Dynamic responses under the excitation of pulse sequences

This paper studies the dynamic responses of SDOF system under pulse-dominant excitations. The purpose of the study is to prepare for scrutiny of some near-field pulse-dominant ground motions and their potential to cause structural damage. Extending the single pulse dynamics, we consider the effect of pulse sequences. This kind of excitation was particularly obvious in some of previous earthquakes such as Northridge (1994) and Chi-Chi (1995). Based on the duration,peak and rise and decay era of the main pulse as well as its relationship with the predecessor and successor pulses, we propose a classification for the pulse sequences. Consequent studies have been carried out for acceleration, velocity and displacement response spectra of the main pulse with either a predecessor or a successor pulse. The analysis also includes general response behaviors in different fundamental period segments and special aspects of response at certain points (e.g., the corresponding peak points).     

新世纪中美地震工程研讨会在北京召开

新世纪中美地震工程研讨会于２０００年１１月８日至１１日在北京西苑饭店召开。会议目的是纪念中美地震工程及减灾科技合作二十周年，并面向新世纪商讨地震工程的发展方向及中美乃至世界范围内在地震工程领域的广泛合作。这是世纪之交地震工程界的一次盛会。 会议是由中国地震局、中国建设部、中国国家自然科学基金会以及美国国家科学基金会共同主办，中国地震局负责具体寿备工作。会议中方主席由中国科学院院士胡聿贤教授担任，美方主席由Ｂ．Ｆ．Ｓｐｅｎｃｅｒ教授担任。中国地震局陈章立局长、中国建设部叶如棠副部长、中国国家自然科…     

Local measurement for structural health monitoring

Localized nature of damage in structures requires local measurements for structural health monitoring. The local measurement means to measure the local, usually higher modes of the vibration in a structure. Three fundamental issues about the local measurement for structural health monitoring including (1) the necessity of making local measurement, (2) the difficulty of making local measurement and (3) how to make local measurement are addressed in this paper. The results from both the analysis and the tests show that the local measurement can successfully monitor the structural health status as longas the local mod es are excited. Unfortunately, the results also illustrate that it is difficult to excite local modes in a structure. Therefore, in order to carry structural health monitoring into effect, we must ( 1 ) ensure that the local modes are excited, and (2) deploy enough sensors in a structure so that the local modes can be monitored.