The special features of the deformation for the bearing building constructions with composite reinforcement

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1 Available online at Procedia Engineering 48 (2012 ) MMaMS 2012 The special features of the deformation for the bearing building constructions with composite reinforcement H. M. Kuziomkina a,.. Shimanovsky b *, V. I. Yakubovich b a Gomel Training Center for Management and Professionals, Gomel, , Belarus b Belarusian State University of Transport, Gomel, , Belarus Abstract The finite-element modeling of building constructions with the glass-fiber reinforced plastic and reinforcement on the base of basalt fibers has been carried out. The friction between reinforcement and composite matrix has been taken into account. The analysis of the stressstrain condition for the loaded beam with various physical characteristics of the reinforcement has allowed to define the elasticity modulus of the reinforcement when its relative displacement inside the matrix stops The Authors. Published by Elsevier Ltd Published by Elsevier Ltd.Selection and/or peer-review under responsibility of the Branch Office of Slovak Metallurgical Society at Faculty Selection of Metallurgy and/or peer-review and Faculty under of Mechanical responsibility Engineering, of the Branch Technical Office University of Slovak of Košice Metallurgical Open access Society under at CC Faculty BY-NC-ND of Metallurgy license. and Faculty of Mechanical Engineering, Technical University of Košice. Keywords: fiber composite, finite-element modeling, stress-strain condition, interphase friction. 1. Introduction In recent years the specialists have paid their attention to the needs of the construction field in composite non-metal materials that allow to increase the energy efficiency, corrosive resistance and longevity of constructions and buildings in whole. Owing to the introduction of innovative decisions, improvement of technological processes and application of new raw material components the composites have gained new qualities and performance characteristics and the technical parameters of the materials have allowed expanding the area of their application [1, 2]. The researchers consider the possibilities of applying the glass-fiber plastic for the reinforced concrete. The comparative tests for concrete beams with steel and glass-fiber reinforcement have been carried out. It has been determined that the bearing capacity of the beams reinforced with glass-fiber plastic at short-term loading is very close to the bearing capacity of the reinforced concrete beams. But the comparative fracture strength of the beams reinforced with glass-fiber plastic is higher. So it is recommended to use the glass-fiber reinforced plastic for the reinforcement of the constructions used in the conditions with the quick development of steel reinforcement corrosion. The required properties of these constructions are obtained due to high mechanical characteristics of non-metal reinforcement. Nowadays the technologies along with glass-fiber plastic allow to produce basalt-plastic high-modular reinforcement with the initial elasticity modulus up to 200 GPa and tensile strength up to 1850 MPa that allows to provide the constructions with all necessary strength and operational characteristics. The main physical and mechanical characteristics for composite reinforcement show that: * Corresponding author. Tel.: ; fax: address: tm.belsut@gmail.com Published by Elsevier Ltd.Selection and/or peer-review under responsibility of the Branch Office of Slovak Metallurgical Society at Faculty of Metallurgy and Faculty of Mechanical Engineering, Technical University of Košice Open access under CC BY-NC-ND license. doi: /j.proeng

2 H. M. Kuziomkina et al. / Procedia Engineering 48 ( 2012 ) the calculated resistance to the composite reinforcement break is 1,5-3,0 times higher than the one for the steel reinforcement (Table 1); it shows high corrosive resistance to the aggressive mediums (acid, alkali, salt, sulphureous gas, ammonia water, etc.); its specific weight is 4 times lower than the steel reinforcement (the load on the base is increasing); the coefficients of the linear temperature deformations for the reinforcement and concrete are practically the same (the crack formation in constructions is decreasing); it is a non-conductor; its heat conductivity is 100 times smaller than the steel one (the absence of bridges of cold in the constructions); it doesn t lose its properties under the influence of low temperatures; it is radiolucent (doesn t create shadow effect); it is magnet-inertial (the changes of the construction strength properties from the influence of electromagnetic and electric fields are impossible); the length of the reinforced rod is unlimited (the equipment allows to meet the length requirements of any project); the reinforcement of 4-8 mm may be transported in coils ( m, coil diameter is 0,8 2,0 m depending on the reinforcement length), after uncoiling and cutting the rods are linear; there is the absence of welding. Table 1. Characteristics of composite reinforcement Characteristics Reinforcement Glass-fiber plastic Basalt High-modular Tensile strength, MPa Elasticity modulus, MPa up to Heat conductivity, Watt/m K 0,5 0,35 0,35 In the post-soviet territory up to this date there have been no articulate normative base on the composite reinforcement application and system methodology of the material and its analogs adoption. In the Republic of Belarus the home-produced glass-fiber reinforced plastic of periodic profile requirements are set in standard STB Glass-fiber plastic reinforcement. Technical requirements, but in recent decades this construction material has undergone the significant changes not only in its physical-mechanical and performance characteristics and but in the production techniques (there are several of them) and fields of application too. After the systematization and analysis of the research results for the operating conditions of the composite constructions in service the design of domestic codex TCP containing the ideas of properties and possibilities of non-metal reinforcement application is being planned. Nowadays, among the countries of CIS, Russia has got the best practical skills and experience in glass-fiber reinforced plastic design and application. The computation methods for the reinforced concrete constructions with the characteristics of non-metal reinforcement taken into account are being used when designing the composite-concrete constructions. The American Institute of Concrete has created ACI 440.1R-06 Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars, and the European International Federation on Concrete Reinforcement, Group 9.3 published the document FIB Bulletin 40 FRP reinforcement in RC structures. 2. Finite element model A great number of researchers are modeling the reinforcement with thin rods taking only longitudinal loads [3 6]. Firstly, it does not allow to estimate properly the stresses in the areas of reinforcement-composite matrix interaction because it does not take into account the irregularity of stress distribution along the reinforcing section, secondly, it does not give the possibility to define the influence of friction between the contacting composite phases on its stress-strain condition. To estimate for sure the stresses in the areas of reinforcement-composite matrix interaction and take into account the influence of friction between the contacting composite phases on its stress-strain condition it is necessary to make a model of the reinforcement with 3D deforming solid body as it has been done in our previous works [7 9]. In this paper with the view of defining the differences in the deformation of composite-concrete and reinforced concrete constructions a number of computations for the deformation of the cantilever beam 1 m long and with cm rectangular cross-section with longitudinal asymmetrical reinforcement supported by five steel rods of 2 cm in diameter have been made. It has been accepted that the elasticity moduli of matrix material and reinforced steel are 27 and 200 GPa

3 348 H. M. Kuziomkina et al. / Procedia Engineering 48 ( 2012 ) respectively. For reducing computations for the action of the load symmetrical to the vertical surface of beam symmetry the model equal to the half of the real beam cut by the longitudinal vertical surface has been created. Figure 1 shows the position of reinforced rods in the matrix material. Fig. 1. The scheme of beam volume subdivision. The reinforcement and composite matrix have been modeled by twenty-nodal prismatic finite elements. The necessity of defining the position of internal slipping sites has caused the use of contact elements with the sizes not longer than 2 cm along the reinforcement. It has allowed to define with high accuracy the position of internal slipping sites. Therefore the total number of model finite elements is The computations have been made in such a way that there is Coulomb friction between the composite materials. Besides, to improve calculation convergence the presence of cohesion 100 Pa has been taken into account. The beam loading has been done by the gravity forces of its elements and uniformly distributed pressure of 170 kpa applied to the upper cut. 3. Results Figures 2 6 show the dependences of interphase interaction parameters on the elasticity modulus for glass-fiber reinforced plastic. Line 1 in these figures is the upper central reinforced rod, 2 the upper siding one, 3 the lower one (see Fig. 1). The calculated results demonstrate practically the monotonous change of the analyzed parameters for the upper rods. At the same time when the elasticity modulus for the reinforcement is 68,5 GPa for the lower rods there is the jump in characteristics caused by the type of changes for the relative displacement of the reinforcement and concrete. When the elasticity modulus is lower than 68,5 GPa the relative displacement of the reinforcement and concrete is practically absent. It is defined only by the deformation of the area contacts. Meanwhile at high values of the elasticity modulus there is the displacement of reinforcement relative to concrete that leads to the significant increase of friction stresses and the gap between the composite phases. The analysis of the construction deformation in whole has shown that its vertical deformations changes are insignificant.

4 H. M. Kuziomkina et al. / Procedia Engineering 48 ( 2012 ) Gap Distance, m 0,8 0,6 0,4 0,2 0 Fig. 2. The dependence of maximal gap between the reinforcement and matrix on the elasticity modulus for glass-fiber reinforced plastic. 0,25 Contact Penrtration, m 0,2 0,15 0,1 0,05 Fig. 3. The dependence of maximal penetration of composite materials on the elasticity modulus of rebars. 1,7 Contact Pressure, MPa 1,4 1,1 0,8 0,5 Fig. 4. Maximal contact pressure on glass-fiber reinforced plastic.

5 350 H. M. Kuziomkina et al. / Procedia Engineering 48 ( 2012 ) Contact Friction Stress, kpa Fig. 5. The dependence of maximal contact friction stress on the rebars elasticity modulus. Contact Sliding Distance, m Fig. 6. The dependence of maximal relative displacement of the reinforcement and concrete on the elasticity modulus of glass-fiber reinforced plastic. 3. Conclusions Generally, the deformation characteristics of composite-concrete and reinforced constructions have turned out to be very close and prove the experimental results received by other researchers. But the suggested approach based on the finiteelement construction modeling allows to prognosticate with high accuracy the construction characteristics before its production. Received results show the necessity of ribbing the surface of high-modular reinforcement. Acknowledgements The work is supported by the Belarusian State Program of Scientific Research. References [1] Vlasov, V.., Bertov, V. M., Dolgatchev, A. D., Donov, A. V., Lugovoi A. N., The usage of concrete beams with steel and glass-fiber plastic reinforcement. News of All-Russian Scientific-Research Institute of Hydraulic Engineering named after B. Ye. Vedeneev 244, p. 33. [2] Blaznov, A. N., Volkov, Yu. P., Lugovoi, A. N., Savin, V. F., Prognostication of long-term strength for glass-fiber reinforced plastic. Mechanics of composite materials and constructions 9, p [3] Finite element modeling of reinforced concrete structures strengthened with FRP laminates: Final Report, United States Department of Transportation, Federal Highway Administration, 2001.

6 H. M. Kuziomkina et al. / Procedia Engineering 48 ( 2012 ) [4] Fanning, P., Nonlinear models of reinforced and post-tensioned concrete beams. Electronic Journal of Structural Engineering 2, p [5] Limkatanyu, S., Spacone, E., Reinforced concrete frame element with bond interfaces. Part 1: Displacement-Based, Force-Based and Mixed Formulations. Journal of Structural Engineering 128, p [6] Brožovský, J., Modelování fizikálnè nelineárnino chování železobetonovych konstrukci: Teze diserta ni prace, Brno. [7] Pleskachevskii, Yu. M., Shimanovskii, A. O., Yakubovich, V. I., Kuzemkina, G. M., Modelling of mechanical interaction of reinforcement with composite matrix. Mechanics of machines, mechanisms and materials 1, p. 67. [8] Kuziomkina, H. M., Yakubovich, V. I., Shimanovsky, A. O., Pleskachevskii, Yu. M., The Influence of Cohesion Between the Materials on Stress-Strain Condition of Reinforced Composite, Proceedings of the XXXIX Summer School Conference Advanced Problems in Mechanics, APM 2011, pp [9] Pleskachevskii, Yu. M., Shimanovskii, A. O., Kuzemkina, G. M., Finite-Element Modeling of the Interaction of Reinforcement with Concrete Matrix. Mechanics of Composite Materials 44, p. 209.