Experimental analysis of covering layer-prestressed wire rope reinforced bridges

To study the fatigue properties of reinforced concrete (RC) T-beams strengthened with a composite of prestressed steel wire ropes embedded in polyurethane cement (PSWR-PUC), which is an innovative reinforcement method, two RC beams without strengthening, three RC beams with a composite of prestressed steel wire ropes embedded in polymer mortar (PSWR-PM) and three RC beams with PSWR-PUC were designed. Some key parameters, such as the material into which the wire rope is imbedded, the fatigue loading, and the tension of steel wire ropes, are discussed. The experimental results show that PSWR-PUC reinforcement can significantly improve the monotonicity and fatigue performance of RC T-beams. The PSWR-PUC strengthening can significantly reduce beam deflection and steel bar stress. Under the same load, the maximum strain and strain range of PSWR-PUC reinforced beams are significantly smaller than those of PSWR-PM reinforced beams. Due to the excellent properties of polyurethane cement composite with high strength, high bond, and high toughness, the cracking and peeling phenomenon of polymer mortar in PSWR-PUC reinforced beams did not occur, which can improve the fatigue life of beams by reducing the stress of steel bars. Due to the cracking, falling off, and peeling of polymer mortar, the bonded prestressed wire rope becomes unbonded pre-stressed wire rope, which redistributes the stress of the beam and further increases the stress of the steel bars.

The mechanical behaviors of laboratory-fabricated steel and superelastic shape memory alloy (SMA) wire ropes are assessed in this study through a comprehensive approach encompassing both experimental investigations and finite element (FE) numerical simulations. The assessment of steel wire ropes involves experimental scrutiny under sinusoidal cyclic loading and natural earthquake loading conditions. In parallel, SMA wire ropes’ behaviors are analyzed utilizing FE simulations employing the widely acknowledged ABAQUS software version 2020. The validation of all numerical simulations is undertaken against the experimentally observed behaviors. Moreover, full-scale steel wire ropes are subjected to shaking table tests to validate the simulations, facilitating a comparative analysis between the mechanical responses of SMA and steel wire ropes. The findings demonstrate that SMA wire ropes exhibit superelastic behavior akin to SMA wires, with marginal variations in overall response observed across distinct configurations, akin to steel wire ropes. Furthermore, augmenting the helix angle of SMA wire ropes results in reduced stress and increased strain when exposed to the El Centro earthquake scenario. Nevertheless, the mechanical response of SMA wire ropes closely mirrors that of a single wire.

This paper presents the experimental response of reinforced concrete T-beams strengthened with an innovative technique, namely, a composite of prestressed steel wire ropes (PSWRs) embedded in polyurethane cement (PSWR–PUC). The flexural behaviour of the PSWR–PUC-strengthened beams was investigated. One control beam, three PSWR-strengthened beams and five PSWR–PUC-strengthened beams were constructed and tested under four-point bending. The experimental variables included the material into which the wire rope is embedded, the thickness of the PUC, the number of wire ropes, the loading method and the wire rope anchoring type. The test results indicated that relative to PSWR-strengthened beams, PSWR–PUC-strengthened beams had significantly greater yield load, ultimate load and stiffness at the service load, and these enhancements increased significantly with increasing PUC thickness. Relative to using polymer mortar for PSWR strengthening, using PUC increased the durability of the steel wire ropes in the PSWR–PUC-strengthened composite. The cracking load of the PSWR–PUC-strengthened composite mainly depended on the prestressing effect of the wire ropes. However, after cracking, crack constraint in the PSWR–PUC-strengthened beam was dependent on the crack-suppression effect of PUC, especially during the later cracking stage. PSWR–PUC strengthening can effectively ensure secure anchoring by reducing the number of steel wire ropes required. These results indicate that PSWR–PUC strengthening has potential as an external strengthening technique for concrete structures.

I. IntroductionAs a new type of elevator drive and load-bearing member, the composite steel belt has been used widely. Inside the composite steel belt, there are multiple small-diameter steel wire ropes side by side, and the rope spacing is small. The surface of these side-by-side wire ropes is covered with a special plastic material. So, the composite steel belt has large traction capability and high flexibility, which makes the main engine volume smaller than that of the traditional elevator product mainframe. Furthermore, the composite steel belt has more steel wires than the conventional wire rope, which is more durable and has a longer service life. In additional, the composite steel belt is lighter in weight, and it can effectively reduce the vibration and noise during the operation of the elevator. A number of elevator manufacturers are also gradually adopting and promoting the use of composite steel strips in elevators.However, the surface of the composite steel strip is covered with a wear-resistant plastic material such as polyurethane. In the process of use, if the internal steel wire rope has defects such as warping, breaking, misalignment, and thinning, it cannot be recognized by the naked eye, which affects the safety of the elevator. If the internal wire rope has potential defects at the time of leaving the factory, it is easy to scratch the surface rubber material, which is more likely to cause an accident. Therefore, the damage detection of the composite steel belt plays an important role in the safe operation of the elevator [1]. The rope in the composite steel belt belongs to ferromagnetic component, electromagnetic detection methods is ideal for its non-destructive testing [2]. In addition, the electromagnetic detection method has also been used for fine steel wire rope detection and achieved a good detection effect [3]. The wire ropes inside the composite steel belt are just fine steel wire ropes. Electromagnetic finite element simulation analysis (FEA) can provide magnetic field status reference for electromagnetic detection of wire rope [4]. The application of some magnetic dipole model analysis and related algorithms in electromagnetic detection also provides relevant references for the detection of wire rope defects[5,6].II. Simulation and Excitation Structure DesignThe schematic diagram of the common composite steel strip structure is shown in Fig. 1(a), and the excitation structure is established as shown in Fig. 1(b). By selecting the appropriate size of permanent magnet and yoke, the wire ropes in the composite steel belt are excited to near saturation.In the simulation, three defects appear on the first, fifth and ninth wire ropes at the same time. Extract the radial magnetic flux leakage directly above and below each wire rope and above and below both sides of the 1st and 10th wire ropes, as shown in Fig. 1(c) and Fig. 1(d). It can be seen that on the defective wire ropes, the radial magnetic flux leakage is large, and on the wire rope without defects, the magnetic flux leakage is very small. Therefore, magnetic detection sensors (such as hall, anisotropic magneto-resistive, giant magneto-resistive, fluxgate, tunnel magneto-resistive, etc.) can be arranged above and below each wire for picking up the magnetic flux leakage signal, thereby detecting the defect.III. Experimental and ResultsSince the diameter of the wire rope and the distance between the ropes inside the composite steel belt is small. The hall element having a small volume and high sensitivity is selected as the detecting sensor. The halls are placed above and below each wire rope. For the signal processing, the hall output signals above and below each wire are first summed up. Then the noise and interference signals are filtered out by a bandpass filter. Subsequent use of a comparator to determine the defect.Fig.2a) shows a photograph of a steel belt with three defects, each of which is located on a wire rope inside. Fig.2b) shows the design of the steel wire rope detection device inside the composite steel strip and the detection result when the second defect is detected. **

Observation of ultrasonic guided wave propagation behaviours in pre-stressed multi-wire structures

Machine-vision-based defect detection, instead of manual visual inspection, is becoming increasingly popular. In practice, images of the upper surface of cableway load sealing steel wire ropes are seriously affected by complex environments, including factors such as lubricants, adhering dust, natural light, reflections from metal or oil stains, and lack of defect samples. This makes it difficult to directly use traditional threshold-segmentation-based or supervised machine-learning-based defect detection methods for wire rope strand segmentation and fracture defect detection. In this study, we proposed a segmentation-template-based rope strand segmentation method with high detection accuracy, insensitivity to light, and insensitivity to oil stain interference. The method used the structural characteristics of steel wire rope to create a steel wire rope segmentation template, the best coincidence position of the steel wire rope segmentation template on the real-time edge image was obtained through multiple translations, and the steel wire rope strands were segmented. Aiming at the problem of steel wire rope fracture defect detection, inspired by the idea of dynamic background modeling, a steel wire rope surface defect detection method based on a steel wire rope segmentation template and a timely spatial gray sample set was proposed. The spatiotemporal gray sample set of each pixel in the image was designed by using the gray similarity of the same position in the time domain and the gray similarity of pixel neighborhood in the space domain, the dynamic gray background of wire rope surface image was constructed to realize the detection of wire rope surface defects. The method proposed in this paper was tested on the image set of Z-type double-layer load sealing steel wire rope of mine ropeway, and compared with the classic dynamic background modeling methods such as VIBE, KNN, and MOG2. The results show that the purposed method is more accurate, more effective, and has strong adaptability to complex environments.

Prior to the SCORCH JIP, industry guidance for steel wire ropes specified only a maximum service life for various rope constructions, providing no insight into the corrosion degradation processes affecting mooring ropes at different locations in the mooring line and under different working conditions, or to potential differences in manufacture. One of the objectives of the SCORCH JIP was to address this gap in knowledge by providing design guidance on the specification of mooring wire ropes and analytical tools to estimate the design service life of mooring wire ropes for particular site conditions, especially in tropical waters. In the wire rope component of the JIP, field recovered specimens were examined and field tests on wires and wire ropes were performed to quantify the effects of external factors driving degradation of wire ropes in marine environments, including: protective coating; blocking compound, temperature, flow velocity, oxygenation and dynamic loading. Failure modes for wire rope were analysed based on the examination of recovered samples from in- service wire ropes, inspection records from different floating production units (FPUs), reported experiments in the field and experiments in literature. Experimental testing (both field tests and laboratory tests) of individual wire strands and complete wire rope constructions were carried out at a number of locations with varying environmental conditions. These data were then analysed to derive a phenomenological model that represents the observed behaviour of both ropes and individual wire layers. Amongst the key findings of the SCORCH JIP investigation was that the corrosion endurance of steel wire rope mooring lines is largely driven by the longevity of the galvanizing or other galvanic protecting coating, and the blocking compound, which forestall the direct corrosion loss of metallic area of the relatively small steel wires. Two major mechanisms by which zinc oxidation occurs and the major environmental contributors to the acceleration of wire degradation were identified; and efficacy of various rope protection methods were assessed. A predictive model was derived which characterised the rate of zinc dissolution, performance of blocking compound and corrosion rates for different exposure and working conditions. The outcome of the wire rope component of the SCORCH JIP was a significant advancement in industry knowledge on the corrosion behaviour of steel mooring wire ropes.

The trend to produce oil at constantly deeper water has led to the development of floating production solutions for the exploitation of the energy resources in these areas. It is a fact that steel wire ropes have been used and arc being proposed used, as line segments in the majority of the mooring systems of these units/ships. This paper specifics requirements for the materials, design, manufacture and testing of large diameter offshore mooring steel wire ropes and may serve as a technical reference document in contractual matters between the purchaser and the manufacturer. Typical applications covered are permanent moored floating production systems (IT%), offshore loading systems and mobile offshore units. Introduction Steel Wire Rope Constructions. Steel wire rope segments of mooring lines could be of various constructions as shown in Figure 1. Other type of constructions e.g. eight strand, may also be used if relevant experience can be documented. The six strand construction type includes a number of strands wound in the same rotational direction around a center core to form the wire rope, The number of strands and individual wires in each strand (e.g,6×41,6×49,6×6 1,6×91) are governed by required strength and bending fatigue considerations for the wire rope, This construction generates torque as tension increases. The torque balanced strand type constructions (multistrand, spiral strand, half locked and full locked coils) arc attractive for use with permanently moored platforms/vessels since they do not generate significant torque with tension changes. These constructions use layers of individual wires (or bundles of wires) wound in opposing directions to obtain the torque balanced characteristics. The half locked and full locked coil constructions consist of one or more layers of shaped individual wires over the basic spiral strand construction resulting in a design more resistant to the ingress of corrosion media, The shaped layer(s) of individual wires will also prevent any outer wire fracture from unwinding. These constructions will normally give higher load capacity related to nominal diameter due to the increased metallic area, compared to other constructions. Corrosion Protection Measures. A common design requirement is that wire rope segments in mooring lines arc to be protected against corrosion attacks throughout the design life. The wire rope is therefore assumed to be fully protected such that its fatigue life approaches that in air. This is normally ensured by the following measures or combinations thereof:Sacrificial coating of individual wires.Application of a blocking compound on each layer of the strand during stranding, The compound should till all crevices in the wire rope, strongly adhere to individual wire surfaces and have good lubricating properties.Cathodic protection by spinning zinc or other sacrificial anode alloy wires in one of the outer 3 layers of the wire rope during manufacture.Surface sheathing of the wire rope by an extruded plastic jacket in order to prevent ingress of seawater and flushing out of blocking compound. The ends of each wire rope segment are normally terminated with sockets (cast or welded). Free bending at the sockets outlet can reduce the wire rope fatigue life.

Through the experiment of the four RC beams strengthened with SWR externally prestressing, the shear resistant effect of Strengthened beams under cracking width of the original beams is studied in the paper. The ultimate load was confirmed by the test of the basic beam. First the presplitting load were respectively 50%, 60%, 70%, 80% of the ultimate load of basic beam, and seconly cracks were repaired with JN-L low viscosity pouring sealant, lastly experiment beams were strengthened by shear reinforcement of the external prestressing with steel wire rope. Loading method is the single point loading, and the shear span ratio is 2.0. The results show that: the cracking width of original beam has certain effect in shear resistant capacity. When the cracking width was less than 0.2 mm, the effect of injecting glue was not ideal and the shear resistant capacity is lower. When the crack width was bigger, the effect of injecting glue was more ideal, so the effect of reinforcement was better. When the cracking width was greater than 0.28 mm, the ultimate load was no longer improved. The smaller inclined cracking width in strengthening is, the worse repairing effect and the bigger strain value of stirrup is. Each strengthened beams’ wire rope strain increment was nearly close before cracking. As the decrease of original beams crack width, crack repair effect was weak, and the external strain increment of wire rope becomes bigger under the same load. The trend was very clear after the stirrup yielding.

As a key component of the hoisting system of the crane, the steel wire rope will bear a variety of loading actions such as stretching, bending, vibration and impact in the process of traction hoisting. Therefore, it is important to determinate the dynamic characteristics of the steel wire rope under complex loads and understand the stress-strain state to predict the risk of hoisting operation in advance. This article takes the bridge crane as the engineering background, first, a dynamic model of a steel wire rope lifting system based on ADAMS/Cable was established, and the dynamic stress spectrum of the steel wire rope during the lifting process was calculated and obtained. Secondly, by establishing the geometric model and finite element model of the wire rope, the tensile stress and wire displacement distribution of the wire rope and the contact stress between the wire rope and the pulley and the wires inside the wire rope are analyzed during the lifting process of the crane. The final results show that the instantaneous acceleration of the steel wire rope increases the maximum tensile stress of the steel wire rope by 37% compared with the stable lifting stage at the instant of starting the steel wire rope, causes an increase in the stress amplitude of the wire rope cross section, and the lifting process of the steel wire rope is accompanied by unstable vibration loads. The analysis found that the outermost cross-section of the steel wire rope's outer strand was subjected to the greatest stress, and its local maximum tensile stress amplitude was increased by 56% compared to the stable lifting stage. The contact stress generated by the contact between the steel wire rope and the pulley causes contact wear on the external and internal strands of the steel wire rope, and promotes fatigue fracture of the steel wire rope.

Based on a comparison of the advantages and disadvantages of existing strengthening methods, this paper proposes a new strengthening technique with prestressed high-strength steel wire rope (P-SWR) for reinforced concrete (RC) beams. The paper presents the theoretical basis of this new method, an experimental programme of flexural strengthening of RC beams with P-SWR, and a comparison between the results of experimental tests on the proposed methods and the results for a carbon-fibre-reinforced polymer (CFRP) sheet and steel plate. The effectiveness parameters, including the loading method (direct loading or pre-damaged loading), the layers of steel wire rope, bonding or lack of bonding between the steel wire and concrete, and the types of anchorage are discussed. Test results show that the P-SWR can significantly improve the cracking load, stiffness, yield load and ultimate load of RC beams. The final failure model for the beams strengthened with P-SWR has typical characteristics, such as steel yielding, crushed concrete and fractured steel wire ropes. The width of flexural cracks in the concrete beams is effectively controlled. This method also exploits the strain capacity of the wire rope to its limits. Furthermore, the advantages of this new technique include minimum site disruption, minimal increase in the size of the repaired member, minimum scaffolding, superiority for fire and corrosion resistance, and low cost; the method presented is therefore an attractive alternative to existing strengthening methods.

This study investigates the macroscopic mechanical behavior of steel wire ropes under corrosive conditions, specifically focusing on the effects of sulfuric acid exposure. The goal is to simulate and analyze the degradation process in service by conducting monotonic tensile tests on both undamaged and artificially pre-damaged 19 × 7 circular strand steel wire ropes. These ropes were subjected to varying levels of corrosion in order to evaluate their mechanical properties. To systematically explore the influence of multiple factors on the degradation process, the Taguchi method was applied, utilizing an L9 orthogonal array with three experimental factors: sulfuric acid concentration, immersion time, and the number of strands removed from the wire rope. Each factor was tested at three levels to determine its impact on corrosion resistance. Steel wire ropes were exposed to sulfuric acid concentrations of 20 %, 30 %, and 40 % for immersion times of 1–3 h, with 0, 2, and 4 strands removed. The maximum tensile strength decreased from 516.415 N in the reference sample to between 482.83 N and 35.63 N after corrosion, corresponding to a 6.5–93.1 % reduction. Statistical analyses, including the signal-to-noise ( S / N ) ratio and analysis of variance (ANOVA), were used to identify the optimal parameter settings for maximizing mechanical performance. The results indicate that the number of strands removed has the most significant influence on the rope’s mechanical properties, followed by the concentration of sulfuric acid and the immersion time. A confirmation test was performed to verify the accuracy and consistency of the optimal parameter configuration, ensuring the reliability of the findings. This study highlights the importance of optimizing key parameters to enhance the corrosion resistance of steel wire ropes, thus extending their service life in corrosive environments. The use of the Taguchi method in this context demonstrates its effectiveness in optimizing mechanical properties and provides valuable insights for improving the durability of wire ropes in industrial applications.

This study investigates the cost-effectiveness of using steel wire ropes (SWR) and synthetic polyester ropes (PR) in floating offshore wind turbine (FOWT) mooring systems compared to traditional steel chains. The research focuses on identifying potential cost savings and assessing their dependence on floater type. In this regard, a semi-submersible floater and a spar-buoy floater are considered at 200 m and 300 m water depth, respectively. The study encompasses the comprehensive design and evaluation of three mooring system designs per floater type: a conventional catenary system with steel chains, a hybrid catenary system with chains and steel wire ropes, and a hybrid catenary system with chains and polyester ropes. The objective is to compare on the basis of specific key performance indicators (KPI’s) the material cost of the mooring system, the floater motions, the mooring line tension and lifetime, the tower and hub acceleration, and the blade root and tower base combined bending moments. Analysis of the three mooring system designs indicated that all are viable solutions for both spar-buoy and semi-submersible floating Wind Turbine (WT) configurations. Both SWR and PR proved effective for station-keeping in hybrid rope-chain mooring systems. Consistent across all designs, chains exhibited fatigue-driven behavior, while ropes (SWR and PR) demonstrated ultimate-driven characteristics. The analysis indicates that the suitability of rope-based mooring systems may depend on various interacting parameters including design offset, imposed pretension, and water depth. Cost analysis highlighted the potential economic benefits of hybrid systems, particularly concerning reduced material costs and potentially reduced installation costs.

Mining wire rope, a frequently used load-bearing element, suffers various forms of damage over extended periods of operation. Damage occurring within the wire rope, which is not visible to the naked eye and is difficult to detect accurately with current technology, is of particular concern. Consequently, the identification of internal damage assumes paramount importance in ensuring mine safety. This study proposes a wire rope internal damage noise reduction and identification method, first of all, through a three-dimensional magnetic dipole model to achieve the detection and analysis of the internal damage of the wire rope. Simultaneously, a sensor system capable of accurately detecting the internal damage of wire rope is developed and validated through experimentation. A novel approach is proposed to address the noise reduction issue in the design process. This approach utilizes a particle swarm optimization variational modal decomposition method to enhance the signal-to-noise ratio. Additionally, a dual-attention mode, which combines channel attention and spatial attention, is integrated into the CNN-GRU network model. This network model is specifically designed for the detection of internal damage in steel wire ropes. The proposed method successfully achieves quantitative identification of internal damage in steel wire ropes. The experimental findings demonstrate that this approach is capable of efficiently detecting internal damage in wire rope and possesses the capacity to quantitatively identify such damage, enabling adaptive identification of wire rope.

Steel wire ropes widely used in the marine environment are subjected to aggressive species of corrosive attack. The surface of the steel wire ropes is usually protected by galvanizing. The thickness of the zinc coating depends on the class of galvanizing. Case studies presented will illustrate how service life can be influenced by the local conditions including the type of zinc coating. This paper presents typical corrosion failure analysis investigations performed on steel wire ropes used in the marine industry of Trinidad and Tobago. Case study 1 shows the stranded wire rope attached to a mooring buoy located at a remote location in the ocean. The wire rope failed approximately one year after installation at a point at the base of the socket. Case study 2 showed a spiral strand steel wire rope installed on a Link belt crane located in a marine environment. The rope also failed after one year in service. The analysis performed on the failed components comprised a number of analytical techniques and testing methods that resulted in the determination of the root cause of failure being a lack of lubrication that eventually caused coating damage, peening, embrittlement, inter-strand nicking and fretting wear of the wire ropes. Recommendations were suggested to prevent the occurrence.