On the issue of modeling thermal stresses during concreting of massive reinforced concrete slabs

Abstract

On the issue of modeling thermal stresses during concreting of massive reinforced concrete slabs

Nesvetaev G.V., Koryanova Y.I., Chepurnenko A.S., Sukhin D.P.

Incoming article date: 22.04.2022

The expediency of using modeling using the finite element method to study the influence of certain prescription-technological factors on the resulting temperature fields and temperature stresses during the construction of massive foundation slabs is substantiated. A simplified method for determining thermal stresses based on the reduction of a three-dimensional problem to a one-dimensional one based on the hypothesis of flat sections is considered. The dependence is proposed and the quantitative values ​​of the parameters for calculating the kinetics of heat release of concrete in the temperature-shrinkage block are substantiated. As a result of the implementation of a numerical experiment on the influence of the duration of breaks between overlapping layers, the temperature of the environment and the concrete mixture, the class and kinetics of concrete hardening, and heat transfer parameters, the dependences of the level of tensile stresses on these factors over time were obtained. It is shown that when developing technological regulations for concreting, the determination of technological parameters (the intensity of laying the mixture, the thermal resistance of the formwork, the arrangement of working joints, etc.) is impossible without taking into account the kinetics of concrete hardening, determined by the prescription features of concrete mixtures.

Keywords: massive monolithic structures, temperature fields and stresses, prescription-technological factors, heat release of concrete, stress-strain state