故宫灵沼轩的动力特性及抗震性能研究

故宫灵沼轩是我国最早建造的钢铁-砌体组合结构之一,具有重要的历史、艺术和科学价值。为了评估灵沼轩在地震作用下的结构安全状况,建立了灵沼轩结构的三维有限元模型,并对其进行了动力特性和地震时程分析,得出了其固有频率、模态振型、地震位移响应和地震应力响应。结果表明:灵沼轩整体结构布置对称性较高,扭转刚度较大,对抗震较为有利;在8度多遇地震、设防地震和罕遇地震作用下,灵沼轩的金属结构部分及砌体结构部分的顶点位移和层间位移角均符合现行规范要求,砌体结构部分的第三主应力响应均小于材料的抗压强度,不存在压溃风险。在8度多遇地震和设防地震作用下,砌体结构部分的第一主应力响应均小于材料的抗拉强度,结构不会发生拉裂。但在8度罕遇地震作用下,砌体结构的部分位置拉应力超过材料的抗拉强度,这些位置存在开裂危险。最后,综合动力特性和抗震性能分析的结果,提出了灵沼轩的抗震加固建议。     

'Geographical Expeditions': Assessing the benefits of a student-driven fieldwork method

A student-driven fieldwork method, focused in a local metropolitan area, is described and assessed. Developed for a second-level course in cultural geography, it was inspired by the 'Geographical Expeditions' originally devised by William Bunge in the 1960s. It is one solution to maintaining fieldwork in the syllabus for a large class, at the same time as providing benefits for participants in terms of challenge and autonomy. Student responses are compared with the merits of fieldwork as claimed in the literature. In view of concerns expressed about increasing student 'disengagement' from commitment to university study, active participation in a 'Geographical Expedition' is a strong motivating factor.     

Seismic Vulnerability Assessment of Hybrid Steel-Timber Structure: Steel Moment-Resisting Frames with CLT Infill

In this article, seismic vulnerability assessment is carried-out on a novel hybrid structure (steel moment resisting frame (SMRF) and cross laminated timber (CLT) infill panels). For the seismicity of Vancouver, Canada, a three-bay, 3-, 6-, and 9-story height SMRFs are designed for two ductility levels (ductile and limited ductility). To study the seismic vulnerability CLT infilled building, parametric analysis was performed by varying infill configuration (bare frame, one-bay infilled, two-bay infilled, and fully infilled). The structure is modeled in OpenSees and nonlinear dynamic analysis is performed. Peak inter-story drift demand and corresponding FEMA performance limits (capacity) values are used to compute the corresponding fragility curves. From the analyses, it can be seen that as more bays are infilled, the fundamental period and seismic vulnerability is reduced significantly. The results highlight that, within the performance-based earthquake engineering, different objectives can be met with varying the CLT configuration.     

Floor Response Spectra for Bare and Infilled Reinforced Concrete Frames

The objective of this article is to study the effects of structural nonlinear behavior on Floor Response Spectra (FRS) of existing reinforced concrete frames. This study examines how the FRS vary with the level of post-elastic behavior in buildings of different number of stories and masonry infill wall configurations. The effect of damping modeling assumptions is also investigated. Differences and similarities with findings from the literature are discussed. On the basis of the obtained results, a commentary on the adequacy of basic assumptions used in predictive equations proposed by different seismic codes is offered.     

Seismic Behavior of FRP-Retrofitted Reinforced Concrete Frames

Although a significant number of studies have been conducted on the behavior of the reinforced concrete beam-column joints retrofitted with FRP materials, limited investigation considered the overall seismic behavior of the retrofitted frames. In this article, experimental and numerical studies are performed on a scaled-down eight-story and two full scaled low-rise ordinary moment resisting frames (OMRFs) retrofitted with FRP at the joints. Additional, rotational stiffness of the joints is implemented into pushover models to predict seismic performance and behavior factor of the retrofitted frames. Results indicate that FRP retrofitting is more effective than steel braces for low- and medium-rise OMRFs.     

郑韩故城出土战国晚期铁器腐蚀产物分析

为了分析郑韩故城遗址出土战国晚期铁器的锈蚀产物类型,采用X射线衍射和金相显微观察等现代科技手段,对郑韩故城遗址内仓城铸铁遗址出土的13件样品进行综合研究。通过分析比较样品间的锈蚀程度,发现铁质文物的锈蚀机理复杂,成分多样;一些锈蚀产物中出现明显的分层,锈蚀不均;部分铁器中还存在着活性锈蚀物,其保存状态与金相组织有着密切关系。     

红外光谱在文物保护中的应用介绍

文物信息的提取与研究对于揭示古代遗物包涵的人类社会、文化等历史信息有着举足轻重的作用:一方面可以了解古代的工艺技术特征,探寻文物制作技术起源及其发展历程;另一方面可以进行病害调查分析,为保护文物提供有价值的信息。本工作以红外光谱技术为出发点,细致梳理了目前红外光谱在文物保护中的应用,包括无机质文物中青铜器、土壤、颜料、珠宝玉石,有机质文物中纸张、丝织品、彩绘胶料、有机残留物,以及保护材料。提出该技术具备应用范围广、特征性强、无损或微损样品、不受样品物态限制等优势,但同时不适合分析含水样品、定量分析时误差大、解析图谱时依靠经验等局限性。揭示显微红外光谱技术在无损分析文物方面的广大前景,为文物保护研究与实践提供参考和借鉴意义。     

山东大汶口文化酒器初探

中国有悠久的酿酒传统,近年来利用科技手段进行陶器残留物分析,使我们能够获得史前时期酿酒技术的直接考古学证据。本文对山东王因和西夏侯遗址出土的4件大汶口文化时期的陶器进行微植物和微生物分析,初步揭示了海岱地区在距今6200～4600年的酿酒传统。即,利用麹、根霉和/或毛霉制麹,以粟黍、小麦族、葛根、栝楼根和百合为主要原料而酿造麹酒。制作精致的磨光黑陶高柄杯是饮酒器,红陶杯和灰陶瓶也与酒有关。海岱地区和中原地区在新石器时期使用不同的酒器,但利用多种植物酿造麹酒是共有的酿酒方法。     

法国巴黎集美博物馆藏克孜尔石窟壁画调查与原位考证

本文在前人研究基础上,结合笔者数十年的石窟工作经验以及远赴国外广泛调查的结果,将法国巴黎集美博物馆收藏的15块克孜尔石窟壁画残片进行了核对与测量,找到了全部壁画所出洞窟及原位,并通过电脑技术对图片进行了复原。     

The political ecology of water memory: Contending narratives of past hydraulic infrastructures in Barcelona (2015–2021)

In the context of ecological emergency and crisis of representation of the capitalist democracy, the battles over water management have become ever more politicised: who is to administer water resources, how, and with what legitimacy? This article examines a disregarded dimension of the recent water conflict in Barcelona by looking into the politics of memory as part of a struggle for legitimacy between the private water company Agbar, and Barcelona en Comú (BeC), the political platform governing the city since 2015, and defending the ‘remunicipalisation’ of water. By combining memory studies and critical discourse analysis we pay attention to the dynamic resignification of the hydraulic infrastructure as spaces or “sites of memory” (lieux de mémoire; Nora, 1998). Barcelona en Comú narrative retrieves a forgotten past of local sites and experiences in public management of water. In contrast, Agbar defends its legitimacy by advancing a narrative of linear progress and social inclusion that re-signifies its 150-year long history and co-opts key “empty signifiers” (Laclau, 2005) from the discourse of the Indignados and BeC. Theoretically, we advance that a temporal turn in political ecology and geography, complementing the concern with spatiality, could usefully draw on memory studies to analyse the growing memorialization of water discourses and sites, as well as their political significance. The article thus investigates a question that has not been systematically explored by political ecologists: how the entanglement of space and historical memory is mobilized in the conflict over the use and management of the environment.