Planned Service Life Research Articles

Repurposing oil and gas infrastructure as artificial reefs – a global perspective

More than 7000 offshore oil and gas (O&G) installations are found across 53 countries throughout the world’s oceans. During their life span, these structures provide a habitat for marine life and can support diverse assemblages. At the end of planned service life, they are decommissioned which usually involves the complete removal of infrastructure from the ocean, resulting in the loss of these marine communities. Various countries have repurposed O&G platforms as artificial reefs as an alternative solution to decommissioning, such as the Rigs-to-Reefs (R2R) program developed by the United States (US). The repurposing of O&G platforms may have benefits in preserving or enhancing ecological communities, as well as reducing the impacts and costs associated with removal and disposal onshore. The placement of O&G platforms in the ocean as artificial reefs demands prudent planning and high-level management to ensure the anticipated benefits are delivered and potential impacts are managed. The US National Artificial Reef Program (NARP) along with the R2R program provides guidelines on various aspects of artificial reef use, including planning, site selection, design and management. Since 1980, the US has successfully converted more than 593 O&G platforms to permanent artificial reefs due to the active participation and support of O&G operators, government, local fishing and diving communities. Other countries are also taking initiatives to repurpose their O&G infrastructure. The aim of this paper is to identify key considerations in the repurposing of O&G infrastructure as artificial reefs, using the US R2R program and other geographies as examples.

Influence of Maintenance Funds on Improve Road Steadiness with the Curva Expert Program

Sustainable road construction is instrumental in improving connectivity among regions and economies while also offering road users a diverse range of options within the traffic network. To ensure optimal road performance for users, it becomes essential to allocate adequate maintenance funds that correlate with the planned service life. This necessity originates from a profound understanding of the significant influence maintenance funds have on road steadiness. Therefore, this study aims to establish a comprehensive road steadiness model, investigating the influence of toll roads as new routes and the impact on maintenance funds. The analysis included national roads across 15 cities in Central Java Province, Indonesia, covering a distance of 759.75 km from 2018–2023. Using a quantitative approach, the study adopted the Curva Expert program to evaluate the values of road steadiness and maintenance funds. The results showed a 5.78% enhancement in road steadiness over the period from 2018 to 2023, underscoring the positive impact of sustainable road construction practices and the allocation of adequate maintenance funds. The establishment of relationship between road steadiness and maintenance funds was established through a regression value of R2=0.94. This statistical correlation is represented by the equation y= 90.521 + 0.022x, providing a quantitative understanding of how maintenance funds influence road steadiness. The insights obtained from the outcomes of road steadiness modeling reiterate the significance of investing in additional routes and ensuring sufficient maintenance funds to improve performance. Doi: 10.28991/CEJ-2024-010-02-014 Full Text: PDF

Lifetime assessment for container vessels

This study presents novel reliability-based technique, being especially useful for lifetime assessment of multi-dimensional dynamic systems, consisting of cross-correlated components, that have been either measured, or numerically simulated over representative time span. This study has potential applications within wide range of marine structural systems design, where reliability analysis is required. As demonstrated in this study, it is possible to accurately forecast risks of a system failure due to excessive structural responses. Furthermore, time series-based traditional reliability techniques do not always manage system's high-dimensionality, along with complex cross-correlations between different system components. When sailing in harsh weather, cargo ships are exposed to structural damage risks, this study used operating cargo vessel as an underlying example. Another serious safety concern for modern ship trans-Atlantic navigation is the potential loss of cargo, due to the ship's violent movements. Simulating such a situation is quite challenging, due to waves and ship motions being both non-stationary and highly nYar. Validity of laboratory tests may also be questioned, hence, on-board data, gathered from actual cargo ships during their trans-Atlantic voyages, under realistic storms gives a unique research opportunity.Novel Monte Carlo based multi-dimensional reliability method, based on-board measurements is presented in this study. Advocated methodology can be applied to a large variety of complex sustainable marine systems, that are designed to endure environmental loadings for the entire length of their planned service life. This study's approach offers the opportunity to robustly and accurately evaluate operational risks of an entire nonlinear multidimensional dynamic system.

Carbon Storage Tanker Lifetime Assessment.

CO2 capture and storage (CCS) is an important strategy to reduce global CO2 emissions. This work presents both cutting-edge carbon storage tanker design, as well as novel reliability method making possible to extract useful information about the lifespan distribution of carbon capture systems from their recorded time history. The method outlined may be applied on more complex sustainable systems that are exposed to environmental stresses throughout the whole period of their planned service life. The latter is of paramount importance at the design stage for complex engineering systems. Novel design for CCS system is discussed and accurate numerical simulation results are used to apply suggested novel reliability methodology. Furthermore, traditional reliability approaches that deal with complex energy systems are not well suited for handling high dimensionality and cross-correlation between various system components of innovative dynamic CO2 storage subsea shuttle tanker. This study has two distinctive key features: the state of art CCS design concept, and the novel general purpose reliability method, recently developed by authors, and particularly suitable for operational safety study of complex energy systems.

Feasibility study of calculation methods for tram track stiffness

Nowadays, design and construction of new urban tramlines require feasibility study of calculation methods for stiffness. A calculation method for tram track stiffness with noise and vibration insulation systems has been developed in this paper. Theoretical analysis of the impact of rail insulation systems on tram-to-slab load transfer has revealed the potential options and factors influencing the choice of a system. The new design method obtained makes it possible to predict the distribution of loads on the load-bearing foundation surface. Different variants of rail/slab load distribution have been determined depending on the mechanical characteristics of rail profiles. Tram track slab stiffness has been calculated for three design models such as rigid surface pavement, bridge structure and foundation slab. The design of the tram track as foundation slab allows calculating slab reinforcement as accurately as possible because the surface pavement takes into account the planned service life and tram flow density in the area under survey.Field experiments have demonstrated a better convergence of theoretical and experimental data when designing the slab as foundation. As a result, a new method for calculating the foundation slab stiffness of a tram track has been proposed taking into account planned service life, tram flow density and other factors.

Prediction of Earth Dam Seepage Using a Transient Thermal Finite Element Model

With the majority of the United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS)-sponsored earthen dams exceeding their planned service life, seepage is a concern since it is a common failure mechanism among earthen dams as a whole. Seepage occurs when water penetrates a hydraulic barrier to create open pathways, channels, or piping leading to internal erosion or stability issues due to increased effective stress. Due to the complex geometries of these hydraulic structures, time-dependent boundary conditions, and complicated failure analyses, numerical approaches have been used to estimate seepage. However, the existing numerical models are either computationally expensive or assume steady-state conditions. This work develops the framework for using a transient thermal finite element analysis (FEA) model as an analogy to predict transient seepage. The FEA model is compared to a transient analytical model to verify the approach. A sensitivity analysis of the FEA model shows that the time aspect of seepage flow is dependent on the medium, i.e., soil, and not on the fluid properties.

ACCOUNTING OF COSTS FOR THE OPERATION OF AGRICULTURAL EQUIPMENT UNDER THE CONDITIONS OF USING THE GLOBAL POSITIONING SYSTEM

Introduction. Digitization of agricultural activities formed the prerequisites for the practical implementation of the philosophy of "precision agriculture" based on geo-information technologies in the functioning of agricultural enterprises. The use of modern geo-information technologies and the global positioning system optimizes not only the processes of cultivating land and growing agricultural products, but also fundamentally changes the methodology and organization of accounting. In particular, accounting of costs for the agricultural machinery operation based on information generated by GPS technology is subject to automation. The purpose of the article is to improve the accounting of operational costs in agricultural activities using the global positioning system and to automate the cost calculation of services provided by agricultural machinery to third-party customers. Results. The expediency of using information generated by GPS navigators about the location of motor vehicles and special equipment, travel routes, mileage, speed of movement, stops and parking lots for the digitization of accounting is substantiated. The methodology and organization of the accounting of costs for the agricultural machinery operation using GPS technology have been improved such as: fuel based on the comparison of the fuel indicators in the tank; lubricants and technological fluids after identifying the time (mileage) of the need for their replacement; salaries of drivers and support staff in proportion to the movement mileage of special equipment while performing production tasks; social insurance funds of employees of agricultural enterprises; depreciation deductions according to the proportional (production method); technical maintenance and current repairs at the end of the planned service life of spare parts, units and aggregates; forecasting the need for repairs to ensure the uninterrupted functioning of agricultural enterprises. Depending on the location of vehicles and special equipment, the order of accounting is proposed: general production costs for moving special equipment to the places of its operation; production costs within the spatial and territorial limits of the main agricultural activity of land cultivation; production costs for the provision of production services by special equipment to third-party customers; transport and procurement costs for transportation of agricultural products to places of their storage or processing. Based on the accumulated information about the costs associated with the agricultural machinery operation, a scheme for operational costing of services provided to third-party customers using the calculation unit - the kilometer of motor vehicles and special equipment movement was developed. Conclusions. The use of the global positioning system in combination with other geo-information technologies forms a significant information resource about the costs on the operation of agricultural machinery for the effective management of agricultural enterprises. Other geo-information technologies, the use of which transforms accounting and management of agricultural activities, are electronic cartography and aerial visual monitoring of agricultural works using drones, which are the subject of further scientific research.

Durability of concrete based on the remaining life of the building Case study: reinforced concrete in klaten district

<p>Concrete durability is the ability of concrete to last as it was originally planned, in the structure of a building can be defined as the ability to maintain function, stability and aesthetics due to environmental influences so as not to incur large maintenance and repair costs during the planned service life. The durability aspect is very important, especially for infrastructure that has a fairly long service life. Building life is the period or time during which a structure is required to continue to function as planned. In building structures whose construction has been completed, both new and old buildings, specific data related to the quality of the concrete and the planned age of the building is quite difficult to obtain, this is because the influence during the implementation of construction is also not good in governance. documentation, both technical documents and other non-technical documents, therefore it is necessary to have a sufficiently representative tool to test the concrete quality of a building that has been completed to comply with the quality of the built concrete.</p>

DEVELOPMENT OF THE TECHNOLOGY FOR IMPROVING THE STRENGTH CHARACTERISTICS OF GAS-THERMAL COATINGS USING THERMODYNAMIC EFFECTS

The application of various types of functional and protective coatings made of inorganic materials to parts made of conventional structural materials will be able to solve the issue of ensuring the planned service life of modern devices, machines and mechanisms. Electric arc metallization, characterized by relatively high productivity and low cost of coating, serves as one of the methods of applying gas-thermal coatings. However, the high porosity of the resulting coatings, their low adhesion strength to the substrate and plastic properties prevent the widespread use of this method. (Research purpose) The research purpose is in studying the chemical, thermal and mechanical effects on samples obtained by electric arc metallization, on the adhesive, cohesive and strength properties of the coating and the areas of connection of the coating with the substrate. (Materials and methods) The authors used electric arc metallization and gas-dynamic spraying to obtain the necessary coatings. A mechanical effect on the coating was studied using the machine IZH- 250TV and special research equipment to determine the properties of coatings and substrates. (Results and discussion) Gas-thermal coatings can be successfully used in the manufacture of new and restoration of worn parts of agricultural machinery. The processing of metallized samples by surface plastic deformation are expedient and necessary. Chemical and thermal treatment has a positive effect on the properties of the coating and the substrate, increasing the value of microhardness by 50-70 percent. The use of supersonic metallization devices leads to an increase in adhesive strength by 30-35 percent. (Conclusions) The study showed that chemical and thermal treatment has a positive effect on the properties of the coating. Plastic deformation of the sprayed surfaces is practically equivalent to thermodynamic effect. It is recommended to use plastic deformation for spraying cylindrical surfaces.

Vpliv podnebnih sprememb na dinamiko glivnega razkroja lesa v Sloveniji

The intensity of fungal decay depends mainly on wood species, temperature and precipitation events. To estimate the planned service life of wood and to determine the maintenance intervals of wooden buildings, it is necessary to assess how wood behaves in a given environment. There are a variety of models that have been developed to assess the loading of wood. The approach most commonly used in practice is that developed by Theodore Scheffer. Scheffer proposed a climate index (Scheffer climate index) based on the number of rainy days and monthly average temperatures. Based on these data, Scheffer climate index for chosen locations in Slovenia was calculated. The results of the analysis of climatic conditions show that the Schef%fer climate index is higher than it was decades ago at most of the analysed sites in Slovenia. The intensity of decomposition increased at all analysed locations, with the exception of Portorož. The largest increase in the Scheffer climate index was ob%served in Rateče.

Analysis of decayed Norway spruce wood impregnated with CCB after 14 years of outdoor exposure

Wood in outdoor applications is exposed to abiotic and biotic factors. If we want to slow down the decay, the wood must be protected. In the past, biocidal products based on copper, chromium, and boron compounds (CCB) were one of the most important solutions for wood protection under extreme conditions. Although CCB is in practice no longer used in the EU, it can serve as a reference for the evaluation of new biocidal products. At the field test site of the Department of Wood Science and Technology, Biotechnical Faculty, an experiment has been carried out under real conditions for 14 years, in which impregnated samples are exposed to the weather according to a double-layer test. In the case of treated wood, we often find that the wood decays faster than expected. In this work we want to determine what contributes to decay based on the analysis of decayed impregnated wood from the field test site. The results show that sufficient retention and penetration of the active substances into the wood ensures the planned service life.

Probabilistic Prediction of Corrosion Damage of Steel Structures in the Vicinity of Roads

The design, construction, and maintenance of steel structures must be carried out in a way that ensures they will be able to reliably operate for the whole duration of their planned service life. To ensure sufficient durability, it is necessary to determine and evaluate the characteristics of the appropriate environment in which the structure will be placed. This submission focuses on the specific environment surrounding roads that are treated with de-icing salts during winter maintenance. It investigates the dependency between corrosive damage to the structure and the relevant parameters of the environment. Basic corrosive factors include temperature, relative humidity, deposition of chlorides and sulfur dioxide, precipitation, the pH of precipitation as well as many other parameters. An accurate estimate of corrosive damage requires an analysis of the long-term trends in concentrations of individual corrosive factors, while respecting their randomly varying attributes. The article, hence, introduces and evaluates stochastic prediction models that are based on long-term programs focusing on the evaluation of the corrosive aggressiveness of the environment, while taking into account random variations of the nature of the input parameters. The use of stochastic prediction models allows us to perform sensitivity analysis that can determine the impact of specific corrosive factors on the corrosive damage caused to the structure. The article is supplemented by sensitivity analysis focusing on an evaluation from the effects of the deposition of chlorides on the corrosive damage to steel bridge structures. The analysis was carried out using data obtained from experimental measurements of the deposition rates of chlorides in the vicinity of roads in the Czech Republic.

Теоретичне обґрунтування експлуатаційних властивостей деталей автомобілів, зміцнених композиційними покриттями, методом кластерних компонентів

A number of parts of car systems and units in the process of operation are subject to intensive wear and fatigue processes, and therefore do not withstand the planned service life. An important reserve for increasing the reliability and efficiency of such equipment is the strengthening of the working surfaces of its parts with composite materials and coatings. This method of strengthening makes it possible, controlling the structure of composite materials and coatings, to form the necessary set of performance properties of parts to ensure the appropriate level of reliability and increase durability. However, this requires theoretical justification to establish a correspondence between the structure, composition, distribution of chemical elements applied to the parts of the composite coating and their performance properties, such as wear resistance, fatigue strength, etc. The purpose of this work is a theoretical justification for the use of the method of cluster components to determine and form a set of necessary performance properties that ensure reliable and efficient operation of parts of systems and units of cars. The article theoretically substantiates the operational properties of automobile parts hardened with composite coatings using the method of cluster components. By choosing certain sets of parameters, as well as varying the system of restrictions on them, it is possible to form a complex of operational properties of parts. To simplify the packing model for composite materials and coatings, it is assumed that fillers of different compositions have an isometric shape and the same size. A regular structure is proposed, corresponding to the packing of spheres of the same size. It is shown that such packings form lattices similar to atomic crystal structures. The dependences of the function of the properties of composite coatings on the content of each of the types of cluster components are revealed. The method of cluster components, describing changes in the properties of composite coatings from the ratio of components, makes it possible to control a set of operational properties and obtain high-quality coatings to increase the durability of parts of systems and vehicle units. As a result of the conducted researches it is offered to consider composite coverings and composite materials as the systems characterized by a certain complex of operational properties depending on filler content and regularity of structure. According to the theory of cluster components, the content of the component determines the parameters and properties of composite coatings and materials. The method of cluster components makes it possible to present a set of operational properties as an additive model of its components. The packaging of components in composite coatings and materials is represented by atomic crystal structures: simple cubic, volume-centered cubic, face-centered cubic and hexagonal densely packed. The implementation of the method of cluster components on the example of a binary system of components A and B is considered. The basic configuration in accordance with the approximations of the statistical ordering theory is chosen. The visual interpretation and physical content of a mixture of powders, components of composite coatings and materials, particles A and B are given. The configurational entropy and formation of cluster components of the intermediate composition AB along with the basic AA and BB are considered. Based on the π-theorem, a complete set of quasi-chemical reactions is outlined. For binary composite coatings and materials АСВ1-С the matrices of size and relative content of components are constructed, the quasi-chemical formalism of the method of cluster components and the law of active masses for volume-centered cubic lattice are used. This is taken into account when building functional models of operational properties. Their specification on the criterion of correctness is carried out.

Fatigue reliability analysis of crêt de l’Anneau viaduct: a case study

Fatigue of reinforced concrete is often not considered for civil engineering structures since the self-weights of reinforced concrete structures are very high (in case of normal strength concrete) while live loads are relatively small, which leads to very small stress variations during service duration of the structure. However, particularly for bridge structures with increased use of high strength concrete and increase in traffic loads, this scenario is reversed and fatigue verification becomes much more important for the safety. This paper presents a probabilistic approach for reliability assessment of existing bridges along with reliability-based calibration of fatigue-design-factors based on the S-N approach, calibration of S-N approach with fracture-mechanics approach and reliability updating using inspections along with a case study for the Crêt de l’Anneau viaduct in Switzerland. It has been observed that, a designer needs to design the structure for fatigue life of 3.5–4.5 times the planned service life, in order to achieve the target annual reliability index of 3.7 at the end of the service life. Further, the presented framework can easily be extended to any other viaducts to estimate the fatigue reliability and maintain the safety level throughout the entire service duration.

Challenges of decommissioning offshore wind farms: Overview of the European experience

In the coming years, an important number of offshore wind turbines will reach the end of their initially planned service life. In a wind turbine end-of-life scenario, owners can decide between extending the life of the asset, repowering the site or decommissioning. This decision-making process is affected by important sources of uncertainty, especially in offshore environments. The limited experience makes the decommissioning procedure challenging, as it is still largely unexplored. This work assesses the current state of knowledge about the challenges surrounding the decommissioning process of an offshore wind farm. The four main challenges encountered are identified and analysed in detail, namely the regulatory framework, the overall planning of the process, the logistics and vessels’ availability, and the environmental impacts confronted. Ultimately, this paper aims at stimulating the dialogue among stakeholders and raising the awareness of adequately regulating and preparing the upcoming decommissioning of offshore wind farms in Europe.

Behavior of two eco-compatible duplex systems used in the construction industry against corrosion

Two types of coated steels are currently competing in the construction industry: the hot-dip galvanized steel (HDGS) and the 55%Al–Zn alloy coated steel (HDZAS). Both systems are typically coated by a chromate-based conversion film, which is dangerous for human health and environment. Furthermore, for aesthetics purposes and/or to prolong their expected or planned service life, they are painted designing each paint system as a function of the service conditions to which they will be subject to. The present work reports on a comparative study of two duplex systems: steel/metal coating/organic coating. In both cases, the chromate-based pretreatment was replaced by another one that features γ-mercaptopropyltrimethoxysilane (MTMO) as an active element. The organic coating used was a water-based polyurethane. Behavior of this paint against corrosion was assessed by exposing the samples in salt spray or humidity chambers, and monitoring its evolution by electrochemical impedance spectroscopy, visual observation, scanning electron microscopy and energy dispersive X-ray analysis. The results revealed that: MTMO was suitable for promoting adhesion both in HDGS and HDZAS; in humidity chamber, both duplex systems provided good protection; the presence of corrosion products of the base steel and paint blistering was detected in the HDGS/paint system seventy-two days after exposure; however, 150 days after that, none of these effects were observed in the HDZAS/paint system; differences in behavior were significant in Salt spray chamber: speed of paint delamination from the mark done and the bulk of corrosion products generated was much higher in HDGS/paint system than in HDZAS/paint.

Innovative Solutions for the Construction and the Repair of Hydraulic Structures

Abstract Hydraulic structures underlie extraordinary conditions due to their prominent function and exposure. Thus, high demands have to be made both on construction and maintenance or repair of the structures, respectively. In order to fulfill these demands new and special technologies have to be developed that ensure an effective construction and guarantee to meet the planned service life of the building required by the owner. Against this background two innovative methods for both construction and repair of hydraulic concrete structures are presented in the present paper. The methods are based on modern concrete technology and enable to either build concrete dams in flowing water or perform concrete repair below the water level. Both methods were developed at the Institute of Concrete Structures and Building Materials at the Karlsruhe Institute of Technology (KIT), Germany and were applied in practice for construction of the Bribin underground hydropower plant in Indonesia and for repair of the river hydropower plant of Albbruck-Dogern in Germany.

Fatigue Resistance of Typical Fatigue Prone Riveted Steel Railway Bridge Structural Detail

There are still a lot of riveted steel railway bridges built in the first half of 20th century in service, and so it is important to pay attention to their evaluation. Their fatigue resistance represents one of the most determining factors on decision making process oriented to possibility of their further exploitation after finishing their planned service life. The standard method of fatigue assessment according to Eurocode EN 1993-1-9 is based on categorization of structural details, which reflects their predisposition to fatigue failure. The paper deals with laboratory investigation of the riveted connection of stringer to cross beam of a railway bridge deck. This structural detail is typical by frequent occurrence of fatigue cracks, but its categorization according to standard mentioned above is at least questionable. In order to investigate and define the fatigue category of this detail more properly, the laboratory tests on specially adapted specimens were performed.

Laboratory tests of a typical fatigue prone riveted steel railway bridge structural detail

There are still a lot of riveted steel railway bridges built in the first half of 20th century in service, and so it is important to pay attention to their evaluation. Their fatigue resistance represents one of the most determining factors on decision making process oriented to possibility of their further exploitation after finishing their planned service life. The standard method of fatigue assessment according to Eurocode EN 1993-1-9 is based on categorization of structural details, which reflects their predisposition to fatigue failure. The contribution deals with laboratory investigation of the riveted connection of stringer to cross beam of a railway bridge deck. This structural detail is typical by frequent occurrence of fatigue cracks, but its categorization according to standard mentioned above is at least questionable.

Numerical Modeling of the Long-Term Behavior of Passive Fire Protection Mortars Applied on Concrete Tunnels

Experiences show that the design of overlay mortars is a complicated matter as far as long-term durability and dimensional stability are concerned. In many cases, applied mortars crack or delaminate a few years after application. The same is true for passive fire protection mortars (PFP mortars). The mortar must remain crack free and must not delaminate during the planned service life, that means the fire protection requirements must be combined with the durability requirements. In this paper, an approach based on a numerical model is used to forecast the long-term behavior of PFP mortars. By means of this model, the time-dependent humidity, temperature, stress, and strain distributions, as well as the crack formation can be calculated in a realistic way. The minimal adhesive strength between overlay and substrate which is necessary to prevent delamination during the planned service life has been calculated. Material properties and climatic boundary conditions have been taken into account. The results allow the tailored optimization of PFP mortars.