外文翻譯---通過(guò)建筑結(jié)構(gòu)設(shè)計(jì)以改善建筑物的抗倒性(編輯修改稿)
2025-02-12 12:08 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 ore substantial connections and/or additional reinforcement in floor slabs In an interesting recent development, that recognizes the link to the generation of catenary action, US Guidance has restricted the use of tying between the structural members to situations in which it can be demonstrated that the associated connections can carry the required forces whilst undergoing rotations of radiance. Where this is not possible, tying should act through the floors and the roof. However, recent studies (Nethercot et al 2010a。 Nethercot et al 2010b) have suggested that tying capacity correlates poorly with actual resistance to progressive collapse. Moreover, being prescriptive, it does not permit the meaningful parison of alternative arrangements a fundamental feature of structural design. In its most frequently used form the alternative load path approach presumes the instantaneous loss of a single column and then requires that the ability of the resulting damaged structure to bridge the loss be demonstrated by suitable calculation (Gudmundsson and Izzuddin 2010). The approach may be implemented at varying levels of sophistication in terms of the analysis。 for example, recent thinking in the United States (SEI 2010) makes provision for any of: linear static, nonlinear static or nonlinear dynamic analysis and provides some guidance on the use of each. It may also be used as the basis for more sophisticated numerical studies of particular structures and particular incidents . forensic work。 the best of these–which are likely to be putationally very demanding–have demonstrated their ability to closely replicate actual observed behaviour.3. Essential features of progressive collapse Three features have previously (Nethercot 2010) being identified as essential ponents of any reasonably realistic approach to design against progressive collapse:*c Events take place over a very short timescale and the actual failure is therefore dynamic.*c It involves gross deformations, generating large strains, leading to inelastic behaviour as well as change of geometry effects.*c Failure essentially corresponds to an inability of the structure in its damaged state to adopt a new position of equilibrium without separation of key elements.Figure 2: Simplified multilevel approach for progressive collapse assessment Additional features, designed to make the approach attractive for use by practicing Engineers have also been proposed (Nethercot 2010):*c Process should consist of a series of steps broadly similar in concept to those used for “conventional” structural design.*c It should, preferably, be capable of implementation at a variety at levels of plexity–with the choice reflecting the importance of the structure.*c Any required analysis should utilise familiar techniques。 where these require putations beyond “hand methods”, these should be based on the use of available analysis software.*c A realistic and recognisable criterion of failure should be used.*c Approach should permit study of cause and effect and be suitable for the making of quantitative parisons. It was against this background that the studies at Imperial College London have been undertaken. An approach incorporating the three essential features but observing the five desirable features was originally developed (Vlassis 2007)。 it has subsequently been refin
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