Experimental Measurement And Theoretical Analysis On The Temperature Stress Of The Main Buliding Super-long Structure

In recent years, in order to meet the functional requirements of the building, super-length reinforced concrete structures are used more and more. These structures generally set no or fewer expansion joints, and their length is far beyond the standard limit values of expansion joint spacing. The super-long concrete structures under temperature load will have a greater deformation and stress, which lead to structural crack damage and affect the normal use of the building. However, most of super-long structures do not appear to damage due to thermal stress. Therefore, thermal stress is worthy to research in super-long concrete structure design.The engineering background of this paper is the super-long main power plant in JingDeZhen. This paper analyses the temperature stress of the super-long main plant by experimental measurements, and combined with the theoretical analysis and validation by finite element method. The main content is as follows:1. Firstly, this paper researches the mechanical and physical properties of plain concrete and reinforced concrete, proposes the concept of a reinforced concrete beam equivalent elastic modulus and the equivalent coefficient of thermal expansion, and establishes the mechanical and physical model of the reinforced concrete; what’s more, the expression is deducted about the equivalent elastic modulus and the equivalent coefficient of thermal expansion of the reinforced concrete beam, with the consideration of the material’s coordination of longitudinal deformation. Secondly, this paper also establishes a reinforced concrete beam bending model, gives the stress calculation expressions of concrete and reinforced under the load of temperature, axial force and bending moment.2. Specimens of plain concrete beams and reinforced concrete beams are made, and the measuring device is set up in the laboratory. So the equivalent elastic modulus and the linear expansion coefficient of reinforced concrete beams and plain concrete beams could be measured by the experiments.3. The thermal stress and deformation of the super-long plant in Jingdezhen are monitored in real time. A lot of experimental data about the changes of temperature, strain and stress is obtained, through the sensors of temperature, strain and stress laid in the plant and two MCU-32data loggers installed.4. Using the finite element software Midas/Gen and the material parameters measured by the experiments above, the finite element model of the actual long concrete frame structure is established and the deformation and mechanical properties of the long structure under temperature loading are analyzed. The finite element results are compared with the experimental results, and the results agree well, which verifies the reliability of the material parameters measured.This paper makes the practical engineering structure as the research object, and combines theoretical analysis with experimental measurement. The work has certain reference value for the study of the thermal stress of the super-long concrete structure.