Study On Atonement Of Long Period Ingredient In Earthquake Ground Motions Based On Wavelet

Simulated strong-motion seismograph records restricted by seismograph performance lose long period ingredient, so it can't satisfy earthquake resistance design of long period structures which grow day by day. Digital strong-motion seismograph records or broad band and very broad band (BB and VBB) records of Chinese Digital Seismograph Network which contain very low frequency ingredient are insufficient, especially the strong earthquake ground motion records, and it can't become to be sufficient in a short time, because the strong earthquakes occur scarce. The simulated strong-motion seismograph record and the selected digital strong-motion seismograph record are decomposed into time domain components which represent different frequency band by using 2^th cardinal B-spline wavelet and Mallat algorithm, and then the low frequency band of simulated strong-motion seismograph record which is lost or distorted is replaced by the corresponding frequency band of digital strong-motion seismograph records. This article proposes a new effective method to atone long period ingredient to simulated strong-motion seismograph records in the present condition.The main research work is as follows:1) The present situation of earthquake ground motion records is summarized, as well as the research situation and results of long period ingredient of earthquake ground motion at present. The present research's restricting factor and the existed question has been induced.2) It is studied that the feasibility and measure to atone long period ingredient to simulated strong-motion seismograph records based on wavelet analysis method. Firstly earthquake ground motion is decomposed into time domain components which represent different frequency band by using 2^th cardinal B-spline wavelet, and then the long period ingredient of simulated strong-motion seismograph records which are lost or distorted are atoned by the long period ingredient of digital strong-motion seismograph record which are reliable, so that the simulated strong-motion seismograph records can be used as input earthquake ground motion of the long period structure in time interval analysis.3) How to carry on the standard of atonement of long period ingredient in earthquake ground motions by using wavelet analysis is studied. The detail is adjusting frequency and amplitude on the most superior double target control's corresponding frequency band by using the wavelet analysis method. The example proved that after the adjustment the earthquake ground motions not only includes effective long period ingredient but also satisfy the request of most superior double target method to choose waves ,as also the validity of atonement of long period ingredient in earthquake ground motions based on wavelet.4) The problem existing in the most superior double target method to choose waves is studied based on combined spectrum, proposed that the most superior double target method to choose waves should be used to control the combined spectrum, not only the acceleration response spectrum as usual.The research results indicated that the atonement of long period ingredient in simulated strong-motion seismograph records based on wavelet is feasible and effective. This method satisfies that samples pick many times from the identical collection, it can produce a series of earthquake ground motions which satisfied the location condition request where the structure is to be constructed, establishes the small sample storehouse of earthquake ground motions input, and has enriched the resources storehouse of earthquake ground motions input.