The proposed methodology aims to determine and forecast the technical condition of bridge elements, which could serve as an advanced engineering tool for assessing reliability and durability. It is developed based on fundamental studies that synthesize the experience of studying the physical–mechanical and physical–chemical properties of materials in bridge structures operating under real conditions. The theoretical foundation of the methodology is a reliability model and residual lifetime prediction of bridge elements based on Markov’s theory. The developed methodology is designed for assessing the technical condition of individual bridge elements, followed by a comprehensive evaluation of the entire structure. Reliability during operation is adopted as the indicator of technical condition. This quantitative reliability indicator in the model serves as a criterion for evaluating the safety level of bridge elements; ranking of bridge elements as necessary for specific types of repair, reconstruction, or replacement; strategic planning of expenditures for repair or reconstruction under limited funding; and forecasting the remaining resource of elements. An evaluation and prediction algorithm for the technical condition of bridges is proposed for the application of the developed methodology. A mathematical experiment of the developed methodology was conducted, which confirmed the adequacy of the proposed hypothesis, i.e., the use of the reliability model and the prediction of residual lifetime of bridge elements. First, a three-step mechanism for refining the technical condition of the bridge is proposed, significantly enhancing the accuracy of the calculations. Therefore, the developed methodology holds practical value and can serve as a basis for information-analytical systems for managing the condition of bridges.

This paper considers the processes of cost management and the duration of road maintenance projects. A conceptual model is proposed to describe the relationship between time, cost, and quality of projects, which is based on the theory of the «silver triangle». Based on the results of studying the influence of factors, a model has been built for determining the cost and duration of road maintenance projects. Multiple optimization approaches to the components of the «silver triangle» of projects were used. The model constructed at the stage of initiating projects for the maintenance of roads, in contrast to the previous ones, is based on the pre-project level of quality indicators. Owing to the introduction of additional parameters and coefficients, the proposed model of cost management, quality, and duration of road projects was calibrated. The model graph was constructed and optimization was carried out on the example of a long-term road operation project. The algorithm of application of cost and duration management model of highway projects under conditions of uncertainty has been developed, which was checked for adequacy at an estimated error of about 3 %. This makes it possible to assert the effectiveness of the devised model for solving tasks related to project management for maintenance. The model was used to perform calculations based on a real example of the project, which showed that the optimization of the parameters of long-term contracts for the maintenance of highways produces a multiplier effect. This is expressed by reducing the administrative costs of the customer, reducing the responsibility of road services, creating prerequisites for stable financing of road works, the satisfaction of road users, and building strong partnerships between the customer and contractor

The article presents the results of determining the strength of non-destructive methods of cement concrete pavement on bridges. According to the results of the research, a differential curve, a reliability curve and the inverse value of the accumulated frequency of compressive strength of cement concrete are constructed. It is established that the cement concrete of the investigated objects corresponds to the strength class according to the normative documents. However, the results of visual, instrumental and thermal imaging inspection of areas on the bridges revealed a number of defects in the cement-concrete pavement and pavement slabs, which can lead to loss of the pavement structure strength. In particular, it was found that the destruction of the inspected reinforced concrete slabs of bridges mainly occurs under the influence of corrosion and loss of the working part volume of the steel reinforcement, unsatisfactory condition of the compensation seams on the supports. It is determined that cracks in reinforced concrete slabs occur due to low resistance of concrete to bending loads, due to which steel reinforcement is exposed to aggressive environments. In turn, it was proved that structural cracks in concrete occurred due to excessive loading, which led to overstrain of the structure, and non-structural cracks - due to internal stresses caused by thermal loads and various linear expansions of materials. Thermal imaging study revealed a significant difference in temperature in the pavement structural elements, which in the future leads to the destruction of cement-concrete pavement. It was found that the peeling of the protective layer of metal reinforcement on the studied bridges is caused by the phenomenon of electro-chemical corrosion. The experience analysis of cement-concrete pavement of the studied objects allows to prepare proposals for the construction of cement-concrete pavement of bridges and overpasses using modern materials, in particular, non-metallic reinforcement.

Development of a model of the weight of motor roads parameters as part of the information and management system of monetary evaluation

This paper reports a study into the main parameters of long-term contracts for the maintenance of roads. Weaknesses in existing methods and models of substantiation of the initial characteristics of contracts have been identified. It is established that the main reason for the transition to long-term contacts in the road sector is the need to improve the efficiency and effectiveness of road asset management. This determines the main goal to maintain the operational condition of all components of roads at a level that ensures the satisfaction of user requirements and contributes to the preservation of assets. A simulation model for substantiating the parameters of long-term contracts for road maintenance has been built, which makes it possible to simulate forecast assessments of the characteristics of contracts. Underlying this study is the Monte Carlo method, as well as the triangular law of distribution, models of deterioration and restoration of the condition of road elements. Taking into consideration these models, it was established that the error in justifying the parameters of long-term contracts according to the devised method is up to 10 %. The devised model was tested by applying the developed original LTCsimula program using an example of the section of a motorway with a length of 87.3 km with an average level of requirements. According to the results of the test, the assessment of the laws of distribution of value, as well as the amount of deductions and profits of a long-term contract, was carried out. The calculation results demonstrated the model’s capability to determine the strategies for the maintenance of roads, taking into consideration the risk of implementing a contract with an error of up to 3.9 %. The practical use of the devised simulation model makes it possible to improve the efficiency of operational maintenance of roads, as well as to save from 10 % to 40 % of the cost of road maintenance