Anchor Block Research Articles

Optimization of Prestressed Anchor Cable Layout for Left Pier of Jinchuan Hydropower Station

With the increase of the flood discharge capacity of the flood discharge structure, the size of the flood discharge orifice is widened, which leads to the increasing thrust of the radial gate. A large tensile stress zone will be formed at the connection between the anchor block and the pier, which may lead to concrete cracking. The optimization design of the prestressed anchor cable of the pier has always been a concern of the engineering community. In this paper, the left pier of Jinchuan Hydropower Station is taken as the research object, and the finite element simulation model is established. The layout position of prestressed anchor cable is optimized, and different layout schemes of prestressed anchor cable on the left pier are designed and calculated. The results show that when the amount of main anchor cable is the same, it should be arranged outside the pier as far as possible; under the condition that the number of main anchor cables on the inner side of the pier is constant, when the direction of the main anchor cable force is consistent with the direction of the radial gate thrust, the main anchor cable prestress plays the greatest role; the arrangement of balance cable has no obvious effect on the tension of concrete at pier neck. It can provide reference for structural design.

ANALISIS STABILITAS BLOK ANGKUR/BACKSTAY JEMBATAN GANTUNG JURANGSARI KABUPATEN SEMARANG

The suspension bridge construction program is part of President Joko Widodo's Nawa Cita Program, namely developing Indonesia from the outskirts. The location of this research is the Jurangsari Suspension Bridge Construction Project, Semarang Regency, while the object of this research is the stability of the anchor blocks.In this research, calculations were carried out on the stability of the anchor blocks. The data used includes design drawing data and soil investigation data at the location. The data was processed and analyzed using the Excel spreadsheet program.The results of the analysis concluded that the stability of the anchor block at the service limit conditions was safe against shear with SF=5.5 > 1.5 and overturning SF= 57.0 >1.5 while under extreme conditions/seismic it was safe against shear with SF= 6.81 >1.1 and overturning SF = 21.09 >1.1. The bearing capacity of the soil to withstand its own weight and the forces acting on the anchor block in the conditions of safe service limits on the allowable bearing capacity with maximum s= 132.52 kN/m2 and s minimum = 119.26 kN/m2, s maximum <s permit 292.137 kN/m2 or 2.20 times greater than the s maximum that occurs, whereas in extreme conditions the soil tension that occurs at s maximum = 190.09 kN/m2 and s minimum = 142.74 kN/m2, s maximum <s permit 292.137 kN/ m2 or 1.54 greater than the maximum s that occurs. Settlement that occurs in the anchor block under safe service limit conditions is Si = 0.441 cm and in extreme conditions is Si = 0.633 cm, both conditions the safety factor for the decrease is £ 1.0 cm.

The Design and Construction of Anchor Block Pedestrian Cable-Stayed Bridge on Celebes Island

The Design and Construction of Anchor Block Pedestrian Cable-Stayed Bridge on Celebes Island

Laboratory Investigations on the Mode of Failure in Frictional and Low-Cohesive Materials Under the Load of a Ground Anchor

Ground anchors are widely used in many types of construction works, such as stabilization of rock slopes, wind turbines, concrete dams and bridge towers. Some of the modes of failure for these anchors still have an insufficient scientific basis, and that applies especially to what happens in the ground when overloaded. This paper presents investigations on the failure development in frictional and low-cohesive materials which are subjected to loading by an embedded anchor with a free length towards the surface. The failure development is demonstrated through a series of small-scale physical model tests performed in the laboratory. The physical model setup consists of a transparent PVC test chamber, a rigid «anchor block», and a hydraulic jack. The model is instrumented with a camera, an extensometer and a load cell to continuously record the failure development and resistance from the material as the anchor block is pushed through the sample material. The main question investigated is how the failure appears, as a failure along the whole pull-out body at once or as an advancing fracture along the plane, where in the first case the shear capacity of the material will be the main input in calculations, and for the second case, one also needs to take failure propagation into account.

A Multi-Objective Optimization of the Anchor-Last Deployment of the Marine Submersible Buoy System Based on the Particle Swarm Optimization Algorithm

Marine submersible buoy systems hold significant value as critical equipment in marine science research. This study examines a marine submersible buoy system that includes an anchor block, mooring line, battery compartment, power supply cable, and submersible buoy. The anchor-last deployment method is a conventional strategy for deploying marine submersible systems. Initially, the other components are positioned on the sea surface, followed by the deployment of the anchor block from the ship’s deck. The anchor block will pull the battery compartment and submersible buoy into the water and eventually sink to the seabed. In this deployment process, ocean currents have a relatively large impact on the anchor block’s landing position. Increasing the weight of the anchor block will make the anchor block land on the seabed sooner, which can minimize the impact of ocean currents. However, an overabundance of weight can generate a significant strain on both the cables, potentially resulting in cable breakage. In order to find the parameters that can make the anchor block reach the seabed as soon as possible and ensure that the tension force of the cables does not exceed the maximum, a dynamic model of the deployment process is established based on computational fluid dynamics (CFD) and solved using the Runge–Kutta method of the fourth order. Particle swarm optimization is employed to optimize the key parameters. The penalty function is used to constrain the particle space. The findings indicate that the utilization of particle swarm optimization is efficacious for optimizing the parameters of submersible buoy systems for marine applications. Optimized parameters allow the anchor block to reach the seafloor quickly and the tension on the cables to not exceed the given value.

Study on safety assessment methods of gravity anchors based on a simplified mechanical model

Gravity anchor blocks are a common type of ground anchor used for suspension bridges, whose bearing depends on its large body and gravity. As there is no stratum requirement, the safety of the anchor block is important for bridge stability. This study summarizes all available estimation indexes, calculating methods, and evaluation criteria for gravity anchor block safety for the Ruili bank of the Banjin Dam grand suspension bridge. The anti-overturning, anti-sliding, base stress, and deformation safeties were comprehensively evaluated using methods including the suggested specification method (SM), simplified mechanical method (SMM), and finite element method (FEM), the results of which were compared and analyzed. The reasons for errors and improved formulas and working conditions were presented. The main conclusions were as follows. 1) The methods for calculating different evaluation indexes according to specifications lack consistency. Moreover, FEM requires that designers have good computer skills and has low feasibility in practice. 2) The SMM for gravity anchor block safety estimation as described in this study, whose indexes cover systematic and overall, the computational formula is simple and speedy, with relatively conservative results and good practicability. 3) SM, SMM, and FEM were all used for the safety estimation of gravity anchor blocks in Ruili bank. The anti-overturning and anti-sliding stability coefficients must all meet the specification requirements of 2.0. SM cannot be used to estimate the base tensile stress under limited conditions. SMM denoted tensile stress at 2.5 times the main cable design force, compared to 3.2 P for FEM. Deformation calculation methods are not given by SM, but can be suggested by SMM based on the elastic mechanics. The horizontal displacements under design load conditions were 122 mm (SMM), 108 mm (FEM), and 44 mm (composite foundation treated by root piles), with a safety standard of <80 mm. The vertical displacements were 338 mm (SMM), 110 mm (FEM), and 123 mm (composite foundation treated by root piles), with a safety standard of <160 mm. These findings proved the feasibility of SMM for the safety design of gravity anchor blocks in cases lacking regional experience.

Antimicrobial Brushes on Titanium via “Grafting to” Using Phosphonic Acid/Pyridinium Containing Block Copolymers

AbstractCoating medical implants with antibacterial polymers may prevent postoperative infections which are a common issue for conventional titanium implants and can even lead to implant failure. Easily applicable diblock copolymers are presented that form polymer brushes via “grafting to” mechanism on titanium and equip the modified material with antibacterial properties. The polymers carry quaternized pyridinium units to combat bacteria and phosphonic acid groups which allow the linear chains to be anchored to metal surfaces in a convenient coating process. The polymers are synthesized via reversible‐addition‐fragmentation‐chain‐transfer (RAFT) polymerization and postmodifications and are characterized using NMR spectroscopy and SEC. Low grafting densities are a major drawback of the “grafting to” approach compared to “grafting from”. Thus, the number of phosphonic acid groups in the anchor block are varied to investigate and optimize the surface binding. Modified titanium surfaces are examined regarding their composition, wetting behavior, streaming potential, and coating stability. Evaluation of the antimicrobial properties revealed reduced bacterial adhesion and biofilm formation for certain polymers, albeit the cell biocompatibility against human gingival fibroblasts is also impaired. The presented findings show the potential of easy‐to‐apply polymer coatings and aid in designing next‐generation implant surface modifications.

Three-dimensional finite element analysis of a vertical anchor embedded in granular soil

ABSTRACT The present study aims at investigating the behaviour of concrete anchor blocks in cohesionless soil through numerical modelling. A three-dimensional finite element analysis using PLAXIS 3D was conducted to examine the effect of various factors, including anchor shape, embedment depth, and the presence of a groundwater table, on the pullout resistance of anchor blocks. The results showed that anchor shape affects the pullout resistance, particularly for anchor blocks with small aspect ratios. The presence of groundwater table between the ground surface and the base of the anchor block affects the pullout resistance of the anchor block. Based on the results, an empirical correlation was developed to account for the effect of the groundwater table on pullout capacity. The study also compared different pullout capacity prediction models with the results of the numerical simulations for varying embedment depth ratios. The failure modes of the soil body were critically observed and discussed.

Diblock Copolymer Stabilized Liquid Metal Nanoparticles: Particle Settling Behavior and Application to 3D Printing.

Eutectic gallium indium (EGaIn) is a liquid metal with promising applications due to its favorable thermal and electrical conductivity, low viscosity, and metallic nature. For applications, including imaging, catalysis, and nanomedicine, stable EGaIn particles with submicron diameters are required. However, the low viscosity and high density of EGaIn have typically precluded the formation of stable submicron particles due to rapid EGaIn droplet coalescence. In this work, we show that poly(acrylic acid)-block-poly(N,N'-dimethylacrylamide) copolymers are able to effectively stabilize EGaIn nanodroplets formed upon ultrasonication, where the poly(acrylic acid) block anchors the polymer to the EGaIn surface and the poly(N,N'-dimethylacrylamide) block provides colloidal stability to the particles in solution. Although the high density of EGaIn causes rapid particle settling, the behavior is predictable, which allows the average particle size to be controlled through centrifugation. We demonstrate that stable EGaIn particles with sizes on the order of 50-100 nm and narrow particle size distributions can be easily obtained using this method and further used in photopolymer resins to prepare 3D printed EGaIn-polymer hybrid materials. The predictable sizes and high stability of these EGaIn nanoparticles should allow further applications in soft-electronics, nanomedicine, catalysis, and other nanotechnology.

Study of concentrated anchoring, siting, system layout and preliminary cost analysis for a large scale Kuroshio power plant by the cross-stream active mooring

The development of large scale ocean current power generally encounters difficulties associated with water depth, seafloor engineering, storms and current meanders. The Cross-stream Active Mooring (CSAM) is a recently proposed new concept to overcome these issues. It features serial mooring of multiple turbines on a common tether as a linear array, single point anchoring and applying hydro sails to position the linear array across current streams over deep seafloor or seabed not suitable for anchoring construction. The CSAM can change the linear array's horizontal position to track meandering velocity core to increase system power capacity and adjust its depth to avoid storms. This paper proposes and studies a new concentrated anchoring concept of high capacity based on slope enhancement and assembled anchors to resolve issues of anchoring on rocky undersea ridges in many areas along the Kuroshio. Two new gravity anchor designs making use of seafloor landforms are devised and analyzed. Efficiency of assembled anchor blocks is analyzed and tested using models. Anchoring sites, anchor implementation and large scale deployment with an example 1 GW power plant in the Kuroshio southeast of Taiwan are discussed. A preliminary cost analysis of the anchors and of the CSAM-based example power plant is also presented.

Numerical Simulation Research on the Anchor Last Deployment of Marine Submersible Buoy System Based on VOF Method

Marine submersible buoy systems are widely-used equipment for ocean resource development. The marine submersible buoy system studied in this paper consists of the submersible buoy, the battery compartment, the anchor block, the mooring line, and the power supply cable. To study the mechanical behavior and obtain the speed variation of each component during the anchor last deployment, this paper establishes the free surface computational fluid dynamics model of marine submersible buoy systems based on the VOF method. This model includes the incompressible Navier–Stokes equations, the Renormalization-Group turbulence model, and the fractional areas/volume obstacle representation method. The free fluid surface is tracked using the VOF method. The lumped mass method is used to simulate the mooring line and power supply cable. The results showed that the tension forces increase when the mooring lines were straightened. Subsequently, the tension forces gradually decrease with oscillations. After the anchor block sinks to the sea floor, the positive buoyancy of the battery compartment and the buoy will cause large tension on the mooring line and power supply cable.

Shear Test of Pre-stressed Anchor Block and Fracture Mechanism Analysis of Anchor Cable

Shear Test of Pre-stressed Anchor Block and Fracture Mechanism Analysis of Anchor Cable

CAPACITY ANALYSIS OF SPUN PILE WELDING JOINTS  300 mm

Welded joints with the SMAW (Shielded Metal Arc Welding) welding connection type on spun pile  300 mm must be calculated to have the same capacity as the pile and must withstand blows during the driving process. The strength of steel sheath on the piles with a minimum yield stress of 210 MPa (BJ 34), the breaking stress of the welding wire electrode was 60 ksi, we calculated the value of the connection loaded with tensile forces on the plate with yield and fracture conditions was sought and the value of the connection that was loaded with tensile forces on the weld at base material and welding, the result showed that the weld joint capacity value was 237,504.40 kg (237.50 tons or 2,329.13 kN). It was compared with the maximum force bore by 1 pile was 1,082.84 kN and the force on the anchor block was 495.40 kN, the capacity of the welded joint is safe against them.

Structural Design Tuak River Pedestrian Suspension Bridge Anchor Block Type Rigid Symmetric with LISA

Anchor blocks are one of the components and elements that are very risky for suspension bridge construction, because almost The ability The Suspension bridge resistance rests on the cables held in place by the anchor block. This anchor block behavior study is to find out the major stress information occurring in the anchor block elements. In this research, the researcher refers to the Circular Letter of Design Criteria for Rigid Symmetrical Pedestrian Suspension Bridge, and conducts structural modeling using the finite element method-LISA program on anchor blocks. Condition of the anchor block after receiving the appropriate tensile force from the round table at a span of 96 meters, the tensile force of the suspension bridge cable is 664.6 kN, resulting in a stress of 6.184 N/mm2 on the concrete surface of the anchor block using the concrete grade is fc 30 MPa, in the suspension cable of the bridge there is a tension of 22.26 N/mm2 at the point of work. The results of the analysis of the anchor block used on the Tuak River Suspension Bridge with a span of 96 m can meet the required criteria, namely the axial load-bearing capacity, which is greater than the maximum axial force that occurs in the Borpile configuration. In the analysis of the finite element method using the LISA FEA device, a significant stress occurs in the anchor block section with the suspension bridge cable as shown in Figure 9, this occurs because of the large tensile force on the suspension bridge cable and the ability of the anchor block to remain in a stable condition is known.

Influence of an Offshore Mussel Aquaculture Site on the Distribution of Epibenthic Macrofauna in Îles de la Madeleine, Eastern Canada

Mussel farming influences benthic environments by organic loading and the addition of physical structure within aquaculture leases. This study evaluated near-field (distance to mussel aquaculture structures, line-scale) and bay-scale (inside vs. outside a blue mussel, Mytilius edulis, farm) effects of an offshore mussel farm in Îles de la Madeleine (Canada) on epibenthic macrofaunal communities. Benthic communities were evaluated by underwater visual counts using SCUBA in June and July 2014. The mussel farm influenced benthic communities at line- and bay-scales. Overall, crabs (Cancer irroratus, Pagarus pubecsens, Pagarus acadianus), sea stars (Asterias rubens), Northern moon snails (Polinices heros), and American lobsters (Homarus americanus) were more abundant in farm sites than outside of farm sites and ocean quahogs (Arctica islandica) were more abundant outside. No clear spatial trend was observed for winter flounder (Pseudopleuronectes americanus) and the sand dollar (Echinarachnius parma) but both species differed (flounder) or showed a trend to differ (sand dollar) between sampling dates. Spatial structure in the distribution of macrofauna was evident within the aquaculture lease as most species were more abundant directly below and close to mussel lines and anchor blocks. There was no spatial structure in non-farm sites. Further investigation is needed to evaluate if mussel farms serve as ecological traps for the species that congregate within them. The long-term effects of the observed spatial effects of offshore mussel culture on macrofauna fitness remains unknown.

A Simple and Robust Method to Prepare Polyelectrolyte Brushes on Polymer Surfaces

AbstractA simple and robust method is presented to immobilize a heparin‐analog polyelectrolyte on inert hydrophobic surfaces. It is demonstrated that an amphiphilic block copolymer consisting of linear polyglycerol sulfate (lPGS) and a benzophenone modified anchor block can be bound to polystyrene surfaces in a facile dip‐coating procedure. The chaotropic salt guanidinium chloride is used to overcome the aggregation of the polymer as well as the repulsion between highly hydrated sulfate groups and the polystyrene surface. Irradiation with UV light tethers the polymer chains covalently to the surface. The resulting coating exhibits an aggregate morphology that resembles the aggregation behavior in solution, with a coating thickness of 8 nm. The behavior of the surfaces is dominated by the polyelectrolyte brush coating. They swell and collapse in response to different ionic strengths of the surrounding medium, and bind proteins via electrostatic interactions. The coating is stable toward physiological conditions over the course of several weeks. Coated surfaces bind to proteins of the complement cascade when in contact with dilute blood serum, which results in a decrease of complement activity to 78 ± 4%. The coating procedure can also be applied to other nonactivated polymer surfaces, as demonstrated on a polypropylene fleece.

Study on Temperature Control of Gravity Anchorage without Cooling Water

This paper uses Midas Fea simulation software to analyze the hydration heat of a suspension bridge anchorage mass concrete construction without cooling water. According to specific boundary conditions and convection coefficients, the concrete heating process and cooling process are simulated. Analyze the influence of surface air convection coefficient on the surface tensile stress of the cast layer, and the influence of the pouring interval on the interlayer stress of the anchor block, and the temperature difference between the inside and outside of the concrete when the anchor block is layered. It is found that reducing the surface convection coefficient of the pouring layer can effectively improve the stress condition, and the pouring interval has little effect on the stress.

Non‐Covalent Polymer Surface Modification of Cellulose Nanocrystals Using Block Copolymers

AbstractCellulose nanocrystals (CNC) possess desirable mechanical and optical properties that make them a candidate in the development of the next generation of polymer‐based composites. However, CNC also have a critical issue associated with their use: their hydrophilicity and incompatibility with hydrophobic polymers. CNC surface properties must be modified for them to be successfully implemented by the industrial sector. Grafting (co)polymers chains on the CNC surface can provide compatibility to CNC with hydrophobic matrices and expand their potential range of applications. In this communication preliminary results of a simple method to functionalize CNC surface are reported using block copolymers, where a cationic block anchors via complexation to the anionically charged CNC surface and the other block acts as a stabilizing block, providing dispersibility in various solvents. This is a much simpler and less expensive method than current routes based on covalent modification. The block copolymers poly(polyethylene glycol methacrylate)‐b‐poly(N‐butyl‐N′‐vinyl imidazolium bromide) (PPEGMA‐b‐PBuVIm) and poly(styrene)‐b‐PBuVIm (PS‐b‐PBuVIm) are first synthesized via nitroxide‐mediated polymerization and then non‐covalently adsorbed on the CNC surface. The functionalization has been confirmed via FT‐IR and TGA. The dispersion of polymer‐modified CNC materials in organic solvents is evaluated via dynamic light scattering. Modified CNC yielded stable dispersions in organic solvents.

DESIGN OF THE DOBRA CHANTI SUSPENSION BRIDGE IN DISTRICT TEHRI GARHWAL, UTTARAKHAND, INDIA

Since the Tehri dam was constructed on the River Bhagirathi in 2006, considerable productive land areas, many villages, including old Tehri town in Tehri-Garhwal district has been submerged. It has also disconnected the travel and transportation routes along the east slopes of the reservoir, making the local residents lose access to the New Tehri town, which is equipped with resident-friendly facilities including health and education institutions and markets. Accordingly, the Uttarakhand Government has proposed to build the Dobra-Chanti H.M.V. Suspension Bridge to meet the local demand for an easy intra-regional accessibility, especially between the left and right sides of the River Bhagirathi. The project consists of a single-span suspension bridge, an approach bridge at each end of the suspension bridge, and slope protection work on each side. The suspension bridge has a 440m-long stiffening truss girder, 57m-tall steel towers, locked coil cable systems including suspenders, and anchor blocks. The approach bridges are reinforced concrete bridges with T-shaped beams. And river side slopes installed on both banks are protected and stabilized through CC blocks, shotcrete, and anchor bolts. All cek dimension has met the requirement

Determination of optimal Distance of Anchor-blocks in Buried Oil Pipelines Considering the Effects of the Dynamic Soil-Pipe Interaction

In this paper, by using direct modeling of the soil-pipe line system using finite element modelling (FEM) in OpenSEES software and integration with the particle swarm optimization (PSO) algorithm which is provided in MATLAB software in the reciprocating method, which is repeated in enough epochs, the optimal intervals of the anchor blocks has been gained and the effect of different parameters of pipe diameter, pipe length, burial depth, different soils and different earthquake stimuli on the seismic behavior of pipes having anchor blocks investigated. The results show that the change in the depth of the burial and the diameter of the pipe has no effect on the anchor block optimal intervals. Also, increasing the length of the pipe will cause to increase the proposed optimal distance between the anchor blocks. The levels of earthquake hazard and soil type, as well as the length of the pipe, are factors affecting on the distance between the anchor blocks. The simultaneous effect of softening the soil and increasing the level of the earthquake hazard increases the distance between the anchor blocks.