Hydraulic Steel Research Articles

Deep CNN-based semi-supervised learning approach for identifying and segmenting corrosion in hydraulic steel and water resources infrastructure

The United States faces significant challenges due to corrosion, with its impact on military and civilian infrastructure incurring over $20 billion in annual maintenance costs. The damage due to corrosion is profound, threatening structural safety, reducing esthetic value, and leading to costly repairs. To mitigate these effects, the Unified Facilities Criteria and Unified Facilities Guidance Specifications advise the use of protective coatings on metal surfaces. Early corrosion detection is crucial for maintaining structural integrity and minimizing maintenance costs. Recent breakthroughs in artificial intelligence and deep learning, including accurate corrosion classification, have significantly revolutionized the detection and management of corrosion. Despite these advancements, automatic corrosion segmentation in civil infrastructure remains challenging due to the scarcity of images and the labor-intensive annotation process. Moreover, existing segmentation methods are unable to manage the complexities that come with high-resolution corrosion images. This paper proposes a novel, semi-supervised, convolutional neural network-based image segmentation method for the automatic identification and segmentation of corrosion on coated steel surfaces, using both unlabeled and labeled corrosion images and leveraging the mean teacher model. The proposed novel method involves three steps: (1) utilizing high-resolution digital microscopy to capture detailed images and dividing them into manageable patches; (2) applying a semi-supervised learning approach, leveraging unlabeled corrosion images for enhanced segmentation precision; and (3) employing a smoothing module to improve the continuity of information. The proposed corrosion detection method has demonstrated promising performance with only 67% labeled data, achieving mean precision, recall, F-1 measure, and intersection over union of 90.0%, 96.2%, 92.7%, and 87.1%, respectively. Even with just 33% labeled data, the method maintains strong performance when compared to fully supervised deep learning models. This demonstrates a substantial data resource saving while ensuring accurate and reliable corrosion detection, which is crucial for infrastructure health monitoring. The successful validation of this approach provides a method that dramatically reduces the amount of visual data required to generate a reliable model.

Advanced Materials Methods Driving New Life in Critical Infrastructure

Fatigue damage is a major threat to many hydraulic steel structures (HSS). HSS experience fatigue loading during operation and are exposed to harsh environmental conditions that reduce fatigue life. The common methods to inspect and repair HSS is time-consuming and costly. Studies investigating the use of bonded Carbon and Basalt fiber reinforced polymer (CFRP, BFRP) to repair fatigue cracks in HSS are lacking. The main objectives of this study was to increase the bonding of FRP, investigate the effectiveness of different fiber-reinforced polymers, and perform experiments on different retrofitting configurations. In this study, eight large-scale center-cracked panels were tested under mode I loading under different environmental conditions, repair materials, and retrofitting configurations. Results indicated that the use of both CFRP and BFRP are both effective at extending fatigue life. Steel retrofitted with full patches of BFRP that cover the crack can reached infinite fatigue life. This article will conclude with several examples where FRP’s have been used to repair lock gates.

Round robin experiment to detect, size, and characterize flaws in the welds of existing hydraulic steel structures using phased array ultrasonic testing

Limited information exists on the ability of nondestructive testing techniques to detect, size, and characterize flaws in existing hydraulic steel structures (HSS). Round robin experiments were conducted using phased array ultrasonics to inspect welded steel specimens representing joints in existing HSS. Technicians detected 83% of the flaws scanned, but detection rates varied widely by flaw and technician. Uncertainty in flaw size estimates, represented by 90% confidence bounds on the ratio of estimated to actual length or height, ranged from 0.52 to 2.10 for length and 0.32 to 3.59 for height. Planar, volumetric and laminar flaws were accurately characterized 80% of the time.

Weathering tests to investigate the durability of anti-corrosion coatings and on-site repair materials

Steel structures are exposed to multiple environmental impacts that lead to reduced durability. Organic paint systems are a resilient mechanism to protect hydraulic steel structures from corrosion. Coatings lead to a decreased corrosion progress at damaged areas. In this work, we investigated the time dependency of undercoating corrosion in the neutral salt spray test in detail by conducting a long-term experiment. Thereby, the fundamental model of corrosion progress was investigated, leading to an increased reliability in approval procedures of coatings and in the choice of test parameters.Additionally, repair materials for on-site repair of damaged coatings were investigated in weathering tests to compare their performance with conventional coatings. These materials are used for short-term repairs of small damaged areas in order to postpone replacement of ailing structures, thus enhancing the durability of steel structures.

Segmentation and grade evaluation of corrosion on hydraulic steel gates based on image-level labels

Segmentation and grade evaluation of corrosion on hydraulic steel gates based on image-level labels

Numerical Calculation of Static Strength Performance of Planar Gate Structures

As an important part of the ecological environment, rivers provide an important guarantee for the production and life in China. At present, domestic and foreign for the construction of the gate has been gradually shaped, hydraulic steel gate gradually developed as a hydroelectric power station high head, flood discharge flow of large gate type, the smooth opening and closing of the gate is related to the entire water conservancy hub and downstream of the safety of the residents' lives. For the safety of plane gate, this paper adopts Ansys software to establish a finite element model of plane gate, and calculates the most dangerous point stress of plane gate by considering its most unfavourable loading condition. At the same time, the service life of the allowable stress reduction was considered. The analysis results show that the planar gate meets the strength safety. The main beam is simplified into slender beam and thin-walled deep beam, and the calculation formula of slender beam in the mechanics of materials and thin-walled deep beam in the literature is used to calculate the positive bending stress in the mid-span cross-section of the main beam of the gate, and a comparative analysis is carried out with the results of Ansys, which shows that the positive bending stress in the mid-span cross-section of the main beam obtained by simplifying the main beam into a thin-walled deep beam is more close to the results of Ansys calculation. The results of this paper provide an important reference for the structural strength analysis of planar gates.

Numerical Simulation and Application of Radial Steel Gate Structure Based on Building Information Modeling under Different Opening Degrees

The safe and stable operation of the radial gate is highly essential for hydropower stations. As the dynamic load of gate, water flow generally causes the irregular distribution of strength, stiffness, and the stability of the gate structure. Traditional simulation technology is usually used to investigate the impact of water flow on gate structure; however, there is a lack of integration and interaction of building information modeling (BIM) and numerical simulation technology to study this issue. Therefore, this paper proposed a computational framework combing BIM and numerical simulation to calculate and analyze the large complex hydraulic radial steel structure. Firstly, the 3D model of the radial gate was established by MicroStation2020, then, the finite element model was output by using it. Secondly, the change laws of strength, stiffness, and stability of the radial gate were analyzed by Ansys-Workbench2020R2 under different opening degrees. The numerical simulation results show that the maximum equivalent stress value was 142.19 MPa, which occurred at the joint between the lower longitudinal beam and the door blade. The maximum deformation was 3.446 mm, which occurred at two longitudinal beams’ middle in the lower part of the panel. When the opening degree is 0.0 m–9.0 m, the natural vibration frequency increases irregularly with the increase in the opening of the gate. Three main vibration modes of the gate vibration were obtained. It proves that it is feasible to analyze the structural performance of radial gates by using BIM and numerical simulation. Finally, the BIM and numerical simulation information management process was established to make the simulation results more valuable. This study expands the application value of BIM and provides a new research idea for large complex hydraulic steel structural analysis. The information management process described in this research can serve as a guide for gate operation and maintenance management.

Flexural and Tensile Performance of Laminated GFRP as Suitable Alternative to Hydraulic Steel Gates

Flexural and Tensile Performance of Laminated GFRP as Suitable Alternative to Hydraulic Steel Gates

Experimental and Numerical Investigation for Optimum Design of Hydraulic Steel Gates

Experimental and Numerical Investigation for Optimum Design of Hydraulic Steel Gates

Mechanical characteristics analysis of cantilever hydraulic steel pipe structure in construction machinery under low-speed impact

Mechanical characteristics analysis of cantilever hydraulic steel pipe structure in construction machinery under low-speed impact

Application and Development of Hydraulic Steel Structure Safety Information Management System in Pumped Storage Hydropower

In the context of the current energy structure transition and the rapid advancement of clean energy, the reliability of hydraulic steel structure equipment plays a crucial role in the stable operation and efficiency improvement of pumped storage hydroelectric power stations. With technological advancements, strengthening the digital management of hydraulic steel structures has become a focal point in the industry's development. This paper takes the "JinZhi" system developed by the PowerChina HuaDong Engineering Corporation Limited as an example to deeply explore the practical application of hydraulic steel structure safety information management system and its significant role in enhancing operational efficiency and safety. By analyzing industry development trends, the paper reveals the challenges and potential opportunities encountered during digital transformation and proposes targeted recommendations for future development direction. The research demonstrates that the integrated application of information technology can effectively improve the management quality and safety level of hydraulic steel structures, ensuring the efficient and stable operation of power stations, and providing valuable insights for similar industries aiming to achieve digital transformation.

Mechanical characteristics analysis of cantilever hydraulic steel pipe structure in construction machinery under low-speed impact

Mechanical characteristics analysis of cantilever hydraulic steel pipe structure in construction machinery under low-speed impact

Bearing stress detection and evaluation of hydraulic steel gate members

Based on the principle of mathematical statistics, we describe the theory and algorithm of establishing the stress characteristics of gate members by using the method of data regression analysis based on multiple levels of actual load detection data. Following, we demonstrate the test results of an arc gate of a spillway dam by regression analysis. Then, we calculate the structural stress state under the design condition by regression equation, and the finite element results are used to verify each other. Finally, according to the current standard, we give the safety evaluation of the structure stress calculation data under the design condition.

Study on Analysis Principle of Spatial System Method for a Hydraulic Steel Gate

The target of this paper is to ensure that the spatial system method has scientific and efficient rules to follow in structural analysis of a hydraulic steel gate, and to overcome the problems of randomness and fuzziness in the analysis process. Based on the idea of part and whole, the analysis principle of the spatial system method for a steel gate is systematically studied using the combination of theoretical calculation, finite element analysis, and prototype testing. First, the method is verified, with theoretical calculation used to ensure the authenticity of geometric modeling, the appropriateness of the element type, the rationality of meshing, the accuracy of constraints, and load application when the spatial system method is used to analyze the gate structure (panel, arm, and beam). The specific and practical feasible analysis principles of using the spatial system method to analyze the gate structure are provided. Second, the analysis of the gate structure is carried out using the analysis principle of the spatial system method. Finally, a prototype test is used to verify the analysis results of the spatial system method. Based on the prototype test results, the maximum absolute error of static displacement is 0.58 mm and the maximum relative error of static stress is 9.19%, which verifies the rationality and accuracy of the analysis principle of the spatial system method. The key technical problems restricting the transition of the gate structure analysis from the plane system method to the spatial system method are preliminarily solved. This first exploration is made for the popularization and application of the spatial system method, and lays a technical foundation for improving the quality and efficiency of gate structure design.

Numerical Analysis of Flow-Induced Vibration of Deep-Hole Plane Steel Gate in Partial Opening Operation

Hydraulic steel gates are the core adjustment mechanism for water conservancy projects, the safety of which is related to the safety of the entire water conservancy project. In this study, the issue of flow-induced vibration under the influence of pulsing water pressure when the deep-hole plane steel gate construction is partially opened is investigated using a numerical calculation approach of CFD–CSD coupling. The time-history pulsating pressure loads of each part are first determined by tracking the upstream, bottom, and downstream pulsating water pressure loads under partially open operation conditions of the gate. The impact of the water in front of the gate on the natural vibration mode and frequency of the gate is then investigated based on the analysis of the dry/wet modes of the gate structure. Additionally, the hydrodynamic load is applied to the finite element model of the gate structure while taking into account the fluid–structure coupling effect, and the results of the gate flow-induced vibration response are obtained. Three typical local opening relative openings are chosen, with the operating state of the design water head (Hs = 70 m) of a deep-hole plane steel gate as an example. According to the analysis’s findings, the gate’s natural vibration frequency is greatly lowered under the influence of the water in front of it, and its amplitude increases by 50%. The pressure value pressing on the gate changes dynamically as it is partially opened and discharged. The maximum dynamic displacement value and the maximum dynamic stress value of the gate both appear in the middle and lower part of the gate under the condition of partial opening, and both occur when the relative opening is e/H = 0.125. The maximum displacement value is 3.43 mm, and the maximum stress value is 161 MPa. The maximum dynamic displacement and dynamic stress of each gate component steadily decrease with an increase in the relative openness. The gate dynamic response analysis approach described in this research can serve as a guide for hydraulic engineering design.

Deformation Control Monitoring of Basement Excavation at Field Construction Site: A Case of Hydraulic Servo Steel Enhancement Geotechnology

This study presents two field cases of deep excavation using the hydraulic servo geotechnology as an enhancement to the lateral support. The first excavation process was preceded with numerical simulation to investigate the deformation of excavation pit with and without servo geotechnology. Optimised axial loading capacities from the numerical simulation were adopted at the actual excavation site. On the second excavation site, servo geotechnology was applied directly on the excavation process during actual construction without prior numerical simulation. The results showed that the servo steel support geotechnology restrained above 70% of lateral displacements of the excavated walls, and ground surface influence zone settlements were kept within the acceptable warning limits. Prior application of the numerical simulation before field excavation optimised axial loads and kept the deformation caused by excavation within project limits. The numerical simulation of servo geotechnology deformation control capacity for deep excavation projects is validated, and this study provides a practical and significant reference on similar projects.

Application of improved radar chart in the health evaluation model of hydraulic gate

In view of the multi-factor influence of stress, deflection, vibration, corrosion and other factors involved in the state assessment of hydraulic steel gates, established a gate health assessment system including the target layer, criterion layer and indicator layer. A hydraulic health assessment model combining fuzzy analytic hierarchy process and improved radar chart method is proposed. In this method, the fuzzy analytic hierarchy process is used to determine the weight of each index, and then the improved radar chart method is used to evaluate the criterion layer and the target layer respectively, and the gate evaluation level is standardized and drawn into the radar chart. An example of comprehensive evaluation of a radial gate is given, which visually expresses the various factors that affect the gate. While giving the health evaluation result of the gate state, it fully reflects the actual state of all aspects of the gate.

The Effects of Deteriorated Boundary Conditions on Horizontally Framed Miter Gates

The U.S. navigable infrastructure is a system of waterways dependent upon hydraulic steel structures (HSS) to facilitate the passage of ships and cargo. The system is linear in the sense that if one HSS is impassable, the entire river system is halted at that point. The majority of the HSS in this system were built in the first half of the 20th Century, and over seventy percent of them are past or near past their design life. Miter gates are critical HSS components within the system and many are showing signs of structural distress from continued operation past their design life. Common distress features include shear cracking within the pintle socket, partially missing Quoin blocks, fatigue fracturing, and bolt failure in the pintle region. This article focuses on gaining a fundamental understanding of the consequences of quoin block deterioration on a miter gate. The work was conducted by developing a computational model of a miter gate with different levels of quoin block deterioration. This model was validated using analytical solutions. The deterioration results demonstrated that the miter gate thrust diaphragm and quoin post experienced changes in their limit states due to deterioration. The results also demonstrated that the miter gate could overcome up to 10% of quoin block deterioration.

Influence of rivet clamping stress on fatigue crack growth behaviour

AbstractSteel structures built between 1850 and 1940 are mostly made of mild steel. Riveting was the dominating joining technique. Fatigue failure respectively fatigue safety is of major concern if these structures are cyclic loaded such as bridges and hydraulic steel structures. Considering the period of operation of almost hundred years, the determination of the remaining fatigue life is the main aim of the assessment of these structures. The clamping force of the rivets significantly influences the crack propagation. Clamping stress is caused by the shrinkage of hot driven rivets while cooling down. The clamping force and the corresponding friction at the contact surfaces reduces notch stress at the rivet hole and thus also the crack driving force. In this paper, experiments for determining the rivet prestressing as well as the friction at the contact surfaces of riveted joints are presented. For typical design details numerical models are generated to determine notch stresses for uncracked components and stress intensity factors for cracked components. Regarding to crack growth rates, only few data have been published for old mild steels so far. Thus, the research program also includes experimental investigation of crack growth parameters.

Safety Evaluation of Hydraulic Steel Gate Based on TOPSIS Model

The paper aims to evaluate the safety of spillway’s steel gates in Xiaoling Reservoir. The weight of each evaluation index was obtained by analytic hierarchy process. Based on the detected data, TOPSIS model was used to evaluate the safety of main components for each gate. And then the comprehensive safety evaluation for spillway’s gates was carried out on this basis. The results were as follows. The coating of supporting arm was thin for gate 1. The coating of main beam and supporting arm was thin for gate 2. The coating of supporting arm was thin and the corrosion was serious for gate 3. The order of the three gates safety was gate 2 > gate 1 > gate 3. The results can reveal the safety situation of the gates and provide a reference for engineering maintenance.