Development of Collaborative Structure Analysis (CSA) System and Its Application to Investigate Effects of Soil-Structure Interaction

In this article, a collaborative structure analysis (CSA) system is developed for integrating different finite-element simulation programs. In this system, a simulated structure is divided into multiple substructures, and the interaction between the substructures is considered. Interfaces for the commercial finite-element program ABAQUS and for an open-source framework for structure analysis, OpenSees, are developed to achieve CSA integration. The CSA system is applied to analysis of a soil-structure interaction (SSI) problem, and the effects of SSI are investigated, and the efficiency and accuracy of the system are demonstrated.     

Experimental and Analytical Study of Seismic Soil-Pile-Structure Interaction in Layered Soil Half-Space

The dynamic interaction of pile foundations, embedded in a horizontally stratified soil profile, with superstructures under low to moderate earthquake excitation can be handled in different ways. In this article, the soil-pile-superstructure dynamic interaction problem has been investigated using the coupled finite element-boundary element method. Comparison with shaking table experiments of a small scale model pile shows a good correlation with the proposed method in terms of the kinematic response of pile foundations and the structural response. A parametric study of the proposed model has yielded important results essentially concerning the amplification factors of the pile foundation and the superstructure.     

Identification of Suitable Limit States from Nonlinear Dynamic Analyses of Masonry Structures

Performance-based earthquake engineering, developed over the last decades for the design and assessment of other structures, can also be applied for masonry structures if the particularities of masonry are incorporated into the procedure. According to this methodology, structural performance can be assessed according to damage states which are identified through displacement/damage indicators. While various methods for the identification of limit states from the results of nonlinear static analyses exist, the identification of damage states from the results of nonlinear dynamic analyses is still uncertain. This article investigates a number of criteria allowing to identify the attainment of significant limit states from the results of time history analyses, in terms of appropriately identified response quantities. These criteria are applied to five building prototypes and their results are compared. A comparison with the limit states derived from nonlinear static analyses is also made.     

Reduction Factors for Seismic Design Spectra for Structures with Viscous Energy Dampers

A simple mathematical expression is proposed to estimate spectra reduction damping factors for seismic design of systems with viscous dampers. The expression is obtained from the ratios between ordinates of uniform hazard spectra associated with two different return intervals (50 and 125 years), corresponding to sites with different types of soil within the Valley of Mexico. The expression proposed depends on the dominant period of the soil, and on both the vibration period and damping ratio of the structural system. Values of the damping factors proposed here are comparable to those recommended by different authors and seismic design building codes.     

Effects of Different Record Selection Methods on the Transverse Seismic Response of a Bridge in South Western British Columbia

The seismic response of a continuous 4-span bridge designed according to the current Canadian seismic provisions is investigated using Incremental Dynamic Analysis (IDA). Different earthquake types, including shallow crustal events, interface Cascadia subduction, and deep inslab subduction are considered. The median collapse capacities calculated using different record selection methods including Conditional Mean Spectrum (CMS)-based, Uniform Hazard Spectrum (UHS)-based, and epsilon-based methods are compared. The use of the epsilon-based method generally resulted in the highest collapse capacity predictions, but the CMS-based method was less sensitive to the number of records considered in the IDA.     

清代早期四合如意云寸蟒纹织金妆花缎的结构分析与保护修复

受北京艺术博物馆的委托,对两件香色地四合如意云寸蟒纹织金妆花缎进行保护修复。两件妆花织物质地柔软、组织结构紧凑、纹样细腻、设色庄重。但经长期自然和人为因素的影响,织物多处破损、开裂、脱丝、破洞、污渍等,圆金和片金纹纬上的金片大量脱落,整体污染较为严重,质地脆弱,无法研究和展出。本文通过研究妆花所承载的历史文化信息、综合织物的质地、组织结构、纹样形态、设色特征等诸多因素,将其定为清早期织物。应用三维视频显微镜和电子丝绸尺软件对织物组织结构、破损程度进行了分析。在此基础上,制定了保护修复工作目标和方案。修复后的两件织物基本恢复了原貌,效果较好,可以作为研究中国丝织品的实物根据。     

二十世纪有关纸的考古发现不能否定蔡伦发明造纸术（1）

近几十年来,我国考古工作曾先后在一些西汉遗址和墓葬中发现了若干纸状残片,于是引起国内外许多学和广大人民的关注和提出疑问。是否蔡伦前约二百年就有了纸?造纸术还是不是蔡伦发明的?新发掘的纸状物到底是个什么样?经对历次的发掘作了详细的调查研究和分析化验,结论认为：20世纪有关纸的考古发现不能否定蔡伦发明造纸术。     

一种新型古丝绸强度测定仪的研制

为了克服目前利用抗拉强度分析方法检测古丝绸老化强度的缺点,通过对古丝绸抗拉强度分析,利用电子天平的称量精度和记录、显示功能,结合控速、控力和固定试样的机械部件,对测定仪的机械、电路、软件部分进行了设计,研制出一种新型的古丝绸强度测定仪。用古丝绸强度测定仪对古丝绸进行了测试,结果显示古丝绸强度测定仪能很好地测定古丝绸的抗拉强度。该仪器为定量测定古代丝织品老化程度提供了一种较为精细的手段。     

旅游目的地定位突出属性的识别——轮换方格分析技术的运用

随着旅游市场竞争日趋激烈,目的地定位的重要性愈加突出。然而,国内研究和实践对"把握旅游者兴趣和需求"这一定位首要工作普遍认识不足,且实施不到位。鉴于此,本研究对目的地定位中"击中消费者心灵"这一关键环节的实施从理论和实证上进行了阐释。理论上,分析了目的地突出属性与定位之间的关系及当前国内误区。实证上,引入轮换方格分析法,以国内十大海滨城市目的地为要素,阐释了识别旅游者对竞争目的地相比较的目的地突出属性的方法程序。此外,对旅游者访谈结果与目的地业界代表访谈结果的比较发现,供需双方在旅游者需求的认识上不吻合。文章最后还对本研究的应用价值和局限做了总结。     

东部地区流动人口城市融入的比较研究

以东部地区城市特色比较明显的6个城市的问卷调查为基础,结合中国的实际情况构建了衡量流动人口城市融入的指标体系,通过主成分分析对6个城市流动人口的城市融入程度进行了比较。研究发现6个城市流动人口融入程度存在着明显的差异,环渤海的青岛和沈阳流动人口的城市融入程度最高,而珠江三角洲地区的东莞和长三角的温州流动人口的城市融入程度最低,介于两者之间的是长江三角洲地区的无锡和京津冀地区的北京。总体而言,北方城市流动人口的融入程度总体上要高于南方城市。流动人口城市融入程度的差异反映了城市特色或性质的不同。城市规模、城市所在区域的文化特色、城市经济特征、流动人口在总人口中的比例都是影响城市融入的重要因素。对于南北方流动人口城市融入的差异,方言具有很大的影响,推广普通话有利于流动人口的城市融入。