Controlled Rocking CLT Walls for Buildings in Regions of Moderate Seismicity: Design Procedure and Numerical Collapse Assessment

Controlled rocking heavy timber walls are designed to rock on their foundations in response to earthquakes. For regions of moderate seismicity, it is proposed that this rocking behaviour can be adequately controlled using only post-tensioning, even with a large force-reduction factor and no supplemental energy dissipation. This article presents a force-based design procedure for controlled rocking cross-laminated timber walls without supplemental energy dissipation, including a method for estimating higher mode effects. Fragility analyses of three prototype walls demonstrate that the procedure can limit the probability of collapse to <10% during a maximum considered earthquake in a region of moderate seismicity.     

现代仪器分析技术在皮质文物保护中的应用

随着现代科学技术的不断发展,越来越多的仪器分析技术和方法被应用到皮质文物保护领域。分析检测是获取文物病害信息和评估保护效果的重要途径,可以为文物保护修复提供科学依据。文章介绍了表面分析、光谱分析和波谱分析、热分析以及联用技术等现代仪器分析方法和技术的特点和优势,以及它们在皮质文物保护中的应用情况。皮质文物本身蕴含着大量丰富的信息,对皮质文物开展系统全面分析研究,从宏观和微观等不同层面定性和定量研究环境因素对皮质文物物理、化学性质以及微观结构的影响。建立皮质文物检测结果数据库和皮质文物病害标准图库,以及构建皮质文物劣化和病害防治保护效果评价体系是未来研究的主要发展方向和趋势。     

Collaborative Networks for Effective Ecosystem‐Based Management: A Set of Working Hypotheses

Ecosystem‐based management (EBM) represents a comprehensive approach to better govern the environment that also illustrates the collaborative trend in policy and public administration. The need for stakeholder involvement and collaboration is strongly articulated, yet how and for what purposes collaboration would be effective remains largely untested. We address this gap by developing and evaluating a set of hypotheses specifying how certain patterns of collaborations among actors affect their joint ability to accomplish EBM. Content analyses of management plans drawn from five EBM planning processes in Sweden are combined with analyses of the collaborative networks through which these plans have been developed. Our results indicate that system thinking and the ability to integrate across different management phases are favored by collaborations between different kinds of actors, and by project leaders being centrally located in the networks. We also find that dense substructures of collaboration increase the level of specificity in the plans in regards to explicating constraints on human activities. Having many collaborative ties does however not enhance the overall level of specificity. Our results also show that different network characteristics can give rise to similar EBM outcomes. This observed equifinality suggests there is no single blueprint for well‐performing collaborative networks.     

1500 Years of Pottery: Neutron Activation Analysis of Northern Chilean Domestic Ceramics from Caleta Vitor and Clay Samples from Nearby Valley,Coast and Highland Contexts

This paper presents the findings arising from neutron activation analysis (NAA) of northern Chilean domestic ceramic samples from Caleta Vitor (n = 38) and clay samples (n = 15) from nearby valley, coast and highland contexts. This study presents the first NAA data set of ceramics spanning a temporal period of 1500 years (c.2000 to c.476 bp ) from the Vitor Valley as well as the first attempt to use NAA to characterize potential clay sources in the region. On the basis of this study, we argue that the majority of domestic ceramics from Caleta Vitor share compositional similarities with clay samples collected from nearby valleys, allowing us to infer that the Caleta Vitor populations primarily procured their clay for domestic ceramics from local sources throughout a 1500‐year period. Thus, despite the fact that there were inter‐regional interactions during this period that included the influence of powerful Andean polities, it would appear that domestic ceramics continued to be produced locally, and by implication it can be argued that such interactions did not substantially affect this sphere of material culture production. Further, the apparent continuities in domestic ceramic production allow us to reflect on local decision‐making processes throughout the cultural phases considered in this research.     

The White Marble of the Arch of Augustus (Susa,North‐Western Italy): Mineralogical and Petrographic Analysis for the Definition of its Origin

The Arch of Augustus in Susa (north‐western Italy) was built in 9–8 bc by King Cottius, to celebrate the treaty between the Romans and the Gauls. It is made of white marble, which was considered for a long time to be locally extracted, but no archaeometric studies have been performed up to now. Therefore, a multi‐analytical study based on petrographic (optical and scanning electron microscopy), electron microprobe and stable isotope analyses was carried out on the marble from the arch and from reference samples, with the aim of defining the provenance. All the data confirmed that white marble belonging to the metamorphosed carbonate cover of the Dora Maira Massif, known as Foresto marble, was used for the Susa Arch. This choice was probably made for economic reasons, but also due to the relative independence of the ruling family of the Alpes Cottiae, which was obviously interested in promoting a local marble.     

Sustainability of Highway Bridge Networks Under Seismic Hazard

In order to evaluate the seismic risk of transportation networks, it is necessary to develop a methodology that integrates the probabilities of occurrence of seismic events in a region, the vulnerability of the civil infrastructure, and the consequences of the seismic hazard to the society, environment, and economy. In this article, a framework for the time-variant seismic sustainability and risk assessment of highway bridge networks is presented. The sustainability of the network is quantified in terms of its social, environmental, and economic metrics. These include the expected downtime, expected energy waste and carbon dioxide emissions, and the expected loss. The methodology considers the probability of occurrence of a set of seismic scenarios that reflect the seismic activity of the region. The performance of network links is quantified based on individual bridge performance evaluated through fragility analyses. The sustainability and risk depend on the damage states of both the links and the bridges within the network following an earthquake scenario. The time-variation of the sustainability metrics and risk due to structural deterioration is identified. The approach is illustrated on a transportation network located in Alameda County, California.     

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.     

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.     

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。