Showing papers on "Embedment published in 2015"
129 citations
TL;DR: In this paper, a computational fluid dynamics study was conducted to quantify the fracture conductivity loss due to proppant embedment on a theoretical basis, and the results were benchmarked with the results from an experimental study conducted with Berea sandstone samples.
126 citations
TL;DR: In this paper, the effect of parameters such as end condition of fiber (smooth or hooked-end), embedment length, water/binder ratio, paste phase of RPC, steel micro fiber, and curing conditions on fiber-matrix pullout behavior were determined.
105 citations
TL;DR: In this paper, the experimental findings of 180 pullout tests conducted on GFRP bars embedded into high-strength concrete blocks covering different parameters were presented, including bar diameter size (12 or 16mm), embedment length (4 or 6 times the bar diameter), bar end condition (straight and headed), and concrete cover (1.5, 2.5 and 5 or 7 times bar diameter for straight bars and 8 or 10.5 times for headed bars).
87 citations
TL;DR: In this article, a semi-empirical interface model is proposed to simulate the bond-slip behavior of reinforcing bars in well-constrained concrete columns, assuming that the normal stress of the interface is proportional to the bond stress.
Abstract: A new interface model to simulate the bond-slip behavior of reinforcing bars is presented. The model adopts a semiempirical law to predict the bond stress-versus-slip relations of bars, accounting for the bond deterioration caused by cyclic slip reversals, the tensile yielding of the bars, and the splitting of concrete. The wedging action of the ribs is represented by assuming that the normal stress of the interface is proportional to the bond stress. The model has been implemented in a finite-element analysis program and has been validated with laboratory experiments that include monotonic and cyclic bond-slip and anchorage tests of bars with different embedment lengths and a test on an RC column subjected to cyclic lateral loading. The model is easy to calibrate and computationally efficient, and it accurately predicts the bond-slip behavior of bars embedded in well-confined concrete. It also simulates bond failure attributable to the splitting of concrete in an approximate manner.
75 citations
TL;DR: In this paper, the results from three-dimensional dynamic finite element analysis undertaken to provide insight into the behaviour of torpedo anchors during dynamic installation in non-homogeneous clay were reported.
62 citations
TL;DR: An analytical model for the behavior of fully grouted cable bolts under axial loading condition is provided in this article, which considers the elastic, softening and debonding behaviour at the cable/grout interface using a tri-linear model.
61 citations
TL;DR: In this article, the results from dynamic installation of a torpedo anchor in strain softening, rate dependent soft clays, quantifying the effects relative to results for ideal Tresca material.
54 citations
TL;DR: In this paper, pullout tests were performed to understand the bond behavior between the basalt fiber reinforced plastic (BFRP) bar and the engineered cementitious composite (ECC), and the effects of the bar diameter, the embedded length, the cover thickness, and the properties of matrix materials on the bond performance.
54 citations
TL;DR: In this paper, a series of model tests were conducted to provide insight into the behavior of a torpedo anchor during dynamic installation and monotonic pullout in lightly overconsolidated calcareous silt.
Abstract: Challenges associated with dynamically installed anchors include prediction of the anchor embedment depth, which dictates the anchor's holding capacity. This is particularly true for calcareous sediments, as very little performance data exist for this anchor type in these soils. This paper reports results from a series of model tests undertaken to provide insight into the behaviour of a torpedo anchor during dynamic installation and monotonic pullout in lightly overconsolidated calcareous silt. The tests were carried out in a beam centrifuge, varying the drop height and consequently the impact velocity, and the consolidation period prior to anchor pullout. The mudline load inclination was also varied to encompass various mooring configurations. The centrifuge model test data were used to calibrate: (a) an analytical dynamic embedment model, based on conventional bearing and frictional resistance factors but with strain-rate-dependent undrained shear strength for the soil; and (b) an analytical quasi-stati...
51 citations
TL;DR: In this paper, the authors investigated the shape and size of the failure envelopes of the skirted circular foundations under a practical range of embedment ratio, soil strength heterogeneity, soil-skirt interface and level of vertical mobilisation.
Abstract: The response of skirted circular foundations with rough and smooth soil–skirt interface to combined loading is investigated. The shape and size of the failure envelopes of the skirted circular foundations under a practical range of embedment ratio, soil strength heterogeneity, soil–skirt interface and level of vertical mobilisation are compared to those of solid embedded circular foundations and skirted strip foundations. The results show that both the foundation geometry and soil plug inside the skirt compartment significantly influence the uniaxial capacity and the shape and size of the failure envelopes. Approximating expressions for solid embedded foundations do not capture the shifting eccentricity of the failure envelopes of the skirted circular foundations. A new approximating solution for describing the failure envelope as a function of embedment ratio, soil strength heterogeneity and soil–skirt interface is proposed. Scaling factors accounting for the decreasing uniaxial capacity of skirted found...
TL;DR: In this article, the influence of embedment, soil self-weight and anisotropy on the bearing capacity of a grey-blue clay from Taranto in Italy was investigated.
TL;DR: In this paper, the capacity of dynamically installed anchors in soft normally consolidated clay was examined experimentally through a series of field tests on a 1:20 reduced-scale anchor, achieving tip embedment of 1.5-2.6 times the anchor length, before being loaded under undrained conditions at various load inclinations.
Abstract: The capacity of dynamically installed anchors in soft normally consolidated clay was examined experimentally through a series of field tests on a 1:20 reduced-scale anchor. The anchors were installed through free fall in water, achieving tip embedment of 1.5–2.6 times the anchor length, before being loaded under undrained conditions at various load inclinations. Vertical anchor capacities were between 2.4 and 4.1 times the anchor dry weight and were satisfactorily predicted using the American Petroleum Institute approach for driven piles. Anchor capacity under inclined loading increased as the load inclination approached horizontal; the field data indicated this increase to be up to 30% for the minimum achievable inclination of about 20° to the horizontal. Corresponding large-deformation finite element analyses showed a similar response, with the maximum capacity occurring at a load inclination between 30° and 45° to the horizontal. The finite element results demonstrate that, for the anchor geometry cons...
TL;DR: In this article, the response of bucket foundations on sand subjected to planar monotonic and cyclic loading is investigated, and the experimental soil foundation response is interpreted within the macro-element approach, using an existing analytical model, suitably modified to accommodate the footing embedment and the application of cyclic load.
TL;DR: In this article, the bearing capacity factors of a shallow embedded horizontal strip footing placed on a sloping ground surface were determined by using the lower bound theorem of the limit analysis in conjunction with finite elements and nonlinear optimization.
Abstract: By using the lower-bound theorem of the limit analysis in conjunction with finite elements and nonlinear optimization, bearing-capacity factors, N-c and N-gamma q, with an inclusion of pseudostatic horizontal seismic body forces, have been determined for a shallow embedded horizontal strip footing placed on sloping ground surface. The variation of N-c and N-gamma q with changes in slope angle (beta) for different values of seismic acceleration coefficient (k(h)) has been obtained. The analysis reveals that irrespective of ground inclination and the embedment depth of the footing, the factors N-c and N-gamma q decrease quite considerably with an increase in k(h). As compared with N-c, the factor N-gamma q is affected more extensively with changes in k(h) and beta. Unlike most of the results reported in literature for the seismic case, the present computational results take into account the shear resistance of soil mass above the footing level. An increase in the depth of the embedment leads to an increase in the magnitudes of both N-c and N-gamma q. (C) 2014 American Society of Civil Engineers.
TL;DR: In this paper, pull-out specimens were tested to investigate the bond behavior of superelastic NiTi (Nitinol) SMA wires to carbon fiber reinforced polymers (CFRP).
Abstract: In this research pull-out specimens were tested to investigate the bond behavior of superelastic NiTi (Nitinol) SMA wires to carbon fiber reinforced polymers (CFRP). A total of 45 pull-out specimens were tested monotonically up to failure. The test parameters considered include the wire diameter and embedment length. A digital image correlation (DIC) system was used to identify the onset and propagation of debonding. Based on the experimental observations two debonding mechanisms were observed: complete debonding after the onset of martensitic transformation of SMA wire, and complete debonding before the onset of wire transformation. The former mechanism predominated, while the latter mechanism governed for larger diameter wires with shorter embedment lengths. A 3-D non-linear finite element model (FEM) was developed to predict the pull-out behavior. A cohesive zone model (CZM) was used to model the interface. A parametric study was conducted using the FEM to quantify the parameters of the cohesive zone model. The results demonstrate that the proposed modeling approach can be used to characterize the bond behavior of superelastic SMA wires embedded in FRP composites.
03 Jun 2015
TL;DR: In this article, three-dimensional smoothed particle hydrodynamics (SPH) simulations were used to simulate particle embedment when 219.2 and 362.9 µm angular silicon carbide particles impacted a strain and strain rate hardening 6061-T6 aluminum alloy target under various process conditions.
TL;DR: In this article, the authors investigated the response of massive caisson foundations to combined vertical (N), horizontal (Q) and moment (M) loading by a series of three-dimensional finite element analyses.
TL;DR: Based on Johansen yield theory and experimental observations, mechanical models and capacity equations for nail connectors used in wood-frame shear walls with cross-prefabricated ply-bamboo sheathing panels were studied as discussed by the authors.
Abstract: Based on Johansen yield theory (European yield model) and experimental observations, mechanical models and capacity equations for nail connectors used in wood-frame shear walls with cross-prefabricated ply-bamboo sheathing panels were studied. Embedment strength of ply-bamboo panel was obtained in accordance with a British Standards Institution (BSI) standard. Monotonic and cyclic tests of nails applied in timber-bamboo shear walls were performed to validate the capacity equations. The adopted capacity equation based on European yield model meets the test results well, in the average and with a reduced scatter. The theoretical and experimental results obtained from the research suggested a capacity model and equations to predict the bearing capacity of timber-bamboo nail connections, indicating that ply-bamboo panels can be used as sheathings for light-weight timber structures, as well as included in existing timber design code.
TL;DR: In this article, a detailed laboratory experimental model tests was undertaken to study the effect of slope on laterally load pile capacity and p-y curves and it was concluded that the increase in pile-soil relative stiffness increases the lateral resistance against the lateral load and hence the depth of fixity reduces for increase in relative density.
Abstract: A detailed laboratory experimental model tests was undertaken to study the effect of slope on laterally load pile capacity and p–y curves. The paper concerns the method developed in a series of laboratory model tests (27 lateral load tests) to experimentally determine p–y curves. The study was carried out on horizontal ground and two different types of slope such as, 1 Vertical to 2 Horizontal (1V:2H) and 1 Vertical to 1.5 Horizontal (1V:1.5H) with different relative density of 30, 45 and 70 % and three different pile embedment lengths [length to diameter ratios (L/D) of 25, 30 and 35]. The study includes the effect of ground slope, relative density and embedment length on lateral load capacity, bending moment, lateral soil resistance, lateral deflection and p–y curves. From the study it is concluded that the increase in pile-soil relative stiffness increases the lateral resistance against the lateral load and hence the depth of fixity reduces for increase in relative density. It is also found that the soil resistance increases with increase in the depth of the soil, relative density of the soil and the embedment length of the pile whereas the soil resistance decreases with increase in the slope of the ground surface.
TL;DR: In this article, an analytical approach to evaluate the ultimate embedment depth and holding capacity that plate anchors can potentially achieve is proposed, based on a plasticity model for anchor-soil interaction and compatible chain solution.
Abstract: This paper proposes an analytical approach to evaluate the ultimate embedment depth and holding capacity that plate anchors can potentially achieve. Based on a plasticity model for anchor–soil interaction and compatible chain solution, detailed derivations are presented that allow the main dimensionless groups of input parameters to be identified. For typical cases where the weight of the anchor is negligible relative to its holding capacity, explicit expressions are provided in non-dimensional form for ultimate embedment and anchor capacity. A thorough parametric sensitivity study highlights the major factors affecting these quantities. Two practical examples are considered that demonstrate the proposed analytical approach for different types of anchors, in one case revealing significant scope for improved design of plate anchors in order to optimise performance.
TL;DR: In this article, a simplified solution procedure is proposed for estimating the dynamic response of a pile group partially embedded in a layered saturated soil and subjected to horizontal harmonic loading, based on the dynamic interaction factor, the horizontal impedance of the pile group is obtained by using the superposition principle.
Abstract: A simplified solution procedure is proposed for estimating the dynamic response of a pile group partially embedded in a layered saturated soil and subjected to horizontal harmonic loading. In the proposed procedure, the transfer matrix method is first applied to solve the vibration equation of a single pile, from which the stiffness of the single pile is obtained. The existing lateral displacement of the saturated half-space is introduced to build the attenuation function, and the balance equation of passive pile is built accordingly. The simple Winkler model is used to derive the dynamic pile-soil-pile interaction factor. Based on the dynamic interaction factor, the horizontal impedance of the pile group is obtained by using the superposition principle. The calculated dynamic interaction factor and impedance of the pile group are in agreement with earlier results for an idealized case, verifying the correctness of the proposed method. The main parameters, such as the embedment ratio, pile separat...
TL;DR: In this article, a dynamically embedded plate anchor (DEPLA) is a rocket-shaped anchor that comprises a removable central shaft and a set of four flukes, and the flukes constitute the loadbearing element as a plate anchor.
Abstract: A dynamically embedded plate anchor (DEPLA) is a rocket-shaped anchor that comprises a removable central shaft and a set of four flukes. The DEPLA penetrates to a target depth in the seabed by the kinetic energy obtained through free-fall in water. After embedment the central shaft is retrieved leaving the anchor flukes vertically embedded in the seabed. The flukes constitute the load-bearing element as a plate anchor. This paper focuses on the dynamic installation of the DEPLA. Net resistance and velocity profiles are derived from acceleration data measured by an inertial measurement unit during DEPLA field tests, which are compared with corresponding theoretical profiles based on strain rate–enhanced shear resistance and fluid mechanics drag resistance. Comparison of the measured net resistance force profiles with the model predictions shows fair agreement at 1:12 scale and good agreement at 1:7.2 and 1:4.5 scales. For all scales the embedment model predicts the final anchor embedment depth to a high de...
TL;DR: In this paper, the results from three-dimensional dynamic finite-element analysis undertaken to provide insight into the behaviour of OMNI-Max™ anchors during dynamic installation in non-homogeneous clay are reported.
Abstract: This paper reports the results from three-dimensional dynamic finite-element analysis undertaken to provide insight into the behaviour of OMNI-Max™ anchors during dynamic installation in non-homogeneous clay. The large-deformation finite-element analyses were carried out using the coupled Eulerian–Lagrangian approach, modifying the simple elastic–perfectly plastic Tresca soil model to allow strain softening, and incorporate strain-rate dependency of the shear strength using the Herschel–Bulkley model. The results were validated against field data prior to undertaking a detailed parametric study, exploring the relevant range of parameters in terms of anchor mass, impact velocity and soil strength. To predict the embedment depth in the field, an improved rational analytical embedment model, based on the total energy method, was proposed, with the large-deformation finite-element data used to calibrate the model.
TL;DR: In this article, the authors investigate the shape and size of the failure mechanism, as well as the potential trench effects on soil pressures and pipeline strains in the case of a strike-slip fault rupture.
TL;DR: In this article, experimental investigations on the behavior of single, double and triple helical screw anchors under the influence of vertical compressive loads are presented, and simple equations are proposed correlating load and deformation.
Abstract: In this paper experimental investigations on the behaviour of single, double and triple helical screw anchors under the influence of vertical compressive loads are presented. The testing program was conducted on one, two, three and four numbers of model anchors in sand for different depths of embedment keeping shallow and deep mode of behaviour in mind. The experimental setup was instrumented to measure the compressive load and the downward displacement of the anchor. It was observed that the compressive load varied significantly with the installation depth of the anchor and the number of anchors. Based on experimental results, non-dimensional graphs were plotted normalizing the deformation and load axis both and simple equations are proposed correlating load and deformation. Ultimate compressive capacity of multiple anchors was plotted against that of single anchor and simple equations were proposed correlating them. Using these equations an anchor foundation for a particular structure can be easily designed. A 3-D finite element model, PLAXIS, was used to confirm the results obtained from laboratory tests and the agreement is excellent.
TL;DR: In this article, the mechanical behavior of the Japanese "Watari-ago" joints is studied experimentally and theoretically, and a predicting model of the joint is developed by applying wooden embedment theory.
Abstract: Timber joints used in traditional Japanese constructions have no metal plates or fasteners Because these joints resist external force by embedment to each member, they show high ductility The ductile joints get much attention recently Japanese “Watari-ago” joint used in horizontal structure is one such ductile joint The joint consists of two beams with interlocking notches, which build resistance against in-plane shear forces In this paper, the mechanical behavior of “Watari-ago” joints is studied experimentally and theoretically Experimental results show that “Watari-ago” joints can retain resistance after reaching their yield strength and that mechanical behavior varies depending upon notch shape and size In theoretical research, a predicting model of mechanical behavior of the joint is developed by applying wooden embedment theory The model proposed in this study also identifies the size that gives optimal mechanical performance By numerical calculation on the basis of the model, the authors find it quantitatively that the increase of the sizes of beam width and notch depth has greatly effect on the moment resistance
TL;DR: In this paper, a closed-form solution for calculating elastic settlement of ring foundations is proposed, based on displacement influence factors, which are commonly used in the domain of elasticity theory.
TL;DR: In this article, a theoretical approach based on Volkersen theory, assuming a bi-linear constitutive law is developed, and an experimental investigation of threaded rods from glulam elements is presented.