The efficiency of composite steel and concrete frame with flat slabs for medium height buildings
Students Name: Nikolaiev Roman
Qualification Level: master (ESP)
Speciality: Building and Civil Engineering
Institute: Institute of Civil Engineering and Building Systems
Mode of Study: full
Academic Year: 2022-2023 н.р.
Language of Defence: ukrainian
Abstract: Nikolaiev R.V., Kushchenko V.M. (supervisor). Efficiency of composite steel and concrete frame with flat slabs for buildings of medium height. Master’s qualification thesis. ? Lviv Polytechnic National University, Lviv, 2023. Extended annotation At present, the following structural solutions are widely used in the construction of medium-story buildings (up to 9 floors): reinforced concrete frame monolithic, steel frame with a combination of monolithic reinforced concrete floor, steel frame with steel reinforced concrete floor. Among them, boltless frames are considered one of the most effective. The effectiveness of these structural solutions in monolithic reinforced concrete is due to the minimization of the construction height of the ceilings. However, a negative aspect of buildings made of monolithic reinforced concrete is the need for technological interruptions for hardening and strengthening of concrete [1]. In many countries of the world, steel-reinforced concrete accounts for the majority of construction structures that are used for the construction of frame buildings and structures in a steel frame. The combination of a steel-concrete frame with beamless floors combines all the positive characteristics of both steel and reinforced concrete building structures. It should also be noted the prospect of using steel-reinforced concrete frames for medium-rise buildings, which overcomes the above-mentioned disadvantage of monolithic reinforced concrete frames - due to the reduction of technological interruptions for hardening and gaining the strength of concrete. The effectiveness of frames of this type is due to the combined use of supporting steel and reinforced concrete structures, and in this case, steel is used to create the frame of the building, and monolithic reinforced concrete structures are used in the form of ceilings, which are included in the cooperative work with steel beams and crossbars using anchors of various types [2 , 3, 4]. However, the negative properties of composite frames also include a sufficiently large construction height of the ceilings, since in this case the monolithic reinforced concrete slab rests on steel beams from above. Along with the above, it should be noted the effectiveness of reinforced concrete structures with external strip reinforcement, which are described in the works of F. E. Klymenko, Z. Ya. Bliharsky and other authors [3, 5, 6]. The use of external strip reinforcement allows to reduce to a greater extent the structural height of reinforced concrete elements that work for bending. Works [3, 5, 6] considered the possibility of using steel or tubular concrete columns in mixed frames in which the spatial frame of the building is formed as a result of a rigid connection of a monolithic reinforced concrete slab with steel columns of a closed section (round or rectangular). The patent for a utility model [3] presents the structural form of a unit of rigid connection of a monolithic reinforced concrete slab with a pipe-concrete column of round section, in which the principle of external strip reinforcement is applied. The specified structural solution overcomes the main disadvantages of traditional structural systems made of steel-reinforced concrete, because they allow to obtain a spatial composite frame according to the boltless scheme. Thus, the question of researching the effectiveness of boltless composite frames using strip reinforcement is relevant for modern construction. The object of the study is steel-reinforced concrete frames of medium-rise buildings. The subject of the study is the effectiveness of boltless steel-reinforced concrete frames with external tape reinforcement for medium-rise buildings. According to the subject and object of the research, the goal and task of the research were formulated. The purpose of the work is the development of a new structural system of a spatial steel-reinforced concrete boltless frame with the use of external tape reinforcement. Job tasks: 1. Development of a new structural scheme of a boltless steel-reinforced concrete frame with external tape reinforcement of floor slabs for medium-rise buildings. 2. Modeling and analysis of the stress-deformed state of the design of the external tape reinforcement and monolithic reinforced concrete floor in the composition of the boltless frame. 3. Determination of the area of rational application of steel-reinforced concrete boltless frames with elements of external tape reinforcement. Scientific hypothesis - the combination of closed-section steel columns with monolithic reinforced concrete floors in combination with external strip reinforcement allows to obtain an effective spatial boltless steel-reinforced concrete frame Key words: steel-reinforced-concrete frame, boltless floor, beams, strip reinforcement, stressed deformed state, . List of used literary sources: 1. Storozhenko LI. Steel-reinforced concrete structures. Research, design, construction, operation / L.I. Storozhenko, V.M. Surdin, V.I. Sfimenko, V.I. Verbytskny - Kryvyi Rih: KTU, 2007. - 448 p. 2. Klymenko F.E. Reinforced concrete structures with external strip reinforcement. Kyiv "Builder". - 1984. - 83 p. 3. Storozhenko L.1. New constructive solutions of beamless prefabricated ceilings of multi-story buildings / L.I. Storozhenko, D.A. Yermolenko, O.V. Nyzhnyk,// Poltava: PNTU. 2014. - 5 p. 4. DBN V.2..6 – 160: 2010. Steel-reinforced concrete structures. Substantive provisions. Kyiv. – Ministry of Regional Construction of Ukraine 2010. – 81 p. 5. Kortushov P.G. Calculation of junction nodes of monolithic reinforced concrete structures with tubular concrete racks // Collection of scientific articles "Problems of theory and practice of reinforced concrete".-Poltava, 1997.-S. 256-259. 6. Famulyak Yu.E., Klymenko F.E., Barabash V.M. The strength of reinforced concrete beams with end anchors under the action of transverse forces. - Lviv: Lviv State Agrarian University, 2006. - 117 p.