Bolt Connections New Modification for Rod Elements of Metal Constructions of Buildings and Structures
Branch of the North Caucasus Federal University in Pyatigors
Abstract. A new technical solution for mounting joints of metal structures in the form of bolted joints of rod elements on mortise moldings with longitudinal axial slots is presented. With these slits, each of the gussets is divided into identical sections with bolt holes symmetrically bent in opposite directions to the thickness of the gussets, which ensures their overlap joining by means of tightening bolts without single pads or eccentricities. Such a constructive-layout solution of the mortise gussets turned out to be quite an effective fundamental principle for their spatial modification in the form of mortise crosses. The use of such crosses in typical joints of tubular rods eliminates the need for double sets of bolted fasteners and twin pairs of pads from equal-angle corners with chamfers removed. Comparison of the proposed, well-known and standard solutions on the same basic objects showed that the new bolted joints have the necessary and sufficient bearing capacity, provide a reduction in the consumption of structural material and are equal-strength with joined core elements. The versatility of the proposed technical solutions ensures their applicability in bolted joints of rod elements from tubular and rolled (open) profiles, and also increases their availability, rationality and efficiency in the development of new forms of assembly joints of supporting structures of buildings and structures.
Keywords: assembly joints of metal structures, bolted fastenings, joints on mortise gussets, joints on mortise crosses, optimization of butt joints.
Determination of Parameters of Work of Building Constructions under Loading in the Course of their Tests
Institute of Architecture and Civil Engineering of Volgograd State Technical University
Abstract. In article examples of practical application of the portable information and measuring complex on the basis of the analog-digital ZET 210 converter under control of the laptop when carrying out natural tests of various building constructions of industrial buildings and constructions are described, such as, steel and reinforced concrete beams of overlappings, rafter farms, columns, subcrane beams, trunks, delays and other elements of chimneys, metal towers. Tests were carried out within inspection for the purpose of assessment of the current technical condition of the specified building constructions. The actual values of such parameters of work of designs under loading as amplitude, the frequency and logarithmic decrement of free fluctuations, amplitude and frequency of the compelled fluctuations, parameters of technological vibration, linear deformations of material, hardness of steel according to Brinell were measured. Results of measurements were used as technical criteria of estimates when writing the conclusions following the results of inspections.
Keywords: the information and measuring complex, the analog-digital converter, ZETLab, tests of building constructions, measurement of parameters of work of designs under loading.
Volodymyr Mushchanov, Anatoly Orzhekhovsky, Alexander Demidov, Serafym Fomenko, Fedor Stifeev
Features of the Implementation of the Finite Element Method in the Spatial Formulation when Creating Authoring Programs
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article discusses some features of the implementation of the finite element method in the spatial formulation when creating authoring applications for calculating the internal efforts of building structures. The technique of automating the formation of local and global stiffness matrices, the calculation of stiffness matrices of rod elements under various boundary conditions is considered. The method is based on the method of condensation of the stiffness matrix. The most optimal ways of forming the cosine guide matrices and the external load vector are given. The method of calculating the main block of the matrix of cosine guides is based on the use of Euler angles. We consider the method of forming local vectors of the external load, as well as the algorithm for forming the vector of the external load of the system as a whole from local components. A test example of calculating the spatial frame according to the proposed method implemented in the programming language MATLAB is given. The obtained results were compared with the calculation of a similar design in the LIRA-SAPR software package. The difference was less than one percent.
Keywords: building structures, finite element method, cosine guide matrix, stiffness matrix, software.
Andrei Myronov, Yulia Marchenkova, Yulia Ryb, Anatoly Yagmur
Refinement of the Transverse Installation Coefficient of Transport for Steel-Concrete Bridge Spans
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper calculates the coefficients of transverse installation of vehicles AK-15, NK-100 and pedestrian load for the main beams of steel-concrete bridge structure with the use of off-center compression. In the course of engineering calculation the section of the extreme main beam of the bridge construction is checked in accordance with the requirements of the first and second group of limiting states. Two design models of the beam continuous spanning structure of the central part of the bridge construction were simulated in the Lira-SAPR 2013 software complex. Based on the numerical data obtained, the coefficients of transverse installation of transport were determined and the nature of the distribution of the temporary mobile load of transport between the main beams of the bridge was revealed. As a result of the research a comparative analysis of the coefficients of transverse installation of transport was acomplished, obtained by engineering and numerical methods.
Keywords: transverse installation factor (TIF), steel-concrete bridge construction, main beams, temporary mobile transport load, out-of-center compression method, final elements (FE).