The problem of transition zone of structural steel element connected to concrete is discussed in the following paper. This zone may be located for instance in specific bridge composite girder. In such case the composite beam passes smoothly into concrete beam. Because of several dowels usage in the transition zone, the problem of uneven force distribution were discussed through analogy to bolted and welded connections. The authors present innovative solution of transition zone and discuss the results, with emphasis put on the transition zone structural response in term of bending capacity, failure model and force distribution on the connection length. The article wider the already executed experimental test and presents its newest results.

Problems concerning structures dynamics are being one of most important subjects in recent investigations associated with railways constructions. The need of modelling of such structures and their behaviour prediction leads to necessity of seeking new approaches, mainly due to highly increasing speeds of vehicles and traffic intensity. Comparative studies carried out on experimental data, measurements and theoretical research show that models based on multi-layered approach supported by semi-analytical approximations of solutions can give new insight into undertaken analyses. More detailed consideration of roads components and their physical properties, along with application of effective estimations allowing to avoid numerical instabilities linked with extremal dynamic variations, can be important tools in obtaining new solutions both, theoretical and engineering. This paper briefly presents a number of multilayer railway track models, with special emphasis on nonlinear track properties. Existing analytical and semi-analytical solution methods are presented with main advantages of new approaches. The theoretical double-beam system with two nonlinear layers is solved and computational examples are presented along with possibility of their transition to other multilayer structures analysis.

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informuj?ce swoich czytelnik?w o najnowszych osi?gni?ciach naukowych i nowoczesnych rozwi?zaniach technicznych w Polsce i na ?wiecie, popularyzuje problemy techniczne oraz poszerza wiedz? i kultur? techniczn?.

Damage to large reinforced concrete structures is rarely due to design errors. Sometimes, however, a small error can lead to major damage and costly repairs. The article describes the damage, the results of non-destructive and destructive tests, the results of numerical calculations, and the method of repairing a reinforced concrete tank in a sewage treatment plant. The failure was caused by applying the wrong boundary conditions to the reinforced concrete wall support inside an existing biological reactor. During leak testing, one of the new walls cracked and was displaced, which resulted in the tank leaking. An inspection of wall damage and displacement was carried out on termination of the leak testing and while the tank was draining. The causes of the failure were determined based on the inventory information and numerical simulations. Both non-destructive tests of reinforcement and concrete and destructive tests of concrete were carried out. The concrete class of the foundation slab was determined based on a compression test of sample cores obtained from drilling. The aim of the non-destructive tests was to indicate the location and diameter of reinforcement in the damaged wall using electromagnetic and radar methods, as well as the location of internal defects using ultrasonic and radar methods. It was found out that the failure was a result of an incorrect determination of the anchoring length of the reinforcement. Based on the analysis, a plan to repair the damaged wall was formulated and then successfully implemented. In the article the authors proposed the IVD (identification-verification-design) scheme to make the design easier in similar cases.

High-speed rail (HSR) systems provide numerous benefits, including reduced travel time, increased transport capacity, and lower environmental impact compared to conventional rail networks. Recent experience in Poland has confirmed that the design of high-speed rail lines requires the development of new, dedicated structural solutions. One such example is the need to assess the load-bearing capacity of the column-to-foundation connection, which in Poland is designed as a connection with a spacing between the column base plate and the top part of the pile foundation – an uncommon solution in HSR applications. The study included the development of a fatigue damage spectrum in the high-cycle range, taking into account stress variability caused by pressure fluctuations from passing trains. The results establish a relationship between the number of load cycles and pressure values, enabling a simplified estimation of the fatigue strength of the examined connection. Wind effects are influenced by several factors, including train speed, aerodynamic shape, and the angle of load application. The study highlights the sensitivity of the system to boundary conditions and recommends design improvements to enhance fatigue resistance. The novelty of the work lies in identifying critical failure modes specific to distance-type connections and emphasizing the need for full-scale experimental validation in the context of HSR development in Poland.