A lesson from Bass Strait on connectivity conservation

Isolation effects on the distributions of plant species in fragmented forests appear to be weak over tens to hundreds of years and strong over geological eras. The 250 km wide, 6.5 millennia old Bass Strait, and other millennium-scale disjunctions in the range of Eucalyptus regnans forests, were used to determine the effects of intermediate periods of isolation on plant species occurrence and composition. Three of six floristic communities were found on both sides of Bass Strait. The residuals from multiple regression models using climatic variables on the latitude vector were not explained by latitude, indicating negligible isolation effects from Bass Strait. However, there was a lesser compositional effect of disjunctions within land masses than between land masses, suggesting some effect of the larger barrier. No species that commonly occurred with E. regnans and were largely confined to wet forest exhibited absences from any region where the climate and soils were within their range. If areas isolated from each other for millennia can maintain their vascular plant biota, the expenditure of conservation funds on creating corridors to connect large areas separated by anthropogenic landscape modification might require more justification than it is currently afforded.     

The Numerical Study of Base-Isolated Buildings Under Near-Field and Far-Field Earthquakes

The behavior of base-isolated building frame is investigated with the help of a numerical study for far-field and near-field earthquakes with directivity and fling-step effects. Both design-level and extreme-level earthquakes are considered. Selected response parameters are peak floor displacement, acceleration, base shear, and isolator displacement. Inelastic behavior of base-isolated structure during the earthquake is investigated performing nonlinear time history analysis of a ten-story building frame. This study shows that base isolation is not effective for near-field earthquakes. Even for design-level earthquake, the frame gets significantly into inelastic range for earthquakes with fling-step effect.     

Modelling and Seismic Response Analysis of Italian Code-Conforming Base-Isolated Buildings

ABSTRACT

This paper reports on results of nonlinear analyses performed within the RINTC project on an RC building isolated with different systems (High Damping Rubber Bearings, High Damping Rubber Bearings and Flat Sliding Bearings, Friction Pendulum System) and designed according to the Italian design code. The seismic response has been evaluated under different seismic input levels of two sites with different hazard and by considering two Limit States: Global Collapse and Usability-Preventing Damage. The influence of seismic stoppers and modelling uncertainties is also evaluated. Results permit to compute the implicit collapse risk and to identify critical aspects of current design procedures.     

抗日根据地时期的女性离婚问题——以晋西北(晋绥)高等法院25宗离婚案为中心的考察

中共晋西北抗日民主政权建立后即颁布《晋西北婚姻暂行条例》,对女性离婚权予以法律上的肯定。一批农村妇女以情感、经济等原因向丈夫提出离婚,根据地婚姻观念或离婚现象呈现出与以往不同的景观。由于离婚案件频频发生,影响了中共抗战大局,中共中央于1943年发表关于各抗日根据地妇女工作方针的四三决定,修正过去激进的婚姻变革路线,以将妇女关注的重点由婚姻问题转向生产建设并缓解根据地两性之间日益紧张的矛盾。这种策略性的政策转变引起法院对待离婚案件的处理发生演变,即不同时期性质相同或相近之案件,其审理结果迥然相异。这亦说明婚姻变革须立足于现实的客观实际。     

博物馆古建筑保护与功能提升——以南京博物院老大殿改造为例

南京博物院主体建筑老大殿,是中国近代建筑中唯一采用现代结构形式的仿辽代建筑。近年,南京博物院采用整体顶升、隔震加固等先进技术对其进行修缮保护,不仅有效增强了其抗震水平,还扩大了建筑的空间面积、提升了空间使用功能、丰富了展示内容和方式,为优秀古建筑的保护利用提供了新的技术思路,也为优秀古建筑的保护利用与博物馆馆舍建设及博物馆各项事业发展的相互促进积累了成功经验。     

Evaluation of IBC Equivalent Static Procedure for Base Shear Distribution of Seismic Isolated Structures

It has been pointed out that the static lateral response procedure for base isolated structures presented in IBC somewhat overestimates the seismic story force [Lashkari and Kircher, 1993 Lashkari, B. and Kircher, C. A. . Evaluation of SEAOC/UBC analysis procedures, Part 1: Stiff superstructure. Proceedings of a Seminar on Seismic Isolation, Passive Energy Dissipation and Active Control. Redwood City, California. ATC Report 17-1.  [Google Scholar]; Constantinou et al., 1993 Constantinou, M. C., Winters, C. W. and Theodossiou, D. . Evaluation of SEAOC and UBC analysis procedures, Part 2: Flexible Superstructure. Proceedings of a Seminar on Seismic Isolation, Passive Energy Dissipation and Active Control. Redwood City, California. ATC Report 17-1.  [Google Scholar]]. In this article IBC equivalent static method for base shear distribution of seismic isolated structures is evaluated. For this purpose one-story to six-story building models are designed according to equivalent lateral response procedure for different elastomeric isolation systems. The results of equivalent lateral response procedure in parameters such as base shear and vertical distribution of base shear are compared with results obtained from dynamic nonlinear analysis and the efficiency and limitations of its application are investigated. In general, the results of equivalent lateral response procedure in base shears are acceptable within the scope of this procedure, but the proposed triangular distribution of base shear is somewhat conservative. So a new formulation for vertical distribution of base shear is proposed which results in a more realistic distribution of shear over the height of isolated buildings. The accuracy of the new formulation is examined by comparing the resulting responses obtained from this study with those calculated by nonlinear time history analysis.     

Optimal Control of Accelerations in a Base-Isolated Building using Magneto-Rheological Dampers and Genetic Algorithms

This article presents a numerical study aimed at improving effectiveness of the isolation system of an actual building by adding magneto-rheological (MR) dampers that act in parallel to the existing rubber bearings (RB). The building itself is modeled with uniaxial elastic elements. Additional elements that include the RBs and the MR dampers are added at the base of the building and two different genetic algorithms are used to optimize operation of the MR dampers. Maximum acceleration and relative displacement at the top of the building are taken as the variables to be minimized. Records of destructive earthquakes are used as input. A comparison is made between the building responses with RB and the one with the additional control system.     

Comparison of Numerical and Experimental Seismic Responses of FREI-Supported Un-reinforced Brick Masonry Model Building

Comparative study of numerically and experimentally obtained seismic responses of un-reinforced masonry building supported on in-house designed un-bonded fibre reinforced elastomeric isolator (U-FREI) are presented in this article. The effectiveness of U-FREI is established very clearly in terms of controlled dynamic response of the model building. Experimental studies are carried out on a shake table with elaborate instrumentations for measurement of acceleration and displacements at different floor levels. Numerical study of the model building supported on U-FREI is carried out to compare the results with experimental investigation. Multi-linear pivot hysteretic plasticity model is used to simulate the behavior of FREI, while plate elements are used for brick-masonry walls. Experimentally obtained force-displacement curves of FREI are used for defining the properties of multi-linear model representing FREI. The dynamic responses obtained from the numerical studies are compared with those from experimental investigations. This study indicates that the seismic responses of building supported on U-FREI can be numerically evaluated with quite reasonable accuracy. A good numerical model can be judiciously used at the preliminary design stage, followed by actual testing and construction of the base isolated building.     

Uncommon Ground: Holism and the Future of Anthropology

Anthropology has long been a contested field with roots in both scientific and humanistic discourse. The “four-field” approach in American anthropology has been used by some as a means of suppressing conflict and enforcing a false sense of unity. While critiques of the four-field approach are warranted, in fact holism represents anthropology's greatest strength. Anthropology gains a competitive advantage over other disciplines in its ability to combine biological and cultural approaches. Moreover, the four-field model, while historically contingent, is well suited to the institutional and political realities of the American academy, especially the public research university.     

VULNERABILITY OF ELASTOMERIC BEARING ISOLATED BUILDINGS AND THEIR EQUIPMENT

In this paper, we compare the vulnerability of isolated and conventional structures as well as equipment when uncertainty on the excitation and on some of the structural properties is considered. This comparison is performed, mainly, with a series of Monte Carlo simulations. The results clearly show the higher sensitivity of isolated structures and their equipment when submitted to statistically reasonable excitations that are different from those used for their design. This fact is recognised by some, but not all, earthquake regulations, mainly, by considering lower behaviour factors for isolated structures than for conventional ones. Although isolated structures designed according to these recommendations (e.g. FEMA 368) exhibit tow damage less frequently than conventional structures, the probability of failure is similar for both types of structure.