Computational and Experimental Substantiation of Strengthening Reinforced Concrete Structures with Composite Materials of Power Plants under Seismic Action

Abstract

In Russia, a significant number of power facilities built in the 1960s and 1970s are located in regions where seismic effects were revised upward. This has led to an increase in the seismicity of the sites of facilities’ locations by magnitude 1–2 (MSK-64) in comparison with the data of design documentation. During the long-term operating period of power facilities, the load-bearing capacity of building structures, as a rule, decreases. This article presents the results of computational and experimental studies of reinforced concrete structures of thermal power plants and hydroelectric power plants for seismic effects in the range of magnitude 4–10 (MSK-64). The computational studies were carried out using ANSYS 16.0 software, and experimental studies were carried out on stands modeling seismic impacts with the help of hydraulic cylinders. The results of the studies showed that cracking of reinforced concrete structures without strengthening occurs at magnitude 6.0 (MSK-64) of seismic impact, and destruction occurs at magnitude 7.5. Thus, the seismic resistance of structures without reinforcement does not meet the requirements for seismic resistance, and strengthening is required. This study considers a variant of strengthening based on external composite reinforcement with CFRP. It is shown that the strengthening of structures with composite material increases their earthquake resistance up to magnitude 9–10 (MSK-64). This article presents recommendations on the CFRP strengthening of building structures of power facilities, both after receiving damage under seismic impact and in a planned manner to increase seismic resistance. The novelty of this work lies in the fact that quantitative results of increasing the seismic resistance of structures depending on the placement and number of layers of composite material are given.