斜屋顶钢框架结构的弹性屈曲英文文献和中文翻译(10)

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(ii) The results yielded by the application of the proposed SAM (MII , VII , NI I.r , NI I.c, dII) are always conservative and quite accurate (very few errors exceed 5%). Moreover, all the second-order bending moments are practically exact

(no error above 2% and almost all of them below 1%).

(iii) The value (iii1) always increases with the frame span L, (iii2) decreases when the rafters inertia grows (except for the pinned-base frames, for which remains unaltered) and (iii3) greatly increases with the column base stiffness kc (much higher values in fixed-base frames).源-自/751+文,论`文'网]www.751com.cn

(iv) Because of a combination of high and low FS/FAS values, the amplification of the symmetrical sway component is considerably more relevant in fixed-base frames. This relevance decreases as the stiffness kc is reduced and becomes minimal for pinned-base frames. Thus, one observes that: (iv.1) Incorporating MSS in MN S leads to second-order moment estimates MI I.1 (Eq. (19)) that are slightly unsafe in pinned-base frames (3%–5% errors) and quite unsafe in fixed-base frames (13%–22% errors). One then concludes that neglecting the MSS amplification often implies significantly unsafe bending moment estimates.

Validation of the proposed SAM: influence of (L = 30 m, IPE360, kc =6800 kN m)

Validation of the proposed SAM: no horizontal loads, i.e., HEd = 0 (L = 20 m,IPE300, = 10

(iv.2) Incorporating MSS in MAS leads to second-order moment estimates MI I.2 Eq. (20) that are practically exact in fixed-base frames (0%–3% errors) and very conservative in pinned-base frames (12%–21% errors)—of course, an intermediate situation occurs for semi-rigid frames. Then, one concludes that wrongly amplifying MSS often implies excessively conservative bending moment estimates.

(v) All the conclusions and/or remarks included in the previous items remain qualitatively valid when the rafters slope value is changed (see Table 4).

(vi) In the absence of applied horizontal loads (HEd = 0 – seeTable 5) and regardless of the approach adopted (MI I.1 or MI I.2), the SAM prescribed by EC3-ENV and EC3-EN may yield rather inaccurate second-order moment estimates (the errors of MI I.1 and MI I.2 may exceed 20%).no amplification Note also that, because one has MAS = 0, EC3 prescribes— thus, it probably makes no sense to consider MI I.2 in this case (one would take MEd MI ).

摘要本文工作有两个目的:(1)介绍关于考虑了弹性平面内稳定和二阶受力性能的无支撑单层斜屋顶钢框架结构的研究成果；（2）提出、验证和说明一种来设计这种常用类型框架的有效方法的应用。在（1）给出了相应框架屈曲模式和P–Δ二阶效应特点，并且（2）给出了计算相应的分支荷载和二阶弯矩的精确或近似方法之后，我们将这些概念掺入整合到一种有效的设计方法当中去。特别要指出的是，它明显显示出由于椽的坡度，斜屋顶框架和普通梁柱的几何非线性行为是完全不同的。最后，本文通过介绍和讨论柱脚固接和铰接的斜屋顶框架的数据来阐述所提出的概念和方法。

关键词:斜屋顶钢框架结构；屈曲性能；二阶弹性性能；放大的方法；设计方法；欧洲法规3

1、简介

由于它们的高结构效率，这种如图1（a）所见的单层斜屋顶钢框架结构在建筑业中得到了广泛的应用，尤其应用在大跨度工业建筑或运动馆中。事实上，由椽坡度引起的刚度大幅度增加使由细而长的柱子和（大部分）椽建造而成的框架有可能承受相当大的荷载。然而，与正交梁柱框架结构不同，斜屋顶框架结构导致了椽抗压强度的发展（跟相同大小的柱子产生的抗压强度一样），一方面（1）对框架结构的反应产生重大影响，但（2）却经常被大量的设计师们所忽略。在过去的几年中，研究者们致力于用广泛而大量的研究结果来调查并阐述几个关于平面斜屋顶框架结构整体性几何非线性行为的问题。