노후 육상풍력터빈의 부분적 리파워링을 위한 강관 매입형 확대기초의 비선형 구조해석
Nonlinear Structural Analysis of Embedded Ring Foundations for Partial Repowering of Aging Onshore Wind Turbines
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초록
In order to reuse the support structures of aging wind turbines, the structural integrity of pedestals that transfer loads from a tower to a support structure must be properly evaluated. In this study, a numerical analysis model of embedded ring foundations was established by analyzing the failure cases and integrity evaluation cases of embedded ring foundations, which were widely applied to onshore wind farms in Korea. In addition, nonlinear structural analysis was carried out to analyze the effects of (a) boundary conditions, (b) concrete material properties, (c) the presence or absence of rebars, and (d) the shear stiffness of radial rebars through a steel ring. As a result of the analysis, (1) the boundary condition has the greatest effect on the structural behavior and the effective area of the foundation. (2) Due to the low stress state of concrete, the effect of concrete material properties on ultimate strength is insignificant. (3) When the compressive strength of concrete is larger than the ultimate strength, the effect of rebars on structural behavior and load resistance capacity is insignificant. (4) The dowel action of the radial rebar has a relatively large effect on concrete stress.
Abstract
In order to reuse the support structures of aging wind turbines, the structural integrity of pedestals that transfer loads from a tower to a support structure must be properly evaluated. In this study, a numerical analysis model of embedded ring foundations was established by analyzing the failure cases and integrity evaluation cases of embedded ring foundations, which were widely applied to onshore wind farms in Korea. In addition, nonlinear structural analysis was carried out to analyze the effects of (a) boundary conditions, (b) concrete material properties, (c) the presence or absence of rebars, and (d) the shear stiffness of radial rebars through a steel ring. As a result of the analysis, (1) the boundary condition has the greatest effect on the structural behavior and the effective area of the foundation. (2) Due to the low stress state of concrete, the effect of concrete material properties on ultimate strength is insignificant. (3) When the compressive strength of concrete is larger than the ultimate strength, the effect of rebars on structural behavior and load resistance capacity is insignificant. (4) The dowel action of the radial rebar has a relatively large effect on concrete stress.
참고문헌 (10)
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- Ollgaard, J. G., "Shear strength of stud connectors in lightweight and normal weight concrete", AISC Engineering Journal, 71, pp.55~64 (1971)
- Support structures for wind turbines, "DNV GL", DNVGL, ~, pp.DNVGL-ST-0126 (2016)