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Structural Assessment (structural + assessment)
Selected AbstractsBase isolation for retrofitting historic buildings: Evaluation of seismic performance through experimental investigationEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2001Antonello De Luca Abstract An experimental test program on a full-scale model representing a sub-assemblage of the cloister facade of the Sao Vicente de Fora monastery, retrofitted through base isolation, has been recently carried out at the European Laboratory for Structural Assessment of the Joint Research Centre of the European Commission. In this paper an overview of the laboratory model and the experimental results is provided. In particular, firstly the test model is described, including the geometry and mechanical properties of the masonry specimen and the design of the isolation devices; then the testing method and the sub-structuring of the isolation system are described and the seismic inputs adopted for the pseudo-dynamic tests are defined. Finally, the experimental results are discussed and compared to the analogous results obtained on the ,as is', fixed-base sub-assemblage model. The implications of the test outcomes are emphasized and developments of this research line are presented. Copyright © 2001 John Wiley & Sons, Ltd. [source] Improved protonation, collision-induced decomposition efficiency and structural assessment for ,red tide' brevetoxins employing nanoelectrospray mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 8 2006Weiqun Wang Abstract Brevetoxins are a group of natural neurotoxins found in blooms of red tide algae. Previous electrospray mass spectrometry (ES-MS) studies show that all brevetoxins have high affinities for sodium ions, and they form abundant sodium adduct ions, [M + Na]+, in ES-MS, even when trace contamination is the only source of sodium ions. Attempts to obtain informative product ions from the collision-induced decomposition (CID) of [M + Na]+ brevetoxin precursor ions resulted only in uninformative sodium ion signals, even under elevated collision energies. In this study, a nano-ES-MS approach was developed wherein ammonium fluoride was used to form cationic [M + NH4]+ adducts of brevetoxin-2 and brevetoxin-3; a significant increase in the abundance of protonated brevetoxin molecules [M + H]+ also resulted, whereas the abundance of sodium adducts of brevetoxins [M + Na]+ was observed to decrease. Under CID, both [M + NH4]+ and [M + H]+ gave similar, abundant product ions and thus underwent the same types of fragmentation. This indicated that ammonium ions initially attached to brevetoxins forming [M + NH4]+ easily lose neutral ammonia in a first step in the gas phase, leaving protonated brevetoxin [M + H]+ to readily undergo further fragmentation under CID. Copyright © 2006 John Wiley & Sons, Ltd. [source] LOCALIZING HISTORICAL CLUES USING IRT AND PETROGRAPHIC ANALYSES AT VILLA MIRABELLO, MONZA (ITALY)*ARCHAEOMETRY, Issue 5 2009E. ROSINA The rebuilding of Villa Mirabello started in 1666. Built on designs of Gerolamo Quadrio, the project refurbished and enlarged a smaller 16th century country house (,casa da nobile e da massaro'). Archival documents report on the remodelling, which consisted of selective demolition of portions of the structure, re-using most of the masonry as the core of the new building, and the reinforcement of retained masonry by insertion of ,ceppo' stone quoins to update new exteriors. The aim of Quadrio was to create an elegant and sumptuous mansion, suitable for noble owners such as Giuseppe Durini and his family. The plan and a small part of original finishing (,marmorino' plaster decoration) are recognizable nowadays. Nevertheless, there are many questions in interpretation when one compares the documents and the building. That is, Cardinal Angelo Durini made a major modification in the 18th century, and further minor changes were made in the 19th century. Although these latter modifications did not alter the plan, they changed the distribution of rooms and masked both decoration and finishing. After over 20 years of neglect, Villa Mirabello is now close to being restored. Architects in charge ordered a preliminary set of diagnostics to assess damage and study the historical evolution of the building. Integration of IR thermography (IRT) and endoscopy allowed restorers to detect the structure's texture underneath the plaster, and to detect openings filled with masonry. Moreover, archive documents confirmed these results and, above all, defined a date for the use of specific building techniques. This research constitutes a reference for buildings set in the same time and location that do not have significant archival documentation. Active IRT provided useful information for structural assessment (such as location of arches, chimney stacks, different thickness of wall, wooden elements, voids, beams etc.) and for crack pattern evaluation. This information directs design professionals working on this conservation project, and helps define the costs of intervention. [source] Barocke Dachwerke: Konstruktion und Analyse des TragverhaltensBAUTECHNIK, Issue 1 2009Stefan M. Holzer Univ.-Prof. Konstruktion und Tragverhalten historischer Bauwerke haben schon öfter im Zentrum von Forschungsprojekten gestanden, zuletzt ganz besonders intensiv im Karlsruher DFG-Sonderforschungsbereich 315 (Erhalten historisch bedeutsamer Bauwerke). Der hier vorliegende Beitrag ist einem Thema gewidmet, das bei allen diesen Forschungen bisher am Rande gestanden hat, nämlich den barocken Holzkonstruktionen. Die Autoren haben in den letzten Jahren eine große Anzahl barocker Dachwerke in Bayern untersucht, vorwiegend weitgespannte Kirchendächer. Der Bestand solcher Dächer gerade im Gebiet südlich der Donau ist nahezu unüberschaubar groß, und die statische Beurteilung und Ertüchtigung solcher Dächer stellt für den Bauingenieur eine sowohl praktisch und ökonomisch relevante als auch in der Modellbildung anspruchsvolle Aufgabe dar. Bei der Untersuchung der bayerischen Barockdächer hat es sich herausgestellt, dass die dort anzutreffenden Tragkonstruktionen in erheblichem Maße von den typischen mittelalterlichen Dachwerken oder auch von barocken Dachwerken anderer Regionen abweichen: Die barocken Dachtragwerke Süddeutschlands haben , in markantem Unterschied zum mittelalterlichen Dach mit seiner Reihung identischer, voneinander nahezu völlig unabhängiger Gespärre , ausgeprägte firstparallele Tragwirkung. Noch wichtiger , gerade auch im Hinblick auf notwendige Sanierungen , ist aber das äußerst häufige Fehlen eines Zugbandes in Form einer durchgehenden Anker- oder Zerrbalkenlage auf Höhe der Dachtraufe. Die oft weit in den Dachraum ragenden, meist aus Ziegeln gemauerten Gewölbe und Kuppeln machen komplizierte, vielfach statisch unbestimmte Konstruktionen zur Aufnahme der Schubkräfte der Gespärre notwendig. In diesem Beitrag werden typische Konstruktionsvarianten zur Lösung dieser barocken Aufgabe vorgestellt und deren Tragverhalten beleuchtet. Bei allen wichtigen Konstruktionsvarianten stellt sich heraus, dass diese Tragwerke bei der statischen Berechnung im Gegensatz zum klassischen Sparrendachwerk mit Zugband auf Traufenhöhe sehr sensibel auf Modellierungsannahmen reagieren, vor allem auf die angesetzten Steifigkeiten der Verbindungen und Auflager. Nichtlineare Modelle für Verbindungen (z. B. Berücksichtigung der herstellungs- und schwindbedingten Klaffungen) könnten einen wesentlichen Beitrag zum Verständnis des Lastabtrags und zum Nachweis der verbleibenden Standsicherheit solcher Tragwerke liefern (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Construction and structural analysis of baroque roofs. Several research projects, notably within the priority research programme 315, Karlsruhe, have already been devoted to historic constructions, in particular timber constructions. However, it turns out that the results obtained from these previous studies do not carry over to a large , economically as well as historically significant , group of German heritage constructions, namely, the baroque roofs of southern Germany. While numerous constructions of this type are preserved, foundations for their realistic structural assessment are still lacking: These roofs have a much more markedly three-dimensional behaviour than the typical mediaeval roof, due to various longitudinal members such as purlins and St-Andrew's crosses; furthermore, the typical southern German wide-span baroque church roof lacks a tie-beam at the base of the roof, thus requiring complicated, statically indeterminate systems to carry the thrust. The authors of the present paper have conducted an extensive survey of this kind of roof; on the basis of the data collected, characteristic types of such constructions are described, as well as analysed from a structural point of view. It turns out that computational results on such constructions react far more sensitively to changes in the underlying modelling assumptions than other types of roofs where a tie-beam is present. [source] When is glaucoma really glaucoma?CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 5 2007Joseph San Laureano BSci MB BS MMed (Ophthalmol) FRANZCO The approach to the diagnosis and management of glaucoma has undergone considerable changes in recent years. Current concepts of glaucoma diagnosis focus on structural assessment and structure,function correlation, and relies less on the finding of visual field abnormalities. In turn, contemporary approaches to management have also changed and revolve around earlier initiation of pressure lowering medication based on pre-perimetric findings. This article presents an approach to the assessment of the patient with suspected glaucoma, highlighting those structural and ancillary diagnostic investigations that will aid in the correct diagnosis. It also discusses the differentiation of glaucoma from other, non-glaucomatous disease processes. [source] Application of Histomorphometric Methods to the Study of Bone Repair,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2005Louis C Gerstenfeld Abstract ABSTRACT: Standardized methods for the histomorphometric assessment of bone are essential features of most studies of metabolic bone diseases and their treatments. These methodologies were developed to assess coupled remodeling, focusing primarily on osteoblasts and osteoclasts, the anabolic and catabolic rates of these cells, and structural features of mature bone. Research studies on bone healing and the development of new therapeutic approaches for the enhancement of bone repair also require a comprehensive understanding of the basic cellular and tissue level mechanisms that underlie these processes. However, the histological methods developed for metabolic bone disease studies are not completely suitable for studies of bone repair because they are based on assumptions that there is little variation in tissue composition within a sample of bone and not generally designed to quantify other types of tissues, such as cartilage, that contribute to bone healing. These techniques also do not provide tissue-based structural measurements that are relatable to the specific types of biomechanical and radiographic structural assessments that are used to determine rates of bone healing. These deficiencies in current histological approaches therefore point to the need to establish standardized criteria for the histomorphometric assessments that are specifically adapted for the study of bone repair in models of fracture healing and bone regeneration. In this Perspective, we outline what we believe to be the specific structural, tissue. and cellular aspects that need to be addressed to establish these standardized criteria for the histomorphometric assessment of bone repair. We present the specific technical considerations that need to be addressed to appropriately sample repair tissues to obtain statistically meaningful results and suggest specific procedures and definitions of nomenclatures for the application of this technology to bone repair. Finally, we present how aspects of histomorphometric measurements of bone repair can be related to biomechanical and radiographic imaging properties that functionally define rates of bone healing, and thus, how these tools can be used to provide corroborating data. [source] | |||||||||||||