Papers by Keyword: Heritage Buildings

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Authors: Sara Paganoni, Dina D’Ayala
Abstract: Since earthquakes such as Northbridge (1994) and Kobe (1995) gave the impetuous for the development of performance-based design methods, engineers have been strenuously working to the improvement of the seismic behaviour of structures; in fact, high ductility frames, as well as damping and isolation systems, are nowadays common practice in seismic prone areas. Heritage buildings constitute an odd case: many historic centres are still considerably affected by seismic events (L’Aquila, 2009) due to the lack of a methodical retrofit and this, where applied, is still largely based on the increase of stiffness and capacity, without the due care for precious finishings. In order to address the lack of specific passive systems for heritage buildings, the authors have developed two typologies of dissipative devices that can be integrated in traditional steel anchors and installed within the masonry at the joints of perpendicular walls, where out-of-plane mechanisms are likely to form due to poor quality connections. Both prototypes, one based on the plasticity of steel, the other relying on friction, were tested as isolated elements in pseudo-static regime for proofing and fine tuning, and in a dynamic range typical of the seismic frequency content to validate the stability of dissipative loops. The paper focuses on pull-out tests aimed to analyse the behaviour of the hysteretic prototype in respect to traditional steel anchors in masonry panels with low shear capacity. Finite Element (FE) models were also developed and calibrated applying the data from tests. Experimental and computational results are discussed in the following; the need for further theoretical work concludes the paper.
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Authors: Christopher J. Whitman
Abstract: According to the latest official census of 2002, earth construction represented 5.5% of the Chilean building stock. These buildings of traditional construction techniques of unfired earth and straw blocks (adobe), rammed earth (tapial) or wattle and daub (quincha) form a large proportion of Chile’s National Monuments and heritage buildings. In addition to their heritage value, these buildings with their high thermal mass, respond well to the climate conditions of both the altiplano of northern Chile and the Central Valley, zones with high diurnal temperature oscillations, with typical daily temperature differences of up to 20°C. However following the 2005 earthquake in Tarapacá, northern Chile and that of the 27th February 2010 in Central Chile a serious rethink has been required as to the retention and restoration of adobe buildings. Public opinion has labelled earth construction as unsafe and most reconstruction to date has taken place with prefabricated timber solutions which lack the necessary thermal mass to respond well to the climatic conditions. At the same time research into the structural integrity, seismic resistance, maintenance and the living conditions provided by earth construction has been undertaken. In this wider context this paper presents the compilation of international and Chilean research into the hygrothermal properties of adobe construction, in addition to the authors insitu measurements of the temperature and relative humidity in two surviving adobe dwellings in the earthquake hit village of Chépica located in Chile´s Central valley. These measurements are compared with those of a dwelling rebuilt with straw bales and earth render in the same location. Based on this information the paper studies the challenge of rebuilding and restoring heritage buildings whilst providing occupants with the necessary levels of environmental comfort.
186
Authors: Hua Yong Wu, Daniele Zonta, Matteo Pozzi, Paolo Zanon, Michele Corrà
Abstract: An automatic diagnostic monitoring system can guarantee the safety and integrity of a historic building. In this paper, we describe the long term application of a wireless sensor network (WSN) for permanent health monitoring in the Torre Aquila, a historic tower in Trento, Italy. The system consists of accelerometers, thermometers and fiber optic sensors (FOS) with customized wireless modules and dedicated software designed for wireless communication. The whole system was completed and started operation in September 2008, and data from the various sensor nodes are collected continuously, save during periods of system maintenance and update. Based on the first 1.5 years of operation in assessing the stability of the tower, the WSN is seen to be an effective tool. Modal analysis indicates that the tower has two independent structural parts. A comparison between the acquired long term deformation measurements and simulated numerical results shows good agreement. Monitoring of ambient vibration suggests that such vibration is not now a source of concern for the stability of the tower.
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Authors: Maria Adelaide Parisi, Mariapaola Riggio, Chiara Tardini, Maurizio Piazza
Abstract: Synthetic methods for the diagnosis of structures and particularly for their vulnerability assessment rely on simplified calculations and visual inspection. Their effectiveness strongly depends on an accurate calibration of the procedure by which data are collected. A recent methodology for the seismic vulnerability assessment of timber roofs in historical buildings has been applied to the Thun Castle during a study for its rehabilitation. The purpose was twofold: testing and calibrating the procedure on a heritage structure and estimating the capability of the roof structure to resist seismic action, as required in a zone of low but not negligible seismicity.
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Authors: Luigia Binda, Claudio Chesi, Maria Adelaide Parisi
Abstract: The earthquake that hit the city of L’Aquila, in central Italy, on the 6th of April 2009 has severely damaged most of the heritage buildings of the area. Soon after the event, a first survey of damage to ancient churches and palaces has been carried out according to a predefined classification procedure. Subsequently, a more detailed damage analysis was started in order to facilitate decision on future interventions. For one of these churches, S. Biagio Amiterno, damage consisted in the collapse of the upper part of the façade, in the localized collapse of the main vault, and in an extended crack pattern in vaults, columns, and walls. This damage pattern is interpreted here as case study. In more general terms, the exam of specific case studies gives the possibility of shedding light on various issues related to the seismic behavior of the building typologies concerned.
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