Structural Analysis of Historic Constructions

Volumes 133-134

doi: 10.4028/www.scientific.net/AMR.133-134

Paper Title Page

Authors: Claudio Modena, Francesca Da Porto, Casarin Filippo, Marco Munari, Elena Simonato
Abstract: The architectural heritage was seriously hit by the earthquake that occurred on April 6th 2009 in the Abruzzo region, especially considering the effects on a city with the size and with historical and strategic importance as a capital of a region, L’Aquila. The activities to protect that heritage have been centralized in the structure “Protection of Cultural Heritage” at Di.Coma.C. (Command and Control Quarter), managed by the Civil Protection Department. This allowed the cooperation among different involved subjects (Ministry of Cultural Heritage officers, experts on structural engineering from Universities and Fire Brigade teams), with their own specific knowledge. Keystone of the operating process was the standardization of the damage survey and of its immediate and correct interpretation, through dedicated survey forms for churches and palaces. The experience in the field of temporary safety measures was extremely interesting: ideas for engineering the process were developed, in cooperation with the work of the fire brigade men, that are highly experienced technicians in the “emergency” field. Finally, monitoring plans for some important monuments have been set up for the control of the damage progression and the analysis of the structural behavior of buildings after the earthquake and the execution of temporary interventions: two cases (St. Mark Church and the Spanish Fortress) are discussed.
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Authors: Xi Lin Lu, Wen Sheng Lu, Xin Zhang
Abstract: To contradict from the rapid development of economy and urban construction, the conservation and strengthening of historic buildings are becoming more and more important and requiring more wisdoms and new technologies. A new resolution for protecting historic buildings by building moving technology is introduced and discussed with several application projects. Firstly, three building moving methods are presented which include moving building with rolling bars, moving building with slide layer and moving building by trailer transportation. Secondly, control system and structural state monitoring for building moving are described. Lastly some completed historic building moving projects are introduced for demonstrations of this technology application.
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Authors: K.J. Willam, C. Citto, P.B. Shing
Abstract: The paper summarizes the main research findings on masonry infill walls which were obtained within the framework of a comprehensive NSF-NEESR-SG project directed by Prof. Benson Shing at UC San Diego (Shing et al. 2009). The main focus of this contribution are experimental and computational observations on 2/3 scale unreinforced masonry panels bounded by a reinforced concrete frame which were subjected to cyclic push-over testing at CU Boulder under constant vertical pre-loading. This study included two-wythe masonry panels of 133in x75.5in size (3.378 x1.897m) with and without openings in form of eccentric windows and doors. The background experiments did include a suite of masonry prism tests on rectilinear and slanted masonry prisms providing important insight into the composite behavior of mortar and brick construction. The paper concludes with remarks on the experimental observations when the panels were integrated into infill walls of two-bay width and three-story height with and without retrofits of reinforced ECC layers (engineered cementitious composites) which were attached to one side for quasistatic testing at CU Boulder, and to both sides of the wall for dynamic shake table testing at UC San Diego.
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Authors: Ahmet Turer
Abstract: Conservation studies in developing countries might have additional problems to those that are being experienced by leading developed countries. The problems and difficulties mentioned here do not reflect the common practice in Turkey and mostly list rare cases for information purposes. Countries located in Asia and Middle East have rich structural heritage, in number and significance, which are sometimes even a few millenniums old. On the other hand, often times financial or bureaucratic constraints make the conservation studies more difficult, while technical problems remain to be an issue. It is quite interesting that sometimes having available financial support for conservation studies turns out to be the main source of problem, since quick and not well thought interventions end up damaging hundreds of years old surviving structures, rather than conserving them. Other most common application problems include use of Portland cement in humid environments causing salt contamination (which is now widely being avoided), infilling and freezing cracks that used to work as seasonal water table movement based motion or thermal expansion joints that are cyclic in nature, covering the structure to protect but forming unintentional green house effect – micro climates forming fungus, improper drainage to cause support settlements, removing earth fill or structural members to cause structural movements and cracks, strengthening parts of a flexible structure only to make it more rigid and cause to attract more earthquake forces, disable its energy dissipating mechanisms, applying improper chemicals, using incompatible material or irreversible techniques etc. are just a few to mention. The problem solution strategies in conservation studies should include internationally accepted conservation rules. Multi disciplinary teams are always recommended since combination of various expertise areas are mutually needed in conservation studies; architects, geotechnical and structural engineers, geology and material science specialists, archeologists, art historians are among the most important team members. Analytical modeling and simulations, on-field non destructive testing, instrumented monitoring (SHM), and small scale field treatment tests are recommended to be merged and used in conservation studies, because conventional methods or commercial repair/treatment materials available over-the-counter may not always suitable for a given specific case. Reversibility, minimum intervention, and respect to authenticity should be among the main principles to avoid serious conservation problems.
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Authors: Bohumil Kasal
Abstract: Timber is one of the oldest structural materials and has been traditionally used in all parts of the world. Pressures on environmental sustainability lead to revitalization of timber as a modern, highly environmentally friendly and sustainable material. This new interest also sparks the attention of the research and engineering community in the structural applications involving timber. A number of techniques can be used to evaluate health, deterioration and extent of potential damage of historic structures and their components. Because timber is a natural, biodegradable, hygroscopic, and inhomogeneous material, its interaction with the environment presents challenges not normally encountered in materials typically studied by engineers. In addition, high variability of properties even within individual species makes it difficult to make inferences on properties of the investigated systems or even individual components. This requires a multidisciplinary approach and broad knowledge of disciplines spanning from biology and plant anatomy to mechanical properties and statistics. This paper will discuss some of the methods that can be deployed to evaluate historic timber and their drawbacks and limitations. Future directions and needs will be addressed in the last part of the presentation.
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Authors: Federica Ottoni, Eva Coisson, Carlo Blasi
Abstract: The aim of this paper is to show the potentiality of the historical analysis mixed with the experimental data elaboration in identifying the mechanical behavior of an ancient monument. Firstly, an ideal route through the crack pattern of Santa Maria del Fiore dome in Florence is presented herein: the conclusion of the historical debates about the mechanical behavior of the dome are analyzed in light of the statistical interpretation of the last 55years cracks monitoring data. The recall of some historical debates has been fundamental in the comprehension of its mechanical behavior, showing the validity of the empiric-experimental method in ancient master builders solution (the “art of building” rules) to the main problem of the masonry domes: their primeval and ineradicable horizontal thrust on supporting structures. The final aim is to present some results on the beneficent effect of the scaffolding installed on the dome from 1980 to 1996, which seems to confirm the prevision made by Vincenzo Viviani at the end of XVII century on the future consolidation of this dome.
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Authors: Julio Vargas Neumann
Abstract: The acceleration of climate change and the increasing frequency of natural disasters mean that there is an urgent need to adapt conservation strategies for architectural heritage to the world’s new demands and situations. This is particularly relevant for the most vulnerable constructions, such as earthen structures. Because of the dramatic effect that earthquakes can have on architecture, and especially on historical monuments, they have been studied for the past 50 years. Earthquakes divide the world in two very distinct geographic areas: seismic and non-seismic. The seismic vulnerability of earthen architectural heritage, such as earthen structures and mud mortar masonry, evidences in by how weak they are when compared to structures built using other construction materials (10 to 15 times weaker). Humanity’s past experience in the conservation of architectural heritage allows us to be aware of the need to improve and eventually perfect the existing conservation charters, which were discussed and signed in Europe in the last century. These charters do not make a distinction between heritage conservation in seismic and non-seismic areas. It is imperative to address this particular issue, as seismic forces can be too strong for earthen constructions to resist, which can lead to their irreparable collapse. Inspired by the Venice Charter and China´s principles as well as by more modern documents, such as the Burra, Mexico, Zimbabwe, Lausana Charters, researchers have tried to establish adequate and resistant conservation guidelines, based on achieving the best structural performance using a minimum permanent and reversible reinforcement. Although this involves causing some impact on the architectural heritage, it also means that human lives and buildings can be protected. The paper will provide real examples to illustrate these cases and will attempt to outline the conservation principles required to protect vulnerable structures, such as those earthen constructions or mud mortar brick or stone masonry built in seismic areas.
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Authors: Toshikazu Hanazato, Chikahiro Minowa, Yasushi Niitsu, Kazuhiko Nitto, Naohito Kawai, Hideyuki Maekawa, Masayuki Morii
Abstract: In Japan, there exist a total of 22 five-storied timber pagodas constructed before the middle of 19 centuries. All of those pagodas are registered as the important cultural heritages by Japanese Government, while some of them are listed in World Cultural Heritages such as Horyu-ji Temple’s Pagoda that was built in the end of 7th century. As those timber pagodas in seismic areas have survived against earthquakes during their long histories, their earthquake resistant capacity has been studied for a century. However, the actual dynamic behaviors of timber pagodas subjected to large earthquakes should be recorded to understand the seismic performance. Furthermore, an interesting structural issue has recently risen of wind resistant capacity of traditional five-storied timber pagodas, as such tall timber structures may be severely affected by strong wind. In order to record the actual dynamic behaviors during not only earthquakes but also typhoons, we have been conducting earthquake and wind monitoring at Hokekyou-ji Temple in Ichikawa City, next to Tokyo, which has survived for 4 centuries against not only large earthquakes but also severe typhoons. Hence, while the earthquake monitoring has been done by the conventional method utilizing accelerometers, the dynamic displacement of the structural response to wind has been directly measured by a new technique employing an image process system using LED makers and CCD camera, because the wind response includes much longer period component in general, therefore, it must be difficult to measure accurately the wind response by accelerometers. The scope of the present paper are 1) to review the past studies to understand the excellent earthquake resistance of five-storied timber pagodas, as well as, to introduce our research project of seismic and wind monitoring that has been successfully conducted since 2007, 2) to interpret those monitoring records which would be useful for understanding seismic and wind performance of the heritage timber pagodas that have survived for many centuries with describing the simulation analysis of seismic response, and 3) to show the long term monitoring records of the horizontal displacement of the heritage structure.
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