土木工程外文翻譯----歐洲對鋼框架結構抗震設計的評估

1、本科生畢業(yè)設計外文翻譯題 目出處 HYPERLINK / /content/b35k24747458435l/姓名學 號 00000000學院XX學院專業(yè)XX工程指導教師2011年X月 X日英文原文:Assessment of European seismic design proceduresfor steel framed structuresA.Y. Elghazouli 1 IntroductionAlthough seismic design has benefited from substantial developments in recent years, the need t

2、o offer practical and relatively unsophisticated design procedures inevitably results in various simplifications and idealisations. These assumptions can, in some cases, have advert implications on the expected seismic performance and hence on the rationale and reliabil- ity of the design approaches

3、. It is therefore imperative that design concepts and application rules are constantly appraised and revised in light of recent research findings and improvedunderstanding of seismic behaviour. To this end, this paper focuses on assessing the under- lying approaches and main procedures adopted in th

4、e seismic design of steel frames, with emphasis on European design provisions.In accordance with current seismic design practice, which in Europe is represented by Eurocode 8 (EC8) (2004), structures may be designed according to either non-dissipative or dissipative behaviour. The former, through wh

5、ich the structure is dimensioned to respond largely in the elastic range, is normally limited to areas of low seismicity or to structures of special use and importance. Otherwise, codes aim to achieve economical design by employing dissipative behaviour in which considerable inelastic deformations c

6、an be accommodated under significant seismic events. In the case of irregular or complex structures, detailed nonlinear dynamic analysis may be necessary. However, dissipative design of regular structures is usually performed by assigning a structural behaviour factor (i.e. force reduction or modifi

7、ca - tion factor) which is used to reduce the code- specified forces resulting from idealised elastic response spectra. This is carried out in conjunction with the capacity design concept which requires an appropriate determination of the capacity of the structure based on a pre- defined plastic mec

8、hanism (often referred to as failure mode), coupled with the provision of sufficient ductility in plastic zones and adequate over-strength factors for other regions. Although the fundamental design principles of capacity design may not be purposely dissimilar in various codes, the actual procedures

9、can often vary due to differences in behavioural assumptions and design idealisations.This paper examines the main design approaches and behavioural aspects of typical config- urations of moment-resisting and concentrically-braced frames. Although this study focuses mainly on European guidance, the

10、discussions also refer to US provisions (AISC 1999, 2002, 2005a,b) for comparison purposes. Where appropriate, simple analytical treatments are presented in order to illustrate salient behavioural aspects and trends, and reference is also made to recent experimental observations and findings.Amongst

11、 the various aspects examined in this paper, particular emphasis is given to capacity design verifications as well as the implications of drift-related requirements in moment frames, and to the post-buck- ling behaviour and ductility demand in braced frames, as these represent issues that warrant ca

12、utious interpretation and consideration in the design process. Accordingly, a number of necessary clarifications and possible modifications to code procedures are put forward. 2 General considerations2.1 Limit states and loading criteriaThe European seismic code, EC8 (Eurocode 8 2004) has evolved ov

13、er a number of years changing status recently from a pre-standard to a full European standard. The code explicitly adopts capacity design approaches, with its associated procedures in terms of failure mode control, force reduction and ductility requirements. One of the main merits of the code is tha

14、t, in comparison with other seismic provisions, it succeeds to a large extent in maintaining a direct and unambiguous relationship between the specific design procedures and the overall capacity design concept.There are two fundamental design levels considered in EC8, namely no-collapse and damage-l

15、imitation5, which essentially refer to ultimate and serviceability limit states, respectively, under seismic loading. The no-collapse requirement corresponds to seismic action based on a recommended probability of exceedance of 10% in 50 years, or a return period of 475 years, whilst the values asso

16、ciated with the damage-limitation level relate to arecommended probability of 10% in 10 years, or return period of 95 years. As expected, capacity design procedures are more directly associated with the ultimate limit state, but a number of checks are included to ensure compliance with serviceabilit

17、y conditions.The code defines reference elastic response spectra (Se) for acceleration as a function of the period of vibration (T) and the design ground acceleration (ag) on firm ground. The elast ic spectrum depends on the soil factor (S), the damping correction factor (n) and pre-defined spectral

18、 periods (TB , TC and TD) which in turn depend on the soil type and seismic source characteristics. For ultimate limit state design, inelastic ductile performance is incorporated through the use of the behaviour factor (q) which in the last version of EC8 is assumed to capture also the effect of vis

19、cous damping. Essentially, to avoid performing inelastic analysis in design, the elastic spectral acceleration s are divided by q (excepting some modifications for T TB), to reduce the design forces in accordance with the structural configuration and expected ductility. For regular structures (satis

20、fying a number of code- specified criteria), a simplified equivalent static approach can be adopted, based largely on the fundamental mode of vibration.2.2 Behaviour factorsThis type of frame has special features that are not dealt with in this study, although some comments relevant to its behaviour

21、 are made within the discussions. Also, K-braced frames are not considered herein as they are not recommended for dissipative design. On the other hand, eccentrically-braced frames which can combine the advantages of moment-resisting and concentrically-braced frames in terms of high ductility and st

22、iffness, are beyond the scope of this study. The reference behaviour factor should be considered as an upper bound even if non-linear dynamic analysis suggests higher values. For regular structures in areas of low seismicity, a q of 1.5-2.0 may be adopted without applying dissipative design procedur

23、es, recognizing the presence of a minimal level of inherent over-strength and ductility. In this case, the struc- ture would be classified as a low ductility class (DCL) for which global elastic analysis can be utilized, and the resistance of members and connections may be evaluated according to EC3

24、 (Eurocode 3 2005) without any additional requirements.中文翻譯:歐洲對鋼框架結構抗震設計的評估1介紹雖然抗震設計實質性進展受益匪淺，近年來，需要提供實用和相對簡單 的設計方法，不可避免地導致各種各樣的簡化和理想化。這些假設，某些情 況下，有廣告影響預期的抗震性能，因此在合理性和可靠性設計的方法下。 有必要的設計概念和應用不斷評估和修改規(guī)則是根據(jù)最近的研究和對地震 的行為改進的理解。為此，本文在評估潛在的方法和主要流程采用鋼結構工 程的抗震設計中，用強調歐洲設計規(guī)定，制定本規(guī)定。按照現(xiàn)行的抗震設計實踐，這在歐洲被表示Eurocode 8(E

25、C8)(2004), 結構也可以設計出系統(tǒng)根據(jù)或耗散行為。這位前，藉此結構尺寸進行回應主 要集中在彈性范圍內(nèi)，通常是有限的地區(qū)地震活動或結構的低特殊用途與 重要性。否則，編碼的目的是要實現(xiàn)節(jié)約型設計被耗散行為在相當大的彈性 變形能得到滿足在重大的地震事件。在案件的不規(guī)則或復雜的結構，詳細的 非-線性動態(tài)的分析可能是必要的。然而，常規(guī)結構設計的系統(tǒng)具有耗散通 過指定一個經(jīng)常表演結構行為因素(例如力量還原或修改因素),用它來減 少所造成的指定代碼，正如有彈性響應譜。這是進行結合的能力設計概念， 需要采用一種適宜的容量的確定基于一個預先定義的結構塑料機械(通常 稱為失效模式),伴隨著提供充分的在塑性

26、區(qū)和足夠的延性等因素為其它地 區(qū)。雖然基本設計原則的能力設計可能不是故意在各種不同實際的程序代 碼，可以在常隨因為不同的行為假設理想化和理想化設計。摘要本文檢視主要設計方法和行為方面的抗力矩典型配置和中心支撐 幀。雖然這項研究主要在歐洲的指導下，我們的討論也涉及到規(guī)定(以1999 年,2002年,2003 2005a,b 作比較)。在適當?shù)牡胤?，簡單的解析治療，為?說明了引人注目的行為方面和發(fā)展趨勢參考。最近的實驗觀測也做了各種 努力和成果。重點是給設計驗證作為相關要求的含義，時刻幀后屈曲行為和 延性需求的支撐框架，因為這些代表問題，謹慎的解釋和考慮的設計過程。 因此，一定數(shù)量的必要的澄清和可能的修改代碼程序提出了 2種通常的考 慮。2.1極限狀態(tài)和加載的標準歐洲的抗震規(guī)范,EC8(Eurocode 8 2004年)已經(jīng)進化數(shù)年，最近從一個 準標