Hydraulic Steel Structures Research Articles

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.

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.

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.

Research influence of biological corrosion on the strength of steel structures of hydrotechnical construction of long-term operation in aggressive environments

Biocorrosion is caused by the vital activity of various microorganisms that use metals as a nutrient medium or produce products that destroy metal structures. Anaerobic is the most dangerous (growth without oxygen) sulfate-reducing bacteria, which are present in slimy and swamp soils. Bacteria restore sulfate ions to sulfides ions, accelerating corrosion of metal. Life of aerobic bacteria occurs only in the presence of oxygen. Bacteria oxidize sulfur to sulfuric acid, the concentration of which in separate places can reach 10%. Ironobacteria absorb iron in ionic form and excrete it in the form of non-dissolved compounds. Since non-dissolved products are distributed on the metal surface unevenly, the electrochemical heterogeneity of the surface occurs, which accelerates corrosion. Microorganisms formed on the metal surface can cause not only corrosion. They can also increase the concentration of hydrogen sulfide in the environment by increasing the amount of deposits on steel hydraulic structures.
 The greatest danger from the point of view of corrosion is sulfate reducing bacteria (SRB), which are widespread in hydraulic environments. Sulfate renewable bacteria belong to the class of anaerobic bacteria, the vital activity of which can be without oxygen. Aerobic bacteria, such as ironbacteria (IB) and sulfur bacteria or thionic (TB), which are present in groundwater with SRB, is viable only in the presence of oxygen. Anaerobic and aerobic bacteria have a common existence environment, and therefore often the development of one species creates favorable conditions for others.

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.

Erosion characteristics of viscoelastic anticorrosive coatings for steel structures under sand flow

Due to the continuous erosion of anticorrosive coatings on hydraulic steel structures, the coating falls off over large areas, causing exposure and rusting of the steel structure. This process directly affects the normal use of hydraulic steel structures. To study the erosion law of viscoelastic anticorrosive coatings for steel structures in a sand flow environment, three kinds of polyurethane coatings were prepared with different proportions (A:B = 1:1, 1:2 and 1:3), and accelerated physical erosion tests of the above-mentioned anticorrosive coatings for steel structures in a sand flow environment were carried out with traditional epoxy asphalt coatings as the control group. The erosion patterns of various viscoelastic anticorrosive coatings under different erosion times, sand flow velocity and sediment concentrations under sand flow were obtained. The results show that the abrasion amount of coatings is logarithmically correlated with erosion time and exponentially correlated with sand flow velocity. Under higher sediment concentrations (4.0–8.0 kg/m3), the abrasion of the coating increases with increasing sand flow velocity. Under an erosion condition of low sediment concentration (0.5–1.8 kg/m3), the abrasion of the coating undergoes a long period of slow growth. The abrasion of the polyurethane coating is lower than that of the epoxy asphalt coating, and among the tested samples, the 1:3 polyurethane coating has the least abrasion and the best erosion resistance. Based on the results of the accelerated erosion test and the existing erosion theory, a prediction model was proposed for the viscoelastic anticorrosive coating of steel structures under sand flow, and the correctness of the prediction model was verified by the experimental results. The research results have important guiding significance for reasonably predicting the durability of hydraulic steel structures.

Abrasion resistance of polymer and polymer–ceramic composite coatings for steel hydraulic structures

There is an increased demand for abrasive wear-resistant coatings that add durability to steel hydraulic structures, particularly for those subjected to flowing water with debris and alternate wet/dry cycles. These coating systems provide not only corrosion and chemical resistance, but also good erosion and abrasion resistance to the metallic surfaces, which are constantly exposed to flowing water containing sand particles and debris. Generally, vinyl-based coatings are used on hydraulic steel structures to protect them from corrosion and abrasion. However, due to the existence of high water force and debris, the coating is abraded at a faster rate leading to significant maintenance and repair costs. In this study, abrasive wear resistance of conventional vinyl-based coating systems currently used on lock and dam steel structures by U.S. Army Corps of Engineers has been compared with polymer matrix composite coatings, fibrous polymer coatings, and ultrahigh molecular weight polyethylene (UHMWPE). Six coating systems were evaluated through two-body abrasion tests using a reciprocating abrader under dry and wet conditions. Furthermore, wettability of the coating systems and its effect on the wear rate under the presence of water was studied. In addition, scanning electron microscopy of the wear tracks on different coatings was conducted to study and identify their failure mechanisms. Based on the results, UHMWPE and polymer–ceramic composite coatings were found to perform significantly better than the conventional vinyl-based coatings.

Optimal inspection and repair scheduling for mitre lock gates

Hydraulic steel structures, especially lock gates, play an important role in inland waterway transport infrastructure. Navigation lock gates are normally designed to last for 100 years. However, after a few decades of operation, many welded joints of steel mitre gates may suffer deterioration and unexpected failures, occurring primarily due to fatigue. As emergency repairs are costly, time-consuming and disruptive, optimising the operation and maintenance plans of mitre gates is necessary. Risk-based inspection planning has been used for marine structures but is seldom applied to inland navigation lock gates. In this paper, a procedure is proposed for inspecting welded joints using observed water levels. Optimal inspection plans are then evaluated by risk analysis, combining failure probabilities and associated expected costs for different events. A mitre gate is used to illustrate the procedure. It was found that the total expected cost of inspections performed at regular time intervals was generally higher than inspections performed when a certain annual failure probability threshold was reached.

Effects of Adhesive Bond-Slip Behavior on the Capacity of Innovative FRP Retrofits for Fatigue and Fracture Repair of Hydraulic Steel Structures

Over eighty percent of the navigation steel structures (NSS) in the United States have highly deteriorated design boundary conditions, resulting in overloads that cause fatigue cracking. The NSSs’ highly corrosive environment and deterioration of the protective system accelerate the fatigue cracking and cause standard crack repair methods to become ineffective. Numerous studies have assessed and demonstrated the use of carbon fiber reinforced polymers (CFRP) to rehabilitate aging and deteriorated reinforced concrete infrastructure in the aerospace industry. Due to the increase of fatigue and fracture failures of NSS and the shortage of research on CFRP retrofits for submerged steel structures, it is imperative to conduct research on the effects of CFRP repairs on NSS, specifically on the adhesive’s chemical bonding to the steel substrate. This was accomplished by developing a new analytical algorithm for CFRP bond-slip behavior, which is based on Volkersen’s contact shear single lap joint (SLJ) connection. The algorithm was validated by experimental results of fatigue center-cracked large steel plates repaired with CFRP patches. The state of stresses at the crack tip are largely influenced by a combination of the crack tip plasticity radius and overall bond surface area.

Stability verification of hydraulic steel structures

An overview and assessment for buckling verification of plate- and shell-like elements in hydraulic steel structures is given with regard to current standards DIN 19704-1, EN 1993-1-5, EN 1993-1-6, and EN 1993-1-7. Background information is included for verification procedures that require some explanations either due to gaps or fragmentation in several EN parts. A general way forward for the future framework with regard to buckling verification of hydraulic steel structures is proposed based on the findings herein.

Fatigue repair of underwater navigation steel structures using Carbon Fiber Reinforced Polymer (CFRP)

The nation’s Steel Hydraulic Structures (SHS) have significant deterioration caused by the effects of complex phenomena including corrosion and fatigue cracking caused by mixed mode loading. Current methods of repair of SHS, adopted primarily from the bridge engineering industry, have proven ineffective because they were developed for Mode 1 loading (tension) only. Various studies have been carried out to assess the use of CFRP for the rehabilitation of the aging and deteriorated infrastructure systems in the United States, however no research has been conducted on submerged steel structures. This paper presents the evaluation and implementation of an innovative retrofit method of CFRP to repair and strengthen the strut arms of a tainter valve. The evaluation of the retrofit method required a Fitness-for-Service fatigue assessment followed by a Finite Element Analysis (FEA) of the tainter valve with and without the retrofit method. Finally, the article presents the installation procedures used to install the CFRP retrofit and describes the advantages of the innovative repair techniques resulting in two to four folds increase of fatigue life.

Deriving the transition probability matrix using computational mechanics

PurposeThe combined effects of several complex phenomena cause the deterioration of elements in steel hydraulic structures (SHSs) within the US lock system: corrosion, cracking and fatigue, impact and overloads. Predicting the future condition state of these structures by the use of current condition state inspection data can be achieved through the probabilistic chain deterioration model. The purpose of this study is to derive the transition probability matrix using final elements modeling of a miter gate.Design/methodology/approachIf predicted accurately, this information would yield benefits in determining the need for rehabilitation or replacement of SHS. However, because of the complexity and difficulties on obtaining sufficient inspection data, there is a lack of available condition states needed to formulate proper transition probability matrices for each deterioration case.FindingsThis study focuses on using a three-dimensional explicit finite element analysis (FEM) of a miter gate that has been fully validated with experimental data to derive the transition probability matrix when the loss of flexural capacity in a corroded member is simulated.Practical implicationsNew methodology using computational mechanics to derive the transition probability matrices of navigation steel structures has been presented.Originality/valueThe difficulty of deriving the transition probability matrix to perform a Markovian analysis increases when limited amount of inspection data is available. The used state of practice FEM to derive the transition probability matrix is not just necessary but also essential when the need for proper maintenance is required but limited amount of the condition of the structural system is unknown.

Fatigue and fracture life-cycle cost assessment of a Miter gate with multiple cracks

Abstract Fatigue cracks in Miter gates are considered a nuisance as they require periodic inspection and repair. If left unattended, the cracks could grow to reach a critical length and threaten the integrity of the structure. Although the cracks are typically characterized by a stable propagation rate, the scatter in fatigue performance is difficult to quantify and could be on the order of thousands or even millions of cycles. The development of maintenance and management programs for Steel Hydraulic Structures (SHSs) should therefore account for the inherent scatter in performance through probabilistic fatigue assessment. The assessment can be performed through conducting large number of numerical (e.g. finite element analysis) or analytical (e.g. mathematical formulation) simulations that account for the inherent statistical scatter in both load and resistance. In this study, a framework for probabilistic assessment of the propagation rate of cracks in Miter gates using finite element Monte Carlo simulations was developed. The parameters influencing the propagation rate were treated as random variables with predefined statistical distributions. In addition, a life-cycle cost optimization framework was devised using the results of the probabilistic assessment to derive optimal inspection/repair schedule patterns such that the service life of the Miter gate could be extended as required. The framework was tested on nine different cases and an optimal schedule is obtained for each case successfully.

Comparison of corrosion rates obtained from laboratory and field data

Generally, corrosion rates for sheet pile walls observed in nature and those obtained in the laboratory are different. In order to compare natural and laboratory corrosion rates, corrosion tests were carried out with an electrochemical corrosion cell. Various mild steel samples which were taken out from different sheet pile structures were examined with synthetic brackish water and synthetic seawater as immersion media. It was ensured that the electrical conductivity and the pH‐values were identical to those of the natural waters from which the sheet pile samples came from. The experimental results indicate that underwater corrosion rates in nature are only about one tenth to one eighth of the laboratory values. The corrosion rates in nature depend on the media and the corrosion zone. Furthermore, in laboratory test procedures, the initial corrosion is always tested whereas in nature a “protecting” layer of rust is formed, that lowers corrosion. Therefore, comparison of the values of the experiments with those from nature should be defined in accordance to age and zone of hydraulic steel structures. As a consequence, a corrosion coefficient with consideration of the age of structures was formed. The introduction of the coefficients's dependence on the lifetime of the construction allows improved corrosion rate predictions when the chemical composition of the immersion media is detected.

Predicting Future Deterioration of Hydraulic Steel Structures with Markov Chain and Multivariate Samples of Statistical Distributions

Combined effects of several complex phenomena cause the deterioration of elements of steel hydraulic structures on the nation’s lock systems: loss of protective systems, corrosion, cracking and fatigue, impacts, and overloads. This paper presents examples of deterioration of steel hydraulic structures. A method for predicting future deterioration based on current conditions is also presented. This paper also includes a procedure for developing deterioration curves when condition state data is available.

Comparison of Retrofits for Three Strut-Arm Tainter Gates Using a Longevity Corrosion Maintenance Factor

This paper presents a methodology to compare various Tainter gate strut-arm retrofit techniques based on the longevity corrosion maintenance (LCM) factor. The rating system is designed to encourage agencies to select retrofits that will better upgrade existing conditions to meet current design standards for hydraulic steel structures and achieve a long design life. An overview of past Tainter gate failures, governing strut-arm load cases, past strut-arm retrofit strategies, current design standards for hydraulic steel structures, and the consequences of welding or bolting to existing structures has been considered in this study as evidence to support the proposed Tainter gate retrofit comparison methodology. An example problem illustrates how to determine the LCM factor and assign a LCM grade for three retrofit scenarios.

Manufacture, testing and quality assurance of cast stainless steel headers for the CIEL pump limiter of Tore Supra

The Tore Supra tokamak is a fusion device which has been in operation since 1988. Its main features are its superconducting toroidal magnet and its actively cooled first wall. Tore Supra is devoted to the study of physics and technology of long plasma discharges. Its actively cooled first wall is able to remove the energy deposited from the plasma during a very long pulse regime (several hundred seconds). A major upgrade of the Tore Supra in-vessel components, the CIEL project (French Acronym of Composants Internes Et Limiteur), has been implemented and is in operation since 2001. This paper describes the experience gained from the manufacturing of cast stainless steel hydraulic structures supporting the toroidal pump limiter, the main component of the CIEL project, as well as the technical description of this structure, the associated specifications, the difficulties encountered during manufacture and the repair possibilities.

Stiffened Sheathings of Orthotropic Cylindrical Shells

Geometric characteristics of orthotropic shells introduce computational difficulties (discretization of the stiffeners, computing time, interaction at the ring and stringer junctions with the sheathing, etc.). Navigation-dam gates, tidal surge barriers, etc., are hydraulic steel structures composed of orthotropic sheathings, which can now be more easily computed with the development of the LBR-3 stiffened sheathing software. This method is one of harmonic analysis and is founded on the Fourier series expansions. It is based on the analytical solution of the governing differential equations for orthotropic cylindrical shells. These differential equations result from the DKJ method (Donnell, von Karman, and Jenkins) and allow taking into account the torsional stiffness, the lateral bending stiffness, and the exact position of each stiffener. New developments that permit the designing of stiffened cylindrical struuctures with many boundary conditions are presented. After the numerical verifications, an example of a tidal surge barrier design is presented.

Calculation of plastic deformation of the lining of a pipeline transition chamber with cut I-beam ribs

A theoretical and experimental investigation of a lining with ribs of the proposed type was carried out at the industrial laboratory of the USSR Minsitry of Power and Electrification (Minenergo) at the Kharkov Civil Engineering Institute in 1986-1988. The investigations showed that usually under the effect of an external pressure, the total stresses in the lining, i.e., the stresses at points distant from the sites of stress concentration, do not exceed the allowable. At the same time, considerable stress concentration occurs near the ends of the sections of welding the ribs and the occurrence of plastic zones is possible. Therefore, in 1989 the Leningrad Special Design Department for Steel Hydraulic Structures (Lengidrostal') calculated the stress-strain state of the lining, cut I-beam ribs, and weld in the plastic stage of behavior of the material (as applied to the pipeline transition chamber of the Boguchany hydrostation). A decription and results of the calculation are given below. Main Premises. It is presumed that the external seepage or grouting pressure can act on a region of the lining including several support areas (i.e., welded sections of the ribs). With consideration of the regular arrangement of the support areas, it is sufficient to examine a fragment (Fig. i) in which are included: a section of the lining with a length (in each of two directions) equal to half of the spacing of the ribs; a section of the wall of the I-beam, including half of the wall both with respect to length and to thickness; a part of the weld joining the isolated sections of the lining and wall. The conditions of symmetry at the boundaries of the fragment follow from the assumption that fragments adjacent to the isolated one are under the same conditions.