Anchor Bearing Research Articles

Planar clamping anchorage for CFRP plate: Experimental research, friction-adhesion synergistic mechanism and theoretical model

Carbon fiber-reinforced polymer (CFRP) is an anisotropic material, which poses great challenge to its anchorage. In this paper, the performance of a planar clamping anchorage (PCA) for single-layer CFRP plate cable was investigated through the static tensile test. Influencing parameters included interface treatment form, clamping stress, and anchor length. Two interfacial treatment forms were considered: pure friction and friction-adhesion action. Furthermore, the bearing capacity calculation method of friction-adhesion coupling anchor was developed based on the analysis of the process of adhesion and friction. The results indicate that friction-adhesion coupling action significantly improved the anchor bearing capacity compared to pure friction, and the rate of increase in ultimate load displayed a decreasing trend as the clamping stress increased. Additionally, the error between the theoretical and experimental values of anchor bearing capacity for specimens with friction-adhesion coupling anchor was generally within approximately ±10 %.

A large deformation finite element investigation of SEPLA: Failure mechanism and bearing capacities when loaded differently

The Suction Embedded Plate Anchor (SEPLA) is an innovative deep-sea anchoring measure with precise positioning, easy installation, and high anchoring capacity. Most current research on SEPLA revolves around vertical pullout mechanism and thus its vertical bearing capacity. There are relatively few studies concerning its bearing behavior and failure mechanism when SEPLA is subjected to horizontal and moment loading. The latter is practically relevant when SEPLA is exposed to extreme environmental conditions or keyed under preloading. A more in-depth understanding of its failure mechanism under horizontal and moment loading is thereby equally important. In this work, the Coupled Eulerian-Lagrange (CEL) method is used to conduct large-deformation finite element analyses of SEPLA under vertical, horizontal, and moment loading. Emphasis is placed on ascertaining the dissimilarity of soil flow and failure mechanisms when SEPLA is loaded in different directions. Parametric investigation is done to explore the effect of anchor shape and thickness, embedment depth, and soil-anchor interfacial roughness. Semi-theoretical closed form solutions are developed to estimate the uniaxial bearing capacity factor of plate anchors in three directions. These research outcomes are likely helpful in deepening the understanding of SEPLA failure mechanism when loaded in different directions and obtaining more rational estimates of anchor bearing capacity.

Clustering-Based Fuzzy Model for Predicting Anchor Bearing Capacity

Clustering-Based Fuzzy Model for Predicting Anchor Bearing Capacity

Applicability analyses on the end-bearing capacity of gravity installed anchors in clay

As an efficient solution for deepwater moorings, gravity installed anchors (GIAs) have many attractive attributes and play a remarkable role in various deepwater applications. The end-bearing capacity factor offers an efficient method to evaluate GIA end bearing under complex conditions involving multiple factors. It can also assess total anchor bearing capacity. Based on numerous large deformation finite element (LDFE) analyses, two formulas have been developed to calculate the end-bearing capacity factors for GIAs in clay under quasi-static or dynamic conditions. Through rigorous statistical analysis, it is demonstrated that the formulas provide accurate predictions of the end-bearing capacity for various GIAs, particularly those with loading characteristics similar to OMNI-Max anchors, i.e., the padeye location and the loading angle. The contribution of the end bearing to the overall bearing capacity of GIAs is analyzed under various loading conditions. Furthermore, a comparative study proves that the formula accounting for the loading rate effect can be degenerated to evaluate the end-bearing capacity factor of the anchors under quasi-static conditions. The results provide a comprehensive understanding of the end bearing and offer an efficient solution for determining the total bearing capacity of various GIAs in clay under complex conditions. These findings contribute to the advancement of design and performance assessment of GIAs, enhancing their reliability and effectiveness in applications.

Strain Measurement Distributed on a Ground Anchor Bearing Plate by Fiber Optic OFDR Sensor

The safety of soil slopes reinforced by ground anchors can be evaluated by monitoring the tensile force of the anchors. The tensile force of ground anchors can be determined by measuring the strain of the bearing plate that transfers the tensile force of the anchor to the ground. Therefore, in order to investigate the relation between the strain of the bearing plate and the tensile force of a ground anchor, the strain distributed on the bearing plate was measured by a fiber optic OFDR (optical frequency domain reflectometry) sensor, which was fabricated by a tunable laser source, auxiliary interferometer, and main interferometer. This OFDR sensor was operated through a sweep range of 500 GHz with a spatial resolution of 0.2 mm, and a strain accuracy of approximately 4 με, considering the system noise when operating in 5-cm segments. The sensing fiber was circularly bonded onto the bearing plate using epoxy, and the distributed strain was measured on the bearing plate while increasing the load up to 10 tons. From the experimental results, the difference between the strain near the anchor head and the strain at the far site is significant in the region where compression strain is dominant. However, such a tendency did not appear in areas where bending strain dominates. Therefore, in order to monitor an anchor tensile force, it is necessary to carefully study the calibration factor between the anchor tensile force and the strain of the bearing plate.

The Experiment Study of the Special Shaped Anchor Bearing Capacity

The partial stress concentration effect in traditional anchor is serious, leading to overall failure of anchors. Therefore, experiential method had been applied to explore the relationship between bolt bearing capacity, anchor thorn layer, strength of mortar and the block size, through improving the bearing capacity of anchor with the anchor thorn. From the test, below conclusions had been drown: firstly, the special shaped anchor bearing capacity has a linear relation with the early stress of cement mortar at the early stage, while after reaching a certain intensity, the relation would change to be nonlinear, meaning greater mortar strength doesn’t represent better function. Secondly, based on the experiment results, we can conclude that under the condition of single anchor thorn, the bearing capacity of anchor increases with the size of the test cube, representing that given a certain level of anchor thorn stress, the anchor bearing capacity is positively related to the thickness of the cement mortar.

Stress Analysis of New Type Pre-Stressed Anchor Bearing Plate Combining Stamping with Welding Forming and Its Anchorage Zone

An anchor bearing plate transfers the anchoring force from anchor plate to the concrete and the pre-stress is formed in the concrete structure. Currently, the main type of anchor bearing plate is cast iron. It is brittle during transportation and tension process. This paper presents a new type of anchor bearing plate combined stamping with welding forming. The structure of the new type anchor bearing plate is introduced. The stress states of the anchor bearing plate and anchorage zone under work are studied. Various specifications of anchor bearing plate are studied by ANSYS finite element analysis software following the AASHTO specification. The analysis results are compared with the results of the same type of OVM round-shaped anchor plate. The study results show that the new pre-stressed anchor plates combined stamping with welding forming are feasible and more sturdy which can meet the engineering demand.

Study on interaction between soil and anchor chain with finite element method

With the development of offshore engineering, deeply embedded anchors are needed to be penetrated to appreciable depth and attached at the pad-eye. The interaction between anchor chain and soil is a very complex process and has not been thoroughly understood yet. In this paper, the finite element method (FEM) was used to study the interaction of soil-chain system. Results of the analysis show that when the attachment point is at a shallow depth, the load-development characteristics of the chain from FEM are in good agreement with that from the model tests and theoretical analysis. But with the depth increment, the results are different obviously in different methods. This phenomenon is resulted from a variety of reasons, and the plastic zone around the chain was studied to try finding the mechanism behind it. It could be seen that the plastic zone extended in different modes at different depths of attachment points. The interaction between the soil and anchor chain makes the load acting on the anchor decrease, but the soil disturbed surrounding the chain increases the anchor failure possibility. When the anchor bearing capacity is evaluated, these two factors should be considered properly at the same time.

Estimation of Residual Stresses at the Interface between Ground Anchor and Surrounding Soil under Pressure Grouting

The problem of interaction between ground anchor and surrounding soil under pressure grouting is solved by analytical method. This estimation makes it possible to calculate stresses at the interface between anchor and soil, which can be used for determination of anchor's bearing capacity. The problem consists of two stages: stresses in the surrounding soil are determined using prescribed displacements, and after that residual stresses are calculated on the basis of viscoelastic equation.

IMPROVING METHODS OF MONITORING THE THERMAL STATE ELECTRIC LOCOMOTIVES TRACTION ELECTRIC MOTORS

Completion of the review of methods and tools for monitoring the technical condition of tractionelectric motors (TM) has shown that existing technologies do not provide fully reliable results. Should beconsidered the most promising thermal control, has been widely used in transportation, energy, construction,medicine.Purpose of the article - the development of thermal control and predict the remaining life of thewinding insulation of motors based on the systematic thermal overload, which gives an opportunity toincrease the efficiency of the locomotives as a whole and to reduce the breakdown of the number of motors.Most frequently the traction motors to be repaired due to damage to the insulation (30 %), its lowresistance (5 %), the occurrence of the fire by the circular collector (15 %), damage the anchor bearing(15 %).The technology assessment of the technical condition of the anchors TM with thermal control methodcomprising:- Of the operations of preparation and testing of TM by mutual load after repair;- Operative measurement of temperature fields on the outer surface of the armature using a portabletemperature recorder;- Mathematical processing of thermography;- Issue a report on the quality of repair of motor armature.Thermal control system and predict the remaining life of the winding insulation TM allows you to limitthe amount of thermal overloads, and thus reduce the number of failures of electric locomotives and stops.

Influence of padeye offset on bearing capacity of three-dimensional plate anchors

This paper reports advanced three-dimensional large-deformation finite element analyses investigating the effect of the padeye offset on the behaviour of plate anchors. The analyses varied the normalized padeye offset from 0 to 0.5 and identified two counterbalancing effects on the anchor bearing capacity induced by the padeye offset. These are the change in anchor inclination with respect to the direction of loading (detrimental due to the reduction of bearing area) and the reduction of loss of embedment (beneficial, as the anchor mobilizes stronger soil). The results provide insights to optimize the design of plate anchors. The underlying concepts also have applications for other types of anchors.

Landslide Machanism in Xinghai Zhong Long Yuan and Its Reinforcement Technology

The landslide is a global geological disasters, causing casualties and huge economic losses. This paper, the Dalian Xinghai Zhong Long Yuan landslides treatment project, analysis of landslides generated by internal causes and predisposing factors, obtained a landslide failure mechanism, and the causes of slope cutting, improve cut flood drainage structures, prestressed anchor Mississauga solid technical measures. The construction process for top of the hill horizontal displacement, deep horizontal displacement and anchor bearing capacity monitoring results show that the landslide control program is correct and effective measures to achieve the desired effect, made landslides governance success to reference for landslide control work for the Dalian region and the coastal cities.

Considerations on the Design of Keying Flap of Plate Anchors

AbstractOne of the critical issues associated with plate anchor performance and design relates to the reduction of the loss of embedment during the keying process. As deep water offshore sediments typically exhibit an increasing soil strength with depth, the loss of embedment results in a reduction in anchor bearing capacity. A keying flap hinged to the main plate has been developed and adopted by industry with the aim to reduce the loss of embedment by limiting the vertical motion of the anchor. However, uncertainties remain regarding the behavior and the performance of the keying flap. This paper presents a series of numerical analyses performed to investigate the flap rotation mechanism and the condition of activation of the flap. They are compared with existing centrifuge modeling. The numerical results validate the centrifuge observations and demonstrate the nonactivation of the keying flap for typical anchor pull-out conditions.

Mechanical mechanism analysis of tension type anchor based on shear displacement method

Based on the fact that the shear stress along anchorage segment is neither linearly nor uniformly distributed, the load transfer mechanism of the tension type anchor was studied and the mechanical characteristic of anchorage segment was analyzed. Shear stress-strain relationship of soil surrounding anchorage body was simplified into three-folding-lines model consisting of elastic phase, elasto-plastic phase and residual phase considering its softening characteristic. Meanwhile, shear displacement method that has been extensively used in the analysis of pile foundation was introduced. Based on elasto-plastic theory, the distributions of displacement, shear stress and axial force along the anchorage segment of tension type anchor were obtained, and the formula for calculating the elastic limit load was also developed accordingly. Finally, an example was given to discuss the variation of stress and displacement in the anchorage segment with the loads exerted on the anchor, and a program was worked out to calculate the anchor maximum bearing capacity. The influence of some parameters on the anchor bearing capacity was discussed, and effective anchorage length was obtained simultaneously. The results show that the shear stress first increases and then decreases and finally trends to the residual strength with increase of distance from bottom of the anchorage body, the displacement increases all the time with the increase of distance from bottom of the anchorage body, and the increase of velocity gradually becomes greater.

Base calculation of anchor foundations using approximate model testing

The conditions of approximate model testing are used to determine the bearing capacity and deformity of anchor foundations bases. The idea of approximate model testing is to model geometrical dimensions of foundations keeping dynamic similarity, the soil being the same both for model and the prototype. The models of anchor foundation structures such as slabs, inclined piles, cross-bar cylinders, mushroom-like and bored anchors were tested and the resultant data were represented in non-dimensional coordinates. The empirical method of the calculation of the anchor bearing capacity and deformity should be used.This method offers the possibility of plottinq coincidence diagrams in terms of non-dimensional coordinates after conducting several model tests in various scales. Such an approach minimizes the volume of full scale tests.

Use of ground anchors to strengthen the walls of the subsurface section of a Moscow garage

1. The installation of ground anchors by embedding casings with an IP-4603 pneumatic punch on positioning it in the lower section of the casings provides for quality pressure application of grout in the zone of the anchor's fixity; this leads to a significant increase in the anchor's bearing capacity.