大型双槽渡槽地震反应分析

为了得到比较精确的大型双槽渡槽结构的地震反应，根据渡槽结构复杂、影响动力因素较多等特点，采用8结点空间块体单元对渡槽槽身和槽墩进行有限元离散，分别用耦合自由度和多个弹簧单元分别模拟渡槽槽身横向拉杆、加劲肋和盆式橡胶支座，建立了大型双槽渡槽结构地层反应分析的有限元模型，计算了南水北调水利工程中的双洎河大型双槽渡槽的振动特性，并分别用反应谱法和时程分析法对该渡槽进行了地震反应分析，计算结果可为该渡槽的抗震设计提供参考。     

Study of crustal structure with S—wave data from Maqen—Jingbian profile

2-D crustal velocity structure and vp/vs are obtained by processing and interpretation of S-wave data from Maqen-Jingbian deep seismic sounding(DSS)profile.The result shows that there exist obvious differences in 2-D S-wave velocity structure and vp/vs ratio structure along the profile.The S-wave velocities are low and vp/vs ration is high for the westem section of the profile and Haiyuan region,while they are normal for the middle and eastern sections.The changes in lithologic characters of two major anomalous zones are discussed according to lateral variation of S-wave velocity structure and vp/vs ratio structure.It is concluded that the development and occurrence of the Haiyuan strong earthquake is not only related to tectonic activities,but also to lithologic characters of the region.     

Nonlinear Rate Dependent Model of High Damping Rubber Bearing

The accurate analysis of the response of isolated structures requires the application of appropriate models of isolation devices. The purpose of this paper is to analyse a nonlinear strain rate dependent model of a high damping rubber bearing which simulates the horizontal behaviour of the device under specified vertical load using a nonlinear elastic spring-dashpot element. The effectiveness of the model is checked by fitting the experimental data concerning three different rubber bearings. The results of the study show that the model can simulate the bearing behaviour over a wide shear strain range with small simulation errors. This revised version was published online in July 2006 with corrections to the Cover Date.     

Seismic response predictions of multi‐span steel bridges through pushover analysis

In the new trend of seismic design methodology, the static pushover analysis is recommended for simple or regular structures whilst the time‐history analysis is recommended for complex structures. To this end, the applicable range of the pushover analysis has to be clarified. This study aims at investigating the applicability of pushover analysis to multi‐span continuous bridge systems with thin‐walled steel piers. The focus is concentrated on the response demand predictions in longitudinal or transverse directions. The pushover analysis procedure for such structures is firstly summarized and then parametric studies are carried out on bridges with different types of superstructure‐pier bearing connections. The considered parameters, such as piers' stiffness distribution and pier–0.5ptdeck stiffness ratio, are varied to cover both regular and irregular structures. Finally, the relation of the applicability of pushover analysis to different structural formats is demonstrated and a criterion based on the higher modal contribution is proposed to quantitatively specify the applicable range. Copyright © 2003 John Wiley & Sons, Ltd.     

两结构高效阻尼控制体系试验研究

本文通过模拟地震动振动台试验，研究了两个相邻结构模型的地震响应，结构模型采用一种高效阻尼装置(High Efficient Damper for Multi—Structure System即HEDMS)连接。非线性时程分析与振动台试验结果都证明了该阻尼装置能高效发挥软钢阻尼器的耗能能力，从而显著减轻两结构模型的地震响应。同时，研究还指出了进行阻尼装置设计时应该注意的一些问题。     

规整化标定在地震遥测系统中的应用

规整化标定是模拟观测地震仪器标定的一种方法。系统介绍了规整化标定仪器的方法、参数，发现它有许多优点，是标定遥测地震仪器的一种较理想的方法。     

禾青井动水位对断层蠕动与慢地震过程的响应初析

以湖南禾青井深井水位观测的异常图象为例进行定性分析，发现动水位观测有可能直接反映出断层的滑动或断层的慢地震过程，前者可能为地下水物理参量的观测与研究提供亲折思路，后者则可能对震源物理学的发展和地震预报水平的提高具有特殊的意义。     

Noise reduction and detection of weak, coherent signals through phase-weighted stacks

We present a new tool for efficient incoherent noise reduction for array data employing complex trace analysis. An amplitude-unbiased coherency measure is designed based on the instantaneous phase, which is used to weight the samples of an ordinary, linear stack. The result is called the phase-weighted stack (PWS) and is cleaned from incoherent noise. PWS thus permits detection of weak but coherent arrivals. The method presented can easily be extended to phase-weighted cross-correlations or be applied in the τ p domain. We illustrate and discuss the advantages and disadvantages of PWS in comparison with other coherency measures and present examples. We further show that our non-linear stacking technique enables us to detect a weak lower-mantle P -to- S conversion from a depth of approximately 840 km on array data. Hints of an 840 km discontinuity have been reported; however, such a discontinuity is not yet established due to the lack of further evidence.