Thrust network analysis of masonry helical staircases

We exploit a recent generalization of the Thrust Network Analysis (TNA) to analyse masonry structures of extremely complicated and audacious geometry such as helicoidal staircases. Actually, differently from available methods, based on ad-hoc solutions holding for each particular structure, the TNA allows for studying the equilibrium of structures of arbitrary shape by invoking the principles of limit analysis of masonry structures dictated by Heyman. Four paradigmatic monumental staircases, with increased degree of complexity, have been selected as case studies in order to show the versatility and accuracy of the proposed approach. The results entailed from the generalized TNA are also successfully compared, for the first time in the literature, with those related to the adoption of available analytical methods for the analysis of no-tension membranes.     

Evaluation of Structural Intervention in the Quartel das Esquadras,Almeida (Portugal)

ABSTRACT

The “Quartel das Esquadras” is an 18th century infantry barrack located within the limits of the bulwarked fortress of Almeida, in Portugal. An ongoing adaptive reuse project of the building aims to recover its full capacity and also its importance, by implementing a variety of new uses. The architectural intervention results in the need of the structure to withstand new and diverse imposed loads. As the current configuration of the structure will be altered, the main objective of this article is to evaluate the suitability of some of the proposed structural interventions. The current condition has been characterized following a multidisciplinary approach comprising historical research, visual inspection, non-destructive testing, and structural analysis to identify the possible sources of major structural problems. A portion of the building particularly affected by the alterations has been selected to carry out structural analysis. A comparative safety assessment of the selected area in both current and altered condition has been done through finite element modelling and nonlinear static analysis, resulting in an identification of the weaker points against the new implemented loads and alterations. Finally, proposals for the implementation of the studied intervention, as well as recommendations for future research and analyses, have been given.     

建国初期闵行镇归属问题研究

明代中后期,闵行镇凭借其便利的交通条件与繁荣的棉花种植业,成为上海县重要的商业市镇。近代以来,随着上海城市的发展,闵行镇与上海城区间经济联系不断密切,政治地位也日趋重要。新中国成立初期,优先发展重工业的国家政策与华东沿海地区的战略地位,使得民国时期奠定重工业基础的闵行镇备受各方重视。在国家政策、经济体制、地方利益等因素的综合作用下,闵行镇最终由江苏省上海县划归上海市。     

刘铭传的海防思想与实践——兼论台湾省在中国海防中的战略地位

刘铭传以武将而跻身于封疆大吏之列，其一生之建树重在“事功”而非“理论”。正因为如此，他虽然也曾就海防及其相关问题有过全面系统的论说，但其认识水平显然不及同时代之佼佼者。关于台湾在中国海防中的战略地位，他也是在领导抗法保台、建台的过程中逐步加深认识的，并以首任台湾巡抚之地位不遗余力地将其思想主张付诸实践，开创了包括海防在内的台湾近代化新局面。刘铭传加速台湾建设、加强台湾海防的初衷是为了抵御日本的侵略，不料数年之后，台湾竞因北洋海防的崩溃而落入日本之手。这绝不是刘铭传个人的悲哀，实乃国家民族之大悲剧。     

Updating Numerical Models of Masonry Arch Bridges by Operational Modal Analysis

This article aims at presenting and discussing the strategies for updating the finite element numerical modeling of stone masonry arch bridges using operational modal analysis. The study comprehended three bridges: two old ones, the St. Lázaro and the Lagoncinha bridges, and a recently constructed bridge in Vila Fria, Portugal. Updating of the bridge models is performed by comparing the numerical and experimental modal parameters. Three-dimensional detailed numerical models are used to perform modal analysis of the bridges. Experimental modal identification of the bridges is based on the measurement of their acceleration responses during normal operation. The assigned material properties are also based on available results obtained from in situ and laboratory tests and on the results of visual inspection and historical research carried out for both old bridges.     

Construction Features of Doel 1, a 14th‐Century Cog found in Flanders

In 2000, a well‐preserved, c.21 m‐long shipwreck, Doel 1, was found upside‐down in a silted‐up creek near the river Scheldt (Belgium). An interdisciplinary research project was initiated, including 3D registration of all timbers, wood species identification, dendrochronology and archaeobotanical analysis of the caulking material. Doel 1, of which 70% is preserved, displays the construction features of a cog. Unseasoned wood was used and dated by dendrochronology to AD 1325/26. Remarkable features include the symmetrical layout of the bottom planks, the atypical arrangement of the frames to the fore, and evidence of partial dissassembly of the ship after intensive use.     

Petrochemical Identification and Insights on Chronological Employment of the Volcanic Aggregates Used in Ancient Roman Mortars

Through the assistance of trace element and petrographic analyses on 14 samples of mortar aggregates from Roman monuments, including the Porticus Aemilia, the Temple of Concordia, the Temple of the Dioscuri, Temple B and other structures of the Area Sacra di Largo Argentina, and the Villa di Livia, we establish the source area and we investigate the chronological employment of the volcanic materials used in ancient Rome's masonry. In contrast to previous inferences, the petrochemical data presented here show that systematic exploitation of the local ‘Pozzolane Rosse’ pyroclastic deposit has occurred since the early development of concrete masonry, at the beginning of the second century bc , through the early Imperial age. Subsequently, exploitation was extended to the overlying Pozzolane Nere and Pozzolanelle deposits. Only during the early phase of development of the concrete masonry in Rome, volcaniclastic sediments outcropping near the construction sites were mixed with the sieved remains of the tuff employed as the coarse aggregate, to produce the fine aggregate. The results of the study on the investigated monuments suggest the possibility of establishing the chronological identification of three different types of mortars, as a function of the composition of the volcanic material employed in the fine aggregate, which, when implemented by future studies, may contribute to the dating of monuments and archaeological structures.     

Negotiating time and space on a study abroad program in South India

This paper investigates the context of student learning in study abroad programs, drawing on ethnographic research on a semester long study abroad program in South India. We show how students use multiple constructions of time and space as a framework for understanding cultural differences and for understanding what it means for them to “experience” India. We argue that students' conceptualization of space and time in the study abroad location also impacts what kinds of activities they consider to count as valuable forms of learning. Students' ideas about India shape their expectations of what the pace, workload, and activities of the study abroad program in India should entail. Their concepts of Indian time and space lead them to privilege “experience”-based learning over classroom-based or scholarship-based learning. In conclusion, we show how these insights have implications for study abroad pedagogy. Here, we suggest that student learning that is entirely based on “experience” outside the classroom is inherently limited and that students need to contextualize their field-based learning experiences with insights from critical, historical and social science research.     

Seismic vulnerability assessment and fragility analysis of stone masonry monastic temples in Sikkim Himalayas

Buddhist monasteries in Sikkim Himalayas constitute important religious and architectural heritage. These random rubble (RR) stone masonry structures located in high seismically active regions of the Himalayas have suffered varied degrees of damages in the past earthquakes. The study presents seismic vulnerability assessment of four archetypal monastic temples using finite element (FE) analyses. Linear and nonlinear analyses of these structures were conducted in Abaqus FE environment. These analyses identified the damage prone areas of the structures and provided load-deformation behavior under lateral loads. Fragility analyses indicate a high probability of collapse for the specified design level earthquake of the region. The study shows that performance of the structure can be enhanced by improving the strength and stiffness of the stone masonry walls.