海上风电大尺度预应力筒型基础结构预应力优化设计

应用于海上风电工程中的大尺度筒型基础为钢筋混凝土结构,中间的弧形过渡段为塔筒和筒基之间的传力过渡段,因而对其传力性能和防腐性能有着较高的要求.为优化大尺度筒型基础过渡段的传力性能和防腐性能,对基础上部弧形过渡结构施加预应力.借助有限元软件ABAQUS,对施加有预应力的大尺度筒型基础结构进行数值模拟分析.在极限荷载、交变荷载及相同的边界条件下,在弧形过渡结构上作用不同大小的有效预应力,计算各种情况下的弧形过渡结构和基础环梁受力特征,通过其主拉应力、主压应力的峰值以及主拉应力大于2,MPa的分布区域来分析结构受力性能.经过计算分析可知:弧形过渡结构在有效预应力增加到800,MPa时,继续增大预应力值,过渡结构抗裂性能趋于稳定;基础环梁在作用600,MPa有效预应力情况下,其抗裂性能最佳.在基础预应力设计中,应综合考虑两部位的受力变化趋势.有限元模拟的是有效预应力,在实际工程中,除考虑各种预应力损失外,应适当增加张拉控制应力.

Optimal Design for Prestress of Large-Scale Bucket Foundation for Offshore Wind Turbine

The large-scale bucket foundation for offshore wind farm is of reinforced concrete structure. The curved- transition section between the tower and the bucket foundation is the load transition of the foundation. Thus good per- formance of its load transition and corrosion resistance is required. In order to improve the performance of its load transition and corrosion resistance, the curved-transitional structure of the foundation is prestressed by making the stress analysis for the local prestressed large-scale bucket foundation with the finite element software ABAQUS. Un- der the same boundary conditions of applying limit load and cyclic load, different effective prestressed values are exerted on the curved-transitional structure of the foundation, with three factors that contain the maximum principal stress, the minimum principal stress and the area where the maximum principal stress is greater than 2 MPa for the foundation, to analyze the changes of mechanical behavior to the foundation and draw the rational prestress values. After calculation, when the prestress value reaches 800 MPa, with the increase of the prestress value, the crack resistance performance of the curved-transitional structure becomes stabilized; when 600 MPa is applied to the curved-transitional structure, the crack resistance of the ring beams around the foundation achieves the best perform- ance. When prestress design for the foundation is being made, the different performances of the two aspects should be considered. But the finite element software simulates the effective prestress values on the foundation, while in the actual engineering, besides considering the various prestress loss, operators should increase the tension control stress properly.