33407
2304-6295
Construction of Unique Buildings and Structures
2
107
2023
1-60
RAR
RUS
10701-10701
57210972600
0000-0001-6472-9413
Shmelev
Gennady Nikolaevich
Kazan State University of Architecture and Engineering (KSUAE)
gn.shmelev@mail.ru
Russian Federation, Tatarstan republic, Kazan, Zelenaya Str., 1
0000-0003-2662-6020
Khaidarov
Lenar Ilnurovich
0000-0001-7920-9920
Galimullin
Ilshat Albertovich
0000-0002-0205-0859
Shishkanov
Danil Gennadievich
Influence of wind load on connection system of temporary towers
The objects of research are temporary demountable towers. When a wind load is applied to a structure at an angle, an uneven horizontal wind load occurs, which causes the structure to twist. For capital construction projects, due to the massiveness and greater rigidity of the nodes, this is not significant, but for light structures, accounting for this effect is very important. The purpose of the work is to study the connections of such towers and the influence of wind load unevenness on them. Method. Wind load studies are conducted, based on a model of a diving tower with the dimensions of the widest part 12 x 10 m and a height of 28 m. Different methods of calculation are taken into consideration, including the ones based on regulatory documentation and numerical modeling. Software packages allow calculating models with higher accuracy and less time, facilitating manual counting and reducing the probability of error. A gas-dynamic calculation is performed, as a result of which the aerodynamic coefficients are found. Results. A comparative analysis of two methods for calculating wind loads is carried out, after which measures are suggested to increase the load-bearing capacity of the structure.
10.4123/CUBS.107.1
69
Connection system
Wind load
Numerical modeling
Experiment
Design model
Construction
https://unistroy.spbstu.ru/article/2023.108.1/
10701.pdf
RAR
RUS
10702-10702
H-9967-2013
16412815600
0000-0002-8588-3871
Kirsanov
Mikhail Nikolaevich
National Research University Moscow Power Engineering Institute
mpei2004@yandex.ru
Moscow, Russian Federation
Luong
Cong Luan
Frequency spectrum of natural oscillations of the spatial structure of the rod pyramid
The object of the study is a pyramid-type enclosure statically defined in space. The truss has support posts along the contour of the base. The corner buttons are fixed on the support sphere, cylinder, and bracket. Structure with axes of symmetry. The purpose of the study is to give formulas on the dependence of the deflection under the effect of uniform load and the first natural frequency of oscillation on the number of plates, size and mass concentrated at the nodes of truss. Method. By using equilibrium equations at the nodes it is possible to find the forces in the truss elements. The system of equations also includes the responses of the vertical supports located along the contour of the truss structure. From this, it can be concluded that the force distribution on the truss rods does not depend on the number of plates. The deflection and stiffness values of the truss structure are calculated according to the Maxwell–Mohr formula. The lower analytical estimate of the first frequency was obtained using the Dunkerley method. All mathematical transformations are performed in the Maple symbolic mathematics system. The dependence of the solution on the number of panels is obtained by generalizing a series of solutions for structures with a successively increasing number of panels. Results. The value of the first natural frequency is compared with the numerical solution obtained by analyzing the entire spectrum of natural frequencies of the vertical oscillations of the system of masses located in the truss nodes. The frequency equation is compiled and solved using the eigenvalue search operators in the Maple system. The natural frequency spectrum of the truss is analyzed.
10.4123/CUBS.107.2
69
Deflection
Pyramids
Induction
Maple
Natural frequency
Dunkerley method
Spectra of natural frequencies
https://unistroy.spbstu.ru/article/2023.108.2/
10702.pdf
RAR
RUS
10703-10703
P-3728-2017
57194112309
0000-0001-6184-2365
Tyukalov
Yury Yakovlevich
Vyatka State University
yutvgu@mail.ru
Kirov, Russian Federation
GMW-6276-2022
0000-0002-3884-874X
Ashikhmin
Stanislav Eduardovich
Vyatka State University
ashihminstanislav@gmail.com
Kirov, Russian Federation
Quickly constructed joint of precast concrete arch elements
The object of research is the design and stress–strain state of the precast concrete element’s rigid connection. For connection, composite rods are used, which are glued into prepared holes and channels. The reinforced concrete elements are connected by rods vertically and horizontally. In addition, for more uniform stresses transfer, polyurethane sheets are installed at the element’s joint. Method. To analyze the stress-strain state of the precast concrete element’s connection, a flat finite element model is used. The quadrangular physically non-linear finite elements are used for concrete modeling. For calculations, a non-linear stress-strain diagram for concrete, given in the regulatory documents for the reinforced concrete structures design, was applied. The deformation diagram of steel reinforcement is elastic-plastic. Composite rods are deforming elastically. The polyurethane sheets were modeled by nonlinear two-node finite elements working in compression and shear. Results. The quickly constructed structure for connecting precast concrete elements is proposed. A numerical analysis of the stress-strain state of such a connection is performed using the example of calculating the beam and the bridge arch. The comparison of the strength and rigidity of prefabricated and corresponding monolithic structures was made.
10.4123/CUBS.107.3
69
Precast concrete elements
Quickly constructed joint
Composite rods
Epoxy adhesive
Physical nonlinearity
Block arch
https://unistroy.spbstu.ru/article/2023.108.3/
10703.pdf
RAR
RUS
10704-10704
57219014392
0000-0003-3675-5870
Baranov
Aleksey Olegovich
Peter the Great St. Petersburg Polytechnic University
aleksey.o.baranov@yandex.ru
St. Petersburg, Russian Federation
Strakhov
Dmitry Aleksandrovich
Creep of High Strength Concrete at Elevated Temperatures
The object of research is a high-strength concrete containing silica fume, fly ash, and superplasticizer. This work aims to obtain experimental data on the creep strain of high-strength concrete at elevated temperatures and develop the expression for the description of creep strain (the specific creep strain) of high-strength concrete at elevated temperatures. Method. The creep of high-strength concrete at elevated temperatures was studied on not drying samples. Samples of high-strength concrete at the age of 90 days were heated at a rate of 10-15 ° C / hour to temperatures of 90 and 200°C and then loaded a constant load of 30% of the compressive strength of the test specimens determined at the age of 28 days. Results. The experimental studies confirmed other authors' conclusions that the creep strain increases with an increase in the temperature of heating. The creep strain at temperatures of 90 and 200°C by the end of the time under consideration was 3.6 and 4 times higher than the creep strain at a normal temperature of 20°C.
10.4123/CUBS.107.4
69
High strength concrete
Temperature
Creep
Specific creep strain
Fly ash
Silica fume
https://unistroy.spbstu.ru/article/2023.108.4/
10704.pdf
RAR
RUS
10705-10705
12039592100
0000-0003-4283-0400
Korolev
Aleksandr Sergeevich
South Ural State University
korolev@sc74.ru
Chelyabinsk, Russian Federation
Koroleva
Yulia Igorevna
Gusev
Dmitrij Denisovich
Wood (arbolit) concrete for bearing span structures
The object of research is a wood (arbolit) concrete for bearing span structures. The purpose of this work is to analyze the empirical structural, mechanical and deformative properties of constructive arbolit standard samples and reinforced beams in comparison with results of design model calculation. Method. The experimental and computational methods were used in the research. The following necessary parameters for the exploiting load calculation model were tested by the standard methods: compressive and tensile strength, compressive and tensile modulus of elasticity (MoE) of arbolit with D600-D1300 density, B1.5-B5 class. The following significant in design mechanical and deformative properties of reinforced arbolit model beams were tested by 4-point bending test: reinforcement’s stress, beams’ bending moment and deflection under bending load. Results. The experimental data have demonstrated the changing of the tensile stress in beams’ reinforcement under bending load depending on the arbolit’s MoE. The model of this dependence was determined. The application of this model has provided high accuracy of arbolit reinforced beams’ bending moment calculation.
10.4123/CUBS.107.5
69
Wood
Arbolit
Concrete
Wood Concrete
Reinforced Concrete
Strength
Elasticity
Span Structures
Constitutive models
Stress-strain curves
Static loads
https://unistroy.spbstu.ru/article/2023.108.5/
10705.pdf