美國標準中的地震動參數(shù)概念（中英文對照）

1、美國標準中的地震動參數(shù)概念（中英文對照） design earthquakes. the design earthquakes for hydraulic structures are the obe and the mde. 設(shè)計地震： 水工結(jié)構(gòu)的設(shè)計地震有obe和mde，即運行基準地震和最大設(shè)計地震。 the actual levels of ground motions for these earthquakes depend on the type of hydraulic structure under consideration, and are specified in the

2、seismic design guidance provided for a particular structure in conjunction with er 1110-2-1806. 地震動參數(shù)的實際取值跟水工建筑物的類型有關(guān)，具體可參照er 1110-2-1806。 (1) operating basis earthquake (obe). the obe is an earthquake that can reasonably be expected to occur within the service life of the project, that is, with a 5

3、0 percent probability of exceedance during the service life. the associated performance requirement is that the project function with little or no damage, and without interruption of function. 運行基準地震（obe）：obe是指在工程的服務(wù)生命周期中可能合理預(yù)期發(fā)生的地震，即在工程生命周期中超過50%的發(fā)生概率，在該地震作用下，工程的相關(guān)性能要求幾乎沒有或沒有破壞，工程的相關(guān)功能沒有中斷。 (2) max

4、imum design earthquake (mde). the mde is the maximum level of ground motion for which the structure is designed or evaluated. the associated performance requirement is that the project performs without catastrophic failure, such as uncontrolled release of a reservoir, although severe damage or econo

5、mic loss may be tolerated. the mde is set equal to the maximum credible earthquake (mce) or to a lesser earthquake, depending on the critical nature of the structure (see er 1110-2-1806 and paragraph 2-4b). 最大設(shè)計地震（mde）：mde是結(jié)構(gòu)設(shè)計或評估的最大地震動水平。在該地震作用下，雖然引發(fā)嚴重的經(jīng)濟損失和破壞，但是水工結(jié)構(gòu)的相關(guān)性能要求不至于遭到毀滅性的破壞，比如，水庫庫水不至于不受控

6、制地下泄。依據(jù)結(jié)構(gòu)的關(guān)鍵特性，mde等于或小于mce（最大可信地震），參見er 1110-2-1806的2-4b段。 (3) the mce is defined as the greatest earthquake that can reasonably be expected to be generated by a specific source on the basis of seismological and geological evidence. 最大可信地震（mce）：mce是基于地震和地質(zhì)證據(jù)，某個震源合理預(yù)期可能發(fā)生的最大地震。 e. earthquake ground m

7、otion(s). the ground motions for the design earthquakes are defined in terms of smoothed elastic response spectra and, if required, also in terms of acceleration time-histories. standard ground motions selected from published ground motion maps can be used in preliminary and screening studies, and f

8、or final design or evaluation in areas of low to moderate seismicity where the earthquake loading does not control the design. site-specific ground motions, as described in chapter 3, are required for projects with high to significant hazard potential in case of failure and located in areas of high

9、seismicity, and in areas of moderate seismicity where the earthquake loading controls the design (er 1110-2-1806). 地震動參數(shù)：設(shè)計地震的地震動參數(shù)可以是光滑后的彈性反應(yīng)譜，如果有需要，也可以示加速度-時間歷程曲線。對初步的或者方案比選階段的研究，標準地震動參數(shù)可以從已出版的地震動參數(shù)圖上面獲取。在較低或中等地震強度區(qū)域的最終設(shè)計和評估，地震產(chǎn)生的荷載并不是控制因素。第三章所講述的特定場地的地震動參數(shù)針對的是處于高地震地區(qū)的工程、地震是其失事的高影響因素的工程，或者雖然位于中等地震

10、地區(qū)，但地震荷載是設(shè)計的控制因素的工程。 design earthquakes and ground motions 設(shè)計地震和地震動 a. maximum credible earthquake (mce). this earthquake is defined as the greatest earthquake that can reasonably be expected to be generated by a specific source on the basis of seismological and geological evidence. since a project

11、site may be affected by earthquakes generated by various sources, each with its own fault mechanism, maximum earthquake magnitude, and distance from the site, multiple mces may be defined for the site, each with characteristic ground motion parameters and spectral shape. the mce is determined by a d

12、sha. 1、最大可信地震（mce） mce定義為基于地震學理論和地質(zhì)證據(jù)某個震源合理預(yù)期產(chǎn)生的最大地震。一個工程可能同時被幾個震源產(chǎn)生的地震所影響，每個震源有它自己的震源機制、最大地震強度，距離工程場地的距離也不同，因此，一個場地對應(yīng)多個mce，對應(yīng)各自的地震動參數(shù)和反應(yīng)譜。mce由確定性地震危險性分析（dsha）確定。 b. maximum design earthquake (mde). the mde is the maximum level of ground motion for which a structure is designed or evaluated. the ass

13、ociated performance requirement is that the project perform without catastrophic failure, such as uncontrolled release of a reservoir, although severe damage or economic loss may be tolerated. for critical features, the mde is the same as the mce. for all other features, the mde shall be selected as

14、 a lesser earthquake than the mce which provides economical designs meeting appropriate safety standards. the mde can be characterized as a deterministic or probabilistic event. 2、最大設(shè)計地震（mde） mde是設(shè)計或評估某結(jié)構(gòu)所遭受的最大地震動水平。相應(yīng)的性能要求是即使因為地震破壞產(chǎn)生了嚴重的破壞和經(jīng)濟損失，但結(jié)構(gòu)功能不發(fā)生災(zāi)難性失效，比如水庫的不受控泄水。對關(guān)鍵結(jié)構(gòu)，mde等于mce，對其他結(jié)構(gòu)，在考慮合適的安全

15、標準下，也考慮經(jīng)濟的因素，mde相應(yīng)的小于mce。mde可分為確定性和概率性結(jié)果。 c. operating basis earthquake (obe). the obe is an earthquake that can reasonably be expected to occur within the service life of the project, that is, with a 50-percent probability of exceedence during the service life. (this corresponds to a return period

16、of 144 years for a project with a service life of 100 years.) the associated performance requirement is that the project function with little or no damage, and without interruption of function. the purpose of the obe is to protect against economic losses from damage or loss of service, and therefore

17、 alternative choices of return period for the obe may be based on economic considerations. the obe is determined by a psha. 3、運行基準地震（obe） obe是指在工程的使用壽命周期中可能合理預(yù)期發(fā)生的地震，即在工程生命周期中超過50%的發(fā)生概率（如果一個工程的使用壽命是100年，那么需研究的重現(xiàn)期是144年），在該地震作用下，工程的相關(guān) 性能要求幾乎沒有或沒有破壞，工程的相關(guān)功能沒有中斷。設(shè)定obe的目的是避免工程因為性能破壞或丟失而產(chǎn)生經(jīng)濟損失，因此obe的重現(xiàn)期選擇

18、可基于經(jīng)濟性考慮。obe通過概率性地震風險性評估決定。 d. estimating obe and mde ground motions. estimates are usually made in two phases. the first estimates are used as a starting point for the study and are obtained from the national earthquake hazard reduction program (nehrp) spectral acceleration maps (appendix d). site-

19、specific studies in accordance with paragraph 5h(2) are often required for selecting the final estimates of obe and mde ground motions. both dsha and psha approaches are appropriate. combining the results of deterministic and probabilistic analyses is often an effective approach for selecting mde ground motions. 4、obe和mde地震動的評估 obe和mde地震動的評估通常劃分為兩個階段。第一個階段的評估是研究的起點，可通過國家地震減災(zāi)計劃（nehrp）提供的加速度圖（附錄d）獲得相應(yīng)的基礎(chǔ)資料。5h(2)段中的特定場地研究常常要求選取一個最終的obe和mde地震動參數(shù)。dsha和psha方法均為建議的方法。綜合確定的和概率的分析方法常常是選擇mde的有效途徑。 typical results of a probabilistic analys