The objective of this study is to develop a risk-based approach to assessing the ultimate limit state of bridge structures by integrating fundamental theories of damage accumulation (L. M. Kachanov, Yu. N. Rabotnov, A. R. Rzhanitsyn) and substantiating a new type of ultimate limit state based on kinetic criteria. 
A comparative analysis of three classical approaches is performed: L. M. Kachanov's phenomenological theory (continuity parameter), Yu. N. Rabotnov's kinetic theory (damage parameter), and A. R. Rzhanitsyn's probabilistic method (safety characteristic).  
The physical foundations of each theory are revealed, and their advantages and limitations are demonstrated as applied to bridge construction problems. A rationale is provided for the choice of a combined model combining Yu. N. Rabotnov's kinetic equations to describe the rate of damage accumulation, the Kachanov – Rabotnov damage parameter as an integral measure of degradation, and A. R. Rzhanitsyn's probabilistic apparatus to account for the random nature of loads and strength properties.  
Specific results of the study: a modified classification of risk levels with five gradations (from ‘good’ to ‘unacceptable’) and quantitative criteria for the damage parameter and its accumulation rate is proposed; a methodology for determining indicative indicators of the limit state based on increments of relative deformations using kinetic equations of damage is developed; the limit state of the third type is substantiated as the moment of reaching a critical rate of damage accumulation (in contrast to the first type, associated with a critical value of the damage parameter, and the second type with permissible deformations), which makes it possible to identify the mode of progressive destruction before the occurrence of macroscopic defects. The developed methodology can be integrated into bridge condition monitoring systems, and the proposed criteria can be used in the development of regulatory requirements for the operation of structures under increased loads and aggressive environments.  

Ensuring the seismic stability of transport structures is a high-priority task in modern engineering design, especially in the seismically active regions of Central Asia. This paper examines the features of the numerical analysis of the seismic stability of a continuous monolithic highway overpass, considering the prestressing of post-tensioning reinforcement strands and the interaction between the piers and the soil foundation. The object of study is a three-span continuous monolithic reinforced concrete overpass with a 35+ 50 + 35 m span arrangement, located in the city of Jizzakh in a seismic intensity zone of 8 points, over the Tashkent-Samarkand high-speed railway line (Republic of Uzbekistan). The intermediate piers are double-column, 12 m in height; the cross-section of the superstructure slab includes 19 ducts with post-tensioning reinforcement strands. The analyses were performed using two software packages: SHARK (the direct step-by-step dynamic integration method using accelerograms from the actual 1976 Gazli earthquake, with an intensity exceeding 9 points on the MSK-64 scale) and MIDAS Civil (the response spectrum method). The soil foundation was modeled according to the Winkler model using viscoelastic links, the parameters of which were determined from the characteristics of Category III loess-like loams based on their seismic properties (KMK 2.01.03-19). The results of the normal stress calculations in the upper and lower parts of the overpass superstructure are presented. The maximum compressive stress in the upper part of the superstructure was -10.10 MPa (MIDAS Civil) and -3.30 MPa (SHARK); the tensile stress in the lower part was 2.32 and 2.25 MPa, respectively. The identified discrepancy in the results is due to the fundamental difference between the analysis methods: the response spectrum method provides a conservative (overestimated) assessment, whereas direct dynamic integration reproduces a more realistic picture of the stress-strain state. The analyses established that all stress values do not exceed the permissible limits set by SHNK 2.05.03-2022, indicating that the overpass maintains its operational performance during an earthquake with an intensity of more than 9 points on the MSK-64 scale.

This article examines the problem of integrating the concept of survivability into the methodology of sustainable design of bridge structures. Existing approaches to sustainable development in bridge construction focus on the economic and environmental aspects of normal operation, with little consideration of the risks of beyond-design-basis impacts and progressive deterioration. Accidents, even local ones, can negate the environmental benefits of a project and require enormous remediation costs.  
Based on a summary of the works of A. V. Based on the work of Perelmuter, A. G. Tamrazyan, and an analysis of bridge failure statistics, quantitative criteria for assessing survivability are proposed. The survivability coefficient Kv is defined as the ratio of the bearing capacity of the damaged structure to the estimated force in the event of failure of one or more elements. The environmental risk indicator Reco takes into account the probability of beyond-design impact, the conditional probabilities of damage and progressive destruction, and the ratio of the cost of mitigation of the consequences to the cost of construction. An algorithm for designing bridge structures taking into account survivability requirements is presented, including the identification of vulnerable elements, an analysis of local failure scenarios, and a verification of the survivability coefficient. The areas of responsibility of the following elements are substantiated: bearing parts, pylons, cables, suspensions, and superstructures. The recommended values of the survivability coefficient range from 1.0 for secondary elements to 1.3 for pylons. Two concepts of an “ideal” bridge structure are considered, combining durability, maintainability, and survivability. Ensuring survivability is a prerequisite for the true sustainability of transport infrastructure. A conclusion is drawn on the need to take beyond-design impact scenarios into account when assessing the life cycle of structures. The development of numerical methods for implementing the proposed criteria and their verification on specific types of bridge structures are the goals of further research. 

The article discusses current developments in the use of artificial neural networks (ANN – Artificial Neural Network) and machine vision technologies in the operation of engineering structures, with an emphasis on the identification of defects in the examination of bridge structures. Scientific research is aimed at finding the most appropriate methodology to simplify and improve the quality of the survey process, as well as the architecture of the neural network. The analysis of domestic and foreign studies devoted to the automatic detection of defects in building structures using convolutional neural networks (CNN – Convolutional Neural Network), YOLO (You Only Look Once) algorithms, AutoML (Automated Machine Learning) methods and software and hardware complexes based on unmanned aerial vehicles. The advantages and disadvantages of existing solutions related to the dependence of recognition quality on the size of the training sample, shooting conditions, the difficulty of locating low-contrast defects and the need for additional involvement in the process of engineering interpretation of the results are considered. The existing approaches to defect identification have been systematized, and the positive and negative elements of tools in machine vision systems have been identified for their prospective consideration when creating a module for bridge inspection. The conclusion is made about the prospects of introducing neural network technologies into the practice of surveying engineering structures, provided that specialized training samples are formed and the accuracy of the models is independently verified. The availability of a powerful neural network tool for examining bridge structures, trained by engineers on specific examples of the bridge sphere, will simplify the survey and increase the number of structures evaluated per unit of time by one team. In conclusion, a multi-stage approach is proposed for further research, including the recognition of structural elements, the detection and classification of defects, as well as subsequent engineering verification of the results.

Design the load transfer zone on concrete in prestressed structures is a time-consuming and nontrivial task. To confirm the design assumptions, it is necessary to conduct appropriate tests using kits of the prestressing systems. 
The authors have analyzed the new Russian national standard for prestressing systems and compared its requirements with other Russian and international standards.  
The purpose of the research is to experimentally verify the methodology for design the load transfer zone in prestressed concrete structures, as well as to prepare recommendations for designers based on the current and previous research by the authors. 
The article presents the results of testing the load transfer zone on concrete from an anchorage with a bearing cup for 19 strands (OS-19) manufactured by STS LLC, which is the most commonly used anchor in bridges in the Russian Federation. The article includes drawings of the test specimen, photographs of the specimen before and after concreting, and diagrams of the location of indicators on the faces and strain gauges on the reinforcement. The test specimen was used to measure the deformations of the concrete on the faces and the reinforcement bars using strain gauges. The article analyzes the type of the specimen's failure during the testing process. The article provides a brief description of the test specimen's finite-element model and compares the experimental data on concrete deformations and reinforcement stresses with the theoretical values.  
The analysis of the results shows a sufficient convergence of the measured values, indicating the reliability of the design assumptions. However, the authors have discovered a previously unknown effect of reducing the stresses in the longitudinal reinforcement of the specimen. Based on this work and the authors' practical experience, the article provides recommendations for designers of prestressed structures that are not included in existing Russian standards.

A methodology for the quantitative assessment of the stress-strain state of buried corrugated metal bridges based on vibration diagnostics is proposed and experimentally verified. Unlike known approaches limited to the analysis of dynamic coefficients or decrements, the developed method provides a transition from recorded vibration accelerations to stresses. This is achieved by double numerical integration of vibration accelerations to obtain dynamic displacements, which are then recalculated into stresses using a validated finite element model. The algorithm requires static testing on only one object of a group (reference), after which only dynamic tests are applied to the remaining structures. Comprehensive tests on five similar overpasses, including static loading with dump trucks of known mass and synchronous recording of strains with strain gauges and vibration accelerations with triaxial accelerometers, confirmed a stable correlation between the stresses recovered from vibration diagnostics and those directly measured under static loading. The obtained results confirm the applicability of the method for assessing the technical condition of typical structures without repeating static tests. The developed methodology allows, after initial calibration, to perform operational monitoring of the technical condition of corrugated metal structures without traffic interruption, which significantly reduces survey costs and increases operational safety. In contrast to traditional static tests, which require traffic closure and significant time and financial costs, the proposed method ensures repeated use and high cost-effectiveness while maintaining the reliability of the assessment. The established correlation between dynamic and static stresses is characterized by a high correlation coefficient, confirming the reliability of the proposed approach. Thanks to the proposed method, monitoring of buried bridges becomes fast and cost-effective, which is especially important for regular surveys of a large number of similar structures. 

The article examines modern technologies for the construction of geosynthetic reinforced-soil (GRS) bridge abutments and analyzes their structural features. With the rapid development of transport infrastructure and increasing traffic intensity, there is a growing need for effective engineering solutions that can reduce construction time while maintaining the reliability and durability of bridge structures. One of the promising approaches in this field is the use of reinforced-soil technology, which is formed through layer-by-layer compaction of soil combined with geosynthetic reinforcement elements. The interaction between the soil mass and reinforcing materials significantly improves the stability and load-bearing capacity of the structure. 
The purpose of this study is to analyze modern technologies for the construction of geosynthetic reinforced-soil bridge abutments and to identify their structural characteristics. To achieve this objective, existing structural schemes of reinforced-soil abutments were analyzed and international experience in their application in bridge construction was reviewed. 
The paper considers the main types of reinforced-soil abutments used in modern engineering practice, including abutments with separated functions, seat-type abutments, and integral reinforced-soil abutments. For each type, structural characteristics, operational principles, and application areas are examined. Particular attention is given to international experience in the implementation of reinforced-soil technologies in both highway and railway bridge construction, including examples from European countries and Japan. 
The conducted analysis demonstrates that the use of reinforced-soil technologies allows for a reduction in the volume of reinforced concrete structures, improves construction efficiency, and ensures more uniform structural performance during operation. The results confirm the potential of using reinforced-soil abutments in the construction and reconstruction of transportation infrastructure facilities. 

Bringing the road network and its artificial structures up to standard is one of the priority objectives of the ‘Transport Strategy of the Russian Federation through 2030’ and the national project ‘Infrastructure for Life’. Increasing traffic loads and intensity, particularly in the southern direction, on Russian highways places increasingly stringent demands on the technical condition of artificial structures. 
Bridges are the most complex and important elements of road infrastructure, requiring increased attention throughout their entire life cycle. The consequences of unsatisfactory or emergency condition of bridges include economic losses due to changes in traffic patterns, reduced speeds, and reduced throughput. The operation of individual artificial structures and the entire bridge fleet is a complex, multi-factorial process, the effectiveness of which depends on timely decisions and maintenance measures.  
The purpose of this study was to determine the order of actions and planning stages for bridge maintenance from commissioning to reconstruction, and to develop the most effective maintenance strategy for these structures to increase their durability and reduce operating costs. 
The article presents the main stages of bridge operation and their characteristics, the types and sequence of maintenance work, and an algorithm for planning and selecting the optimal strategy for performing the work, taking into account actual time between repairs under limited funding conditions. 

The construction of the Donetsk Metro faces the challenge of tunneling through hard rock strata (mudstones, siltstones, sandstones) with a compressive strength of up to 150 MPa. Traditional mechanized tunnel boring machines (TBMs) and drilling-and-blasting methods have low efficiency due to tool and machinery wear, increased vibration affecting surface infrastructure, and large volumes of excavated waste rock.  
The purpose of the study is to develop a concept of a robotic complex for tunneling in hard rocks based on the synthesis of abrasive waterjet cutting (AWJC) and swarm robotics. The methodology includes a systematic analysis of global experience, the theory of waterjet rock destruction, and the principles of adaptive control of a robotic complex with technical vision. A scheme of a mobile robotic complex is proposed, consisting of two cutting robotic manipulators with a jet pressure of up to 6000 bar, one transport robotic manipulator, a laser scanning system, and an AI module for creating a digital twin of the tunnel face.  
The scientific novelty lies in the substantiation of the use of industrial robotic manipulators organized according to swarm principles with an abrasive waterjet cutting tool for hard rock tunneling, providing high accuracy of the excavation contour (±5–15 mm), the absence of vibration impact on surface infrastructure, and a closed-loop recycling of excavated rock (up to 85 ) with its processing into construction materials (facing tiles, clinker bricks, concrete aggregates). The predicted excavation rate is 2.5–4.0 m/day, and the expected reduction in construction cost is 30–40 . The obtained results are intended for application in the construction of Donetsk Metro tunnels and can be extended to similar geological conditions. 

The relevance of this study is driven by the fact that over 65% of Russia's territory and more than 90% of the Far Eastern Federal District are located within the northern construction and climatic zone. Given the ongoing degradation of permafrost, ensuring the reliability of transport infrastructure throughout all stages of an object's life cycle has become critical for the safety of economic activities and regional connectivity across Russia. The aim of this scientific work is to propose a conceptual approach to ensure the safe construction and operation of facilities in the changing conditions of the Far East and the Arctic. This approach examines the application of information modeling using the example of existing facilities operating in permafrost soils. Solving such problems is only possible with the development of a high-quality geotechnical workforce, capable of assessing and forecasting processes occurring in permafrost and seasonally frozen soil zones. The methodology involves numerical modeling of the foundations of artificial structures (AS), solving thermal field distribution problems, and forecasting changes over a long-term perspective. The result of the work is the creation of information models of real artificial structures of the Russian Railways Far Eastern landfill and confirmation of the possibility of their practical application as part of a common database of information models of transport infrastructure facilities (including the ‘base-foundation’ system) in conditions of degradation of permafrost soils. The approaches to calculations, data analysis, arguments and conclusions presented in the study can be used in the development and updating of the components of the main professional educational programs of higher education, the direction of preparation 08.04.01. Construction, as well as related areas and specialties. 

This article examines the theoretical and applied aspects of assessing the durability and remaining service life of supports on operational railway bridges. The relevance of this topic stems from a combination of several factors: the significant service life of railway bridge structures, the accumulation and development of defects in the main supporting structures, the need to accommodate heavy trains under high traffic conditions, and limited resources for major repairs and reconstruction. 
This article examines the evolution of approaches to durability assessment: from empirical and deterministic to stochastic (probabilistic) models. A retrospective analysis of the industry regulatory framework over a long period of time is performed, summarizing the main approaches and methods characteristic of different periods of structure operation. It is shown that an objective forecast for assessing the remaining service life should be based on historical data on the operation of the structure and the results of periodic observations of the occurrence and development of defects affecting durability. 
This article presents an analysis of the condition of railway bridge channel piers based on statistical data on the presence of defects. Based on the obtained results, graphs of the probability of occurrence of defects in bridge channel piers affecting their service life are constructed depending on the service life of the structures. Probability density plots are presented, which are used to determine the guaranteed service life of the piers before the occurrence of a specific defect. The applicability of this method for predicting the service life and remaining life of piers is established given the availability of relevant statistics on the service history of similar piers. 
It is noted that further research to determine the service life of structures should be based on comprehensive data on the service history of bridge structure components. The data obtained in this study form the basis for predicting the durability parameters of bridge piers and estimating their remaining service life.

The article provides an overview and analysis of modern diamond drilling and cutting technologies used in the reconstruction, widening, and dismantling of massive reinforced concrete bridge structures. Based on the long-term experience of NPP SK MOST LLC since 1994, the article describes key methods used in practice, including diamond drilling of precision holes, cutting with circular saws and diamond wire, and breaking concrete with wedge jacks and hydraulic nippers. The article also provides examples of successful implementation at the Moscow Ring Road, bridges over the Oka, Volga, Sheksna, and other rivers. The comparison of these technologies with traditional impact-vibration methods of dismantling, such as the use of hydraulic hammers, jackhammers, and blasting, has been performed. It has been shown that the use of non-destructive diamond technologies allows for the continuous movement of traffic, reduces the duration of work by 4–6 times, and ensures the reuse of dismantled elements, which saves the cost of repair work. Particular attention is paid to ensuring structural stability during demolition, as well as to applying these technical solutions in constrained urban environments and over railway tracks. The article concludes that diamond technologies are highly effective and promising for bridge reconstruction and demolition, offering significant engineering and economic potential for transport infrastructure construction. The cited examples of repair projects utilizing diamond cutting serve as practical confirmation of the successful execution of these processes while maintaining safety standards.