Probabilistic life-cycle assessment and rehabilitation strategies for deteriorating structures: a case study

When it comes to existing buildings, the estimation of the structural residual bearing capacity is required to evaluate the potential for reuse/conversion. The level of detail and accuracy of surveys dramatically affect structural diagnostics. In order to optimise the experimental survey process, a simulation of the structural life-cycle may be useful.

Based on a previously developed approach of Monte Carlo simulation implemented with a damage law for the life-cycle analysis of newly designed constructions, this paper presents the method application to a historic roof steel structure. It aims to identify critical situations, assess the residual life of the system, and plan possible retrofit strategies for the building conversion.

The case study is a steel frame roof structure of the ex pig abattoir within the complex of the municipal slaughterhouse in Monza (close to Milan, Northern Italy) and protected from the Cultural Heritage Authority. The life-cycle of the structure is here investigated over different stages of the building lifespan along with the damages caused by aging and negligence. The construction was built in 1902, and abandoned in 1984. Therefore, the periods analysed are: from construction to disuse and from disuse to today. The second phase of life, still on going, has significantly sped up the degradation.

The probabilistic evaluation of failure times is discussed and the possible interventions scenarios in terms of costs, and after-maintenance reliability and safety are investigated.     

Mine blast vibration response spectrum for structural vulnerability assessment: case study of heritage masonry buildings

Ground-borne vibrations induced by mine blasting are typically of low amplitudes, which are not considered a major concern for modern engineered structures. However, historic structures are often considered more vulnerable due to inadequate knowledge regarding the state of construction materials and structural response. Specifically, the construction materials used might be fragile or have deteriorated to a stage that could be vulnerable to such vibrations. Simplistic rule based on peak ground motion parameter has been adopted worldwide for safety assessment, while the frequency characteristics of vibrations are not taken into account. Further, there is very limited study on response of heritage structures to near-field blasting. This article presents a practical structural vulnerability assessment method for mine blast-induced vibrations. In particular, a design response spectrum model is proposed based on close range measurements of nearby mine blasting, which is compared with an existing design spectrum model for far-field mine blasts and a typical design spectrum model for earthquake actions. The method is illustrated through a case study of heritage masonry buildings in Australia. The unique blast data presented and the generalized methodology would be useful to both structural engineers and blast engineers in considering potential effects of blasting on heritage structures.     

Tesserae Recycling in the Production of Medieval Blue Window Glass

The purpose of this paper is to develop a means of quantifying glass recycling and to discuss the ‘anachronistic’ chemical composition of medieval blue window glass. This method relies on a new numerical method using kernel density estimates and is based on a database of published glass chemical compositions. It seeks to reveal when, to what extent and why blue tesserae were recycled for the production of French and English blue glass. First, it is suggested that blue glass had an ‘anachronistic’ chemical composition only before the 13th century. Second, the ‘anachronistic’ chemical composition of 12th‐century blue glass comes from the recycling of both blue tesserae and non‐coloured glass. Finally, this recycling was motivated by the scarcity of cobalt sources until mines were found in the 13th century.     

Holocene Palaeoclimates of Africa

Examination of climatic inferences based on palynological, geomorphic, sedimentological, and other proxy data reveals a coherent picture of a generally wet early Holocene and drier conditions, with a time-transgressive clinal change commencing ca, 4500 B.P. The large-scale climatic periods in Africa during the Late Quaternary were interrupted by abrupt oscillations and rapid transitions. The magnitude and direction of climatic changes show distinct regional variation. However, in the monsoon-domain areas, abrupt drought events occurred conspicuously at ca. 12,000–11,500, 8500, 7500, 4500, 4000–3700, and 2000 uncalibrated radiocarbon years B.P. Further investigations are required to gain a more precise chronology of these events, which appear to have been crucial for some of the most salient developments in Africa's prehistory.     

Eratosthenes’ Contribution to Ptolemy’s Map of the World

This article attempts to shed some light on the origins of Ptolemy’s map of the world, which remains a mystery. The premise is that Ptolemy and other ancient geographers largely drew on the same or a similar pool of sources and common beliefs. Similarities between them can, therefore, give us a key to understanding the prehistory of Ptolemy’s map. Comparison of distances on his map with those given by other sources leads to the conclusion that a large area of the map, approximately from the Bosporus to the Indus, reproduced Eratosthenes’ geographical system, with linear distances converted to angular degrees according to Eratosthenes’ own scale. It is argued that this area represents a remnant of an earlier version of Ptolemy’s map. Analysis of latitude and longitude reveals notable differences between Ptolemy’s map and Eratosthenes’ ideas concerning the latitude of Babylon and the Alexandrian prime meridian, and the impact this seems to have had on the shape of neighbouring regions is noted.     

Bridging the cultures: architecture,models and computers in 1960s Cambridge

ABSTRACT

In the 1960s a unique research centre was founded in the Department of Architecture at the University of Cambridge. Before that date research in architecture was fragmentary and consisted largely of individual studies of topics in architectural history. Under the direction of Sir Leslie Martin, who had been appointed Professor of Architecture in 1956, a group of young architecture graduates embarked on a programme of research in the newly established centre for Land Use and Built Form Studies. Informed by the interest in the idea of the ‘model’ that was prevalent across the disciplines in Cambridge at this time and by using the power of the University Mathematical Laboratory’s ‘Titan’ mainframe computer, the group developed conceptual and mathematical models that operated across the range of architectural scales from building to city. This paper describes that work and sets it in the context of Leslie Martin’s role in reshaping architectural education in Britain.     

‘My Dog is My Home’: multispecies care and poverty politics in Los Angeles,California and Austin,Texas

My Dog is My Home is an art activist project in Los Angeles dedicated to sharing testimonies about the redemptive bonds of care and love between homeless persons and their canine companions. These testimonies politicize the structural violence and oppressive norms about propertied citizenship and notions of home that operate to render homeless human and animal lives disposable and ungrievable. Informed by the experts’ testimonies on multispecies homelessness and an engagement with feminist care theory, we bring relational poverty studies into conversation with critical animal studies to reject this framing of homeless lives as disposable and to trouble the idea of property as the fundamental basis for value. We problematize these notions by highlighting the insights gained from witnessing the entangled empathetic relationships forged between homeless humans and dogs. These relationships are not only a window into the political economic material conditions and discourses that reproduce homelessness and the animal-as-property. We conclude that studying these bonds offers a collective politics of multispecies mutuality, care, and love.     

Dome Strengthening By Encircling Ties: A Monitored Experiment

This study describes a new strategy of conservation of historical monuments based on the combined use of monitoring analysis and empiric reappraisal. Over time, the mechanical behavior of domes—their lack of stability due to the horizontal thrusts generated by their self-weight—has been analyzed by architects and engineers, starting from the observation of damage. This process, which was mathematically demonstrated for the first time by the famous Viviani’s analysis of Santa Maria del Fiore in Florence, has provided over the centuries a number of enhancements in dome structural conception, thus leading to the final solution, referred to as encircling tie rod intervention. Based on these premises, the experimental case of Santa Maria del Quartiere dome in Parma, Italy, is discussed herein. Indeed, it has been considered a good opportunity to present the method used in its strengthening-intervention assessment, further validated by the monitoring system installed. In this monitored in-scale experiment, the empiric classical solution to the primeval dome’s thrust finds its confirmation and offers further possibilities of recalibration during time, thus indicating structural monitoring that may be described as a possible and desirable “alternative to intervention”, in step with “minimum intervention” and “reversibility” principles.     

榆阳区明长城典型遗址的雨蚀破坏模式分析

现有的夯土遗址雨蚀病害分类方式关注的是多次降雨后遗址破坏的静态结果,以识别病害、辨明病因为主要目的。为进一步研究水土作用方式在夯土雨蚀病害发育过程中的作用,明确雨蚀病害的动态发育过程,在现场调查的基础上对榆阳区明代夯土长城的雨蚀病害进行分类、统计、分析,综合考虑侵蚀模式、雨蚀动态响应过程和劣化程度三个方面提出雨蚀破坏模式,分别为干湿破坏、冲刷破坏和降雨导致的重力侵蚀三种,三种破坏模式的提出为研究夯土遗址雨蚀和降雨间的响应关系提供新思路。     

《毛诗》经学化的过程及其特点与得失

本文主要论述三个问题：一、西汉前期,有经学的指导思想,但没有《诗经》经学的范本。即《子夏序》是不存在的,并从六个方面加以证明。二、《毛诗》经学化的过程。三、《毛诗》经学化的模式及其特点与得失。