This study presents the results of analyses performed using a dynamic 3D model of a RC skip tower located at a coal mine in Poland. Kinematic excitation was based on acceleration records of a mining tremor (underground mining activity) and an earthquake. Although Poland is not a particularly active seismic region, there are regional seismic phenomena associated with mineral exploitation. These vibrations, generally connected with human activity, are so-called paraseismic events. Whilst mining-related surface vibrations show some similarities with natural earthquakes, there are also some differences. Dynamic calculations were performed in the time domain. Analysis of the results refers to the distribution of stresses and displacements which were compared to the limit values. An additional goal of the study was to examine the possibility of loss of structural stability and the risk of collapse. The reason for making the analysis was the fact that kinematic excitations of high structures had not been taken into account in the design procedure. Using actual recorded surface vibrations caused by rock burst and earthquake as kinematics loads allowed a comparison of the dynamic responses of the structure with two different seismic events.

The prediction and calculation of the volume of gravel and/or sand transported down streams and rivers—called bed-load transport is one of the most difficult things for river engineers and designers because, in addition to field measurements, personnel involved in such activities need to be highly experienced. Bed-load transport treated by many engineers marginally or omitted and often receives only minor consideration from engineers or may be entirely disregarded simply because they do not know how to address the issue—in many cases, this is a fundamental problem in river management tasks such as: flood protection works; river bank protection works against erosion; building bridges and culverts; building water reservoirs and dams; checking dams and any other hydraulic structures. Thus, to share our experience in our paper, bed-load transport was calculated in two river/stream mountain catchments, which are different in terms of the characteristics of the catchment area and the level of river engineering works performed along the stream channel—both are tributaries of the Dunajec River and have similar Carpathian flysh geology. The studies were performed in the Mlyne stream and in the Lososina River in Polish Carpathians. Mlynne is one of the streams in the Gorce Mountains—it is prone to flash flooding events and has caused many problems with floods in the past. It flows partially in the natural river channel and partially in a trained river channel lined with concrete revetments. The stream bed load is accumulated in the reservoir upstream of the check dam. The Lososina River is one of the Polish Carpathian mountainous streams which crosses the south of the Beskid Wyspowy Mountains. It mostly has a gravel bed and it is flashy and experiences frequent flooding spring. At the mouth of the Lososina River, there is one of the largest Polish Carpathian artificial lakes—the Czchow lake. The Lososina mostly transports gravel as the bed load to the Czchow water reservoir where the sediment is deposited. In the early seventies, the Lososina was partly canalised, especially in places where passes inhabited areas. The paper compares the situation of bed-load transport in the Lososina River before and after engineering training works showing how much sediment is transported downstream along the river channel to the Czchow artificial lake. Also compared is the Mlynne bed load transport upstream and downstream from the check dam showing how much sediment might be transported and deposited in the reservoir upstream from the check dam and when one could expect this reservoir to be clogged.

The paper presents a dynamic analysis of the damaged masonry building repaired with the Flexible Joint Method. Numerical analysis helped to determine the effect of the applied repairing method on natural frequencies as well as values of stresses and accelerations in the analyzed variants of numerical model. They confirmed efficiency of the proposed repair method.Key words: polymer flexible joint, dynamic analysis, numerical modeling, dynamic resistance. IPolymer flexible joints that have been used in repairing of damaged masonry buildings [1], have also showed high resistance to the strong dynamic influences, which was confirmed during in situ investigations [2], [3]. Those investigations allowed identifying elastic parameters (Young's modulus) of the analyzed masonry building, estimated for different stages: undamaged, damaged and repaired using the Flexible Joint Method. These parameters were then included in the FEM model, which was subjected to the strong ground motion. Comparison of the dynamic response of analyzed masonry building in different stages is the main aim of this paper. D    A subject of conduced analysis was the storied, masonry building of the transformer station (Fig. 1)

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In current river management, we very often use environment-friendly hydraulic structures when it is required for river bed or river bank protection due to erosion of a river channel. Block ramps are one of many methods used to stabilize river beds. They provide a semi-natural solution to certain river engineering problems in mountain streams. When building block ramps, one can use the dissipative behavior of large rock blocks or boulder elements randomly placed on the river bed to enhance fish migration in an upstream direction; thus, they can serve as fish passes. In this paper, we present the results of the numerical modelling of a bed load transport and the morphological changes of a river bed where a block ramp was designed and built. The main aim of the study was to investigate the difference of 2D modelling of a bed load transport along the mountain stream reach with boulder ramps in comparison to the classical methods of Hjulström, Shields, and Russian standard ST-24-2396. The work was carried out on the stream of one of the chosen low-head hydraulic structures, where 25 identical block ramps were constructed for river training reasons. The novel approach of our study is, for the first time in the field, to show a very detailed analysis of block ramp influence on sediment transport and river morphology changes compared to the classical understanding of those phenomena, as well as 2D model results to give hydraulic engineers an inside look into classical and modern approaches of bed load transport calculations. This might be helpful for designing such kinds of hydraulic structures in the future, in all regions where sediment transport calculations are important but do not always require sophisticated modelling.