Design of concrete canoe reinforced with composite reinforcement

Abstract

To participate in international competitions on concrete canoe among students at the Department of concrete and masonry structures KNUBA has been designed and manufactured concrete canoe reinforced composite reinforcement. The design of the canoe was modeled and calculated in the PC «LIRA-SAPR».The problem of this article is to determine the optimal thickness of the walls of the canoe, the composition of basalt fiber and the scheme of reinforcement of the canoe to ensure its strength and crack resistance, as well as sufficient buoyancy. To achieve the minimum weight of the canoe it is customary to use non-metal reinforcement.The dimensions of the wooden canoe were accepted for the concrete canoe project. In terms of canoeing has a lenticular shape. The total canoe length is 4,3 m and maximum width is 900 mm. The minimum height of the board is 400 mm. According to the accepted manufacturing technology, the walls and canoe bottom have a three-layer construction, consisting of an inner and outer layer of basalt fiber concrete 3… 5 mm thick and an inner layer of expanded polystyrene foam 10 mm thick. To strengthen the most intense zones in the outer layer of basalt fiber reinforced carbon mesh. In the transverse direction, transverse ribs (frames) made of expanded polystyrene 20 mm thick and 20… 30 mm high are arranged. Along the upper sides of the sides, along the keel rib and along the frames, basalt reinforcement with a diameter of 6 mm (2 rods) was installed.To calculate the canoe, its calculation model was developed in the LIRA-CAD PC. The canoe model is made in the form of a shell made of flat triangular finite elements. Linear elements were also added to model the basalt reinforcement. Linear and flat elements are rigidly connected at the nodes.According to the manufacturer, the modulus of elasticity of the rod reinforcement is 70∙103 MPa, and the temporary tear resistance - 1100 MPa, density -1,9 g/m3. The basalt fiber was adopted with a thickness of 20 mkm and a length of 50 mm.Two-component waterproofing solution SILTEK V-33/E-33 was used as the concrete matrix. The amount of basalt fiber was 3%. To determine the characteristics of basalt fiber concrete test cubes with an edge of 75 mm and samples-"eight" were made. As a result of the test, the tensile strength of basalt fiber was compressed at 8.4 MPa and the axial tensile strength was 1.8 MPa.The obtained design characteristics were used to introduce finite element stiffnesses.Canoe loading was applied on its own weight, the weight of two 80 kg paddles and hydrostatic water pressure.As a result of the calculation, mosaics of stresses were obtained. They showed the most intense zones, which were reinforced with carbon mesh.After experimental and numerical studies, we came to the conclusion that non-metallic composite reinforcement can be used in the construction of light structural elements. Such structures are absolutely not susceptible to corrosion. In the future, it is necessary to investigate structural elements that are used in the aquatic environment, such as pontoons, platforms for waterfront homes and more.