The analyses aim to determine aerodynamic force coefficients in the case of airflow around two smooth or rough cylinders positioned at different angles to the direction of wind velocity. Such systems, for instance, may be part of a tubular water slide. The results were compared with the values of the interference coefficient of the cylinders arranged in a row included in Eurocode EN 1991 part 4. The aerodynamic forces of the cylinder systems were determined on the basis of experimental tests conducted in a wind tunnel. To verify the above results, CFD (computational fluid dynamics) simulations were prepared. An important observation is that for the angle of yaw β = 0◦, the negative component of the lift force (lateral) fy is shown, while for the other cases, the situation is opposite and the lateral force points outside the gap (upward). The second is that the results of aerodynamic drag for rough cylinders arranged in a row and calculated according to EN 1991 part 4 may be underestimated. The flow around the pair of smooth cylinders is quite different from that of the rough ones, because during the experiment the first falls into the critical flow regime, while the second has supercritical characteristics.

Double corrugated, self-supporting K-span arch structures are now commonly used globally to make roofs for building structures, as an alternative to traditional solutions. The K-span system has become popular mainly due to the simple and cheap method of its manufacturing and quick installation. Nowadays, new versions of the system are created but still there is no valid design method. Design difficulties are among the causes of failures or even collapses of such structures. Back in the 1970s, the first studies were developed concerning computational analyses of double corrugated arch roofs. They laid grounds for the development of contemporary K-span system technology but have since lost their practical advantages due to changing engineering conditions. The paper presents a review of research and computational methods concerning double corrugated arch structures. The paper discusses selected scientific studies, which were used as the basis for the development of research and computational methods, and their contemporary continuation. Directions for further research and analyses are also presented which could contribute to the future development of science and engineering in the area and could provide inspiration for future studies.

In determining the effects of actions when designing road structures, the influence of the loads caused by the buffeting of the passing vehicles (high-cycle forces) is neglected. Taking into account the fatigue load, they can have a very large impact on the assessment of the load capacity. The subject of analysis is the pressure and velocity distributions around a truck. At the current stage of the work, it can be concluded that the gusts of passing trucks affect the dynamics of the gantry structure and the elements suspended on it, such as platforms or boards. There is a strong suction force. It is possible to simplify the model in such a way that the board and the wind move with the speed of the vehicle while the truck remains stationary. Due to the lack of reliable guidelines for strength calculations of such structures, advanced Computational Fluid Dynamics (CFD) tools were used. This paper also presents a shaking table built by the authors for dynamic loading of structural models. It describes the construction of the shaking table and the kind of movement made by the table deck. It also shows a scheme of the table deck suspension on linear bearings, as well as a scheme of the table motion system.