密肋壁板结构计算模型及Pushover分析

在前期试验和理论研究的基础上,将密肋壁板结构中的密肋复合墙板等效为整体斜撑,提出结构的刚架 - 等效斜撑力学模型,并结合试验数据确立了该模型主要参数的计算方法及塑性铰的设定.采用该模型对一实际密肋壁板结构进行了Pushover分析并进行了抗震性能评估.结果表明采用该模型是实现密肋壁板结构Pushover分析及抗震性能评估的一种有效方法.     

Application of HF radar currents to oil spill modelling

In this work, the benefits of high-frequency (HF) radar currents for oil spill modeling and trajectory analysis of floating objects are analyzed. The HF radar performance is evaluated by means of comparison between a drifter buoy trajectory and the one simulated using a Lagrangian trajectory model. A methodology to optimize the transport model performance and to calculate the search area of the predicted positions is proposed. This method is applied to data collected during the Galicia HF Radar Experience. This experiment was carried out to explore the capabilities of this technology for operational monitoring along the Spanish coast. Two long-range HF radar stations were installed and operated between November 2005 and February 2006 on the Galician coast. In addition, a drifter buoy was released inside the coverage area of the radar. The HF radar currents, as well as numerical wind data were used to simulate the buoy trajectory using the TESEO oil spill transport model. In order to evaluate the contribution of HF radar currents to trajectory analysis, two simulation alternatives were carried out. In the first one, wind data were used to simulate the motion of the buoy. In the second alternative, surface currents from the HF radar were also taken into account. For each alternative, the model was calibrated by means of the global optimization algorithm SCEM-UA (Shuffled Complex Evolution Metropolis) in order to obtain the probability density function of the model parameters. The buoy trajectory was computed for 24 h intervals using a Monte Carlo approach based on the results provided in the calibration process. A bivariate kernel estimator was applied to determine the 95% confidence areas. The analysis performed showed that simulated trajectories integrating HF radar currents are more accurate than those obtained considering only wind numerical data. After a 24 h period, the error in the final simulated position improves using HF radar currents. Averaging the information from all the simulated daily periods, the mean search and rescue area calculated using HF radar currents, is reduced by approximately a 62% in comparison with the search area calculated without these data. These results show the positive contribution of HF radar currents for trajectory analysis, and demonstrate that these data combined with atmospheric forecast models, are of value for trajectory analysis of oil spills or floating objects.     

A new friction law for sliding rigid blocks under cyclic loading

A rigid block sliding down an inclined plane under the action of gravity was monitored with accelerometers and an LVDT to investigate how the transition from static to kinetic friction develops. Once the transition patterns were identified, experiments were carried out to study the response of a dynamically excited rigid block sliding down the inclined plane of a shaking table. Harmonic time series were used as input motions. The laboratory results allowed the definition of a continuous friction law to model the continuous variation of the friction from its static to kinetic condition. This law was implemented into the commercial 3D distinct element code 3DEC to numerically reproduce the experiments carried out, thus validating the friction law. Afterwards, the friction law was used to evaluate the sliding due to the kinetics of the block. Three cases were analyzed: constant friction coefficient, Coulomb friction law and the proposed friction law. These computations were compared to laboratory measurements. It is found that permanent displacements computed by considering the new law are in better agreement with laboratory measurements.     

On a modal damping identification model for non-classically damped linear building structures subjected to earthquakes

A simple modal damping identification model developed by the present authors for classically damped linear building frames is extended here to the non-classically damped case. The modal damping values are obtained with the aid of the frequency domain modulus of the roof-to-basement transfer function and the resonant frequencies of the structure (peaks of the transfer function) as well as the modal participation factors and mode shapes of the undamped structure. The assumption is made that the modulus of the transfer function of the non-classically damped structure matches the one of the classically damped structure in a discrete manner, i.e., at the resonant frequencies of that function modulus. This proposed approximate identification method is applied to a number of plane building frames with and without pronounced non-classical damping under different with respect to their frequency content earthquakes and its limitations and range of applicability are assessed with respect to the accuracy of both the identified damping ratios and that of the seismic structural response obtained by classical mode superposition and use of those identified modal damping ratios.     

新疆南天山环境应力场特征

基于新疆强震固定台和流动观测记录的主要和余震加速度资料，选用了三个分向记录都完整的３７次地震。震级范围为１．８－６．８级，震中距为几至几十公里。根据用位错理论二维断裂力学模式推导的震源峰值、加速度与环境剪应力场关系式计算了新疆南天山环境剪应力值。计算结果表明，新疆南天山环境应力平均值偏高，这与新疆处于特殊构造环境条件有关。     

关于O3层垂直剖面遥感的逆转曲线的数学拟合模式

逆转遥感是当前获得大气O₃层垂直剖面资料的重要方法之一，而逆转曲线的质量对遥感结果的精度至关重要．本文在最小二乘法的基础上，结合逆转曲线的特征，加以适当处理，建立了逆转曲线的拟合数学模式．其性能良好，对研究O₃层垂直剖面的长期演变趋势具有重要意义．     

太湖地区河网水体石油类浓度预测

利用完全混合系统水文动力学模型,对太湖地区河道改造后,由于船型及船流量发生变化而导致的水体石油类浓度的变化进行了预测。通过类比分析得出：预测结果基本符合实际。     

PERFORMANCE EVALUATION OF A THREE-STOREY UNREINFORCED MASONRY BUILDING DURING THE 1992 ERZİNCAN EARTHQUAKE

Seismic performance of a three-storey unreinforced masonry building which survived the 1992 Erzincan earthquake without damage is evaluated. Mechanical properties of the masonry walls have been determined experimentally by using identical brick and mortar used in construction. An accurate material model is developed for masonry and employed in a computer program for the non-linear dynamic analysis of masonry buildings. The analytical results based on measured material properties indicated that masonry buildings which satisfy basic seismic code requirements possess remarkable lateral strength, stiffness and energy dissipation capacity. Accordingly, a simple elastic design approach is rendered suitable for unreinforced masonry under seismic excitations, provided that realistic material properties are employed in design.     

近场立交成因模式及强震预报

详细地讨论了强震孕育的近场立交成因模式,将其应用于强震的预报,并提出了强震预报的思路.作者还进一步讨论了横向断层对传播断层的止裂条件及深部断层的存在等问题.     

Evolution model and formation mechanism of bio-thermocatalytic transitional zone gas

As a new genetic type of natural gas exploration area, the bio-thermocatalytic transitional zone gas (BTTZG) has been highly stressed by geologists both at home and abroad. Systematic study on the generation mechanism of hydrocarbon at the transitional zone is presented. Based on simulating experiments and geochemistry analysis of the source rock with lower evolution, a hydrocarbon-forming model at the transitional zone has been established. The mechanism is proposed that under the condition of low temperature and pressure combining with extremely active structural stress and clay mineral catalysis, BTTZG is formed by de-group of soluble organic matter and polarized compositions through orthocarbon ion as well as by condensation polymerization of aromatic ring-rich insoluble organic matter. This mechanism controls the formation of BTTZG, and furthermore, BTTZG is the product of superimposition and interaction of all the factors mentioned above.