to the region being detached. All of the failure loads were then found to be in satisfactory agreement with the original theory, ignoring frictional effects. Thus, a simple fracture energy criterion is shown to govern the failure of adhesive joints under complex loading conditions, with or without friction acting at the interface.

Body Wave Excitations of Embedded Hemisphere

Abstract: Solutions of three-dimensional vibrations of an embedded hemispherical foundation are presented for excitation by incident plane P, SV, and SH waves with arbitrary angles of incidence The effects of embedment are illustrated by comparing the motion of the embedded hemispherical foundation with those of a rigid disc bonded to a half space of equal radius and excited by the same waves The impedence matrix and the foundation motion are analyzed and compared with similar and reLated approximate solutions In the context of Fourier synthesis, the results can be viewed as representing the transfer functions for the forces and motions of the foundation For arbitrary transient excitation which can be represented by plane body waves, the results can be used to calculate the transient motion of the foundation

Experimental Observations of the Effect of Foundation Embedment on Structural Response

Abstract: Ambient, ring-down, and forced vibration tests were used to determine the effect of foundation embedment on the response of a one-story model structure 10 ft square in plan and 11.4 ft high. The tests, conducted at the full-, half- and unembedded foundation conditions, led to the identification of the fundamental translatory mode in the primary (east-west) and secondary (north-south) directions, and two torsional modes. The forced vibration consisted of horizontally incident SH-waves generated at an excitation structure located 47.5 ft (center-to-center) away. During these tests, detailed measurements of the near-field ground motion and modal displacement ratios were obtained at the fundamental mode in the primary direction. The displacement ratios were used to calculate the structural and foundation-soil stiffnesses and damping coefficients for comparison to theoretical results. Foundation embedment increased the model frequencies and decreased the contribution of the foundation motion to the overall displacement of the superstructure. For the fundamental mode response, which consisted of translatory and rocking motions, the resonant frequency predicted by lumped parameter analysis was higher than that measured experimentally by 25% for the unembedded case. While the experimental and theoretical fundamental mode shapes were in close agreement, the calculated effect of embedment on the response was less than that measured. These results were consistent with the comparison of the impedances and embedment factors. Serious discrepancies between analytical and experimental results were found for the case of torsion; a simple two-degree-of-freedom model was consistent only with the first of the two measured resonant frequencies.

Uplift capacity of rectangular foundations in sand

Abstract: Laboratory model test results for the net ultimate uplift capacity of rectangular foundations in sand are presented. The length-to-width ratios of the rectangular foundations were varied from 1 to 5. Tests were conducted in loose, medium, and dense sands. For square foundations, the critical embedment ratio increases with the degree of compaction of sand and is approximately the same as that proposed by Meyerhof and Adams. For a given degree of sand compaction, the critical embedment ratio increases with the length-to-width ratio of the foundation. A procedure for the estimation of the uplift factor, and thus the net ultimate pullout load for deep foundations, is presented. (Author)

Method related to isostatic hot pressing of preformed bodies of a metallic or ceramic material

Abstract: An object of a metallic material or other ceramic material than silicon nitride or than a material having silicon nitride as its main component is manufactured by isostatic pressing of a body preformed from a powder of the metallic or ceramic material, whereby the preformed body is embedded in glass, for example embedded in a mass of glass particles, and the embedment, with the body and the embedment placed in a vessel which is dimensionally stable at the temperature at which the sintering of the metallic or ceramic material is carried out, is transferred to a melt having a surface limited by the walls of the vessel, below which surface the preformed body is located, and a pressure necessary for the isostatic pressing of the preformed body then being applied on the melt by a gaseous pressure medium.

Design of beds and foundations for rural buildings framed with three-hinge mill bents

Abstract: 1. Until more modern methods of computation are developed, it is recommended that the bearing capacity of beds for rigid rectangular foundations of agricultural buildings framed from three-hinge mill bents with a relative embedment 0.5≤h/B≤1 and angles of incline of the resultant of external loads 20<δ<45° from the vertical be determined by the method outlined in ICR 0.1–76. The method described in SNiP II-15-74 should be used when the relative embedment of the lower surface is less than 0.5 and the angles δ<ϕ.

Deviations of piles during embedment

Abstract: 1. As a pile is embedded, its deviation from the vertical is observed in a soil stratum. The deviation depends on the initial angle of inclineϕ0 of the pile, its structural solution (sectional or whole, type of butt joint), and the physicomechanical properties of the soil.