Applied Mechanics and Materials Vol. 837

Abstract: Analysis of wind flow upon high-rise buildings is very common topic. Nowadays, there are no general or analytical ways how to analyze wind effects on irregular shaped high-rise buildings complexes. Scaled experiments tested in wind tunnels are best for precise solutions, however they are time consuming and expensive too. Therefore we use computational modeling software based on finite volume method to analyze these effects and then, thanks to these analysis we can design structures and optimize them. Paper deals with simplified 3D analysis of wind effects on high-rise buildings complex "Panorama City" located in Bratislava-Slovakia. Through this analysis we obtain results for wind speed near objects and external pressure coefficient as well. Both of them will be helpful to gain insight for future constructions or verification of already constructed ones.

Abstract: The paper deals with numerical analysis of deformations and relative displacements (relative settlement, relative deflection and flexibility) of the shallow square foundations depending on the variable relative stiffness. For solution of the problem finite element method was used with theoretical assumptions of the linearly elastic half-space. Foundation-subsoil contact was modelled by one-directional and bi-directional bond effect. Results of the solution are presented by graphical forms.

Abstract: This paper deals with a problem of earthquake of the cylindrical tank. During the seismic event, the load acts in one direction only, i.e. in the direction of earthquake. This load imposes a non-symmetrical loading of a structure. At seismic load of structure of cylindrical tank was used accelerogram. In final part of the paper some crucial results are presented both in a graphical and numerical way.

Abstract: The first case study used in this work is an existing seven-storey unreinforced masonry building (representing a typical residential building located in the district of L ́Example in Barcelona). The accuracy of the non-linear static procedures was evaluated by comparison with non-linear dynamic analyses for seven ground motion records and different levels of seismic intensity. The results obtained from the analyses showed good performance of the static pushover methods on the analysed building. The second case study used in this work is a two-storey unreinforced masonry building which was tested at ELSA in Ispra, Italy. First a modal response spectrum analysis was carried out. Subsequently, non-linear static analysis was performed using two different computer programmes. The results of the present work were compared with experimental results.

Abstract: Mechanical properties of the laminates reinforced with steel wires based on UHTS (Ultra High Tensile Strength) steel are only slightly worse than popular carbon strips. Thanks to competitive price they become popular strengthening material for concrete structures. The paper presents the results of laboratory tests of beams not efficiently reinforced in shear zone and strengthened along its side surfaces by the L-type overlays made of SRP tape. In addition, in order to ensure a high load-bearing capacity, beams were strengthened against bending. The effectiveness of reinforcement in a comparative test of unreinforced model was analyzed including ultimate capacity, deflection, failure model and strains. The results were used to evaluate the efficiency of SRP shear strengthening.

Abstract: The stability analysis of a slender web loaded in compression is presented. The non-linear FEM equations are derived from the variational principle of minimum of potential energy. The peculiarities of the effects of the initial imperfections are investigated using user program. Special attention is paid to the influence of imperfections on the post-critical buckling mode. Stable load-displacement paths are investigated. The FEM computer program using a 48 DOF element has been used for analysis. FEM model consists of 4x4 finite elements. Full Newton-Raphson procedure has been applied.

Abstract: The article is devoted to compare the size of the creep for a time period of cement pastes with admixture of different amounts of fly ash. Attention is given to the size of the deformations that occur in materials saturated with water and also in the dried matrices. The presented results comparing creep size for cement pastes containing fly ash 30 and 50 %. Influence of the amount of ash and the amount of water to the creep size is evaluated in the conclusion.

Abstract: In the paper small-sample double-loop optimization method is employed to find selected design parameters of a single-span post-tensioned composite bridge to ensure its reliability and load-bearing capacity. The selected approach consists in nesting the computation of the failure probability with respect to the current design within the optimization loop. The analyzed bridge is made of precast post-tensioned concrete girders, each composed of six segments that are connected by the transverse joints. Bridge spatial deterioration brings uncertainty into actual values of concrete strength in transversal joints and of actual loss of pre-stressing. Due to their significant effect on the bridge load-bearing capacity, both were considered as uncertain design parameters with the aim to find their critical values corresponding to desired reliability level and load-bearing capacity.

Abstract: Description of historical covered bridge over Hnilec river so called bottom bridge in Gelnica near the station. History of the bridge. Way of construction of the bridge. Its structural system. Photographs of the bridge and its details. Scheme of the bridge.

Abstract: The stability analysis of an imperfect slender web subjected to the shearing load is presented, a specialized code based on FEM has been created. The nonlinear finite element method equations are derived from the variational principle of minimum of total potential energy. To obtain the nonlinear equilibrium paths, the Newton-Raphson iteration algorithm is used. Corresponding levels of the total potential energy are defined. The peculiarities of the effects of the initial imperfections are investigated. Special attention is paid to the influence of imperfections on the post-critical buckling mode. Obtained results are compared with those gained using ANSYS system.