O uso de resíduos de construção e demolição (RCD) vem ganhando espaço crescente em aplicações na engenharia. Este material adquiriu maior importância a partir da década de 70, com seu emprego ampliado como material granular em concretos de cimento para obras civis e no setor de infraestrutura, principalmente como camadas de pavimentos. O presente trabalho tem por objetivo compreender o comportamento físico e mecânico do agregado reciclado de resíduos de construção e demolição com adição de aglomerantes, a cal hidratada e cimento Portland. Foram construídos três trechos experimentais de uma via urbana com uso de RCD misto na sub-base dos pavimentos: (i) um sem aglomerantes adicionais, (ii) um com adição em usina de 3% de cal hidratada, e (iii) um com adição em usina de 3% de cimento Portland. Todas as amostras coletadas em usina foram caracterizadas em laboratório e foram analisados os comportamentos mecânicos das três diferentes misturas por meio de ensaios de (i) resistência à compressão simples aos 7 dias de cura para os materiais com aglomerantes, (ii) ensaios de módulo de resiliência a 7, 28 e 60 dias de cura para todas as misturas, e (iii) ensaios de deformação permanente com diferentes tensões. Analisando os resultados das misturas a 60 dias de cura, a mistura em RCD apresentou com o menor ganho em módulo de resiliência, enquanto que a mistura de RCD com 3% cimento, apresentou os maiores módulos, e a mistura RCD com adição em 3% de cal obteve um valor pouco abaixo daquele com cimento. Quanto ao comportamento à deformação permanente, verificou-se que a baixos níveis de tensão, todas as misturas apresentaram baixas deformações e comportamento similar. Em maiores níveis de diferença de tensões principais, as misturas estabilizadas apresentaram comportamento estável e as misturas em RCD obtiveram deformação permanente mais significativa. Com o monitoramento deflectométrico foi possível realizar retroanálise, e estimar os módulos de resiliência in situ, cujos valores foram similares aos encontrados em laboratório. Passados quase dois anos, o comportamento funcional e estrutural dos trechos experimentais é satisfatório. / The use of construction and demolition waste (CDW) has been increasing in engineering applications the use of CDW has become more important since the 70s as granular material in cement concrete applications in civil engineering and transportation infrastructure, mainly as pavement layers. This study aims to understand the physical and mechanical behavior of recycled aggregate from construction and demolition waste with the addition of hydraulic binders, as hydrated lime and Portland cement. Three experimental urban pavement sections were constructed using CDW as subbase material: (i) the first one using CDW, (ii) the second one using CDW with 3% of hydrated lime (mixed in the plant), and (iii) the third one employing CDW with 3% of cement (also mixed in the plant). All samples collected in the plant were characterized in laboratory. The mechanical behavior of these materials and mixtures were analyzed through the following tests: (i) compressive strength after 7 days of curing for materials with hydraulic binders, (ii) resilient moduli after 7, 28, and 60 days of curing for all mixes, and (iii) permanent deformation. By analyzing the responses of the mixture after 60 days of curing, the CDW mixture presented, as a crushed stone, the smallest gain on resilient modulus, whereas mixture with 3% cement with CDW had the highest modulus. The mixture with 3 % hydrated lime with CDW showed resilient modulus smaller than the mixture with cement. The permanent deformations at low stress levels were low and similar for the three tested materials. On the other hand, at higher stress level, the stabilized mixtures exhibited stable behavior, and the mixture with CDW shows a significant permanent deformation. The backcalculation based on the measurement of field deflections showed values of resilient moduli in situ similar to the laboratory results. After almost two years, the performance of the experimental sections is considered satisfactory.

Orientador: Marilza Vieira Cunha Rudge / Banca: José Carlos Peraçoli / Banca: Nelson Lourenço Maia / Banca: Geraldo Duarte / Banca: Nelson Sass / Resumo: A hipertensão gestacional está presente em cerca de 10% das gravidezes e ainda é a primeira causa de mortalidade materna no Brasil. O diabetes gestacional complica 7,6% das gestações no Brasil e está associado a esultados perinatais insatisfatórios. Estas complicações cursam com disfunção endotelial e alteração da elasticidade da parede -.vascular. A onometria de aplanação é um método não invasivo, portátil e de fácil aprendizagem que avalia a função endotelial através do estudo da rigidez arterial (perda da elasticidade arterial). Além de avaliar a função endotelial este método oferece estudo indireto de vários parâmentros cardiovasculares centrais. O grande número de informações que este método obtém de maneira não invasiva, faz deste, um instrumento valoroso em pesquisa. Apresenta grande potencial, especialmente, na compreensão dos mecanismos fisiopatológicos que cursam com comprometimento vascular na gravidez. / Abstract: Gestational hypertension affects 10% of pregnancies and is still the first :ause of maternal mortality in Brazil. Gestational diabetes affects 7,6% of gnancies in Brazil and is associated with an unsatisfactory peri-natal come. These complications are associated to endothelial dysfunction and abnormal elasticity of the arterial wall. Applanation tonometry is a nonvasive, portable and easy learning method that evaluates endothelial nction by the study of arterial stiffness (Iost of arterial elasticity). Beyond e endothelial function evaluation, this method gives, indirectly, several central cardiovascular parameters. The great number of information btained non invasively by this method, makes of this, a valuable instrument in research. It has special potential to help in the comprehension of the mechanisms of those diseases that presents with vascular commitment in pregnancy. / Doutor

A norma brasileira para o projeto de estruturas de madeira foi alterada, recentemente, abandonando o método determinista das Tensões Admissíveis e adotando o método probabilista dos Estados Limites. Seguindo tendência mundial, a atual norma brasileira, estabelece um teor de umidade de referência de 12%, no qual devem ser reportados os resultados dos ensaios. Dificilmente se conseguirá condicionar, a madeira para o ensaio, com um teor de umidade de exatamente 12%, portanto, será necessário corrigir os resultados do ensaio para este teor de umidade. A atual norma brasileira propõe expressões, para fazer esta correção nas propriedades de resistência e de rigidez da madeira, baseando-se em poucos resultados de ensaios. O objetivo deste trabalho é aferir as expressões propostas pela norma brasileira, sugerindo as alterações necessárias. Uma proposta para a correção da densidade aparente, não prevista na norma brasileira, também será estudada. Para garantir uma base experimental adequada, estuda-se a influência do teor de umidade sobre as propriedades de resistência à compressão paralela às fibras, tração paralela às fibras, cisalhamento paralelo às fibras (no plano radial-longitudinal), bem como sobre o módulo de elasticidade longitudinal e a densidade aparente, em sete diferentes espécies de madeira, correspondentes às sete classes de resistência adotadas pela atual norma brasileira. Conclui-se o trabalho apresentando uma proposta para correção das propriedades de resistência e rigidez ao teor de umidade de 12%. Apresenta-se também uma proposta para a correção da densidade aparente. / The Brazilian Code, NBR 7190/97 - Design of timber structures, was revisited, recently, abandoning the Allowable Stress Method and adopting the States Limits Design Method. Following world tendency, the current Brazilian Code, establishes a reference moisture content of 12%, in which the test\'s results should be registered. It is not possible to keep the specimen, for testing, with exactly 12% moisture content, therefore, it will be necessary to correct the results for this moisture content level. The current Brazilian Code proposes expressions, to do this correction in the strength and stiffness properties of wood, based on few test\'s results. The objective of this work is to judge the expressions proposed by the Brazilian Code, proposing the necessary alterations. A proposal for the correction of the specific gravity, not presented in the Brazilian Code, it will also be studied. To this purpose, the influence of moisture content on the strength in compression and tension parallel to grain, shear parallel to grain (in the radial-longitudinal plane), as well as on the stiffness (modulus of elasticity) and specific gravity, in seven different wood species, corresponding to the seven Brazilian Code strength classes were studied. The conclusions presents a proposal for correction of the strength, stiffness properties and specific gravity, to the 12% moisture content level.

A madeira tem aplicações já difundidas em diversos setores, no entanto, muitas vezes é utilizada sem o conhecimento de suas propriedades. A caracterização de espécies de madeira consiste em determinar suas propriedades físicas, de resistência e rigidez através de ensaios normalizados. O inconveniente de grande parte desses ensaios é a utilização de equipamentos de alto custo e grande porte, disponíveis apenas em centros de pesquisa. Porém, o ensaio de densidade aparente é de fácil determinação por utilizar equipamentos simples na sua execução. Sendo assim, neste trabalho são determinadas as correlações entre a densidade aparente e as propriedades físicas, de resistência e de rigidez da madeira, de quarenta espécies nativas brasileiras, do grupo dicotiledôneas. Através de análise estatística, foram obtidas expressões matemáticas que permitem estimar, a partir da densidade aparente, grande parte das propriedades de resistência e rigidez da madeira. Tais expressões são apresentadas como proposta para a utilização na caracterização de espécies menos conhecidas, o que viabiliza o adequado emprego de espécies nativas nas mais variadas aplicações para as quais a madeira é indicada. Apresentam-se também aferições das expressões propostas pela norma brasileira NBR 7190, que permitem a caracterização simplificada das resistências da madeira de espécies usuais a partir dos ensaios de resistência à compressão paralela às fibras. / Wood has diffused applications in several sections, however, a lot of times it is used without the knowledge of its properties. The characterization of wood species consists of determining its physical, strength and stiffness properties, through normalized tests. The inconvenience of many of those tests is the use of equipments of high cost and great load, available just in research centers. Even so, the test of specific gravity is of easy determination for using simple equipments in its execution. Being like this, in this study the correlations between the specific gravity, physical and mechanical properties of wood from forty brazilian native species of hardwoods are determined. The mathematical expressions obtained through this study, permit estimate most wood properties of strength and stiffness, based on their specific gravity. Such expressions are proposed as means of characterizing less-known species, what makes possible the appropriate employment of native species in most varied applications for which wood is the indicated material. Furthermore, it is presented the calibration of the expressions proposed by the brazilian code NBR 7190, being these a simplified method of characterizing mechanical properties of common species of wood by means of tests of strength in compression parallel to the grain.

Using material models on the basis of the flow theory of plasticity the asymptotic behaviour of solid mechanics solutions in crack tips, interface corners etc. strongly depends on the local realized load trajectory. For incrementally proportional load paths the equations determining the asymptotic fields are very simple ones. The paper considers two-dimensional statements in the neighbourhood of an interface corner consisting of two material ranges. At a distance from the corner the finite element nodes of a regular net are established in a polar co-ordinate system together with the displacement degrees of freedom. The main idea of the presented singular and non-singular stress and deformation field calculation at interface corners characterizes an replacement of the corner neighbourhood effect to the surrounding body by introducing stiffness actions which in usual manner can be assembled together with the other element stiffness matrices to the global stiffness matrix of the body. According to this there exists an in teresting invariant stiffness independence in corner and crack neighbourhoods. The applied technique allows extensions to non-proportional local load increments simplifying the mathematical calculations for the presentation of stress and strain fields in this general case. All computations are made on modern parallel computers. Concrete examples show the advantages of the presented approach.

Granular materials utilised in the construction of highway foundation layers are currently specified on the basis of index tests. As a consequence, the material acceptability criteria, although developed from many years' experience, do not directly measure a fundamental performance parameter. Once the granular materials are placed and compacted they are rarely checked and as such no assurance can be given to their likely engineering performance in situ. An important performance parameter, the stiffness modulus, describes the ability of the constructed layer(s) to spread the construction (and in-service) vehicle contact pressures and reduce the stresses, and hence strains, transmitted to the lower weaker layers. A significant improvement upon current practice would be to include the specification of 'end product' testing and to include the direct measurement in situ of stiffness modulus to assure performance. A prerequisite of this is suitable site equipment to measure such a parameter, and a sound basis upon which to interpret and utilise such data. Tests do exist that measure stiffness modulus in situ, although in general they measure a 'composite' stiffness, i.e. a single transducer infers the surface strain, under controlled loading, for the construction as a whole and the region affecting the measurement is not precisely known. Currently then, no routine portable device exists for the direct stiffness modulus assessment of the near surface or last layer applied. This would not only provide for consistency of construction, but avoid burying poor or weaker layers. This thesis describes the evaluation of a portable impact test device and research into the behaviour of granular soils subject to rapid transient loads. The requirements for the assessment of pavement granular foundation layers are reviewed, followed by a critical appraisal of current devices that measure the stiffness modulus of material in situ. The prototype impact device, known as ODIN, comprising an accelerometer instrumented swinging hammer, is described. A selection of field data, demonstrating the primary soil influencing factors and correlations with other devices, is presented. Controlled laboratory testing is also described, comprising impact testing with free-falling masses in addition to the ODIN device and for tests on foundations instrumented with pressure cells, that further explains the dynamic behaviour of the material under test. Problems with both hardware and software, associated with high-frequency impact testing are highlighted. In particular, the restraint of the impact mass by the swinging arm mechanical component is observed to lead to a proportion of the impact energy being channelled back into the apparatus during a test. The channelled energy is shown to produce resonance of the apparatus, which in turn leads to problems in interpretation of the accelerometer signal. Numerical methods are then explored and it is demonstrated that the predictions approximated well to the free-falling weights experimental data. Discussion of the research findings concludes with a model for soil behaviour under impact testing, requirements for an improved impact device and the further research work required to realise the potential of such equipment.

Background Right ventricular (RV) diastolic function has been associated with outcomes for patients with pulmonary hypertension; however, the relationship between biomechanics and hemodynamics in the right ventricle has not been studied. Methods and Results Rat models of RV pressure overload were obtained via pulmonary artery banding (PAB; control, n=7; PAB, n=5). At 3 weeks after banding, RV hemodynamics were measured using a conductance catheter. Biaxial mechanical properties of the RV free wall myocardium were obtained to extrapolate longitudinal and circumferential elastic modulus in low and high strain regions (E-1 and E-2, respectively). Hemodynamic analysis revealed significantly increased end-diastolic elastance (E-ed) in PAB (control: 55.1 mm Hg/mL [interquartile range: 44.785.4 mm Hg/mL]; PAB: 146.6 mm Hg/mL [interquartile range: 105.8155.0 mm Hg/mL]; P=0.010). Longitudinal E1 was increased in PAB (control: 7.2 kPa [interquartile range: 6.718.1 kPa]; PAB: 34.2 kPa [interquartile range: 18.144.6 kPa]; P=0.018), whereas there were no significant changes in longitudinal E-2 or circumferential E-1 and E-2. Last, wall stress was calculated from hemodynamic data by modeling the right ventricle as a sphere: (stress = Pressure x radius/2 x thickness Conclusions RV pressure overload in PAB rats resulted in an increase in diastolic myocardial stiffness reflected both hemodynamically, by an increase in E-ed, and biomechanically, by an increase in longitudinal E-1. Modest increases in tissue biomechanical stiffness are associated with large increases in E-ed. Hemodynamic measurements of RV diastolic function can be used to predict biomechanical changes in the myocardium.

Compliant mechanisms are flexible structures that utilize elastic deformation to achieve their desired motions. Using this unique mode of actuation, the compliant mechanisms have two distinct advantages over traditional rigid machines: (1) They can create highly repeatable motions that are critical for many high precision applications. (2) Their high degrees-of-freedom motions have the potential to achieve mechanical functionalities that are beyond traditional machines, making them especially appealing for miniature robots that are currently limited to only having simple rigid-body-motions and gripping functionalities. Unfortunately, despite the potential of compliant mechanisms, there are still several key challenges that restrict them from realizing their full potential. To facilitate this discussion, we first divide the compliant mechanisms into two categories: (1) the stiffer flexural mechanisms that are ideal for high precision applications, and (2) the more compliant miniature soft robots that can reshape their geometries to achieve highly complex mechanical functionalities. The key limitation for existing flexural mechanisms is that their stiffness and dynamic properties cannot be optimized when they have multi-degrees-of-freedom. This limitation has severely crippled the performance of flexural mechanisms because their stiffness and dynamic properties dictate their workspace, transient responses and capabilities to reject disturbances. On the other hand, miniature soft robots that have overall dimensions smaller than 1 cm, are unable to achieve their full potential because existing works do not have a systematic approach to determine the required design and control signals for the robots to generate their desired time-varying shapes.

In view of the recent catastrophes associated with deep excavations, there is an urgent need to provide vital guidelines on the design of the construction process. To develop a simple tool for predicting ground deformation around a deep excavation construction for preliminary design and decision-making purposes, small scale centrifuge models were made to observe the complicated mechanisms involved. A newly developed actuation system, with which the construction sequences ofpropping could be implemented, was developed, the new procedures were proven to give more realistic initial ground conditions before excavation with minimal development of pre-excavation bending moment and wall displacement. Incremental wall deformation profiles generally followed the O'Rourke cosine bulge equation and a new deformation mechanism was proposed with respect to wall toe fixity and excavation geometry. Validation of the conservation energy principle was carried out for the undrained excavation process. The total loss of potential energy was shown to be balanced by the total work done in shearing and the total elastic energy stored in structures with an error term of 30%. An improved mobilizable strength method (MSD) method using observed mechanistic deformation patterns was introduced to calculate the displacement profile of a multi-propped undrained excavation in soft clay. The incremental loss in potential energy associated with the formation of settlement toughs was balanced by the sum of incremental storage of elastic energy and the energy dissipation in shearing. A reasonable agreement was found between the prediction by the MSD method and the finite element results computed by an advanced MIT-E3 model for wall displacements, ground settlement, base heave and bending moment on fixed base walls. For cases of excavations supported by floating walls, the effect of embedded wall length, depth of the stiff layer, bending stiffness of wall and excavation geometry and over-consolidation ratio of soils were found to have a influence on the maximum wall deflection. In general, the predictions fell within 30% of the finite element computed results. A new chart Ψ versus normalized system stiffness was used to demonstrate that MSD could correctly capture the trend of wall displacements increasing with the ratio ofexcavation depth to depth of stiff layer, which could be controlled by increasing wall stiffness for very stiff wall system only. The incorporation of a simple parabolic curvequantifying small strain stiffness of soil was proven to be essential to good ground movement predictions. A new dimensionless group has been defined using the MSD concepts to analyze 110 cases of excavation. The new database can now be used to investigate the relationship between structural response ratio S and soil-structure stiffness ratio R where this is shown on log-log axes to capture the enormous range of wall stiffness between sheet-piles and thick diaphragm walls. Wall stiffness was found to have a negligible influence on the magnitude of the wall bulging displacements for deep excavation supported by fixed-based wall with stiffness ranging from sheet pile walls to ordinary reinforced concrete diaphragm walls, whereas excavations supported by floating walls were found to be influenced by wall stiffness due to the difference in deformation mechanisms.

Group Representation Theory is the mathematical language best suited to describing the symmetry properties of a structure, and a structural analysis can utilises Group Representation Theory to provide the most efficient and systematic method of exploiting the full symmetry properties of any symmetric structure. Group Representation Theory methods currently exist for the Stiffness Niethod of structural analysis, where the stiffness matrix of a structure is block-diagonalised into a number of independent submatrices, each of which relates applied loads and displacements with a particular type of symmetry. This dissertation extends the application of Group Representation Theory to the equilibrium and compatibility matrices which are commonly used in the Force Method of structural analysis. Group Representation Theory is used to find symmetry-adapted coordinate systems for both the external vector space which is suitable for representing the loads applied to a structure, and the internal vector space wh",t-k is-suitable for representing the internal forces. Using these symmetry-adapted coordinate systems the equilibrium matrix is block-diagonalised into a number of independent submatrix blocks, thus decomposing the analysis into a number of subproblems which require less computational effort. Each independent equilibrium submatrix block relates applied loads and internal forces with particular symmetry properties, and hence any states of self-stress or inextensional mechanisms in one of these equilibrium submatrix blocks will necessarily have ~rresponding symmetry properties. Thus, a symmetry analysis provides valuable insight into the behaviour of symmetric structures by helping to identify and classif:)'. any states of self-stress .or inextensional mechanisms present in a structure. In certain cases it is also possible for a symmetry analysis to identify when a structure contains a :ijnite rather than infinitesimal mechanism. To do this a symmetry analysis must b~ carried out using the symmetry properties of the inextensional mechanism of interest. If the analysis shows that any states of self-stress which exist in the structure have "lesser" symmetry properties, then the states of self-stress exist independently from the mechanism and cannot prevent its finite motion.