Optimum Design Approaches for Improving the Seismic Performance of 3D RC Buildings

In this article, a number of design approaches for 3D reinforced concrete (RC) buildings are formulated in the framework of structural optimization problems and are assessed in terms of their performance under earthquake loading. In particular, three design approaches for RC buildings are considered in this study. In the first, the initial construction cost is considered as the objective function to be minimized. The second one is formulated as a minimization problem of the torsional response, while a combined formulation is also examined as the third design approach. The third approach is considered with two distinctive formulations. According to the first approach, the torsional behavior is minimized by minimizing the eccentricity between the mass and rigidity centers, while the second one is achieved by minimizing the eccentricity between the mass and strength centers. It is shown that the optimized designs obtained according to the minimum eccentricity of the rigidity center behave better in frequent (50/50 hazard level) and occasional (10/50 hazard level) earthquakes, while the designs obtained according to the minimum eccentricity of the strength center formulation was found better in rare (2/50 hazard level) events. Designs obtained through a combined formulation seem to behave equally well in the three hazard levels examined.     

Evaluation of Approaches to Characterize Seismic Isolation Systems for Design

Current design codes generally use an equivalent linear approach for preliminary design of a seismic isolation system. The equivalent linear approach is based on effective parameters, rather than physical parameters of the system, and may not accurately account for the nonlinearity of the isolation system. This article evaluates an alternative normalized strength characterization against the equivalent linear characterization. Considerations for evaluation include: (1) ability to effectively account for variations in ground motion intensity; (2) ability to effectively describe the energy dissipation capacity of the isolation system; and (3) conducive to developing design equations that can be implemented within a code framework.     

Beam-Column Joint Model for Nonlinear Analysis of Non-Seismically Detailed Reinforced Concrete Frame

An efficient and simplified plane beam-column joint model that can describe the strength deterioration, stiffness degradation, and pinching effect was developed for the nonlinear analysis of non-seismically detailed reinforced concrete frames. The proposed beam-column joint model is a super-element consisting of eight spring components and one panel zone component, representing the bond-slip mechanism of the longitudinal reinforcement and the shear deformation mechanism of the joint concrete core region, respectively. In order to represent the dynamic response at the system level, the elastic constitutive law is applied to the eight connector springs, while the Bouc-Wen-Baber-Noori (BWBN) model is adopted to describe the hysteretic behavior of the panel zone component. For the implementation of the finite element analysis, the algorithmically consistent tangent of the BWBN model is derived as a uni-axial constitutive model, while the initial stiffness of the panel zone component is determined by the concrete compression strut assumption. The accuracy and efficiency of the proposed beam-column joint model were calibrated at both the component and structural levels by comparing the simulated results with the experimental data for non-seismically detailed joint sub-assemblages and a reinforced concrete plane frame.     

Simplification and Assessment of Modal-Based Story Damage Index for Reinforced Concrete Frames Subjected to Seismic Excitations

Different relations have been represented for the local damage index of structures to date, while the same application is defined for them as can be an indicator of relative sustained damage by the components or stories. Since different force-resisting systems subjected to the ground motions can behave differently, some well-known story damage indices are evaluated for the reinforced concrete frames with regards to their operation during nonlinear time history analysis. Two general concepts of story damage determination are selected for this purpose. SDI is a modal-based story damage index, which is calculated by the modal frequency and mode shapes. The behavior of this local index is evaluated during the seismic excitations. The results were compared with Park-Ang and modal flexibility story damage indices. Based on analytical study on seismic responses of some RC frames subjected to a suit of earthquake records a new story damage index has been developed. It has been derived from a simple global damage equation (softening index) using a normalized ratio of inelastic story shear to its drift. A procedure is recommended to use the proposed equation without any requirement to perform nonlinear dynamic analysis, which can significantly reduce the computational efforts. Distribution of the new represented SDI along the structural height shows a good agreement with damaged state of the RC frames after seismic excitations.     

创建学习型政党 推进党的建设科学化

创建学习型政党是党完成肩负的历史使命的内在要求,是党正确应对国际国内考验的时代需要,也是党解决自身建设问题的现实需要。提升党的建设的科学化水平,必须积极推进学习型政党建设,努力促进全党树立积极学习的新理念,大力加强干部队伍建设,切实完善相关制度,不断促进学习方式的多样化,确保党始终保持求真务实、锐意进取的积极姿态,以更好地带领人民夺取全面建设小康社会的新胜利。     

多元统计分析方法在汉墓等级划分中的应用——以安徽南部西汉早期墓为例

一、前言在考古学研究中,墓葬研究占相当重要的地位。墓葬可以为研究者提供多角度的切入点,具有很多其他考古学资料所无法比拟的信息。有研究者指出,可以通过墓葬研究一个文化的面貌、特征、结构,文化的编年,建立一个文化的时空框架;可以通过墓葬研究一个文化的埋葬习俗,墓葬的埋葬规律以     

贵州辛亥革命中“二·二”事变性质分析

1912年贵州“二·二”事变的发生,给辛亥革命后贵州政局的发展走向产生了重大影响。长期以来,无论是时人或后人,对“二·二”事变的认识和评价,都存在着分歧。在纪念辛亥革命发生100周年之际,分析贵州辛亥革命中“二·二”事变的性质,总结其经验教训,对于更加深入全面了解贵州辛亥革命史具有重要意义。     

Spatial Autocorrelation and the Classic Maya Collapse: One Technique, One Conclusion

A pair of articles appearing recently in this journal (Whitley & Clark, Journal of Archaeological Science12, 377-395, 1985; Kvamme, Journal of Archaeological Science17, 197-207, 1990) apply spatial autocorrelation analysis to the distribution of terminal long-count dates from southern Lowland Classic Maya monuments. The authors employ similar techniques yet arrive at contradictory conclusions regarding the presence of geographical patterning in the collapse of the Classic Maya civilization in this region. Kvamme's contention, however, that Whitley & Clark conducted an inappropriate analysis and arrived at an erroneous conclusion is unsubstantiated. Both articles present appropriate analyses and report results which support the presence of spatial patterning in the Lowland Maya dates.     

科学发展观视野中的生产力范畴

传统的生产力概念把生产力定位于人们改造和征服自然的能力,对此应当给予新的思考和阐述。在科学发展观的视野里,生产力范畴不只是人类征服、改造自然的能力,还应包括人类保护、建设自然的能力;生态环境应该是生产力结构中的基本要素之一;生态建设应成为衡量生产力发展水平的一个重要标志。     

论以人为本与党群关系建设

“以人为本”是科学发展观的核心,它不仅体现了党的群众观的基本要求,而且也为新时期新阶段的党群关系建设奠定了坚实的理论基础。党在执政备件下,落实“以人为本”的要求必须始终坚持执政为民,切实代表好最广大人民群众的根本利益。