Transformers are one of the most important components of the power system. It is important to maintain and assess the condition. Transformer lifetime depends on the life of its insulation and insulation life is also strongly influenced by moisture in the insulation. Due to importance of this issue, in this paper a new method is introduced for determining the moisture content of the transformer insulation system using dielectric response analysis in the frequency domain based on artificial bee colony algorithm. First, the master curve of dielectric response is modeled. Then, using proposed method the master curve and the measured dielectric response curves are compared. By analyzing the results of the comparison, the moisture content of paper insulation, electrical conductivity of the insulating oil and dielectric model dimensions are determined. Finally, the proposed method is applied to several practical samples to demonstrate its capabilities compared with the well-known conventional method.

Early detection of potential defects and identification of their location are necessary to ensure safe, reliable and long-term use of engineering structures. Non-destructive diagnostic tests based on guided wave propagation are becoming more popular because of the possibility to inspect large areas during a single measurement with a small number of sensors. The aim of this study is the application of guided wave propagation in non-destructive diagnostics of steel bridges. The paper contains results of numerical analyses for a typical railway bridge. The ability of damage detection using guided Lamb waves was demonstrated on the example of a part of a plate girder as well as a bolted connection. In addition, laboratory tests were performed to investigate the practical application of wave propagation for a steel plate and a prestressed bolted joint.

Construction objects must be protected not only at the stage of their construction, but also during exploitation. Particular attention should be paid to objects included in the list of monuments. The Act on the Protection of Monuments and the Guardianship of Monuments states that any building that is important for history and science can become a heritage building and should therefore be preserved. The aim of this article was to improve the method of visual assessment of the technical condition of heritage buildings with the use of fuzzy logic. The improved method is to facilitate the comparison of assessments of the technical condition of a building performed at intervals specified in the regulations, often by different people. The research was conducted on the basis of technical expertise prepared for five examined buildings that were tenement houses entered in the register of monuments. The use of the visual method provides for the assessment of individual elements of the object by an expert and a verbal description of the elements using a five-point scale. A significant limitation of this method is uncertainty associated with the exact ranges of the acceptable values, as these ranges are subjective and depend on the opinion of an evaluator. The impact of this limitation can be reduced by applying fuzzy logic. In the fuzzy logic model, as input variables the following were applied; assessments of the technical condition of individual elements of the object (underground structure, load-bearing walls, ceilings, roof, other elements) and an integral indicator of the technical condition of the entire historic object, calculated as the output value.

The article discusses "Rules for using the point rating scales for assessing the technical condition and usability of road engineering objects – second edition", which were introduced by the General Directorate for National Roads and Motorways (GDDKiA) Regulation No. 1/2019. The main objective of "Rules..." was to standardize the method of point rating assessment of technical condition and usability, and in the second edition, to take into account the latest construction and material solutions. Because the results of inspections are analyzed and compared not only at the regional but also at the national level, it is very important for all inspectors in the country to evaluate the technical condition and usability in an analogous manner. While developing the 2nd edition, the authors maintained the assumptions of continuity of inspection system, including adaptation to the inspection manuals, algorithms, and software supporting the management of bridges.