Construction Mechanics                                                                                
 DOI: http://www.dx.doi.org/10.24866/2227-6858/2020-1-16
 Vasilyev A.
 ALEXEY VASILYEV, Candidate of Engineering Sciences, Associate Professor,
Department of Technical Disciplines, ORCID 0000-0001-7783-0000, e-mail: vasil-grunt@mail.ru
Sholom-Aleichem Priamursky State University
70a, Shirokaya St., Birobidzhan, Russia, 679015   

Hollow plates:
calculations as to the second group of limit states

Abstract: During reconstruction and modernization of industrial buildings, due to increased operational loads in the premises, it may be necessary to strengthen the load-bearing elements of the building, hollow core slabs in particular. In order to simplify the calculations, hollow slabs are assumed as core elements of T-section or I-section. In this case, the width of the beam ribs is reduced with due consideration for the voids inside the plate. In this work, the deformative and bearing capacity of hollow core slabs reinforced was studied in several ways. The calculations were performed with allowance for the physical nonlinearity of the samples and with a gradual increase of load till complete loss of bearing capacity. At the same time, in the stretched zone of the plate, the cross-section gradually degraded till formation of a plastic hinge and achievement of the yield strength of reinforcement bars. For modeling and calculations, the ANSYS software package was used. The results were recorded at all stages of stress-strain state. Plates were presented both in the form of I-beams, and with a natural cross-sectional shape. At the same time, several types of plate reinforcement were considered: padding, additional reinforcing, combined method (additional reinforcing together with a padding). It was shown that, for various types of reinforcement, the cracking moment for plates in kind occurs later. It is noted that the particular shape of cross section (I-beam or natural) affects the results of appearance of the first cracks, as well as the magnitude of the maximum deflections, at different stages of stress-strain state and different loading stages. Percent deviations of rigidity of I-beam sections from sections of natural shape for various types of reinforcement were obtained. The original results can be used to update the respective parts of engineering structure design theories, and for substantiation of calculations at reconstruction of buildings and structures. 
Keywords: hollow core slabs, cross-sectional shape, cracking, stress-strain state, deflection.

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