Testing of Superelastic Recentering Pre-Strained Braces for Seismic Resistant Design

Over the past decade, the use of shape memory alloys (SMAs) in passive control devices has been explored. Nevertheless, some aspects in regards to the cyclic behavior of SMAs and the effect of pre-straining need to be clarified. In this study, small-scale shake table tests have been performed to explore the effectiveness of SMA bracing systems as compared to steel bracing systems. The reduced-scale experimental results imply that SMAs used in braces are more effective in controlling the response of a steel frame compared with a traditional bracing system. A finite element model (FEM) of the frame is developed in order to compare the analytical results with the shake table tests. Further, the effect of pre-straining the SMA braces is evaluated through both experimental and analytical studies. The results show that pre-straining improves the performance of the frame compared to the nonpre-strained case. However, as the level of pre-straining increases above approximately 1.0% to 1.5%, the benefits of pre-straining decrease compared with low-to-moderate pre-strain levels.     

Seismic Performance of Tuned Liquid Column Dampers for Structural Control Using Real-Time Hybrid Simulation

This article presents real-time hybrid simulation (RTHS) in a single-degree-of-freedom (SDOF) steel frame incorporated with tuned liquid column damper (TLCD). The SDOF steel frame is numerically simulated, and the TLCD alone is physically experimented on a shaking table. The delay-dependent stability of RTHS system for TLCD investigation is first assessed; and the delay-dependent accuracy is verified by comparing the responses obtained through the RTHS, the conventional shaking table test, and an analytical solution. Then, RTHSs are carried out to evaluate the effects of mass ratio, structural damping ratio, structural stiffness, and peak ground acceleration on the reduction effectiveness of STLCD. The nonlinear behavior of the STLCD is experimentally captured. Finally, the structural responses under STLCD and multiple TLCDs (MTLCD) control are compared. It is found that the performance of STLCD strongly depends on structural parameters and properties of earthquakes; both MTLCD and STLCD induce approximately the same response reductions, and the former can enhance the control performance in certain cases. These results presented here may contribute to improve the design and application of TLCDs in practical engineering.     

Constant Ductility Energy Factors for the Near-Fault Pulse-Like Ground Motions

This study is focused on the constant ductility energy factors for bilinear system under the near-fault pulse-like ground motions. The variation of energy factors is studied in consideration of the earthquake magnitude, rupture distance, damping ratios, and post-yield stiffness ratios. The results indicate that the near-fault pulse-like ground motions would increase the energy dissipation of structures. The energy factors are significantly influenced by the earthquake magnitude. The damping ratios have more obvious influences on the energy factors than the post-yield stiffness ratios. A predictive model is proposed for the application of constant ductility energy factors for near-fault pulse-like ground motions.     

Allegories of Absence: Richard Weiner and Karel Čapek

Abstract

Examining the relationship between two of the most significant Czech writers of the early twentieth century, Richard Weiner (1884–1937) and Karel ?apek (1890–1938), this article sets their divergent developmental paths into the context of broader issues within European Modernism as a whole. The re-emergence of ‘allegory’ as privileged aesthetic category — represented prominently by Walter Benjamin’s work in the 1920s — characterizes a cultural phenomenon that can be termed ‘melancholy Modernism’. Weiner and ?apek’s contrasting responses to this melancholy allegorical impulse trace a fundamental fault line within the philosophical and historical development of Modernism.     

THE USES OF WALTER: WALTER BENJAMIN AND THE COUNTERFACTUAL IMAGINATION

Many authors, both scholarly and otherwise, have asked what might have happened had Walter Benjamin survived his 1940 attempt to escape Nazi‐occupied Europe. This essay examines several implicitly or explicitly “counterfactual” thought experiments regarding Benjamin's “survival,” including Hannah Arendt's influential “Walter Benjamin: 1892–1940,” and asks why our attachment to Benjamin's story has prompted so much counterfactual inquiry. It also explores the larger question of why few intellectual historians ask explicitly counterfactual questions in their work. While counterfactuals have proven invaluable for scholars in diplomatic, military, and economic history, those writing about the history of ideas often seem less concerned with chains of events and contingency than some of their colleagues are—or they attend to contingency in a selective fashion. Thus this essay attends to the ambivalence about the category of contingency that runs through much work in intellectual history. Returning to the case of Walter Benjamin, this essay explores his own tendency to pose “what if?” questions, and then concludes with an attempt to ask a serious counterfactual question about his story. The effort to ask this question reveals one methodological advantage of counterfactual inquiry: the effort to ask such questions often serves as an excellent guide to the prejudices and interests of the historian asking them. By engaging in counterfactual thought experiments, intellectual historians could restore an awareness of sheer contingency to the stories we tell about the major texts and debates of intellectual history.     

Smelting and recycling evidences from the Late Bronze Age habitat site of Baiões (Viseu,Portugal)

Many aspects of bronze production during Late Bronze Age in Western Europe are so far unknown. In the present study selected artefact fragments and metallurgical debris, which include a slag fragment, from the emblematic Late Bronze Age habitat site of Castro da Senhora da Guia de Baiões (Viseu, Portugal) have been studied by optical microscopy, micro-EDXRF, SEM–EDS and XRD. Evidences were found for bronze production involving smelting and recycling. Compositional analysis showed that the artefacts are made of a bronze with 13 ± 3 wt.% Sn (average and one standard deviation) and a low impurity pattern, namely <0.1 wt.% Pb, being comparable with the composition of other bronzes from the same region (the Central Portuguese Beiras). This alloy is generally different from elsewhere Atlantic and Mediterranean bronzes, which show frequently slightly lower Sn contents and higher impurity patterns, namely Pb which is often present as an alloying element. The present study gives further support to early proposals suggesting the exploration of the Western Iberian tin resources during Late Bronze Age, and besides that, it indicates that metalworking and smelting could have been a commonplace activity requiring no specific facilities, being bronze produced at a domestic scale in this Western extreme of Europe.     

Experimental Study on Self-Centering Concrete Wall with Distributed Friction Devices

A self-centering concrete wall with distributed friction devices is proposed to achieve seismic resilient building structures. Unbonded post-tensioned tendons, running vertically through wall panels, provide a restoring force that pulls the structure back toward its undeformed plumb position after earthquake. Two steel jackets are installed at wall toes to prevent concrete spalling and crushing. Friction devices are distributed between the wall and its adjacent gravity columns to achieve controllable energy dissipation, and these devices are readily replaceable. Desirable self-centering and energy dissipation capacities were observed in low-cyclic loading tests, and influences of various parameters on the hysteretic behavior were investigated.     

From Etelāʿāti to Eslāhtalabi: Saʿid Hajjarian,Political Theology and the Politics of Reform in Post-Revolutionary Iran

This article examines the importance of the political thought and praxis of politico, ‘reformist’ strategist and intellectual, Sa?id Hajjarian, and his rethinking of the post-revolutionary Iranian state’s sources and bases of legitimacy in the 1990s and 2000s. It also provides an exposition and assessment of a number of his recommendations for the realisation of ‘political development’ (towse?eh-ye siyāsi) in the post-revolutionary order and their contribution to the discourse of eslāhāt during the presidency of Hojjat al-Islam Mohammad Khatami (1997–2005). Moreover, it attempts to situate Hajjarian within a broader spectrum of reformist political opinion and its proponents within the Islamic Republic of Iran’s political class.     

河南禹县阳翟遗址出土古玻璃的科学分析

考古发掘中出土玻璃器历来受到研究者的重视。其中,通过对古玻璃化学组成和结构特征的科学分析,以探讨其工艺技术及产地问题,是古玻璃研究的重要组成部分。经过多年的研究,学界已对中国古代玻璃的起源、工艺技术特点及产地等问题     

Integrated geophysical surveys for the subsurface mapping of buried structures under and surrounding of the Agios Voukolos Church in İzmir,Turkey

This work presents the results of the integrated usage of geophysics in the Agios Voukolos Church, one of the unique Orthodox constructions in ?zmir. The surveys had two main objectives: to define subsurface characteristics inside and around the church and search for possible structural damage such as cracks and fissures, that may exist in the subfloor of the church. Magnetic gradiometry, ground penetrating radar and electrical resistivity tomography were used in the investigations; this study is the first indoor application of magnetic gradiometry. The studies revealed that several suspicious relics and crypts might have existed under the floor of the church. In addition, investigations of the courtyard area indicated potential buried structures under the settling area of the church. This study demonstrates the importance of the integrated usage of non-destructive geophysical techniques in searching for possible hidden subsurface structures in standing historical buildings. In addition, magnetic gradiometry might be useful in indoor studies, assuming that there are no important magnetic sources near the site.