悬吊式钢混结构体系抗震试验与分析

悬吊式钢混结构体系是一种新型结构体系，通过一榀1／2比例此种框架的拟静力试验，研究了这种结构在低周反复水平荷载作用下的受力特点、变形和耗能能力以及破坏机理等，试验表明此种框架与传统异形柱框架的性能不同，为此种结构体系的应用提供了试验基础。     

结构动力模型试验相似理论及其验证

通过几何比尺为2的两个有机玻璃模型的结构动力试验，验证了结构动力模型试验的弹性相似律和弹性力一重力相似律。得到了以下结论：(1)大小模型频率符合相似律，一阶频率误差为2．7％、4．1％，二阶频率误差为O、6．05％。弹性相似律比弹性力一重力相似律更适合于频率预测的试验。(2)大小模型的加速度、应变符合相似律，弹性相似律的加速度误差为-1．55％～8．75％，应变误差为O．377％～7．297％。弹性力-重力相似律的加速度误差为3．07％～4．158％，应变误差为6．849％～12．959％。(3)不同相似律大小模型的时问比尺吻合很好。加速度与应变时程曲线的波形一致，既无漏峰也无错峰。     

黄土动力学数据处理软件的研制

从数据分析和处理流程和功能模块设计方面讨论了应用Visual Basic进行土动力学数据处理系统开发时的问题及可行的解决方案，介绍了编制的土动力学数据处理系统的主要功能。     

上海地区扁铲侧胀试验计算地基承载力的探讨

通过对扁铲侧胀试验和试验机理的研究和对试验指数的对比分析 ,提出了用扁铲侧胀试验计算地基承载力的方法 ;利用上海地区部分重大工程中的扁铲侧胀试验数据 ,在与室内土工试验、静力触探试验及十字板剪切试验的相关分析的基础上 ,经数理统计后给出了上海地区用扁铲侧胀试验计算地基承载力的经验公式。最后 ,通过与室内土工试验、静力触探试验和十字板剪切试验计算的地基承载力对比 ,分析了本经验公式计算地基承载力的精度。研究分析表明 ,可以用扁铲侧胀试验计算地基承载力     

水域静力触探设备的研制和应用

为详细了解崇明越江通道南港隧道段地层情况 ,设计要求提供长江水域静探资料。简介了我院水域静力触探设备的研制和应用情况     

模拟试验法确定桩基承载力

通过室内中型剪切摩擦试验确定桩与地层间的C、Φ值,依据莫尔—库仑准则确定桩侧摩阻力。桩侧法向应力采用桩土上部荷载引起的作用于桩身的侧向应力,桩端承载力通过室内三轴试验确定,两者之和即为单桩承载力。该方法用于肇源松花江大桥桩基承载力的测试,得出的桩承载力与实测值吻合较好,取得了预期的效果。     

基于小波变换的遥感影像压缩编码

基于小波变换的图像压缩方法能在高压缩比的前提下保持好的重建图像质量,它的多分辨率特性与人类视觉系统非常相近,小波变换的编码技术被广泛地应用于遥感影像的压缩中。介绍了小波理论的相关知识,着重对嵌入零树小波、等级树分割、小波数据的形态学表示算法等方法进行了详细的论述,并对图像编码技术的发展方向进行了展望。     

Evaluation of soil liquefaction in the Chi-Chi, Taiwan earthquake using CPT

During the 1999 Chi-Chi, Taiwan earthquake, many sand boiling phenomena were observed in central Taiwan, which caused severe ground settlement and structure damages. According to the installed accelerograms, the peak ground surface horizontal accelerations in the liquefaction-affected areas range from 774.42 to 121.3 gal. The writers carried out an extensive investigation of soil liquefaction in this earthquake. In this paper, we present results of the CPT exploration and post-earthquake liquefaction analysis. Two hundred and seventy five (275) cone penetration test data were collected from the liquefaction-affected areas, and 46 liquefaction case histories and 88 non-liquefaction case histories were derived that can be used to evaluate the accuracy of existing liquefaction evaluation models. In addition, the strength of the liquefied soils after earthquake and the implication of its liquefaction potential in the future event are discussed.     

An experimental study on seismic responses of multifunctional vibration‐absorption reinforced concrete megaframe structures

Two models are tested on a shake‐table. One of the models is a normal reinforced concrete megaframe structure and the other is a multifunctional vibration‐absorption reinforced concrete megaframe structure in which the laminated rubber bearings are placed between the major frame and the minor frames. Two earthquake motions (the El Centro wave and the Taft wave) are used during the test. This paper presents the dynamic characteristic, the seismic responses and the failure mechanism of these two models under varying peak acceleration levels for each of the earthquake motions. The test results demonstrate that the aseismic behavior of a multifunctional vibration‐absorption reinforced concrete megaframe structure is much better than that of a normal reinforced concrete megaframe structure. Copyright © 2003 John Wiley & Sons, Ltd.     

Dynamic performance of twin curved cable‐stayed bridges

The dynamic behaviour of two curved cable‐stayed bridges, recently constructed in northern Italy, has been investigated by full‐scale testing and theoretical models. Two different excitation techniques were employed in the dynamic tests: traffic‐induced ambient vibrations and free vibrations. Since the modal behaviour identified from the two types of test are very well correlated and a greater number of normal modes was detected during ambient vibration tests, the validity of the ambient vibration survey is assessed in view of future monitoring. For both bridges, 11 vibration modes were identified in the frequency range of 0ndash;10Hz, being a one‐to‐one correspondence between the observed modes of the two bridges. Successively, the information obtained from the field tests was used to validate and improve 3D finite elements so that the dynamic performance of the two systems were assessed and compared based on both the experimental results and the updated theoretical models. Copyright © 2003 John Wiley & Sons, Ltd.