建筑英文文獻及翻譯(共4頁)

1、精選優(yōu)質(zhì)文檔-傾情為你奉上外文原文出處:, 2009, , Pages 147-149動力性能對建筑物的破壞引言：建筑物在地震的作用下，和一些薄弱的建筑結(jié)構(gòu)中，動力學(xué)性能扮演了一個很重要的角色。特別是要滿足最基本的震動周期，無論是在設(shè)計的新建筑，或者是評估已經(jīng)有的建筑，使他們可以了解地震的影響。許多標準(例如：歐標，2003；歐標，2006)，建議用簡單的表達式來表達一個建筑物的高度和他的基本周期。這樣的表達式被牢記在心，得出標定設(shè)計(高爾和喬譜拉人，1997)，從而人為的低估了標準周期。因為這個原因，他們通常提供比較低的設(shè)計標準當(dāng)與那些把設(shè)計基礎(chǔ)標準牢記在心的人(例：喬普拉本和高爾，2000

2、)。當(dāng)后者從已進行仔細建立的數(shù)字模型中得到數(shù)值(例：克勞利普和皮諾，2004；普里斯特利權(quán)威，2007)。當(dāng)數(shù)字估計與周圍震動測量的實驗結(jié)果相比較，有大的差異，提供非常低的周期標準(例：納瓦洛蘇達權(quán)威，2004)。一個概述不同的方式比較確切的結(jié)果刊登在馬西和馬里奧(2008)；另外，一個高級的表達式來指定更有說服力的堅固建筑類型，提出了更加準確的結(jié)構(gòu)參數(shù)表(建筑高度，開裂，空隙填實，等等)。聯(lián)系基礎(chǔ)和上層建筑的震動周期可能發(fā)生共振的效果。這個原因?qū)τ谒麄兊恼駝?，可能建筑物和土地在非線性運動下受到到破壞，這個必須被重視。通常，結(jié)構(gòu)工程師和巖土工程師有不同的觀點在共振作用和一些變化的地震活動。結(jié)構(gòu)

3、工程師們認為盡管建筑物和土壤的自振周期和地震周期都非常的接近。但對于建筑物周期而言，到底是因為結(jié)構(gòu)還是非結(jié)構(gòu)造成的破壞提出了疑問。如果加大振動，建筑物減輕自身的重量對共振產(chǎn)生的破壞有很大的減輕效果。巖土工程的工程師們還沒有完全同意這個觀點，因為土壤可以提高自身的振動周期，與建筑物有相同的振動周期，從而建立了產(chǎn)生共振的條件。這個問題的處理在于這個增加量到底是多少？一般來說這種答案是不可能的，因為它取決于建筑類型和土壤類型。例如，一些普通的混凝土建筑物，對這建筑物增加一個非常大的震動周期，可以知道在平常的振動下就會迅速的遭到破壞，尤其是那些砌體建筑，比如，馬雪凱利建筑(2004)和克勞福建筑(20

4、06)。最后，估計在改裝或者加固后參數(shù)表數(shù)字的變化，通過計算機計算來改變標準的振動周期，阻尼因數(shù)和振動波形。這可以是一個非常好的評估工具對于存在的一些干擾(法拉斯等，2008)。這種效果也可以作為一種診斷工具，對周圍的振動測量很有幫助(布丁和漢斯，2008)。對以上問題的進一步研究，強烈要求建立更加寬廣的原地實驗或者是實驗室實驗，得出實驗結(jié)果來估算。用一個經(jīng)濟實用的方式，來營造動態(tài)特性。Role of Dynamic Properties on Building Vulnerability, 2009, , Pages 147-149IntroductionDynamic properties

5、 have a major role on the seismic behavior and vulnerability of building structures. Particularly, fundamental periods of vibration are needed, both in design of new buildings and in assessment of existing ones, so that their seismic response can be evaluated.Several codes (e.g. CEN, 2003; NZSEE, 20

6、06) recommend empirical simplified expressions between the height of a building type and its fundamental period. Such expressions were calibrated keeping in mind a force-based design (Goel and Chopra, 1997), thus intentionally aim at underestimating period values. For this reason they usually provid

7、e rather low values when compared to those ones obtained keeping in mind a displacement-based design (see e.g. Chopra and Goel, 2000), also when the latter were obtained from numerical simulations performed on carefully set up models (see e.g. Crowley and Pinho, 2004; Priestley et al., 2007). Even l

8、arger differences appear when numerical estimates are compared to experimental results based on ambient vibration measurements that provide very low period values (see e.g. Navarro et al., 2004). An overview of the different approaches together with a comparison of the relevant results is reported i

9、n Masi and Vona (2008); further, period-height expressions for some reinforced concrete building types are given, where the role of important structural characteristics (building height, cracking, masonry infills, elevation irregularities, etc.) is carefully taken into account. Coupling between soil

10、 and building fundamental periods of vibration may cause resonance effects. For this reason also their variation, as a consequence of possible building damage and/or soil non linear behavior during the motion, needs to be considered. Typically, structural and geotechnical engineers have different po

11、ints of view about resonance effect and its variation during a seismic motion. Structural engineers say that whereas building and soil have initially close periods and an earthquake occurs, the building period, as a result of structural and non structural damage, is expected to increase during the m

12、otion, so that the building “hides” itself reducing the heaviest effects of resonance. Geotechnical engineers do not completely agree with this opinion saying that also the soil period can shift towards higher values, that is in the same direction of the building one, thus the resonance condition co

13、uld arise again. The question to be dealt with is: how much is the relative amount of that increase? A general answer is not possible, as it depends on building and soil type. For example, in case of reinforced concrete buildings with masonry infill, a very large increase of the building period can

14、be expected with the level of shaking due to cracking of structural members and, particularly, of brittle masonry infill, see e.g. Mucciarelli et al. (2004), Calvi et al. (2006).Finally, estimating the variation of the dynamic characteristics after retrofitting or strengthening interventions, by com

15、puting the modified values of fundamental periods, damping factors and mode shapes, can be a practical tool to evaluate the effectiveness of the intervention (Farsi et al., 2008). To this purpose and also as a diagnosis tool, ambient vibration measurements can be very helpful (Boutin and Hans, 2008).All the above qu