Concrete design principles are mostly well defined and documented in the literature, including reference standards. Clause 7 provides additional or more detailed rules and guidance that are specific to onshore wind turbine towers and foundations and complement the more general requirements of existing standards.

混凝土构件设计的一般规定可以参考现有的文献和标准，作为对这些出具一般要求的文献和标准的补充，本章对陆地风电机组的塔架和基础提供了更详细的规则和指导。

Clause 7 provides requirements in the form of general statements and analytical methods. Guidance on acceptable calculation methods which are considered to comply with the requirements are presented in Annex H to Annex K.

第七章以一般陈述和分析方法的形式提出要求。应考虑可接受的指导计算方法和附录H~附录K给出的要求是一致的。

The reference standard shall comply with the basic principles of IEC 61400-1 or IEC 61400-2 and should be in compliance with ISO 19338. The reference standard shall give the principles required for the design against fatigue for all possible failure modes.

参考标准应符合国际规范 IEC 61400-1、 IEC 61400-2 和 ISO 19338 的基本要求，并包括混凝土构件不同疲劳失效模式下的设计规定。

The partial safety factors given in IEC 61400-1, IEC 61400-2 and in 5.4 as well as the following factors shall be applied for design of concrete structures as the minimum requirements. The safety factors from the selected reference standard should be considered, and they shall fulfil at least the target reliability of IEC standards.

IEC 61400-1, IEC 61400-2以及5.4节给出的分项安全系数应作为混凝土结构设计中的最低要求。采用的参考标准中的安全系数也应该考虑，并且至少满足IEC标准的目标可靠度。

For the general verifications at the SLS, the partial safety factor for the materials can in general be taken as γ M = 1 , 0 \gamma _{M}=1,0 γM​=1,0.

正常使用极限状态下的验算可取材料分项系数为 γ M = 1.0 \gamma _{M}=1.0 γM​=1.0 。

In the case of prestressed concrete in ULS, the prestress losses and possible variations in the prestress shall be considered. The variations shall be considered by applying the least favourable of the factors γ f , p r e s t r e s s , f a v o u r a b l e \gamma _{f,prestress,favourable} γf,prestress,favourable​ and γ f , p r e s t r e s s , u n f a v o u r a b l e \gamma _{f,prestress,unfavourable} γf,prestress,unfavourable​·

预应力混凝土结构在承载力极限状态下的验算应该考虑预应力损失和变化。按照对结构最不利的状态采用系数 γ f , p r e s t r e s s , f a v o u r a b l e \gamma _{f,prestress,favourable} γf,prestress,favourable​ 和 γ f , p r e s t r e s s , u n f a v o u r a b l e \gamma _{f,prestress,unfavourable} γf,prestress,unfavourable​ 。

In the case of prestressed concrete in FLS and the SLS the variations shall be considered by applying the least favourable of the factors γ s u p \gamma _{sup} γsup​ and γ i n f \gamma _{inf} γinf​ . For FLS and SLS, the recommended factors to be used for post-tensioning with bonded tendons are γ s u p = 1 , 1 \gamma _{sup}=1,1 γsup​=1,1 and γ s u p = 0 , 9 \gamma _{sup}=0,9 γsup​=0,9 , but the recommended factors for post-tensioning with unbonded tendons and for pre-tensioning are γ s u p = 1 , 05 \gamma _{sup}=1,05 γsup​=1,05 and γ s u p = 0 , 95 \gamma _{sup}=0,95 γsup​=0,95.

疲劳极限状态和正常使用极限状态下的预应力混凝土需要通过采用系数 γ s u p \gamma _{sup} γsup​ 和 γ i n f \gamma _{inf} γinf​ 的最不利影响考虑预应力的变化，有粘结预应力筋取为 γ s u p = 1.1 \gamma _{sup}=1.1 γsup​=1.1 和 γ i n f = 0.9 \gamma _{inf}=0.9 γinf​=0.9 ，无粘结预应力筋取为 γ s u p = 1.05 \gamma _{sup}=1.05 γsup​=1.05 和 γ i n f = 0.95 \gamma _{inf}=0.95 γinf​=0.95 。

When measures are taken to reduce the uncertainty on the prestress load, the factors γ s u p \gamma _{sup} γsup​ and γ i n f \gamma _{inf} γinf​ can be taken as γ s u p = γ i n f = 1 , 0 \gamma _{sup}=\gamma _{inf}=1,0 γsup​=γinf​=1,0. While a high accuracy of the tensioning devices may improve the accuracy of the initial level of prestress, the remaining uncertainty with respect to the losses of prestress shall also be considered if rsup and rinf shall be modified.

当采用了有效措施降低预应力荷载测量的不确定度时， γ s u p \gamma _{sup} γsup​ 和 γ i n f \gamma _{inf} γinf​ 可以取为 γ s u p = γ i n f = 1.0 \gamma _{sup}=\gamma _{inf}=1.0 γsup​=γinf​=1.0 。虽然张紧装置的高精度可以提高初始预应力水平的精度，但如果要修改 γ s u p \gamma _{sup} γsup​ 和 γ i n f \gamma _{inf} γinf​ ，还应考虑与预应力损失有关的剩余不确定性。

Where high resistance of a member is unfavourable, an upper value of the characteristic resistance shall be used in order to give a low probability of failure of the adjoining structure.

Concrete towers are subject to the induced stress effect of temperature variations with respect to the temperature at the time of erection as well as to temperature gradients within the tower cross-section as shown in Figure 6.

 

Figure 6 - Thermal effects around tower cross-section

混凝土塔筒的设计应考虑横截面温度梯度的影响和吊装阶段温度应力的变化，如图 6 所示。

    These characteristic temperature actions shall be considered in the design as explained in the following.   a)   Δ T 1 \Delta T_{1} ΔT1​ is a uniform temperature difference with respect to the temperature at the time of erection (constant temperature along circumference and across wall thickness). Δ T 1 \Delta T_{1} ΔT1​ shall be taken as the least favourable of

• T e x t r e m e , m a x − T e r e c t i o n , m i n T_{extreme,max}-T_{erection,min} Textreme,max​−Terection,min​
• T e x t r e m e , m i n − T e r e c t i o n , m a x T_{extreme,min}-T_{erection,max} Textreme,min​−Terection,max​ where T e x t r e m e , m i n T_{extreme,min} Textreme,min​ and T e x t r e m e , m a x T_{extreme,max} Textreme,max​ are the extreme temperature range as defined in IEC 61400-1 :2019, 6.4.2.1. T e r e c t i o n , m i n T_{erection,min} Terection,min​ and T e r e c t i o n , m a x T_{erection,max} Terection,max​ are the allowable temperature range to be defined for the erection of the tower. This temperature action may generary be neglected provided the tower does not incorporate or is not restrained by materials of differing thermal expansion coefficients. On the basis of Δ T 1 \Delta T_{1} ΔT1​, areasonable assumption shall be made for the temperature difference between the tower and foundation which may cause tension due to restraint.

设计中应考虑这些典型的温度作用，如下所述： a)