SUBSTANTIATION OF THE CHOICE OF THE CALCULATION SCHEME OF THE STEEL REINFORCED CONCRETE STRUCTURE FOR THE EFFECTS OF PERIODIC THERMAL INFLUENCES

Visnyk LNAU: Architecture and Farm Building 2017 №18: 97-103

SUBSTANTIATION OF THE CHOICE OF THE CALCULATION SCHEME OF THE STEEL REINFORCED CONCRETE STRUCTURE FOR THE EFFECTS OF PERIODIC THERMAL INFLUENCES

A. Hrytsevych
Lviv National Agrarian University

https://doi.org/10.31734/architecture2017.18.097

Annotation

Intensive development of industrial construction with the use of modern technologies is closely connected with the use of new types of materials mainly of composite structures. Composite reinforced concrete engineering systems can be included there. The process of thermal testing and operation of reinforced concrete elements of building constructions and engineering systems is accompanied by external influence of various physical nature. However, non-uniform thermal actions are the most important from a practical point of view.

The temperature field variation in the inhomogeneous system causes the occurrence of thermal stresses that are able to cause the construction destruction as well as the loss of its efficiency.

Modern estimation methods of state of concrete and reinforced concrete structures are based on the model that treats them as a monolithic monogenic continuum with some averaged properties [1-3]. However, such an estimation methodology of the efficiency of reinforced concrete structures is very close and contains a number of significant simplifying assumptions.

Investigation of temperature fields and their stresses in steel-concrete elements of structures is an important problem of technological thermomechanics and it is necessary for solving a number of technological problems of various branches of modern technology, especially the construction industry. Despite the fact that Portland cement is a part of qualitative and versatile building materials, there is still a necessity to improve their structural properties such as strength, density, plasticity and endurance.

The behavior of heterogeneous media is studied from the point of view of flow mechanics. However, it is very difficult to take into account all the effects peculiar to composites that contain a large number of discrete phases within this type of mechanics. Therefore, idealized geometric models of heterogeneous systems are used and they enable to obtain analytical estimations of the macroscopic properties of non-uniform continuums through the geometric and physical characteristics of their phase constituents. It should be noted that even the investigation of temperature fields is an important independent technical task (the issue of thermal stability of the walls and freezing of the foundations of buildings and constructions).

Key words

thermal conductivity, heterogeneous environment, steel reinforced concrete structure, periode change in time, external temperature environment temperature, homogenization, operational reliability of structural elements

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