ACCOUNTING FOR THE MALLEABILITY OF PRECAST REINFORCED CONCRETE STRUCTURES WHEN CALCULATING BUILDINGS USING PC SCAD OFFICE

Precast reinforced concrete structures are widely used due to many constructional advantages such as faster construction speed, lower construction cost, being environmentally friendly, higher strength, and so on. To study the seismic performance of precast reinforced concrete structures, tests on beam-to-column joints of precast reinforced concrete structures were conducted under low reversed cyclic loading. In total, four joint specimens were produced in this study, including two precast joints and two cast-in-place joints. In addition to the comparison between different types of joints, the axial compression ratio of column was adopted as the main variable in this study. Analysis was carried out on the basis of the observed joint failure mode and relationships derived from the test data such as hysteresis curves, skeleton curves, stiffness degradation curves, energy dissipation capacities, and sleeve joint strain curves. Despite the closeness of energy dissipation capacity between the precast joints and the cast-in-place joints, they had different failure modes. Precast joints feature a relatively concentrated crack distribution in which the limited number of cracks was distributed throughout the plastic zone of the beam. Cast-in-place joints feature more evenly distributed cracks in the plastic zone, especially at the later stage of the loading. The steel slippage of the precast concrete joints was found influenced by the axial compression ratio. Through this study, it is concluded that seismic resistance capacity of precast concrete joint needs to be considered in design and construction and the grouting sleeve splice could be kept away from the hinge zones when precast concrete structures were used in regions of high seismicity. The results in this study can provide a theoretical basis for seismic design of precast reinforced concrete structures, which in turn can promote the application of precast reinforced concrete structures.

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Strength Calculation Features and Tests Results on Bearing Capacity and Operational Serviceability of Hollow-Core Floor Slabs of Formwork-Free Shaping in Seismic Areas

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.a2319.059120 ◽

2020 ◽

Vol 9 (1) ◽

pp. 2219-2225

Keyword(s):

Reinforced Concrete ◽

Bearing Capacity ◽

Construction Industry ◽

Precast Concrete ◽

Concrete Strength ◽

Concrete Structures ◽

High Strength ◽

Reinforced Concrete Structures ◽

Hollow Core ◽

Wide Range

The technology of manufacturing reinforced concrete structures of long-line systems of formwork-free shaping is widely used lately in construction industry in many countries. Using this technology, industrial construction can be carried out in accordance with the requirements of modern regulatory documents that allow projects to be developed individually, and production can be reoriented in a very short time in accordance with emerging needs. This means that on the same production line it is possible to produce various structural elements of buildings and structures. Also, this technology allows the production of structures according to a wide range of products that meet operational requirements, and increases the possibility of their use in design of buildings and structures with various architectural, planning and structural decisions. Prestressed hollow-core slabs of formwork-free shaping reinforced with high-strength wire reinforcement are widely used due to the simplicity of construction and their relatively low cost, as well as their high bearing capacity, large spans and better quality. The problem of their introduction into construction industry of Uzbekistan is that the issues of designing, manufacturing and using them in construction have not been studied. Besides, the production technology of such slabs is mostly associated with the construction in non-seismic areas, and the country does not have an appropriate regulatory framework for the possibility of slab designing and production. The aim of the study is to assess the strength and serviceability of hollow-core slabs of formwork-free shaping, designed on the basis of the proposed structural solution of the slab cross section and intended for construction in seismic areas. Therefor the issues of optimizing the main reinforcement consumption (prestressed high-strength wire reinforcement) at class B30 concrete strength without using the non-stressed reinforcement (reinforcing products) for the product range under consideration were addressed. Theoretical and constructive solutions of the slabs were developed in accordance with the standard requirements of Uzbekistan KMK 2.03.01-96 “Concrete and reinforced concrete structures”, KMK 2.01.03 “Construction in seismic areas” and considering the Euronorm EN 1168-2005 requirements “Precast concrete. Hollow-core slabs”.

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ENERGY SAVINGS IN PRODUCTION PRECASTED CONCRETE

Chronos Journal ◽

10.52013/2658-7556-60-10-3 ◽

2021 ◽

Vol 6 (10(60)) ◽

pp. 13-16

Author(s):

Zaytzhan Vasidovich Kakharov ◽

Nodirbek Bakhtiyor coal Kodirov

Keyword(s):

Reinforced Concrete ◽

Energy Savings ◽

Precast Concrete ◽

Concrete Structures ◽

Energy Resources ◽

Reinforced Concrete Structures ◽

Excessive Consumption ◽

Save Energy

This article discusses the problems of energy savings at enterprises for the production of precast concrete. The rational consumption of energy in the production of prefabricated reinforced concrete is considered, the costs of energy spent on the production of cement and reinforcement are taken into account, excluding excessive consumption of fuel, which leads to energy savings. To save energy resources, a bench technology for manufacturing prefabricated reinforced concrete structures was considered at the enterprises.

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Design of precast reinforced concrete structures of frame buildings: a new set of rules

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.04.04-09 ◽

2019 ◽

pp. 4-9 ◽

Cited By ~ 1

Keyword(s):

Reinforced Concrete ◽

Concrete Structures ◽

Reinforced Concrete Structures ◽

Building Frames ◽

Fine Grained ◽

Rigid Frame ◽

Floor Slabs ◽

Frame Buildings ◽

Spatial System ◽

Precast Elements

Currently, prefabricated reinforced concrete structures are widely used for the construction of buildings of various functional purposes. In this regard, has been developed SP 356.1325800.2017 "Frame Reinforced Concrete Prefabricated Structures of Multi-Storey Buildings. Design Rules", which establishes requirements for the calculation and design of precast reinforced concrete structures of frame buildings of heavy, fine-grained and lightweight structural concrete for buildings with a height of not more than 75 m. The structure of the set of rules consists of eight sections and one annex. The document reviewed covers the design of multi-story framed beam structural systems, the elements of which are connected in a spatial system with rigid (partially compliant) or hinged joints and concreting of the joints between the surfaces of the abutting precast elements. The classification of structural schemes of building frames, which according to the method of accommodation of horizontal loads are divided into bracing, rigid frame bracing and framework, is presented. The list of structural elements, such as foundations, columns, crossbars, ribbed and hollow floor slabs and coatings, stiffness elements and external enclosing structures is given; detailed instructions for their design are provided. The scope of the developed set of rules includes all natural and climatic zones of the Russian Federation, except seismic areas with 7 or more points, as well as permafrost zones.

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Improvement Of Curvilinear Diagrams Of Concrete Deformation

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.08.99-104 ◽

2019 ◽

pp. 99-104

Keyword(s):

Reinforced Concrete ◽

Peak Load ◽

Experimental Studies ◽

Concrete Structures ◽

Deformation Model ◽

Reinforced Concrete Structures ◽

Significant Difference ◽

Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

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