18 research outputs found

    Tectonic design of elastic timber gridshells

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    This paper aims to 'bridge the gap' between engineers and architects for a better understanding of the design process of elastic timber gridshells. The purpose is to inspire architects to develop innovative timber structural forms informed by engineering knowledge. This paper is organised in two parts: the first part is a theoretical reflection on the concept of tectonic and on the combined application of architectural and structural knowledge; the second part is dedicated to the review and definition of the various decisions and consequences during the design and construction of elastic timber gridshells.This work is financed by FEDER funds through the Competitively Factors Operational Programme - COMPETE and by national funds through FCT –Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007633. The support of the Foundation for Science and Technology (FCT) through doctoral fellowship SFRH/BD/104677/2014 is grateful. The support of the Aarhus University through the financial support for participation in this conference

    Identification of Non-Linear Structures using Recurrent Neural Networks

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    Reliability based robustness of timber structures through NDT data updating

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    This work presents a framework for reliability-based assessment of timber structures / members using data gathered from non-destructive test results. These results are used for modeling an update of the mechanical characteristics of timber, using Bayesian methods. These methods are suitable to be used for parameter estimation and also allow updating model uncertainties. From the updated model, decisions upon the life-cycle reliability of existing structures may be taken and maintenance or strengthening actions may be considered. In this work, results gathered from ultrasound testing, Resistograph® and Pilodyn® conducted on chestnut wood specimens were used, as well as correlations between those results and compression strength parallel to the grain tests’ results. The resistant characteristics are also updated assuming deterioration models applied to specific key elements of the structure, thus, being possible to evaluate reliability based in time dependent factors, as well to categorize that structure in terms of robustness.COST E55, STSM-6269Fundação de Ciência e Tecnologia, FCT, through project SFRH/BD/62326/2009

    On the use of NDT data for reliability-based assessment of existing timber structures

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    The objective of this paper is to address the possibilities of using non-destructive testing (NDT) data for updating information and obtaining adequate characterization of the reliability level of existing timber structures and, also, for assessing the evolution in time of performance of these structures when exposed to deterioration. By improving the knowledge upon the mechanical properties of timber, better and more substantiated decisions after a reliability safety assessment are aimed at. Bayesian methods are used to update the mechanical properties of timber and reliability assessment is performed using First Order Reliability Methods (FORM). The results show that different degrees of belief in the updating data may significantly influence the reliability level. The updating data to be used are NDT results obtained with ultrasound, resistance drilling and pin penetration equipments. The tests were conducted on chestnut wood (Castanea sativa Mill.) specimens, and were combined with tests to determine the compressive strength parallel to the grain. The uncertainty of the different NDT results is modeled by Maximum Likelihood estimates. Resistance distributions functions are considered to analyze the difference before and after updating by NDT, showing that lower variations may typically be obtained with the new information. Moreover, updating of the parameters in different deterioration models is considered in order to be able to evaluate the time dependency of the reliability, and information of NDT is also used to calibrate these models. The proposed approach is used for reliability assessment of different structural timber systems. Reliability of the structural system is assessed regarding the failure consequences of individual elements defined as key elements which were determined by their influence on the cross section loss. The results given by the pin penetration tests were the most similar to the reference experimental model with statistic parameters given by the results of destructive tests. The resistance drilling and ultrasound updating schemes led to higher level of reliability than the reference model values, therefore these updating data should be considered with caution, as they can result in unsafe results for the reliability compared to the reference models.Fundação para a Ciência e a Tecnologia (FCT

    Freehand drawing as a didactic instrument

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    This paper was guided by the following research question: how freehand drawing teaching influences design teaching? The bibliography regarding freehand drawing as a design instrument is extensive and diverse, underlining its different associated procedures, such as perception, conception and communication.1 Less relevance has been given to freehand drawing as a didactic instrument, that is, as a means used by instructors and students for the transmission and acquisition of knowledge.2 It is intended to consider the didactic role of freehand drawing and its importance in the architectural design teaching, based on the analysis of the intersections between the courses of drawing and architectural design at the Faculty of Architecture of the University of Porto (FAUP). Considering the progressive loss of relevance of drawing in architectural curriculum plans in recent decades,3 the aim of this paper is to understand why to continue to teach freehand drawing and how this interferes or determines the way of teaching architectural design

    A holistic multi-methodology for sustainable renovation

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    A review of the barriers for building renovation has revealed a lack of methodologies, which can promote sustainability objectives and assist various stakeholders during the design stage of building renovation/retrofitting projects. The purpose of this paper is to develop a Holistic Multi-methodology for Sustainable Renovation, which aims to deal with complexity of renovation projects. It provides a framework through which to involve the different stakeholders in the design process to improve group learning and group decision-making, and hence make the building renovation design process more robust and efficient. Therefore, the paper discusses the essence of multifaceted barriers in building renovation regarding cultural changes and technological/physical changes. The outcome is a proposal for a multi-methodology framework, which is developed by introducing, evaluating and mixing methods from Soft Systems Methodologies (SSM) with Multiple Criteria Decision Making (MCDM). The potential of applying the proposed methodology in renovation projects is demonstrated through a case study

    Tectonic design elastic timber gridshells

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    This paper aims to 'bridge the gap' between engineers and architects for a better understanding of the design process of elastic timber gridshells. The purpose is to inspire architects to develop innovative timber structural forms informed by engineering knowledge. This paper is organised in two parts: the first part is a theoretical reflection on the concept of tectonic and on the combined application of architectural and structural knowledge; the second part is dedicated to the review and definition of the various decisions and consequences during the design and construction of elastic timber gridshells.This work is financed by FEDER funds through the Competitively Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007633. The support of the Aarhus University through the financial support for participation in this conference

    Identification of Non-Linear Structures using Recurrent Neural Networks

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