Orientador: David de Carvalho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-09T05:45:20Z (GMT). No. of bitstreams: 1 MirandaJunior_Gentil_D.pdf: 36304791 bytes, checksum: 88909d0a8735e0e6ebf6251c718ba4cb (MD5) Previous issue date: 2006 / Resumo: O problema de estacas carregadas horizontalmente no topo é freqüente em obras de construção civil e há uma reduzida bibliografia sobre os parâmetros a serem adotados em projetos. Uma situação mais crítica é a de estacas carregadas horizontalmente em solos de alta porosidade, não saturados e colapsíveis. Os objetivos deste trabalho são: (1) proporcionar subsídios para o projeto de fundações com carregamento horizontal, chamando a atenção para o danoso efeito de uma inundação de um solo colapsível; (2) fornecer valores do coeficiente de reação horizontal ('n IND. h') para uma argila silto arenosa de alta porosidade, solo de diabásio, comum na região de Campinas, para condições de umidade natural, solo pré-inundado, solo melhorado com solocimento e solo-cimento pré-inundado; (3) compararos valores obtidos com valores de 'n IND. h' para solos freqüentemente encontrados no interior do Estado de São Paulo e em outras regiões do Brasil; (4) propor uma melhoria das condições do sistema solo-estaca através da troca do solo ao redor do topo da estaca por solo-cimento compactado. Para a análise deste problema, foram realizadas vinte e uma provas de cargas horizontais no Campo Experimental de Fundações da Unicamp, em catorze estacas de quatro tipos, nas quatro condições de solo citadas acima. E foram analisadas outras provas de carga realizadas em Campos Experimentais do Estado de São Paulo, todos localizados em regiões com solos superficiais com características desfavoráveis ao carregamento horizontal. Comparam-se valores do coeficiente de reação horizontal do solo ('n IND. h') para diferentes condições do solo, destacando-se a importância de se obter parâmetros do solo regionalmente. Os principais resultados encontrados foram, além dos valores de coeficiente de reação horizontal para o solo de basalto do local e a compilação de valores para solos de alta porosidade de outras regiões - encontrando-se valores diferentes dos propostos na bibliografia -, a acentuada redução do 'n IND. h' (valoresem tomo de 40 vezes menores) ocasionada pela préinundação do solo, o acentuado aumento do 'n IND. h'(valores em média 5 vezes maiores) com a melhora do solo através do solo-cimento compactado,e a redução do 'n IND. h' com a pré-inundação do solo-cimento (valores em média 7 vezes menores). Nota-se que a redução devido à préinundação do solo-cimento é bem inferior a da pré-inundaçãodo solo na umidade natural. Conclui-se que, num projeto onde há a atuação de esforços horizontais e presença de solo colapsível, é necessário contar com a possibilidade de uma inundação do solo, tomar medidas preventivas contra a mesma e utilizar parâmetros do solo adequados. Ou adotar soluções de melhoria do solo, como a utilização do solo-cimento compactado ao redor da cabeça da estaca, que também podem ser adotadas em casos de baixa resistência do solo superficial (seja o solo colapsível ou não) / Abstract: The problem with piles loaded horizontally at the top is frequently met in civil construction projects and there is a reduced bibliography on the parameters to be adopted in designoA more critical situation is that of horizontally loaded piles in high porosity, non saturated and collapsible soils. The objectives of this paper are: (1) produce subsidies for the design of foundations with horizontalloads, calling attention to the damaging effect of flooding on a collapsible soil; (2) supply values for the horizontal reaction coefficient ('n IND. h') for the soil of the Experimental Field at Unicamp, for the conditions of natural humidity, pre-flooded soil, soil improved with soil-cement and pre-flooded soil-cement; (3) compare values of nh for the soils frequently found in the interior of the State of São Paulo and in other regions in Brazil; (4) propose an improvement in the conditions of the soil-pile system soils by changing the soil around the top of the pile for compacted soil-cement. To analyze this problem, twenty one horizontal loading tests were made in the Experimental Foundation Field at Feagri-Unicamp, on fourteen piles of four types, under the four soil conditions mentioned above. Other loading tests made in Experimental Fields in the State of São Paulo were analyzed, alI of them located in regions with surface soils with unfavorable characteristics for horizontal loading. The coefficients of horizontal soil reaction ('n IND. h') for different soil conditions are compared, emphasizing the importance of obtaining regional soil parameters. The principal results found were, besides the values for the coefficient of horizontal reaction for the basalt soil at the location and the compilation of values for high porosity soils of other regions - encountering different values from °those proposed in literature - an accentuated reduction of nh (values around 40 times less) caused by the pre-flooding of the soil, the accentuated increase in 'n IND. h' values (as a mean, 5 times greater) with the soil improvement by compacted soil-cement and the reduction in 'n IND. h' with pre-flooding of the soilcement (mean values 7 times smaller). It is seen that the reduction due to pre-flooding of the soil-cement is much less than that for pre-flooding the soil at natural humidity. One concludes that in a project where horizontal forces act and in collapsible soil, one must count with the possibility of soil flooding, taking preventive measures against this and using adequate soil parameters or, adopt solutions for soil improvement, as by using compacted soil-cement around the pile head, a procedure which can also be adopted in cases of low surface soil resistance (collapsible soil or not) / Doutorado / Construções Rurais e Ambiencia / Doutor em Engenharia Agrícola

Doctor Educationis / In summary, it has been shown during this study that bimetallic Fe and Mn containing catalysts can be prepared by wet impregnation and not by ion exchange because of the competition between two different metals at different oxidation number. Only a single metallic phase catalyst could be prepared successfully by using ion exchange. / South Africa

Several studies were undertaken by various investigators during the last five decades to better understand the engineering behaviour of unsaturated soils. These studies are justified as more than 33% of soils worldwide are found in either arid or semi-arid regions with evaporation losses exceeding water infiltration. Due to this reason, the natural ground water table in these regions is typically at a greater depth and the soil above it is in a state of unsaturated conditions. Foundations of structures such as the housing subdivisions, multi-storey buildings, bridges, retaining walls, silos, and other infrastructure constructed in these regions in sandy soils are usually built within the unsaturated zone (i.e., vadose zone). Limited studies are reported in the literature to understand the influence of capillary stresses (i.e., matric suction) on the bearing capacity, settlement and liquefaction potential of unsaturated sands. The influence of matric suction in the unsaturated zone of the sandy soils is ignored while estimating or evaluating bearing capacity, settlement and liquefaction resistance in conventional engineering practice. The focus of the research presented in the thesis has been directed towards better understanding of these aspects and providing rational and yet simple tools for the design of shallow foundations (i.e., footings) in sands under both static and dynamic loading conditions. Terzaghi (1943) or Meyerhof (1951) equations for bearing capacity and Schmertmann et al. (1978) equation for settlement are routinely used by practicing engineers for sandy soils based on saturated soil properties. The assumption of saturated conditions leads to conservative estimates for bearing capacity; however, neglecting the influence of capillary stresses contributes to unreliable estimates of settlement or differential settlement of footings in unsaturated sands. There are no studies reported in the literature on how capillary stresses influence liquefaction, bearing capacity and settlement behavior in earthquake prone regions under dynamic loading conditions. An extensive experimental program has been undertaken to study these parameters using several specially designed and constructed equipment at the University of Ottawa. The influence of matric suction, confinement and dilation on the bearing capacity of model footings in unsaturated sand was determined using the University of Ottawa Bearing Capacity Equipment (UOBCE-2011). Several series of plate load tests (PLTs) were carried out on a sandy soil both under saturated and unsaturated conditions. Based on these studies, a semi-empirical equation has been proposed for estimating the variation of bearing capacity with respect to matric suction. The saturated shear strength parameters and the soil water characteristic curve (SWCC) are required for using the proposed equation. This equation is consistent with the bearing capacity equation originally proposed by Terzaghi (1943) and later extended by Meyerhof (1951) for saturated soils. Chapter 2 provides the details of these studies. The cone penetration test (CPT) is conventionally used for estimating the bearing capacity of foundations because it is simple and quick, while providing continuous records with depth. In this research program, a cone penetrometer was specially designed to investigate the influence of matric suction on the cone resistance in a controlled laboratory environment. Several series of CPTs were conducted in sand under both saturated and unsaturated conditions. Simple correlations were proposed from CPTs data to relate the bearing capacity of shallow foundations to cone resistance in saturated and unsaturated sands. The details of these studies are presented and summarized in Chapter 3. Standard penetration tests (SPTs) and PLTs were conducted in-situ sand deposit at Carp region in Ottawa under both saturated and unsaturated conditions. The test results from the SPTs and PLTs at Carp were used along with other data from the literature for developing correlations for estimating the bearing capacity of both saturated and unsaturated sands. The proposed SPT-CPT-based technique is simple and reliable for estimation of the bearing capacity of footings in sands. Chapter 4 summarizes the details of these investigations. Empirical relationships were proposed using the CPTs data to estimate the modulus of elasticity of sands for settlement estimation of footings in both saturated and unsaturated sands. This was achieved by modifying the Schmertmann et al. (1978) equation, which is conventionally used for settlement estimations in practice. Comparisons are provided between the three CPT-based methods that are commonly used for settlement estimations in practice and the proposed method for seven large scale footings in sandy soils. The results of the comparisons show that the proposed method provides better estimations for both saturated and unsaturated sands. Chapter 5 summarizes the details of these studies. A Flexible Laminar Shear Box (FLSB of 800-mm3 in size) was specially designed and constructed to simulate and better understand the behaviour of model surface footing under seismic loads taking account of the influence of matric suction in an unsaturated sandy soil. The main purpose of using the FLSB is to simulate realistic in-situ soils behaviour during earthquake ground shaking. The FLSB test setup with model footing was placed on unidirectional 1-g shake table (aluminum platform of 1000-mm2 in size) during testing. The resistance of unsaturated sand to deformations and liquefaction under seismic loads was investigated. The results of the study show that matric suction offers significant resistance to liquefaction and settlement of footings in sand. Details of the equipment setup, test procedure and results of this study are presented in Chapter 6. Simple techniques are provided in this thesis for estimating the bearing capacity and settlement behaviour of sandy soils taking account of the influence of capillary stresses (i.e., matric suction). These techniques are consistent with the methods used in conventional geotechnical engineering practice. The studies show that even low values of capillary stresses (i.e., 0 to 5 kPa) increases the bearing capacity by two to four folds, and the settlement of footings not only decreases significantly but also offers resistance to liquefaction in sands. These studies are promising and encouraging to use ground improvement techniques; such as capillary barrier techniques to maintain capillary stresses within the zone of influence below shallow foundations. Such techniques, not only contribute to the increase of bearing capacity, they reduce settlement and alleviate problems associated with earthquake effects in sandy soils.

Background Loading efficiency within logistics is a research area which has been given a lot of attention by researchers during recent years. Pallet Loading Problem has been presented as a mean to tackle the loading efficiency issue in this area. Loading efficiency can be measured in terms of fill rate of the load and the number of reclaimed gods. Different loading methods presents advantages and disadvantages regarding the two presented areas fill rate and returned gods.      Purpose The purpose with this study is to examine the different issues related to implementing an efficient pallet loading method, with the help of a comparative study of alternative loading methods. In order to accomplish this, different key factors are located and identified in which the relation between these factors is displayed. Research in this area has highlighted that a streamlining of the loading process has assisted organizations in reducing their costs. The cost reduction is an effect of the reduced transport and reclaimed gods.   Methods In this comparative study of alternative loading methods, key factors in different loading methods were identified and analyzed. The data for the three key factors were collected through archival research, unstructured interviews and observations of the different procedures. The analytic tests of the data where conducted through SPSS with the likes of descriptive statistic, non-parametric t-test, correlation and logistic regression.     Results In the result of this thesis, the differences of studied loading methods are presented based on the defined key factors. Each loading method is individually analysed and later compared to the other alternative loading method in order to decide which method is the most efficient, based on the presented key factors. The analyses in the tests presents a connection between fill rate and claims but also between claims and loading method.     Conclusions Between the two presented loading methods, free pallet loading and standing pallet loading, there’s a significant difference based on the analysed key factors. Free pallet loading is concluded to be the more efficient loading method in each of the analysed categories fill rate, claims and cost of claims. This concludes free pallet loading to be the more sustainable and economically beneficial loading method. / Bakgrund Lastningseffektivitet inom logistiken är ett område som dem senaste år fått mycket uppmärksamhet där pallastning av produkter är ett centralt område. En lastningseffektivitet kan mätas i den totala fyllnadsgraden för lastningen samt vilken skaderisk det medför. Två centrala begrepp vilka studerats för lastning är Pallet Loading Problem samt Reclaimed Gods.            Ovanstående ämnesområden presenterar fördelar samt nackdelar med olika lastningsmetoder.   Syfte Syftet med denna studie är att undersöka problematiken kring att tillämpa en effektiv pallastning med hjälp av en jämförelsestudie kring alternativa lastningsmetoder. Detta då för att identifiera och kartlägga nyckelfaktorer samt sambandet mellan dessa i en lastningsprocess. Forskning visar på att en effektivisering av lastningsprocessen har hjälpt olika företag att reducera sina kostnader, genom en minskning av transport samt minimering av skaderisk för det lastade godset.   Metod Tillvägagångssättet för denna studie var att göra en jämförelsestudie där nyckelfaktorer i olika lastningsmetoder skall analyseras. Tre olika faktorer för lastning analyserades, där underlag för analysen införskaffades ur organisationens datasamling genom arkivforskning, observationer samt ostrukturerade intervjuer. Analyserna gjordes i SPSS genom de olika dataanalystesterna, deskriptiv statistik, icke parametriskt t-test, korrelation samt logistisk regression.   Resultat Resultatet av studien visar hur lastning skiljer sig åt med avseende på de tre olika nyckelkoncepten beroende på vilken metod som ligger till grund. Respektive lastningsmetod analyseras för sig själv för att sedan jämföras, detta då för att identifiera vilken som är effektivast beroende på nyckelfaktorer. Resultatet presenterar ett samband mellan claims och fyllnadsgraden samt mellan claims och metodval.    Slutsats Slutsatsen av denna studie är att bland de två presenterade lastningsmetoderna, löst liggande samt stående pallastning finns en signifikant skillnad sett till nyckelfaktorerna vilka undersökts. Löst liggande pallastning är en effektivare modell sett till samtliga av de undersökta nyckelfaktorerna det vill säga fyllnadsgrad, claims samt kostnaden vilken uppkommer i samband med claims. Detta medför att löst liggande lastning är den mer gynnsamma lastmetoden sett till både ett hållbarhets och ekonomiskt perspektiv.

Fiber reinforced polymer composite laminates make up more than 50% of modern aircrafts. Such composite laminates are exposed to various environmental and in-service thermo-mechanical load conditions. Transverse/intralaminar cracking is usually the first form of damage appears in a composite laminate and they tend to increase in number during the service life. The growth in number of these cracks significantly degrades the thermo-elastic properties of the composite laminate and eventually leads to final failure. Thus, it is important to predict the crack density (number of cracks per unit length) growth in both non-interactive crack density region and interactive crack density region and its effect in thermo-elastic properties degradation. Non-interactive crack density region is the region where the cracks are far apart and stress perturbation between cracks do not overlap. Interactive crack density region is where the cracks are close to each other and stress perturbation between cracks overlaps and affects the formation of new cracks. In this study, transverse cracks in thick Glass Fiber Epoxy (GF/EP) cross-ply composite laminates under quasi-static tensile loading and tension-tension fatigue loading have been analyzed and predicted. In the first paper attached here, increase in number of transverse cracks in GF/EP cross-ply laminates under quasi-static tensile loading at room temperature (RT) are analyzed using 2 material systems. The failure stress distribution in 90° plies of the laminates is defined by Weibull distribution and the Weibull parameters are determined from crack density versus applied thermo-mechanical transverse stress in 90° layer (σTCLT) data points within the non-interactive crack density region. The crack density growth is then predicted versus the σTCLT and applied mechanical strain in the laminate from the determined Weibull parameters using Monte Carlo method and the stress distribution models between adjacent cracks. The predicted results using the novel stress distribution model introduced here were in good agreement with the non-interactive and interactive crack density regions of test results. The importance of using the Monte Carlo method and novel stress distribution model to predict the whole crack density region have been emphasized in the article, in addition to that it also redefined the interval of non-interactive crack density region.  The second paper expands the concept from the first paper, to address the tension-tension fatigue loading at RT. It deals with the crack density analysis and prediction in [0/90]s GF/EP laminate under fatigue loading at RT. The fatigue tests were performed at 3 maximum stress levels. Here the Weibull parameters were determined from the data points within the non-interactive crack density region in quasi-static and fatigue loading. From the determined Weibull parameters of each stress level and using Monte Carlo method and the novel stress distribution model, the crack density versus the number of fatigue cycles were predicted and in good agreement with the fatigue test results at the respective stress level. The intention here was to use Weibull parameters of one stress level to predict crack density at arbitrary stress levels. Based on it, the predicted results were not sufficiently good and suggested to revisit the Weibull parameter determination by performing fatigue tests at two stress levels.  In the attached paper 3, new methodology on crack density growth simulation and Weibull parameter determination in tension-tension fatigue loading has been developed. In the newly developed methodology, in detailed fatigue tests are performed at one maximum stress level to obtain all data points and at higher stress level to obtain one data point that is a crack density data point at certain number of cycles to determine Weibull parameters. Using the determined Weibull parameters from non-interactive crack density region, the whole crack density region was successfully predicted for other stress levels.

No description available.

No description available.

Unintentional injuries present a major threat to the health and welfare of humans. Over 120,000 deaths and over 30,000,000 non-fatal injuries are estimated annually in the United States. The leading causes of nonfatal injuries vary with age, but falls, motor vehicle collisions (occupants), and being struck by or against are among the top 4 leading causes of unintentional injury for all ages. The loading mechanism that cause forces to be transmitted to the body during these events can cause a wide assortment of injury types with a range of severities. Understanding the biomechanical response to loading in these environments can facilitate efforts in injury mitigation. Biomechanical responses can be quantified by performing controlled laboratory experiments with human volunteers and surrogates, such as anthropomorphic test devices (ATDs) and post mortem human surrogates (PMHSs). The overall objective of this dissertation is to quantify the biomechanical response to loading regimes present in motor vehicle collisions, falls, and when being struck by or against an object using human volunteers and surrogates. Specifically, the research will achieve the following: quantify the dynamic responses of human volunteers, Hybrid III ATD, and PMHSs in low-speed frontal sled tests; quantify the neck response of human volunteers and PMHSs in low-speed frontal sled tests; quantify the kinetic and kinematic responses of PMHSs and the Hybrid III ATD in high-speed frontal sled tests; characterize thoracic loading as a result of same level falls using a Hybrid III ATD; and quantify the ability of children to swing sword-like toys and the human kinematic response that could be anticipated as a result of forceful impact using a Hybrid III 6-year old head and neck. / Ph. D.

<p>  </p> <p>Post-installed bonded anchors find a wide range of application in construction industry due to their versatility and flexibility in accommodating diverse engineering needs. Engineering practices often encounter situations where space constraints within a building member lead to unusual anchor group geometric configurations. Multiple anchor groups with small inter-group spacing (closely spaced anchor groups) emerge as a result. The stress-field and overall behaviour of individual anchor groups is affected by the presence of other closely spaced anchor groups. Situation become more intricate when these closely-spaced anchor groups are installed in close proximity of edge, subjected to different loading conditions and involve different eccentric loading scenarios.</p> <p>The current design standards provide limited and very conservative guidelines for designing and analysing closely spaced anchor groups where spacing between neighbouring anchor groups is less than the critical anchor spacing. This paper presents a 3-dimensional (3D), Finite Element (FE) study on the tension and shear behaviour of closely spaced anchor groups under various geometric and loading conditions. Different parameters such as inter-group spacing, presence of nearby edge and loading positions (eccentricities and symmetry of loading) for models loaded in tension, are numerically investigated. In case of shear loads, anchor groups with similar / different edge distance in the direction of loading and different loading positions are investigated. In this study, concrete cone break-out failure for tension loaded anchor groups and concrete edge failure for shear loaded anchor groups are considered as critical failure modes. </p> <p>Numerical analysis is carried out using microplane model for concrete with relaxed kinematic constraint as the constitutive law. 3D, finite element, Mascroscopic Space Analysis (MASA) program is used to numerically investigate the behavior of closely spaced anchor groups under different geometric and loading conditions. The numerical modelling approach is first verified and validated against available experimental results on anchor groups and then used to carry out a detailed and systematic study. Parametric study on a wide range of geometric configurations containing multiple anchor groups subjected to different loading positions (centric / eccentric) is carried out.</p> <p>Comparison study is conducted to check the numerical resistance capacities against analytical values calculated using existing concrete capacity design (CCD) method incorporating existing reduced embedment depth / edge distance approach and newly developed virtual edge approach. The virtual edge approach considers a virtual edge to assign individual tributary areas to individual anchor groups in calculating the concrete breakout resistance of anchorages. Evaluation of results indicate that virtual edge approach is appropriate, rational and reasonably conservative to consider the influence of presence of neighbouring anchor group on the capacity of given anchorage. A new set of guidelines is recommended to design closely space anchor groups for arbitrary geometric and loading conditions.</p>

<p dir="ltr">Fire is an extreme event that can lead to failure of structural components and potentially collapse of the structural system or sub-systems. Currently, there are no comprehensive, research-based methodologies for performance-based fire structural design (PBFSD) of composite wall-to-floor connections subjected to gravity loads and realistic fire scenarios. The existing studies primarily focus on the performance of simple shear connections to steel columns, and lack approaches for structural design of floor systems and their connections to walls (wall-to-floor connections) at elevated temperatures. This study addresses the need for evaluating the performance of composite floor systems and composite wall-to-floor connections under fire loading and developing research-based approaches to conduct performance-based structural design of these systems at elevated temperatures.</p><p dir="ltr">This study aims to give a simpler design method for shear tab and single angle shear connections at elevated temperatures by specifying retention factors for steel yield strength, ultimate strength, bolt material strength, and weld metal strength at elevated temperatures. The connection limit state equations specified in AISC Specifications are modified to incorporate these factors for higher temperatures. Additionally, an archetype building is designed and one floor system is evaluated using Finite Element Analysis (FEA) to assess the robustness of the structure and its resistance to collapse using PBFSD.</p><p dir="ltr">It also discusses the application of fire protection materials for steel members to resist fire scenarios for specified durations. Various fire scenarios, including ventilation-controlled and fuel-controlled fires were evaluated to assess localized behavior at the connection points and the overall behavior of the structural compartment. The FE analyses included various fire scenarios, compartment locations (interior, edge, or middle), and fire protection scenarios (2-hour rating fire protection, or no fire protection on interior beams). The composite floor system is evaluated for a combination of these scenarios under fire and gravity loading.</p><p dir="ltr">Through this study, a comprehensive analysis of the behavior of composite floors systems and associated connections in SpeedCore Wall Systems (C-PSW/CF) under fire loading is achieved.</p>