Tensile and Shear Experiments using Polypropylene/Polyethylene Foils at different Temperatures

An experimental campaign on a thermo-plastic copolymer of polypropylene/polyethylene (PP/PE) serves to investigate the rate- and temperature-dependence of the material. Isothermal tensile and shear experiments for four different constant displacement-rates and temperatures (−10 ◦C - 120 ◦C) are conducted, monitored by means of a Digital Image Correlation (DIC) system. The tensile experiments are carried out within the large deformation range, where localization phenomena are observed. This requires the application of a full-field deformation analysis system to develop stress-stretch (strain) diagrams, which are necessary with regard to aspects of constitutive modeling. In addition to these experiments, a modified three-rail shear tool was designed in order to investigate the shear behavior of PP/PE. Apart from the rate-dependence, the relaxation behavior is investigated for both tensile and shear load conditions by means of multi-step relaxation tests at different temperatures in order to obtain indications about the equilibrium stress state of the material

Use of BIM in rehabilitation and assessment of the built heritage: from the visible to the intangible

Building Information Modelling (BIM) has been increasingly expanding its application to different fields of civil engineering and Historic building information modelling (HBIM) is an example of that. Although, the concept has already drawn the attention of several researchers, there are still many limitations to a full and holistic process that may take HBIM to the same level of applicability that BIM used for new construction has. Traditionally, assessment of existing structures, specially heritage structures, begin with the documentation of all important information dealing with the history, characteristics, type, material, uses and applied techniques, among other relevant information that may be retrieved by different sources. Further on, a geometrical survey accompanied with visual inspection and non or semi destructive testing leads to the geometry definition of the structure and to its condition (damage/defects) mapping. All of this information, must be analysed for consequent structural assessment and after stored in a proper database in order to monitor the condition change of the structure along time. This paper, presents a framework for use of BIM in rehabilitation and assessment of the built heritage, based on the review of recent works, as to allow a better understanding of the potential for the management of important and significant structures. The paper deals with the dilemma of bringing what a “traditional” assessment can see to how intangible information may be applied.This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT Foundation for Science and Technology within the scope of the project POCI01-0145-FEDER-007633

Propagation of visual inspection on timber members through Bayesian methods

In this work, the variation of bending stiffness parameters of existing timber elements is assessed by analysis of an existing database of empirical results and by using Bayesian inference methods. The framework of this study initially considers the analysis of existing results from visual inspection and bending tests made to chestnut timber elements including a statistical analysis of the significance of different visual grades within the same size scale. After, Bayesian Probabilistic Networks are used to analyze the distribution of defects and to infer on the visual grading of neighboring segments for predicting the mechanical properties of the element. Finally, the results of the inference process are implemented in a finite element model of random generated elements where the information given by visual inspection on a local level is propagated to the global scale. The comparison between the experimental results and the results obtained through this methodology provided low percentage errors (lower than 3%) given that a significant benchmark sample size was available.This work was partly financed by FEDER funds through the Competitivity 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 financial support of FCT, through national funds, within the scope of the project Protimber, PTDC/ECMEST/1072/2014, is acknowledged. The financial support of FCT, through national funds, within the scope of the project Protimber, PTDC/ECMEST/1072/2014, is acknowledged. The support of the European Commission, within the scope of the Horizon 2020 project SAFEWAY, ref. 769255, is acknowledged