Prestressed concrete sleepers are the most common type of the sleepers used on the railroad. They serve as rail supports and absorb loads induced by trains. Sleepers are important for the durability and safety of the railroad and are exposed to various loads and an agressive environment during exploitation. Therefore, different types of appearing damage can determine their reliability. The article briefly discusses possible causes of damage and the deterioration of prestressed concrete sleepers. End cracking and damage at the rail seat was determined during the inspection of used sleepers. Therefore, the strain state and cracking of the rail seat of the sleeper was analysed under static and dynamic loads. The paper provides the obtained results of experimental research of used and new sleepers.

The main aim of this paper is to provide a broader analysis of the transfer lengths of different types of fiber-reinforced polymers (FRPs) and to provide corrections to the existing theoretical models. Therefore, this paper presents a description of the main factors that influence the transfer lengths of different types of FRPs based on experimental results found in the literature. A database of more than 300 specimens was compiled with the results of the transfer lengths of different FRPs and the main influencing parameters. The analysis of the database results showed that the transfer length of the carbon fiber composite cable (CFCC) strands depends on the type of prestressed reinforcement release. Therefore, in this article, the new coefficient α_t = 2.4 is proposed for the transfer length of suddenly released CFCC strands. Additionally, the transfer length of the aramid fiber reinforced polymer (AFRP) depends on its surface conditions. Therefore, new coefficients α_t = 1.5 and α_t = 4.0 are also proposed for the transfer lengths of smooth braided and sanded and rough AFRP bars, respectively. Furthermore, the proposed coefficients α_t = 2.6, α_t = 1.9, and α_t = 4.8 found in the literature were validated with the analysis of a larger database of the transfer lengths of glass fiber-reinforced polymer (GFRP) bars, carbon fiber-reinforced polymer (CFRP) bars, and gradually released CFCC strands, respectively. Moreover, the main existing theoretical models are presented, and the comparison of theoretical and experimental transfer length results is discussed. However, the low number of specimens prestressed with basalt fiber-reinforced polymer (BFRP) bars prevented the deeper analysis of the results. the analysis of the transfer length and the proposed new values of the coefficient α_t provides possibilities for adapting it to design codes for engineering applications and performing additional research that fills the missing gaps in the field.

Nowadays, prestressed concrete sleepers are the most common type of sleepers. In different countries all over the world prestressed concrete sleepers are designed with different shapes, with different types of prestressed reinforcement and arrangements in cross-section. Additionally, different manufacturing methods and techniques are used for prestressed concrete sleepers. These railway members are stiff, durable and can withstand heavy loads. Despite that, damaged or deteriorated prestressed concrete sleepers appear on railway tracks even before the end of their service life. Therefore, there is a need for better understanding of the behavior of different types of prestressed concrete sleepers to optimize their design. The rail seat section of the sleeper is the most affected part of sleeper. Therefore, analysis of experimental results of bearing capacity, cracking, and deformation of the rail seat section of sleeper under static and dynamic loads are provided in this article. Furthermore, different types, diameters, and anchoring methods of prestressed reinforcement were analyzed in this article. Additionally, comparison of experimental results of different types of prestressed concrete sleepers is discussed.

In this manuscript, we present the results of three-dimensional finite element analyses performed in the cloud of a large-scale model of the Gediminas Hill buildings and the construction remains of the Upper and Lower castles in Vilnius city. The greatest challenge associated with the simulated numerical model is the difficult geological layer surface inclinations and soil–structure interaction behavior prognosis, which require significant computational resources. The purpose of this research work is to present current and possible worst-case scenarios for Gediminas Hill, considering its buildings and construction remains, regarding the stability of its slopes through a safety analysis. The construction of a numerical three-dimensional model of Gediminas Hill allows for us to assess the soil–structure interaction behavior. The results of non-linear analysis on the created model are in agreement with the tendencies observed in direct geodetic measurements and the relevant landslide history.