Physical and Numerical Approaches for the Optimal Insertion of Seismic Viscous Dampers in Shear-Type Structures

This article presents the results of an exhaustive parametric analysis which compares the performances offered by various systems (which lead to both classical and non classical damping matrices) of added viscous dampers in shear-type structures. The aim of the research work here presented is the identification of the system of added viscous dampers which maximizes the dissipative properties under an equal “total size” constraint. The choice of the systems of added viscous dampers considered in the comparison is carried out both using a numerical approach (based upon the use of genetic algorithms) and a physically based approach (based upon the properties of classically damped systems). The comparison is carried out through the numerical evaluation of the dynamic response of representative shear-type structures to both stochastic and recorded earthquake inputs. The results obtained using both approaches indicate that a damping system based upon the mass proportional damping component of the Rayleigh viscous damping matrix (referred to as MPD system) is capable of optimizing simultaneously a number of different performance indexes, providing the best “overall” damping performances. The MPD system is characterised by viscous dampers (a) which connect each floor to a fixed point and (b) which are sized proportionally to the corresponding floor mass.     

Seismic Response of Secondary Systems Supported by Torsionally Yielding Structures

Substantial damage sustained during several recent earthquakes was non structural in nature. The economic consequence in terms of non structural component damage far exceeded the structural damage. Currently, there are several analytical studies that address the interaction between non structural components or Secondary systems (S-systems) and the main supporting structure or Primary system (P-system). Only a few of these analytical approaches have been proposed to evaluate and characterize the response of the S-systems attached to torsionally coupled P-systems. In addition, the experimental verification for the analytical approaches is scarce.

In the current study, the results and observations of an experimental research program conducted to characterize the behavior of both stiffness eccentric and mass eccentric torsionally coupled Primary-Secondary systems (PS-systems) are presented. From this experimental investigation it was found that the torsional yielding of the primary system has significant implications on the deamplification of near tuned secondary system response. The location of the S-system mounted on the P-system affects the peak response amplification, and interaction with the coupled P-system.     

Evaluation of the Nonlinear Seismic Response of an Earth Dam: Nonparametric System Identification

A system identification framework is proposed to investigate the nonlinear dynamic response of massive earth dams using the seismic motion recorded by a sparse array of accelerometers. The framework includes a methodical step of nonparametric analyses to characterize the involved loading conditions and response mechanisms. This nonparametric step provides essential information to reduce the indeterminacy of the associated parametric identificatin problem and ensure a proper model selection, calibration, and validation. The proposed framework was applied to the Long Valley earth dam (California) and benchmarked using records of a series of 1980 earthquakes. This article presents the conducted correlation, spectral motion reconstruction, and nonparametric stress-strain analyses. These analyses revealed a complex three-dimensional dynamic response marked by non uniform boundary conditions and a shear stress-strain behavior slightly less nonlinear than what was observed in triaxial tests of soil samples taken from the dam core.     

Experimental Study on Seismic Performance of Mechanical/Electrical Equipment with Vibration Isolation Systems

A prototype diesel generator equipped with a vibration isolation system consisting of restrained isolators (denoted as I/system) is quasi-statically and dynamically tested. Sequentially, the seismic simulation tests are conducted to further investigate the effectiveness of additional snubbers incorporated into the vibration isolation system (denoted as I/R system). Comparing the test results to the static design demands specified in ASCE 7-10, the recommended component amplification factor could represent the horizontal acceleration amplification phenomenon of the generator equipped with I/R system; however, the seismic force demands for static design of I/R system might not be appropriate and conservative enough.     

Analytical Seismic Assessment of a Tall Long-Span Curved Reinforced-Concrete Bridge. Part I: Numerical Modeling and Input Excitation

The seismic response of bridges is affected by a number of modeling considerations, such as pier embedment, buried pile caps, seat-type abutments, pounding, bond slip and architecturally flared part of piers, and loading considerations, such as non-uniform ground excitations and orientation of ground motion components, which are not readily addressed by design codes. This article addresses a methodology for the nonlinear static and dynamic analysis of a tall, long-span, curved, reinforced-concrete bridge, the Mogollon Rim Viaduct. Various modeling scenarios are considered for the bridge components, soil-structure interaction system, and materials, i.e., concrete and reinforcing steel, covering all its geotechnical and structural aspects based on recent advances in bridge engineering. Various analysis methodologies (nonlinear static pushover, time history response to uniform and spatially variable seismic excitations, and incremental dynamic analyses) are performed. For the dynamic analyses, a suite of nine earthquake accelerograms are selected and their characteristics are investigated using seismic intensity parameters. A recently developed approach for the generation of non-uniform seismic excitations, i.e., spatially variable simulations conditioned on the recorded time series, is used. Methods for the evaluation of structural performance are discussed and their limitations addressed. The numerical results of the seismic assessment of the Mogollon Rim Viaduct are presented in the companion article (Part II). The sensitivity of the bridge response to the adopted modeling, loading and analyzing strategies, as well as the correlation between structural damage and seismic intensity parameters are examined in detail.     

浙江越窑青瓷标本信息数据库管理系统的设计与实施

对文物标本进行系统分析归纳是传统工艺研究的必要途径,为实现越窑青瓷标本资料的资源共享,提高实验室工作效率,实现分析数据的科学管理,本研究开发设计了“浙江越窑青瓷标本信息数据库管理系统”.该系统基于B/S结构模式,以浙江省博物馆陶瓷标本中心的各类越窑瓷片标本来源、形态、化学成分、物理性能、显微结构、制作工艺等相关信息数据为基础,采用Wi ndows平台,以Visual Studi0 2010为开发环境,结合ASP.NET 4.0框架以及SQL Server数据库技术而构架.经过系统测试和实际运行证明,此管理系统具有良好的应用界面,交互性强,运行稳定,数据处理方便等优势,对实现古陶瓷研究信息资源共享,全面开展越窑青瓷的科学化研究提供了一个良好的数据平台.     

北京延庆岔道城明代城墙灰浆失效因素研究

古代砖砌墙体多用灰浆作为黏结材料,其老化失效是墙体损毁的重要原因之一.本文应用红外热成像仪、X-射线荧光分析仪、X-射线衍射仪和离子色谱仪等,分析了北京市延庆地区明代岔道城遗址灰浆及其保存环境状况,通过模拟老化试验探讨了影响其长期保存的主要因素,为此类砖砌墙体保护与维修提供依据.     

对文物博物馆管理体制创新的思考

文物托管、博物馆托管触及博物馆行业的最敏感问题即文物资源匮乏、国家小型博物馆及民营博物馆如何很好地发挥作用。文物托管是对社会文物资源的整合,有利于文物的保护和管理。博物馆托管是有效的管理机制的推广,是行业内部对博物馆各种资源要素的优化。文物托管是社会流散文物登记的一种形式,为建立合理的社会流散文物保护管理体制而探索创新。     

Rationalizing the Guerilla State: North Korean Factory Management Reform, 1953–61

This article examines the Taean Management System (TMS), a North Korean factory management reform program of 1961. Three factors explain why the TMS emerged at the time it did: first, influence from the Soviet Union and China since 1945 provided the knowledge of factory management; second, decreasing foreign aid since the mid‐1950s urged the North Koreans to search for ways to increase productivity; and third, the rise of an ideology of self‐reliance excluded the option of being integrated into the international economy. The resulting TMS, which arose at this juncture as an amalgam of rationalization and ideology, was the origin of modern management in North Korea.     

谭克敏与抗战时期贵州的新县制改革

国民政府于1935年结束地方军绅势力长期控制贵州的局面,随后在县以下推行保甲制,加大国家权力向地方社会渗透的力度,希望将基层社会全面纳入国民政府的掌控之中,但收效甚微。1940年,谭克敏就任贵州省政府民政厅长后,开始大力推行新县制,内容包括整理行政区域、调整行政机构、创建民意机关、训练基层干部等诸多方面。谭克敏作为贵州出生的本土官员,其主持的民政厅成为贯彻中央意志和协调地方利益的关键机构。在人才缺乏、经费拮据的情况下,通过新县制的实施,国家权力在贵州基层社会以前所未有的力度向下渗透。