Distribution of Earthquake Total Input Energy of Structures

This paper discusses the distribution regularity of earthquake total input energy of structures between hysteretic energy and damping energy and their influencing factors taking account of various factors.The results can serve as the basis for the energy method of aseismic structural design and energy analysis in the study of damage criteria.     

Maximum Displacement Estimation of Seismic Structures Based on Hysteresis Energy

Based on characteristics of hysteretic energy of structures which are simplified single freedom degree systems and under the short duration impulse modle mid duration and long duration modle earthquakes, correlation between the maximum hysteretic energy increment per cycle and the maximum inelastic displacement of different structures is investigated. Simplified equations to estimate the maximum inelastic displacement are obtained. The validity of the equation is recognized. It is pointed out that the impact destroy of the structures may occur when energy increment per cycleis 50 80 percent of total hysteretic energy, and the maximum hysteretic energy increment per cycle, and that the maximum inelastic displacement can be used to evaluate aseismic capacity.If energy increment per cycleis small relative to total hysteretic energy, the destroy of the structures by cumulate dissipation energy may occur, and the total hysteretic energy can be used to evaluate aseismic capacity.     

Seismic Isolation Design of a Brick Masonry Residential Building

In this paper, the seismic isolation design of a brick masonry residence building in Liyang City is described.The aseismic behavior of the isolated building under earthquake is studied with time history analysis method.The calculation results show that the isolated building has excellent aseismic behavior and keeps elastic state under seldom occurred earthquake.     

结构消(耗)能元件芯材SN490B本构关系数值模拟

采用消(耗)能元件的结构在遭受地震作用时,元件芯材首先屈服进入塑性阶段,利用其滞回变形消耗地震输入能量,保护主体结构,元件芯材本构关系的数值模拟是对采用消(耗)能元件结构进行抗震分析与设计的基础。为更真实地模拟结构消(耗)能元件芯材在单调和循环荷载下的本构响应,更准确地对采用消(耗)能元件结构进行结构弹塑性地震响应分析,对常用作消(耗)能元件芯材的日本高延性钢材SN490B的单调、循环加载本构及循环骨架曲线进行了数值模拟,包括：采用Esmaeily-Xiao二次流塑性模型模拟材料在单调荷载作用下弹性段、屈服段、强化段和二次流塑段4个阶段;采用混合强化模型模拟材料循环荷载作用下的本构响应,运用大型通用有限元软件ABAQUS结合数值模拟参数对16种不同循环加载制度下的循环加载试验进行模拟,并与试验结果进行对比;采用Ramberg-Osgood模型、无量纲化的Ramberg-Osgood模型及两段式模型模拟循环骨架曲线。研究结果表明：所采用数学模型可以较好地模拟SN490B钢材单调、循环加载本构响应及循环骨架曲线,数值模拟与试验结果拟合较好。     

Seismic Concept Analysis of High-rise Diagrid Tube Structures

In order to study the seismic concept of high-rise diagrid tube-core tube structures,CFST diagrid tube-concrete core tube structures were designed based on typical project.The elastic-plastic time history analysis method is adopted and the components yield order is summarized based on their plastic developing processes.The influences of wall thickness,inclined column cross section and coupling beam height on the components yield order are studied and the distribution of seismic fortification lines between tubes are presented.The main factors exerting influence on structure lateral stiffness are analyzed and the key components of structure lateral stiffness and plastic energy dissipation are achieved.The seismic concept of this structure is discussed considering the three level earthquake fortification criterion and components yield characteristics at last.     

Improved Modal Capacity Spectrum Method for Estimating Seismic Performance of Structures

Performance-based seismic design involves how to confirm inelastic displacement demand of structures under earthquake in concise and reasonable way. Two shortages need to improve in analyzing the elastic-plastic seismic responses of structures if the traditional capacity methods are employed. The shortages are the uncertainty of equivalent high damp of elastic-plastic structures and the limitation of the higher order vibration mode effect being not taken into account. To solve these problems, the authors propose the concept and analyzing process of improved capacity spectrum method based on modal pushover analysis and the elastic seismic responses spectrum modified by strength reduction coefficient and ductile coefficient. The example of analyzing the performance of frame structure is shown which may be a simple and effective method used in engineering. This method has application potential in Performance-based seismic design.     

Active Control of Building Structure Using Artificial Neural Networks

A study on application of artificial neural networks(ANN) to active structural control is presented. A feedforward neural network with an adaptive back propagation training method is used in this paper. In the back propagation training, the learning rate is determined by ensuring the decrease of the total error function of the output training patterns at each training cycle. Four-layer-BP networks is constructed to produce the active force for the building structure subjected to earthquake excitation. Numerical examples of single-degree-of freedom systems under earthquake excitations are given to illustrate the effectiveness of the proposed control strategy.     

Experimental Investigation on the Aseismic Behavior of Seismic Damage Masonry Wall Retrofitted with Grouting and Steel Hoops

In order to accurately evaluate the aseismic behavior of the seismic damaged masonry pagodas destroyed by Wenchuan earthquake and strengthened after the earthquake, a test was conducted to acquire related parameters on seismic performance from the specimens made by masonry and retrofitted with grouting and steel hoops. Taking a seismic damaged ancient masonry pagoda in Sichuan as a case study, four kinds of primitive specimens are fabricated by simulating the conformation of the masonry pagoda. Then the primitive specimens are destroyed under cycle loads and the damaged specimens are repaired by grouting and steel hoops. Cycle controlling tests are conducted with the specimens and relevant data are acquired. Experimental results showed that grouting combined with steel hoops could improve the ductility and energy dissipation capacity of a seismic damage of brick masonry structure, but it do a little to improve the stiffness of a seismic damage structure. And the cracking load of the repaired masonry is much lower than the original undamaged structure.     

基于能值理论的荥经县土地系统脆弱性分析

土地系统脆弱性作为制定土地可持续发展政策的重要依据,已成为当前土地系统可持续发展研究的重要组成部分。应用能值分析方法,在对荥经县土地系统能值投入产出动态分析的基础上,对土地系统脆弱性状况进行分析,旨在为当地区域可持续发展寻求途径和对策。研究结果显示：（1）从1996—2011年,全县土地系统总能值投入从1.36E+21 sej增加到2.37E+21 sej,总能值产出从1.59E+21 sej增加到1.96E+21 sej;（2）土地能值密度、人均能值及环境负载率均呈现增长趋势;（3）能值投入产出比及可持续发展指数均有所下降。结果表明荥经县人民生活水平虽有所提高但土地系统所承受的环境压力却越来越大,其脆弱性在逐渐增强。     

Study on constant current control of inductive power transfer with parameter identification

Aiminy at magnetic exciting current (resonant current) control, a constant current control method based on dynamic parameter identification is put forward. With energy conversion analysis, the energy storage, supply and dissipation functions of the system resonant network are constructed. The reflecting impedance identification functions are obtained by constructing the energy equilibrium relations in a period and among several periods. Furthermore, a constant current control strategy by regulating the system input voltage with Buck converter is presented. Combining the relations among system input voltage, the envelope of resonant current and the input of Buck converter, the constant current control law is proposed. The control law is verified with experiments. For the proposed method, in parameter identification, only the data of zero crossing point of resonant voltage and current are required, which reduces the complexity and costs of sampling system. Also, the constant current control law does not need complex computation and is easy to implement.     

Seismic Performance and Failure Process of Long-Span Bridge With High Piers

Based on OpenSEES platform, elastic-plastic structural model of long-span bridge with high piers is established. This paper utilizes time-history analysis method to analyze seismic responses of bridge under consistent or multi-support seismic excitation. Seismic performances and failure process for bridge with high piers are studied. Analysis results show that characteristics of seismic excitation and the way of excitation input have some effect on failure sequence and the occurrence or location of plastic hinge for bridge piers. The failure mode for high piers assumes bending failure, and the failure for top of pier is frequently prior to that of pier bottom, which should be paid enough attention.     

Probabilistic Seismic Damage Analysis of Inelastic Structural System

A novel numerical model for seismic damage analysis of inelastic two degree of freedom (2DOF) system under bi directional excitations was developed by taking the strength degradation, stiffness deterioration and pinching effect into account. The influences of bidirectional excitations, strength degradation, stiffness deterioration and pinching effect on statistical characteristics of seismic damage index of inelastic 2DOF system were investigated using 69 selected earthquake records. The results show that seismic damage index of inelastic 2DOF system can be described as either the Lognormal or the Frechet distribution variable; the seismic damage index of inelastic 2DOF system can be approximated by the square root of sum of square (SRSS) of seismic damage index of single degree of freedom (SDOF) system; an decrease in post yielding stiffness or consideration of strength degradation, stiffness deterioration and pinching effect may increase the seismic damage index remarkably.     

Near Crack Line Elastoplastic Solution for an Eccentric Cracks Loaded by the Pore Water Pressure

By using near crack line analysis method and Mohr-Coulomb strength criterion,the elastic-plastic solution for near crack line of an eccentric cracks loaded by the pore water pressure under large scale yielding condition is analyzed.The elastic stress fields,the plastic stress field,the unit normal vector of the elastic-plastic boundary near the crack line,the elastic-plastic stress fields near crack line are identified.The change pattern of the length of the plastic zone and the pore water pressure is presented.Besides,the elastic-plastic analytical solution for an eccentric cracks loaded by the pore water pressure is obtained.     

Accomplishment of Elastic-plastic Analysis in Geotechnical FEA

In order to realize elastic-plastic analysis in geotechnical FEA, in this paper, firstly, the method how to realize elastic-plastic analysis in Super-Sap is discussed. Then, this paper stresses to introduce the principle and the steps used to achieve the accomplishment of elastic-plastic analysis in Super-Sap. Finally, an engineering practice is given to prove that the geotechnical FEA elastic-plastic analysis and visualized post-processing can come true by it rapidly.     

北京郊区多目标产出循环型农业效益评估——以房山区南韩继大型养猪—沼气生态经济系统为例

随着资源危机与环境压力日益增大,循环农业在现代农业经济中发挥着重要作用。本文以房山区周口店镇南韩继村沼气站和南韩继村养猪场为研究对象,采用能量、能值和经济评价方法分别对北京郊区典型万头猪场、运行十几年的沼气发酵系统及二者相互循环后的生态经济系统效益进行了综合评估,从而对北京郊区循环农业发展的基本形式进行了定量分析,将为京郊循环农业的进一步发展提供决策依据。研究表明,从能量角度而言,二者循环以后,总能量产出效率为1.77,总能量投入经济产出效率为87%,分别比两个单独亚系统（养猪亚系统：1.37、64.1%,沼气亚系统：0.35、0.31）都大大提高;从能值角度而言,二者相互循环以后,净能值产出率为38.04,比猪场净能值产出率（161.5）降低,但使沼气站净能值产出率由负变为正,有力证明了农业系统经过循环以后,循环效益显著增大;从经济评价角度,二者相互循环以后,财务内部收益率为26.8%,大于设定的基准财务收益率10%。在设定的折现率15%时,财务净现值=261.0万元>0,投资回收期为3年,说明,循环生态经济系统在财务上也具有可持续性,经济效益显著。     

The Expert System of Fuzzy Evaluation on Aseismic Performance of Building structure Type

Based on analyses and studies on basic knowledges such as expert system,engineering database and language,a model frame of Expert Decision Design System EDDS is built up,which consists of expert system as the main component.An example of EDDS application in aseismic building structure type choosing is presented,while its feasibility and advantages are demonstrated simultaneously.     

Simulation of nonstationary stochastic earthquake ground motion based on orthogonal Hilbert spectrum

A new method is proposed for the simulation of nonstationary stochastic earthquake ground motion based on orthogonal Hilbert-Huang transform (OHHT) spectra of its sample observations. Orthogonal EMD method is introduced to treat with IMF. OHHT avoids leakage of energy compared with conventional HHT, and it can be used for analysis of nonstationary signal. The average of the Hilbert spectra over the samples is defined as the Hilbert spectrum of the earthquake motion process and used as the target in the simulation of the process. Random Phase is also introduced to simulate nonstationary earthquake. The statistic characteristics function of stochastic process is given in the paper. Simulations of two earthquake ground motion are carried out. The results show that the samples can accurately reflect amplitude and frequency nonstationary of records. Samples and record of same earthquake ground motion process have same statistic characteristics.     

Analysis of Seismic Dynamic Responses of Tunnel throughFault Zone in High Earthquake Intensity Area

Based on dynamic time history analysis, dynamic response behavior of an un supported tunnel through fault zone which was simulated by interface and solid elements was studied under uniform input earthquake wave excitation. The analyses of response behaviors, including displacement difference, acceleration magnification, and plastic zones and so on, were carried out when earthquake wave excitation was input along transverse, longitudinal and vertical of tunnel respectively. The results show that simulation method for fault zone is effective; the earthquake causes obvious displacement difference at fault zone and surrounding rock contacting part. The maximal displacement difference reaches to 51.8mm under transverse uniform input earthquake wave excitation. And the displacement difference under vertical and longitudinal is only 44.3% and 23.1% of the transverse value, respectively; the acceleration magnification in fault zone is significantly greater than that in surrounding rock. Shear failure zone appears at the fault zone and surrounding rock contacting part, and it is especially prominent under input longitudinal earthquake wave excitation. It is proposed that fault zone has significantly influence on the dynamic performance of tunnel. The fault zone and the transitional zones are the control zones of seismic design when tunnel passes through fault zone, thus, the study on the anti seismic measures should be further strengthened.     

Analysing the energy balances of sugar beet cultivation in commercial farms in Germany

Energy balances are increasingly used to assess the energy efficiency and productivity of agricultural production. In this study, energy balances for sugar beet cultivation in commercial farms in Germany were calculated. 109 farmers with 285 fields were interviewed about the sugar beet cultivation 2004. The energy input and the energy output were calculated with standardised balance-sheet approaches and energy equivalents. Calculated energy balance parameters were the energy gain (energy output less input), the output–input ratio (energy output versus input) and the energy intensity (energy input versus natural yield measured in Grain Equivalents). A factor analysis was performed to explain the variation of the energy balance parameters between the fields by crucial factors for energetic efficiency and productivity. Fields with similarly valued factors were grouped into common clusters by a cluster analysis and a discriminant analysis. The influence of specific growing conditions and cultivation methods on the energy balances were examined for the clusters.Total energy input (median: 17.3 GJ ha⁻¹), energy output (261.7 GJ ha⁻¹), energy gain (244.6 GJ ha⁻¹), output–input ratio (15.4) and energy intensity (87.4 MJ GE⁻¹) revealed a significant variation. The total energy input was significantly lower and the energy yield was significantly higher than in previous studies. Thus, the energy gain and the output–input ratio have clearly risen compared to earlier studies. Today, sugar beet cultivation is energetically more productive and efficient than the cultivation of many other arable crops in Middle Europe.The intensity of the cultivation measures irrigation, catch crop cultivation, tillage and N fertilisation as well as the management of all cultivation measures and the site were determined as crucial factors for energy efficiency and productivity. The intensity of the different cultivation measures influenced the total energy input significantly, but no influence on the energy output was determined. In contrast, the cultivation management (quality and adaptation of cultivation measures) was mainly responsible for the energy output. Whereas the cultivation management mostly explained the energy gain, the factor cultivation management and the factors representing cultivation intensity together were responsible for the output–input ratio.Cluster and discriminant analysis resulted in the formation of 13 clusters. For clusters with an above-average energy gain and output–input ratio, the intensity and in particular the management of cultivation measures were essential for optimising the energy balance.     

Response Spectrum Method for Seismic Response Calculation of Pipeline System Multiply Supported on Structures

In order to ensure the function of building in the earthquake, reduce economic losses and facilitate post-disaster relief, it is necessary to accurately evaluate the seismic performance of pipeline system on the structure under seismic excitation. Considering this practical need, seismic response calculation methods of piping systems on structures were systematically studied. Firstly, theoretical derivation was performed based on the pseudo-excitation method for seismic response of pipeline system. It is found that the formula in previous studies has obvious defect: the accurate relative displacement values of degree of freedom near the supports can not be obtained in the formula. Thereby, the theoretical basis for derivation was mended to correct the defect, and the uniform combination expressions available for pipeline's seismic response calculation which is in the form of ground response spectrum or floor response spectrum were presented. Moreover, the simplified formulas and calculation method of correlation coefficients in the obtained expressions were put forward according to the assumption of white noise earthquake excitation. Finally, case studies were adopted to verify the proposed method's effectiveness and applicability in the seismic response calculation of pipeline system.