There is a lack of detailed information about wind flow and distribution of wind pressure around atypically shaped high-rise buildings. The national standard EN 1991-1-4 Eurocode 1 used to determine the effects of wind on the territory of Slovakia (and indeed other countries of the European Union) does not have a procedure for determining the effects of wind on objects of triangular shape. This presents a problem for designers and engineers, as there exist no generally binding/valid rules to follow when performing the wind effect analysis. This paper shows the procedure of identification and results of the external wind pressure coefficient for the triangularly shaped high-rise building. Two methods of calculation have been chosen for this purpose. First, experimental measurements were performed on a scaled model of the building cross-section in the wind tunnel. Subsequently, software simulations were performed on the same scaled model in the CFD (computational fluid dynamics) program ANSYS CFX. Results of wind pressure were obtained for two directions of wind flow measured in 16 sampling points distributed irregularly around the circumference of the model. Results were mutually compared and verified. At the end, the wind flow effects on a real-size triangular high-rise building in the built-up area performed by software simulation are shown.

This paper deals with the design of a five-storey hospital building, in which we focus on the deterministic and probabilistic analysis of its slab foundation. The hospital building bearing structure was modeled as a reinforced concrete skeleton. The Boussinesque model was selected for the subsoil under the plate foundation, which was a model of the elastic half-space, where properties of individual layers of the subsoil were entered according to the geological survey. The geological topology consisted of clay gravel and also included a layer of clay sand. In the stochastic solution, the variance of values was considered for individual mechanical properties of different types of soil. We analyzed the influence of the variance of input values on the resulting deflections, strain, and stress state of the plate foundation. Two variants of the solution were considered on the given numerical example. Probability calculations confirmed the probability of failure, which was allowed for the second limit state.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

Tanks have been currently used for the storage of various substances, in particular as drinking water storage tanks and for storage of various technical fluids. Rectangular tanks have advantages over cylindrical tanks, such as: lower sensitivity to unilateral loads and better use of space when used in a system of tanks. The rectangular tank analyzed in this article is filled with water. During the dynamic analysis of the tank, it was loaded by an accelerogram of a natural earthquake. In the calculation, the method of direct integration over time was used, considering damping. From the accelerogram a response spectrum was generated and applied as an additional loading of the tank. The static model of the tank was created in the ANSYS program, which works on the basis of the finite element method (FEM).

The use of very thin, subtle and light structures as an external part of buildings causes many problems related to wind induced vibration. Constructions of this type occur mostly as a part of roofs or design facades. The principal idea of this paper is to show dynamic response of triangular lamella exposed to wind gusts, which frequency is equal to the first natural frequency of the lamella. By the two-way software fluid-structure interaction (FSI) analysis, oscillation of the lamella was detected. The solution of two-way FSI analysis requires co-simulation between computational fluid dynamics and structural mechanics. In the simulation, it was essential to simulate conditions that if met, create resonant vibration of the lamella caused by vortex shedding on the leeward side of the structure. If the frequency of vortex shedding matches the resonance frequency of the structure, the structure begins to resonate and vibrates in harmonic oscillations driven by the energy of the flow. In this case, vibration rises and structure can be damaged or deformed permanently. For the long-term vibration, fatigue stress and subsequently fatigue failure is significant. By the usage of empirically derived equations, input data for the software simulation were obtained. It was important to consider mainly natural frequency of lamella, frequency of vortex shedding behind the structure and also correct properties of air such as wind speed, frequency of wind gusts, density of an air and Strouhal number. As a conclusion, dynamic response of lamella in the form of deformation and wind stream pattern depending on time is shown. It has been also shown that if the inputs are specified correctly to software simulation it is possible to analyse time history of many variables such as deformation, wind speed, and acceleration. By this method, it is possible to determine not only the maximum variables such as deformation or wind speed, but also its entire time history. In practice, it is therefore possible to create different design situations and, on their basis, design the lightweight non-bearing structures exposed to the wind.

Nowadays, there are increasing use of very thin, subtle and light structures in the field of building constructions. We can find such a structures as part of roofs or design facades. By using these lamellas like, non-bearing structures as a part of architectural design of buildings, it is necessary to consider wind effects on these structures. Subtle structures of this type are prone to vibration in the transverse direction of the wind flow. The fact that the vibration occurs depends on wind parameters (wind velocity, direction of an air flow) and it also depends on the properties of lamella (shape, length, mass, natural frequency, support type). The principal idea of this article is to show susceptibility of lamellae-like structures to transverse resonant vibration caused by the phenomenon called Von Karman effect. Comparison of susceptibility to transverse resonance vibration was analysed on the different shapes of lamellas loaded by different wind speed. Analysis was based on usage of empirically derived equations. Von Karman effect arise from wind flow past an object. Turbulence in the form of vortices are formed at the object and shed into the flowing stream intermittently. The potential problem is that this turbulence can induce vibrations into the lamella itself. In terms of this vibration problem, two frequencies are interesting. Von Karman shedding frequency is the frequency at which the vortices are formed and shed at the object. The vortex-shedding frequency increases with the velocity of the wind flow and decreases with the size of the object. Natural frequency of the object depends on the construction of the lamella itself. Parameters of lamella as a shape, mass, length, elasticity modulus of material and support types are directly involved in the calculation of natural frequency. Worst case scenario in the term of transverse resonant vibration occurs when the natural frequency of lamella is equal to the vortex-shedding frequency. In this case vibration rises and structure can be snapped or deformed permanently. In the long term vibration, fatigue stress can be significant. At the conclusion hazardous wind speed and recommendations for different shapes and parameters of lamellas are shown.