基于集对分析模型的岷江上游流域震后水质综合评价

汶川大地震是我国建国以来强度最大、破坏最严重的一次地震,给我国带来巨大的人员伤亡和经济损失。岷江上游流域生态环境较为脆弱,地震、泥石流、滑坡、崩塌等地质灾害经常发生,极易造成突发性水源污染。通过引入基于熵权改进的集对分析模型,对岷江上游流域映秀镇周边水源地进行综合评价,最好、平均、最差三种情况评价结果均为Ⅰ级。结果表明,"5.12"汶川特大地震对岷江上游流域部分水源地水质影响不大,震后岷江上游流域水质无明显变化。     

Analysis of earthquake management design for nuclear power plants (NPPs) incorporated with artificial intelligence (AI) method

It has been studied to analyze the operations in nuclear power plants (NPPs) where the human error could make a trigger to the nuclear disaster following the earthquake in South Korea. The earthquake warning system and its related control algorithm are modeled by the machine learning (ML) of artificial intelligence (AI) where the neural networking is done as a major role. The AI-based control system could give the very good performance in the earthquake incident which is shown by the system dynamics (SD) based simulations. Hence, the nuclear safety system needs the AI based alarming technology which could be a much more advanced control system incorporated with the conventional multiple-barrier concept in NPPs.     

锅炉膨胀中心的设置与导向载荷计算方法的研究

本文主要讨论了导向载荷的计算方法及过程，重点论述了风载荷和地震作用的计算，采用了竖直向下的计算模型。通过对NG－220/9．8－M15锅炉的计算表明，这方法是可行的。图3表3     

Seismic performance of a whole Geosynthetic Reinforced Soil – Integrated Bridge System (GRS-IBS) in shaking table test

A scaled plane-strain shaking table test was conducted in this study to investigate the seismic performance of a Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS) with a full-length bridge beam resting on two GRS abutments at opposite ends subjected to earthquake motions in the longitudinal direction. This study examined the effects of different combinations of reinforcement stiffness J and spacing S_v on the seismic performance of the GRS-IBS. Test results show that reducing the reinforcement spacing was more beneficial to minimize the seismic effect on the GRS abutment as compared to increasing the reinforcement stiffness. The seismic inertial forces acted on the top of two side GRS abutments interacted with each other through the bridge beam, which led to close peak acceleration amplitudes at the locations near the bridge beam. Overall, the GRS-IBS did not experience obvious structure failure and significant displacements during and after shaking. Shaking in the longitudinal direction of the bridge beam increased the vertical stress in the reinforced soil zone. The maximum tensile forces in the upper and lower geogrid layers due to shaking happened under the center of the beam seat and at the abutment facing respectively.     

“5·12汶川大地震”带给我们的反思

文章通过对“5.12汶川大地震”灾区的实地考察,从建筑规划选址、结构、材料与施工等环节分析了部分建筑遭受破坏的原因,并指出加强建筑设计、施工与管理,提升建筑质量,从而提高建筑的防灾能力。     

Damage Analysis of Hanshin Expressway Viaducts during 1995 Kobe Earthquake. III: Three-Span Continuous Girder Bridges

Almost all the single reinforced concrete (RC) piers from P35 to P350 received consistently severe damage, considering the large residual inclination of piers included in earthquake-induced severe damage. However, some of the piers in the section from P35 to P350 remained lightly damaged, and this phenomenon is observed especially in many piers under fixed bearings in continuous girder bridges. In this study, using experimentally based models for metal bearings and installing them to an existing FEM code, a nonlinear dynamic response analysis of a continuous girder bridge system is conducted. It is shown that the results depend on the ground motion, but the fuse effect of the breaking of the bearings could have been a reason for the phenomenon.     

Hybridization of genetic algorithm with immune system for optimization problems in structural engineering

Optimization is the task of getting the best solution among the feasible solutions. There are many methods available to obtain an optimized solution. Genetic algorithm (GA), which is a heuristic type of optimization method, is discussed in this paper. The focus of the paper is the use of GA for large dimensionality design problems, where computational efficiency is a major concern. The motivation of this paper is to hybridize GA with an immune system mechanism by avoiding the implementation of penalty constants, which are highly sensitive to the choice of algorithm parameters. The principal advantage of the immune system is in its seamless integration with GA-based search for optimal design. It is being hybridized with the immune system mechanism. The hybrid GA and immune system is applied for the design of the optimal mix of high-performance concrete (HPC), which is still based on trial mix and for which no rigorous mathematical approach is available. As such, to infer the values of strength and slump, a wavelet back propagation neural network or wavelet neural network is used for any HPC mix. It is necessary to minimize the cost of HPC/unit weight of HPC subjected to strength and slump constraints. The interwoven algorithm is also applied to obtain optimal sectional areas for minimum weight of space trusses subjected to static loading. Formian programming language is used for the generation of the space trusses, and Feast package is used for the static analysis of the trusses. In addition to the induction of immune system in the GA for constraint handling, it is being applied in this particular application for improving the search of GA in obtaining the best optimal solution. For obtaining the optimal sections of space trusses subjected to earthquake loading, SAP 90 package is used, and reliable results are obtained.     

Cost effect of earthquake region and soil type for office buildings in Turkey

In this study, the change in the load-bearing system cost of a reinforced concrete office building has been investigated in relation to the earthquake regions and soil types. Three different office projects each with five stories were investigated. The structural design calculations have been made according to four different soil types and four different earthquake regions. According to each combination, concrete, steel and formwork adopted approximations were calculated to reach the rough cost of each office building. The changes in the cost of projects according to the soil type and earthquake region were examined with multiple regression analysis and analysis of variance. In general, the change in cost has been observed around 22% between first and fourth soil type and 14% between first and fourth earthquake region.     

Neural Networks for Decentralized Control of Cable-Stayed Bridge

The system identification and vibration control of a cable-stayed bridge are considered difficult to achieve due to the bridge’s structural complexity and system uncertainties. In this paper, based on the concept of decentralized information structures, a decentralized, nonparametric identification and control algorithm with neural networks is proposed for the purpose of suppressing the vibration of a documented six-cable-stayed bridge model induced by earthquake excitations. The control strategy proposed here uses the stay cables as active tendons to provide control forces through appropriate actuators. Each individual actuator is controlled by a decentralized neurocontroller that only uses local information. The feature of decentralized control simplifies the implementation of the control algorithms and makes decentralized control easy to practice and cost effective. The effectiveness of the decentralized identification and control algorithm based on neural networks is evaluated through numerical simulations. And the adaptability of the decentralized neurocontrollers for different kinds of earthquake excitations and for a damaged cable-stayed bridge model is demonstrated via numerical simulations.     

Statistical evaluation of the damage potential of earthquake ground motions

This study focuses on the damage potential of earthquake ground motions based on the inelastic dynamic response of equivalent single degree of freedom structures. Their yield resistances are selected in accordance with seismic design codes. An index accounting for the accumulation of damage due to inelastic excursions is used to represent structural damage. A set of 94 ground motions are employed for this analysis, which are all scaled to the same peak ground acceleration of 0.4 g. Earthquake ground motions are classified with respect to both the ratio of peak velocity to peak acceleration (V/A ratio) and their effective excitation duration. The effect of these parameters on damage potential is investigated by using sensitivity analysis and probabilistic techniques. It is concluded that both V/A ratio and effective duration significantly influence the damage potential of earthquake ground motions, although they are not represented appropriately by the spectral definitions of earthquake excitations in seismic design codes.