Showing papers on "Embedment published in 1989"
TL;DR: In this article, upper and lower bounds for the vertical limit load at a given penetration of a pipe into cohesive soil are presented, and the maximum range between the bounds occurs at one radius penetration, where the difference between the upper bound and lower bound varies from about ten percent for the rough pipe case to approximately 25% for the smooth pipe case.
Abstract: Penetration of a pipe into cohesive soil is an important consideration in offshore pipeline engineering, especially as such penetration affects on-bottom stability of the pipeline. If the soil is described as a perfectly plastic cohesive material then the calculation of the limit load at a given penetration reduces to a plane strain problem in plasticity theory. Upper and lower bound solutions to this penetration problem are presented. The maximum range between the bounds occurs at one radius penetration. The difference between the upper and lower bounds varies from about ten per cent for the rough pipe case to approximately 25% for the smooth pipe case. Parametric studies demonstrate the effect of embedment depth, pipe-soil adhesion, soil surface heave, and increasing soil strength on the vertical limit load. The solutions presented are shown to compare favorably with test data. La penetration d'un conduit dans un sol coherent represente un aspect important de la construction des pipelines au large, surt...
137 citations
TL;DR: In this paper, an approach for stability analysis of geosynthetic reinforced earth structures over firm foundations is presented, which involves both internal and external stability analyses, based on variational limiting equilibrium and satisfies all equilibrium requirements.
Abstract: An approach for stability analysis of geosynthetic reinforced earth structures over firm foundations is presented. The approach involves both internal and external stability analyses. The internal stability analysis is based on variational limiting equilibrium and satisfies all equilibrium requirements. Two extreme inclinations of reinforcement tensile resistance are investigated: orthogonal to the radius defining the geosynthetic sheet, and horizontal, signifying the as‐installed position. Although a horizontal positioning requires slightly longer anchorage to assure pullout resistance, the slip surface is shallower when compared to the orthogonal case. As a result, the required total embedment length is longer for the orthogonal inclination. The external stability analysis is an extension of the bilinear wedge method and it allows a slip plane to propagate horizontally along a reinforcing sheet. The results for both the internal and external stability analyses are conveniently presented in the form of d...
117 citations
TL;DR: In this paper, the results of a series of experimental investigations conducted to determine the manner in which the performance of a footing located at the crest of a sloped fill can be inf ected.
Abstract: This paper summarizes the results of a series of experimental investigations conducted to determine the manner in which the performance of a footing located at the crest of a sloped fill can be inf...
78 citations
TL;DR: In this article, a table of impedance functions and effective input motions for rigid square foundations embedded in a uniform elastic half-space is presented, including numerical results obtained by a hybrid approach for embedding to half-width ratios ranging from 1/3 to 3/2.
Abstract: Tables of impedance functions and effective input motions for rigid square foundations embedded in a uniform elastic half-space are presented. The tables include numerical results obtained by a hybrid approach for embedment to half-width ratios ranging from 1/3 to 3/2 and by a boundary element method for surface foundations. Media characterized by Poisson’s ratios of 1/4, 1/3 and 0.4 are considered. The impedance functions include vertical, torsional, horizontal, rocking, and coupling terms. Effective foundation input motions for vertically incident P and SH waves and for horizontally incident SH waves are also listed.
76 citations
01 Jan 1989
TL;DR: In this paper, the behavior of headed studs embedded in a large concrete block and loaded in tension with the support reactions relatively far away from the anchor is controlled by stable growth of the circumferential failure crack up to maximum load.
Abstract: According to the experiments the behavior of headed studs embedded in a large concrete block and loaded in tension with the support reactions relatively far away from the anchor is controlled by stable growth of the circumferential failure crack up to maximum load. Just before reaching maximum load the area of cracked concrete is only some 25% to 30% of the whole surface of the fracture cone, which is mainly formed in the descending part of the large embedment depth loaddisplacement curve the load transferred in the cracked area is relatively small compared to the total load.
54 citations
01 Jan 1989
TL;DR: In this article, an empirical model has been developed which predicts soil resistance to lateral motion of untrenched pipelines, and the model represents a significant improvement compared to the Coulomb friction estimation traditionally used in pipeline stability calculations.
Abstract: This paper describes a research project into pipe-soil interaction conducted by SINTEF on behalf of the American Gas Association (A.G.A). An empirical model has been developed which predicts soil resistance to lateral motion of untrenched pipelines. Full scale pipe-soil interaction tests were conducted for three soils providing data for the empirical relationships in the model. The tests confirm previously reported results; that soil resistance is strongly dependent on pipe embedment and soil condition (shear strength of clay and relative density of sand). Pipe embedment is estimated empirically from the energy dissipated in the soil and soil resistance is split into two components; a sliding component and a penetration dependent component. In this manner the soil model accounts for the effects of cyclic pipe movements on soil resistance. The new model represents a significant improvement compared to the Coulomb friction estimation traditionally used in pipeline stability calculations. Especially on soft clay and loose sand and in general at high lift forces, the predicted soil resistance is larger than that predicted using friction coefficients typical in design.
46 citations
TL;DR: In this article, a hybrid approach is used to obtain the dynamic response of rigid square foundations embedded in an elastic half-space, where the response of an embedded square foundation can be approximated by that of a cylindrical foundation with an equivalent circular base and the same embedment depth.
45 citations
01 Feb 1989
TL;DR: In this article, the authors investigate the design and behavior of single cast-in-place and retrofit concrete anchors under static, fatigue, and impact tensile loads, and anchor types were categorized according to these behavior modes.
Abstract: The purpose of this study was to investigate the design and behavior of single cast-in-place and retrofit concrete anchors under static, fatigue, and impact tensile loads. The following types of anchors were tested: (1) Cast-in-place anchor bolts and embeds; and (2) Retrofit anchors--(a) adhesive anchors (epoxy, polyester, and vinylester); (b) grouted anchors; (c) expansion anchors (torque-controlled); and (d) undercut anchors. The study described in this report involved 178 tests. Load-deflection behavior was recorded for each test. Behavior of adhesive anchors was studied with respect to variations in installation, orientation (vertical, horizontal, and overhead), and in hole cleaning techniques. Most anchors had a 5/8-in. nominal diameter. Required embedment lengths for the cast-in-place anchors were estimated using the criteria of ACI 349 Appendix B. Embedment lengths for the embeds, expansion, undercut, and some adhesive anchors were determined by the individual anchor manufacturer, and some anchors were only available in fixed lengths. Behavior modes of anchors were identified under static, fatigue, and impact tensile loads, and anchor types were categorized according to these behavior modes. Recommendations are given for embedment depths and installation techniques for anchors of each type. Recommendations are made for further research, some of which will be addressed in future reports produced by this project.
45 citations
TL;DR: In this paper, a simple procedure to compute the static and dynamic rocking stiffness of arbitrarily shaped rigid foundations embedded in a reasonably deep and homogeneous soil deposit is developed, based on an improved understanding of the physics of the problem, substantiated by the results of extensive rigorous parametric studies using the boundary element method.
Abstract: A simple procedure to compute the static and dynamic rocking stiffness of arbitrarily shaped rigid foundations embedded in a reasonably deep and homogeneous soil deposit is developed. The method is based on an improved understanding of the physics of the problem, substantiated by the results of extensive rigorous parametric studies using the boundary element method, and including analytical and numerical results available in the literature. Analytical expressions and dimensionless graphs are developed, applicable to both saturated and unsaturated soils, a variety of basemat shapes, and a wide range of embedment depths and types of contact between the vertical sidewalls and the surrounding soil. A numerical example illustrates the applicability of the method, while a companion paper (Fotopoulou et al. 1989) presents a simple method for determining the radiation damping of embedded foundations.
35 citations
TL;DR: In this article, the authors compared the results of a limit equilibrium approach and a finite element study to predict the embedding depth and the maximum bending moment of a cantilever retaining wall.
Abstract: The design of embedded cantilever retaining walls is often based on approximate limit equilibrium calculations. In this Paper the results of a limit equilibrium approach are compared with the results of a finite element study. Predictions of both embedment depth and maximum bending moments are compared and the finite element study is used to show the influence of such parameters as initial soil stress conditions and construction procedure. For the finite element study an elasto-plastic constitutive law is used to model the soil behaviour. The soil is assumed to behave in a fully drained manner with zero pore fluid pressures everywhere. Effective stress parameters are used to define the soil strength. The results of the comparison indicate that both the limit equilibrium method used in the Paper and the finite element approach give similar predictions of the embedment depth required to ensure stability. The maximum bending moment was calculated using two different limit equilibrium approaches. Generally it...
33 citations
TL;DR: In this article, polyimide coated multi-mode optical fibers were embedded between layers of the composite beam in order to measure strain as the beam is deformed, and the results discussed.
Abstract: A way in which to control vibrations at the tip of a flexible beam prompted this research. Polyimide coated multi-mode optical fibers were embedded between layers of the composite beam in order to measure strain as the beam is deformed. A close look at the embedment of the optical fibers between layers of preimpregnated unidirectional carbon fiber tape after cure is shown, and the results discussed. Mechanical tests were performed on composite specimens with embedded optical fibers and photographs of embedded optical fibers after the mechanical tests were performed are shown in detail.
TL;DR: In this article, an advanced boundary element algorithm developed by incorporating isoparametric quadratic elements and a sophisticated self-adapting numerical integration scheme has been used for this investigation.
Abstract: In this paper, results of a detailed investigation on the dynamic response of rigid strip foundations in viscoelastic soils under vertical excitation are presented. An advanced boundary element algorithm developed by incorporating isoparametric quadratic elements and a sophisticated self-adapting numerical integration scheme has been used for this investigation. Foundations supported on three types of soil profiles, namely, homogeneous half-space, stratum-over-half-space and stratum-over-bedrock are considered. The influence of material properties like Poisson's ratio and material damping as well as the influence of geometrical properties such as depth of embedment and layer thickness are studied. The effect of the type of contact at the soil-foundation interface is also investigated.
TL;DR: In this paper, boundary element procedures are employed in the frequency and time domain to determine the dynamic response of rigid foundations and flexible elastic structures when placed on or embedded in an elastic soil medium under plane strain conditions.
TL;DR: In this paper, the authors describe test procedures and apparatus suitable for standardized embedment tests on solid wood or wood-based sheet materials, and the need for specimen fabrication techniques and specimen support arrangements which reflect the stress conditions for fasteners inserted into members of real joints.
Abstract: Embedment tests yield foundtion moduli and embedding strengths which can be input to beam-on-foundation models which predict the load-deformation behaviour of wooden joints with laterally loaded fasteners such as nails or bolts. Test procedures and apparatus suitable for standardized embedment tests on solid wood or wood-based sheet materials are described. The need for specimen fabrication techniques and specimen support arrangements which reflect the stress conditions for fasteners inserted into members of real joints is emphasized.
TL;DR: In this paper, the effects of the existence of compliant bedrock and of subsurface inhomogeneities on the site amplification and the seismic response of rigid strip footings are analyzed using boundary elements in a plane strain model for zoned viscoelastic media.
Abstract: Effects of the existence of a compliant bedrock and of the subsurface inhomogeneities on the site amplification and the seismic response of rigid strip footings are analyzed using boundary elements in a plane strain model for zoned viscoelastic media. Semielliptical soil deposits having several aspect ratios and boundless horizontal layers are assumed in the context of a parametric study. Several different values for the bedrock compliance and the foundation embedment are considered. The study is carried out for P and SV waves. The variation of the site amplification for the points along the surface of the different alluvial deposits is analyzed. The kinematic interaction of embedded foundations is shown to be very sensitive to the width of the alluvial deposit. It is also shown that, as a general rule, the site amplification and the seismic response of foundations decrease with bedrock flexibility. Results for the diffraction of waves by an elastic cylinder included in a complete space are also presented.
TL;DR: In this paper, the authors used the method of multiple scales to obtain an approximate analytical solution of the vertical vibration of foundations on soil, taking into account the nonlinearity of the soil structure, radiation, hysteretic and viscous damping, and the effect of embedding.
Abstract: A study is reported in which the method of multiple scales is used to obtain an approximate analytical solution of the vertical vibration of foundations on soil. The study takes into account the nonlinearity of the soil structure, radiation, hysteretic and viscous damping, and the effect of embedment. Large responses of a foundation resting on a soil occur when the excitation frequency is equal to the natural frequency of the vibratory system, or the primary resonance. These and other findings from the study are discussed.
TL;DR: In this paper, a simplified mathematical model of the coupled horizontal and rocking vibration of an embedded foundation is described, in which only four parameters are required in the displacement expression and the parameters can be backcalculated from the dynamic response of the foundation with the present model.
Abstract: The paper describes a simplified mathematical model of the coupled horizontal and rocking vibration of an embedded foundation. Vibration tests of the foundation with different embedments were conducted and compared with different methods. Conclusions drawn from the theoretical analysis and dynamic experiments are presented. For the method here described, only 4 parameters are required in the displacement expression. The parameters can be backcalculated from the dynamic response of the foundation with the present model. As embedment increases, the calculated error is excessive from the modified parameters method in which the additional moment caused by lateral resistance of side soil is not considered. With increasing embedment of the foundation, the stiffness and damping of the coupled horizontal and rocking vibration of the footing increases rapidly and the resonant amplitude decreases. Thus, foundation embedment may be effective for shock absorption.
TL;DR: The torsional response of rigid foundations embedded in a non-homogeneous elastic soil with a weathered crust is investigated in this article, where the authors use an integral equation method based on displacement and traction Green's functions of the weathered nonhomogeneous medium.
Abstract: The torsional response of rigid foundations embedded in a non-homogeneous elastic soil with a weathered crust is investigated The shear modulus of the weathered crust is assumed to decrease linearly with depth and that of the underlying non-homogeneous soil increases linearly with depth The problems related to both rigid circular and cylindrical foundations are examined by using an integral equation method based on displacement and traction Green's functions of the weathered non-homogeneous medium Numerical solutions for torsional stiffness of rigid circular foundations are presented for different depths of embedment, gradients of shear modulus profile and depths of weathered crust A closed form solution based on a simplified stress field in the soil is also developed to evaluate the torsional stiffness of a rigid cylindrical foundation The torsional stiffness derived by using the approximate solution is compared with the rigorous solution based on exact Green's functions L'article examine la resist
01 Mar 1989
TL;DR: In this article, the behavior and design of steel-to-concrete connections whose strength is controlled by the strength of the anchor steel is addressed, based on experimental results and is based on limit design theory.
Abstract: The connection of steel members to concrete is a common structural feature, with applications in both highway and building construction. A typical steel-to-concrete connection includes the following: a steel attachment consisting of a baseplate welded to the attached member; the anchors that actually do the connecting; and an embedment of the anchors into the concrete. The behavior and design of these connections is not well defined by existing design standards. Steel-to-concrete connections can be divided into two categories: connections whose strength is controlled by the strength of the anchor steel; and connections whose strength is controlled by the strength of the embedment. Based on experimental research conducted at the University of Texas at Austin, the behavior and design of steel-to-concrete connections whose strength is controlled by the strength of the anchor steel is addressed. An analytial model for calculating the strength of these connections is presented. The model is developed from experimental results and is based on limit design theory. Experimental results are reported for 44 friction tests and 46 ultimate-load tests of multiple-anchor steel-to-concrete connections loaded monotonically by various combinations of moment and shear. Test specimens included steel attachments with rigid and flexible baseplates, connected to concrete with threaded cast-in-place or retrofit (undercut and adhesive) anchors. The results of this sutdy are incorporated into a "Design Guide for Steel-to-Concrete Connections."
TL;DR: In this paper, an experimental investigation to determine bond stress, free-end slip, and relative deformation between a reference plane in the masonry and an originally coplanar point on the steel (slip) is conducted.
Abstract: An experimental investigation to determine bond stress, free-end slip, and relative deformation between a reference plane in the masonry and an originally coplanar point on the steel (slip) is conducted. Stack pull-out specimens constructed of grouted nominal 6-in concrete or clay masonry units, reinforced with #4 or #7 bars, are subjected to monotonic or cyclic loadings. The method for evaluating slip incorporated slip-wires connected to linear variable differential transformers (LVDTs). Strain gages provide strain in the steel bars from which stresses in the reinforcing bar and bond stresses can be calculated. Free-end slip information is also collected. These data are useful in developing an understanding of the physical mechanism associated with bond, slip, and bond deterioration. The bond stress, which develops between the reinforcement and the surrounding grout, is a complex phenomenon dominated by the interlocking action of the reinforcing bar ribs embedded in the grout mass. To determine bond stresses and slip, six specimens are constructed and tested. Three specimens of 16 in length are reinforced with a #4 bar, and three, of 32 in length are reinforced with a #7 bar. The bond stress and slip distribution curves are evaluated from experimental data. In addition, short embedment specimens, consisting of prisms of 6-in concrete masonry units (nominal size 6×8×8) are tested. The embedment length is varied from 1 to 6 in. Ten specimen configurations was replicated three times. The nominal bond stress and free-end slip are obtained.
01 Mar 1989
TL;DR: In this paper, the behavior and design of steel-to-concrete connections whose strength is controlled by the strength of the anchor steel is addressed, based on experimental results and is based on limit design theory.
Abstract: The connection of steel members to concrete is a common structural feature, with applications in both highway and building construction. A typical steel-to-concrete connection includes the following: a steel attachment consisting of a baseplate welded to the attached member; the anchors that actually do the connecting; and an embedment of the anchors into the concrete. The behavior and design of these connections is not well defined by existing design standards. Steel-to-concrete connections can be divided into two categories: connections whose strength is controlled by the strength of the anchor steel; and connections whose strength is controlled by the strength of the embedment. Based on experimental research conducted at the University of Texas at Austin, the behavior and design of steel-to-concrete connections whose strength is controlled by the strength of the anchor steel is addressed. An analytical model for calculating the strength of these connections is presented. The model is developed from experimental results and is based on limit design theory. Experimental results are reported for 44 friction tests and 46 ultimate-load tests of multiple-anchor steel-to-concrete connections loaded monotonically by various combinations of moment and shear. Test specimens included steel attachments with rigid and flexible baseplates, connected to concrete with threaded cast-in-place or retrofit (undercut and adhesive) anchors. The results of this study are incorporated into a Design Guide for Steel-to-Concrete Connections (A).
TL;DR: In this paper, a simple limit equilibrium analysis, which considers two possible extreme inclinations of a reinforcement's resistance force, shows that predictions based on the Ka-analysis may not always be safe.
01 Jan 1989
TL;DR: In this paper, a method to estimate the expected pipe embedment crated by wave induced oscillatory pipe motions is presented. But this method is not applicable to the case of submarine pipelines.
Abstract: This paper describes a method to calculate the stability, against lateral movement, of submarine pipelines resting on the seabed and exposed to wave or combined wave and current loadings. The method provides an estimate of the expected pipe embedment crated by wave induced oscillatory pipe motions. Based on this expected pipe embedment into the soil, realistic hydrodynamic and soil force formulations 1.2 are used to check pipe stability for loadings expected during the design event.
01 Feb 1989
TL;DR: In this article, the authors investigate the design and behavior of single cast-in-place and retrofit concrete anchors under static, fatigue, and impact tensile loads, and anchor types were categorized according to these behavior modes.
Abstract: The purpose of this study was to investigate the design and behavior of single cast-in-place and retrofit concrete anchors under static, fatigue, and impact tensile loads. The following types of anchors were tested: (1) Cast-in-place anchor bolts and embeds; and (2) Retrofit anchors: (a) Adhesive anchors (epoxy, polyester, and vinylester); (b) Grouted anchors; (c) Expansion anchors (torque-controlled); and (d) Undercut anchors. The study described in this report involved 178 tests. Load-deflection behavior was recorded for each test. Behavior of adhesive anchors was studied with respect to variations in installation, orientation (vertical, horizontal, and overhead), and in hole cleaning techniques. Most anchors had a 5/8-in nominal diameter. Required embedment lengths for the cast-in-place anchors were estimated using the criteria of ACI 349 Appendix B. Embedment lengths for the embeds, expansion, undercut, and some adhesive anchors were determined by the individual anchor manufacturer, and some anchors were only available in fixed lengths. Behavior modes of anchors were identified under static, fatigue, and impact tensile loads, and anchor types were categorized according to these behavior modes. Recommendations are given for embedment depths and installation techniques for anchors of each type. Recommendations are made for further research, some of which will be addressed in future reports produced by this project (A).
Journal Article•
TL;DR: The complex joint action was decomposed into simple components and modeled with elastic springs representing the stiffnesses associated with nail-head embedment, shank withdrawal, and crushing at the interface between the main and side members.
Abstract: The complex joint action was decomposed into simple components and modeled with elastic springs representing the stiffnesses associated with nail-head embedment, shank withdrawal, and crushing at the interface between the main and side members. Test methods were developed to measure each stiffness empirically and regression models were developed for predicting these stiffnesses from the specific gravities of the joined members. The model was verified in the linear range by comparing experimental and predict rotational stiffnesses for single- and multiple-nail joints.
TL;DR: Etude des vibrations non lineaires de poutres, tenant compte des inerties axiales et transversales dans l'equation de mouvement.
TL;DR: In this paper, an experimental investigation was carried out to study the effect of embedment and load eccentricity on the depth of the rupture surface beneath v footings loaded to failure.
Patent•
24 Mar 1989
TL;DR: In this article, the reproducibility of contact hole embedment at a high aspect ratio was improved by introducing a reactive gas or particle beam in parallel with a substrate and introducing the beam flux of an inert gas or etching gas from the direction perpendicular thereto.
Abstract: PURPOSE:To improve the reproducibility of contact hole embedment at a high aspect ratio by introducing a reactive gas or particle beam in parallel with a substrate and introducing the beam flux of an inert gas or etching gas from the direction perpendicular thereto. CONSTITUTION:The substrate 3 is mounted onto a substrate holder 2 in a vacuum vessel 1. An introducing port 4 is positioned in parallel with a contact hole in the substrate 3 and the reactive gas or particle beam is introduced thereon. One front end of the introducing port 6 is formed to a slit shape to supply the beam flux of the sheet-shaped inert gas or etching gas along the surface of the substrate 3. The substrate 3 is preferably rotated at this time. Etching of the substrate 3 surface can be executed simultaneously with film formation in the contact hole of the substrate 3 or alternately with film formation. As a result, embedment efficiency of the contact hole is improved and embedment is executable with the good uniformity and controllability.