Valery Maksymenko a, Pavlo Voytenko b
Investigation of the stress-deformed condition of the base plate on based of three-dimensional models
a Research Institute of Construction Execution
b Kyiv National University of Civil Engineering and Architecture
Abstract. Three alternative designs of a foundation slab in three-dimensional representation with regard to the concrete features modification has been designed during the investigations. The data of the stressed and strained state of a foundation slab having made on the heart of the thin slabs theory of Kirchhoff-Love by adoption of three-dimensional finite elements with regard to the refining theories of Reysner-Nugda, Ambartsumyan, etc. have been obtained on evidence derived from the spatial design scheme of a high-rise building. The investigation object is the expediency evaluation of application of the spatial finite elements at the thick foundation slabs design. In accordance with the realistic conditions, the structural schematic drawing of a building has been simulated completely including the effect of the constant wind and seismic loads. A consequence of the obtained results is the fact that the simulating method enables to investigate time history of the stressed and strained state of a foundation slab both in layout and in thickness. The derivation of an optimum pattern of force transmission on to a pile foundation is also the significant findings of the investigations.
Keywords: foundation slab, spatial finite element, rigidity matrix, triaxial compression, stressed and strained state, pile foundation, three-dimensional model.
Olena Shynkevych
Crack resistance and deformability of complex-activated calcareous and siliceous composites
Odessa State Academy of Civil Building and Architecture
Abstract. The paper is focused on the study and properties control, containing parameters of mechanics of failure in complex activated calcareous and siliceous composites to fabricate wall injection molding products by casting energy conservation technique. The proportional dependence of the critical stress intensity factor (kIс) from fine aggregate content of calcareous and siliceous fine-grained concrete has been set up on the basis of the test and statistic pattern indicating the possible identity of the cracking mechanisms in cement and calcareous and siliceous composites. The findings have shown that with increasing of the fine aggregate content, the probability of microcracks retardation by filling grains have been grown. The subordination to the local optimum of the critical stress intensity factor when affected by hardening conditions has been set up: kIс increases to its maximum, then decreases. The deviation from the optimal values of hardening conditions and compositions leads to reduction of kIс connecting with the formation of prerupture zone on the contact of a matrix with a filler in these conditions. The impact of composition factors and technique on the modulus of elasticity has been analyzed. The expediency of application of the set of quality indicators, including crack resistance and deformability at compositional optimization and hardening conditions of activated fine calcareous and siliceous composites.
Keywords: crack resistance, critical stress intensity factor, calcareous and siliceous composites, test and statistic modelling, activation, modulus of elasticity.
Feofan Shevchenko, Sergiy Tsarenko
Common and different properties of beams and trusses
Donetsk National Technical University
Abstract. The paper cites the investigations of the approximate analysis accuracy of through bar structures in the form of trusses and towers by means of replacement with their equivalent bars of adduced rigidity. The principle methods of movement determination in a truss as a beam system, i.e. from a bending moment with regard to an additional deflection from a transverse force depending on the truss lettuce diagram and its sections have been considered. The simplified analysis of the movement in a beam system with its application to an equivalent beam changing a truss contained in application of the More formula with regard of the transverse force has been offered. The examples of the simplified method application of change of a truss to an equivalent beam for analysis of a metal tower on to rigidity, dynamic analysis of trusses to the natural and forced oscillations have been given. At dynamic analyses, the gained equivalent beams with distributed parameters have been changed by bars with a reduced mass under conditions of frequency equality of the basic tone of oscillations of the system with distributed parameters and frequencies of an equivalent beam with a reduced mass.
Keywords:approximate analysis, through bar structures, trusses, towers, equivalent system, systems with distributed parameters, reduced mass bars, frequency equality.
Vadim Gubanov, Irina Meginskaya
Analytical treatment of structural conceptions and engineering state of cellular communication guyed masts
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper offers the field examination findings of the cellular communication guyed masts. The central tenets of the guyed masts examination technique in view of zoning have been described. The classification of structural conceptions of the common guyed masts have been made. The analysis of their merits and demerits from the point of view of reliability, durability, ease of manufacturing, erection and operation has been made. The commonest defects and damages of the masts having a profound impact on structural behaviour as a whole have been revealed and systematized. The impact of deviation of the axes of guys from design position on mast deformability at various combinations of loads has been considered.
Keywords: guyed mast, examination, guys, flanges, joint, defects, structural conceptions.
Yaroslav Lelyk, Alexander Berlach, Pavel Berlach
Selection ground of fundamental geometric parameters of forming element at formwork design for space curvilinear surfaces
Lesya Ukrainka Volyn National University
Abstract.While designing a panel formwork for curvilinear surfaces the need arises for analysis of geometric parameters of forming elements to permit the approximation of space curvilinear surface in automatic operation. The problem solution has been considered to be as a basis for the paper. The task of determination of one-type type elements enabling to dissect the given surface on has been set up. The evaluation criteria of similarity of the elements have been revealed. The formulas enabling to approximate the curvilinear surface of a hull by one-type panel elements in automatic operation that is equivalent to determination the number of panel types necessary for erection of the given curvilinear surface formwork have been devised.
Keywords: formwork, formwork panels, approximation, building, structures, cast-in-place coating, surfaces, designing, one-type elements, geometric parameters.
Oleksiy Belous a, Yevgen Kolesnyk b
Structural considerations of energy efficiency of translucent enclosing structures
a Donbas National Academy of Civil Engineering and Architecture
b State-Run Enterprise «Research Institute of Building Structures»
Abstract. The paper considers the problem of energy translucent walling by selecting the optimal constructive decision nodes window (door) to block non-transparent part of the wall. The basic criteria for energy efficiency, which is necessary to optimize. These consist of: resistance to heat brought translucent (opaque) enclosure design, the temperature difference between inside air temperature and reduced temperature of the inner surface of wall enclosing structure, the minimum temperature of the inner surface of the linear coefficient of heat transfer. These design principles to ensure the selected criteria indicators. Research conducted for the nodal connections window structure on the basis of PVC profiles of Veka Softline 70 AD and fifteen types of constructive external opaque wall construction. For the linear rate of heat transfer coefficient defined the basic principles of the estimated assessment. According to the results of the studies identified some of the features and patterns that arise in assessing the translucent walling the specified criteria.
Keywords: translucent fencing design, energy efficiency, linear coefficient of heat transfer window node connection, temperature field.