Stress-Strain State of a Precast Monolithic Bent Element

Abstract

Despite the high level of development of the theory of calculation of reinforced concrete structures in the Russian Federation, the methods of calculation of prefabricated monolithic structures proposed by regulatory documents require appropriate clarifications related to the design features of these elements. Such features include different values of the ultimate deformations and stresses of concrete, different physical properties of precast and monolithic concrete, the need to ensure joint deformation of different- aged concrete relative to each other, and more.

Having considered the design features of the formation of the stress-strain state of a prefabricated monolithic structure, the authors of the article propose a method for calculating a prefabricated monolithic bent element, which allows to evaluate the stress-strain state and determine the bearing capacity of a prefabricated monolithic structure. The proposed methodology is based on the well-known criterion of exhaustion ofload-bearing capacity,laid down, among other things, in the regulatory documents of the Russian Federation - the achievement of maximum deformations of concrete and/ or reinforcement.

The description of the stages of the stress-strain state of a precast-monolithic structure, in which precast and monolithic concrete are simultaneously included in the deformation process, is proposed. At the same time, the given method allows to calculate and evaluate the stress-strain state (SSS) at all stages of SSS, and both in the case of incomplete and complete passage of the normal crack of the assembled part of the element.

A comparative analysis of the calculation results with the data obtained during experimental studies (both on deformations and the bearing capacity) is performed.

The factors affecting the joint deformation of mixed- growth concretes are indicated, and design solutions allowing joint work (to exclude mutual displacement) of precast and monolithic concretes relative to each other are given.