70 research outputs found
Evaluation of the dynamic behavior of a GFRP-SFRSCC hybrid footbridge
This paper presents results of numerical investigations on the dynamic behaviour of a hybrid
footbridge made of glass fiber reinforced polymer (GFRP) pultruded profiles and a steel fibre reinforced
self-compacting concrete (SFRSCC) slab. Finite element (FE) models were developed to simulate the
dynamic response of the footbridge when subjected to human induced vibrations. Results obtained were
compared with requirements defined in several standards in order to verify the performance of the
footbridge regarding the fulfilment of comfort criteria. In addition, direct and indirect verification methods
were compared to assess the applicability of the latter when used with GFRP-SFRSCC hybrid structures
Ten-year variations in population structure of pink-shrimp in a southwestern Atlantic Bay affected by highway construction
OBJETIVOS: A estrutura populacional de Farfantepenaeus brasiliensis e F. paulensis, consistindo principalmente de juvenis, foi avaliada durante a construção de uma via expressa ao longo de uma área de manguezais. Regiões estuarinas do sul do Brasil funcionam como locais de reprodução, berçários e de crescimento de uma variedade de organismos, incluindo duas das mais importantes espécies de camarões comerciais do Atlântico Sul Ocidental. Camarões foram coletados no Saco dos Limões, Baía Sul, Florianópolis, Estado de Santa Catarina, trimestralmente, de dia e de noite, entre 1997 e 2006. Flutuações em abundâncias de camarões podem estar relacionados aos seus ciclos de vida, com as maiores abundâncias no verão e primavera, ao invés de impactos promovidos pelas atividades de dragagem durante a construção da via expressa.OBJECTIVES: Population structures of Farfantepenaeus brasiliensis and F. paulensis, consisting mainly of juveniles, were evaluated during the construction of an expressway along a mangrove area. Estuarine regions in southern Brazil function as sites for reproduction, nursery and growth of a variety of organisms, including two of the most important species of shrimp for fisheries in the southwestern Atlantic. Shrimps were collected in Saco dos Limões creek, Baía-Sul, Florianópolis, State of Santa Catarina, four times a year, by day and night, between 1997 and 2006. Fluctuations in the abundances of shrimp appear to be related to their life cycles, with largest abundances in Summer and Spring, rather than to impacts promoted by dredging activities during the expressway construction
Bond behavior between glulam and GFRP’s using pullout bending tests
Com o objectivo de avaliar o comportamento da ligação entre lamelados colados e varões de
GFRP, quando aplicados de acordo com a técnica NSM, foi realizado um programa experimental
composto por ensaios de arrancamento por flexão. Neste programa experimental foram
analisadas três variáveis: o tipo de GFRP (2 tipos), a localização do FRP/dimensão da ranhura (2
tipos) e o comprimento de amarração (Lb=30 mm, 60 mm, 120 mm e 180 mm). A instrumentação
inclui a medição dos deslizamentos na zona solicitada e na extremidade livre, bem como a força
de arranque. Vinte e nove provetes foram ensaiados sob controlo de deslocamento com recurso a
um sistema servo-controlado. O presente trabalho descreve os ensaios e apresenta e discute os
resultados obtidos.To evaluate the bond behavior between glulam and GFRP rods using the near-surface mounted (NSM) strengthening technique, an experimental program was carried out by means of pullout bending tests. In this experimental program three variables were analyzed: the GFRP type (2 types), the GFRP location/groove size (2 types) and the bond length (Lb=30 mm, 60 mm, 120 mm and 180 mm). The instrumentation includes the loaded and free end slips, as well as the pullout force. Twenty nine specimens were tested under displacement control using a servo controlled equipment. In this work the tests are described, and the obtained results are presented and discussed.Fundo Europeu de Desenvolvimento Regional (FEDER) - Operational Programme for Competitiveness
Factors (COMPETE)Fundação para a Ciência e a Tecnologia (FCT) - PTDC/ECM/74337/200
Response of FRP-glulam slab systems under five-point bending load
Full-scale slab strips were tested in order to analyze the flexural response of
FRP-glulam slab systems under monotonic loading. The type of strengthening technique
(externally bonded reinforcement – EBR and near-surface mounted – NSM) and the increase
target in terms of ultimate load capacity (20% and 40%) were the main studied parameters.
GFRP sheets were utilized in the EBR technique, while GFRP rods were applied in NSM
technique. In this work the tests are described in detail, and the obtained results are presented
and discussed
Object oriented programming : data preparation and visualization of FEM models
In this paper two object oriented applications are described. The former is intended to
generate data associated with the finite element method (FEM) and the later is a
three-dimensional visualization tool named 3DMesh. Both are based on the principles of
object oriented programming, namely encapsulation, inheritance and polymorphism. To
support the preparation of FEM data, a language named 3DO was developed. Its syntax is
similar to a subset of the C++ programming language. 3DO is based on object construction
and modification by methods that require a small number of arguments. With this tool, mesh
generation, definition of properties and loads and mesh refinement can be performed with
limited user effort, even when the model is complex. All the generated information can be
visualized with the program 3DMesh. This application is based on the OpenGL library and
uses the Microsoft Foundation Classes to simplify its integration in the MS-Windows
environment. 3DMesh implements an interactive navigation technique that allows the
visualization of the model interior, preserving its integrity. Model attributes and the results of
the FEM analysis can also be visualized
Space-time distribution of the ichthyofauna from Saco da Fazenda estuary, Itajaí, Santa Catarina, Brazil
Copyright © 2009 Coastal Education and Research Foundation (CERF).A Ictiofauna do estuário Saco da Fazenda foi estudada mensalmente entre julho de 2003 e junho de 2004 em quatro áreas definidas em função das características fisiográficas e da representatividade do estuário nesta região. Foram capturados 4502 exemplares, distribuídos em 42 espécies, 35 gêneros e 21 famílias. Engraulidae foram os peixes mais abundantes, onde Cetengraulis edentulus dominou nas capturas. As espécies de ocorrência ocasional, representadas, principalmente por indivíduos juvenis, predominaram nas amostragens. As maiores abundâncias ocorreram durante os meses de verão e outono, em contraste com as elevadas biomassas na primavera-outono; sendo que a área IV diferenciou-se das demais, por contribuir com as maiores capturas. Os índices de riqueza, diversidade e equitabilidade, apresentaram padrões semelhantes de flutuação, com valores elevados nos meses de primavera e verão. O índice de Jaccard revelou uma maior similaridade na composição da ictiofauna entre as áreas II e IV, enquanto a menor ocorreu entre I e IV, provavelmente devido às diferentes áreas destes locais.ABSTRACT: From July 2003 to June 2004, the physiographic characteristics of the ichthyofauna of the estuary of Saco da Fazenda were studied in four defined areas representative of the estuary. A total of 4502 individuals were captured, with 42 species, 35 genera, and 21 families. Engraulidae were the most abundant fish, and Cetengraulis edentulus dominated the captures. The species of occasional occurrence prevailed in the samplings and were represented mainly by juvenile individuals. The highest abundances occurred during the months of summer and autumn, in contrast with high biomasses in the spring and autumn; area IV contributed the largest captures. The richness indexes, diversity, and equitability presented similar flotation patterns, with high values in spring and summer. The Jaccard index revealed a greater similarity in the composition of the ichthyofauna in areas II and IV, while the lowest happened between I and IV, which is probably due to the different sizes of these areas. This paper clearly shows the relevance of this estuary, albeit strongly impacted, for recruitment of small fish mainly during summer and autumn months
A full-scale innovative GFRP-concrete hybrid footbridge : description and testing
The present paper describes the construction process of a full-scale innovative GFRP-concrete hybrid footbridge, and summarizes the main tests performed. This footbridge is 11 m long, 2 m wide, simply supported, and composed of two pultruded I-shaped GFRP girders (0.2 m x 0.4 m) and a 0.04 thick deck in steel fiber reinforced self-compacting concrete (SFRSCC). To evaluate the static and dynamic behavior of this footbridge, short and long-term load tests, and dynamic tests were performed.(undefined
Bond behavior between glulam and GFRP's by pullout tests
To evaluate the bond behavior between glulam and GFRP rods, applied according to the near-surface mounted strengthening technique, an experimental program composed of beam and direct pullout tests was carried. In this experimental program three main variables were analyzed: the GFRP type, the GFRP location into the groove, and the bond length. From the monitoring system it was registered the loaded and free end slips, and the pullout force. Based on these experimental results, and applying an analytical-numerical strategy, the local bond stress-slip relationship was calculated. In this work the tests are described, the obtained results are presented and discussed, and the applicability of the inverse analysis to obtain the local bond law is demonstrated.This work is supported by FEDER funds through the Operational Programme for Competitiveness Factors - COMPETE and National Funds through FCT – Portuguese Foundation for Science and Technology under the project PTDC/ECM/74337/2006. The authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly: INEGI, S&P Clever Reinforcement Ibérica Lda., Portilame, MAPEI and Rothoblaas
Review and analysis of advances in functionalized, smart, and multifunctional asphalt mixtures
Road pavements are designed to withstand road traffic and weathering actions while ensuring comfortable and safe riding conditions as well as low costs and damage to the environment. When a road pavement has additional abilities or reacts to an external stimulus, it is considered to be smart and multifunctional. Examples of such abilities that have been investigated in asphalt mixtures are photocatalytic, superhydrophobic, self-cleaning, de-icing/anti-icing, self-healing, thermochromic, and latent heat thermal energy storage abilities. These abilities are developed using different materials such as nano/microparticles (including semiconductor materials and microcapsules), fibers, phase change materials (PCMs), and dyes, often using dissimilar techniques such as spray coating, volume incorporation, spreading, and asphalt binder modification. Owing to their large surface areas, road pavements are true recipients for large amounts of nano/micromaterials, and consequently, act as important “tools” to stimulate an emerging sector related to the scale of production of materials in the form of nanoparticles. Moreover, smart and multifunctional road pavements can be included in the domain of clean technology (e.g., photocatalytic pavements that promote the environmental depollution of NOx-type gases emitted as vehicle exhaust gases). In this context, they can contribute to materializing the transition to a novel socio-economic model known as “Green Recovery” that is environmentally friendly, sustainable, and inclusive. This model is a very important path toward economic and employment recovery, a vision to which many countries are strongly committed. Therefore, this work reviews new capabilities imparted to asphalt mixtures and provides recommendations.This work was supported by FCT (Fundação para a Ciência e a Tecnologia) under the framework of the Strategic Funding UIDB/04029/2020, UIDB/04650/2020, and UID/FIS/04650/2019, and the PTDC/FIS-MAC/6606/2020, PTDC/FIS/120412/2010, and PEst-OE/ECI/UI4047/2019. The first author would like to acknowledge the FCT for the Ph.D. scholarship (SFRH/BD/137421/2018) and the third author
would like to thank CNPq - Conselho Nacional de Desenvolvimento
Científico e Tecnológico - for the PQ 1-D scholarship (308,360/2017–6)
Assessing photocatalytic asphalt mixtures: practical and laboratory methods for measuring air quality
Air pollution in urban areas has become a major global concern, leading to a series of programs
and regulations to be implemented to reduce it. Among the various pollutants that affect air quality
is nitrogen monoxide (NO), which, once in the atmosphere, oxidizes into nitrogen dioxide (NO2).
The combination of NO and NO2 refer to the nitrogen oxides (NOx), which, besides being harmful
to health, have a negative impact on the environment with acid rain and intensify the greenhouse
effect. This issue is exacerbated in large cities due to the high concentration of pollutant-emitting
vehicles. To mitigate this problem by cleaning the air, researchers are investing in photocatalytic
capability that can be applied to the surface of various substrates. Titanium dioxide (TiO2) is a
highly utilized material, especially when aiming to attain both photocatalytic and self-cleaning
abilities.
The application of TiO2 over asphalt pavements has become an important topic in Transportation
Engineering as a way of functionalized conventional pavement into a substrate where it becomes
feasible to alleviate the environmental damage related to pollutant emissions, mainly NOx. The
application of photocatalytic materials on asphalt pavements has the necessary conditions to
increase the success of reducing pollutant levels. Pavements present a large area and are closer to
vehicle exhausts. In addition, a major part of asphalt pavements is exposed to sunlight, which can
activate the photocatalytic reaction. Due to these benefits, researchers have conducted studies that
evaluate photocatalytic efficiency on surfaces of asphalt pavements.When evaluating photocatalytic efficiency, the literature describes a series of methods based on
laboratory and field tests. In the laboratory, efficiency can be evaluated by degrading different
organic dyes and degradation gas tests. For the first method, some dyes are widely used, such as
methylene orange (MO), methylene blue (MB) and rhodamine B (RhB). For testing, samples of
asphalt mixtures are immersed in an initial dye solution and exposed to light irradiation. Over
time, changes in the solution absorbance (and, consequently, concentration) are monitored using
spectrophotometry. The photocatalytic efficiency is calculated as a function of the maximum
absorbance of the dye and the time.
The second test follows the ISO 22197-1 standard, which specifies a test method for determining
the air purification performance of materials with photocatalysis on the surface. To simulate and
ensure the photocatalytic reactions occur, the experimental setup must contain an air compressor,
pollutant source, humidifier, photoreactor, light source and pollutant analyzer. The photocatalytic
asphalt mixture sample is placed inside the photoreactor and exposed to a controlled amount of
pollutants, light and humidity. The gas flow is continuously injected into the photoreactor and
subjected to light irradiation, and gas concentration is monitored over a period of time. The
photocatalytic efficiency can be assessed by the net amount of pollutants that the sample removes.In field applications, one method that can be used to evaluate the efficiency is the air quality
monitoring stations by conducting a comparative analysis of pollutant concentrations in a specific
area before and after installing photocatalytic asphalt pavements. Those stations have sensors that
collect outdoor air and distribute it through analyzers. These analyzers continuously and
automatically measure various atmospheric pollutants, determining their concentrations in the
ambient air "in real-time". Typically, they are fixed at strategic points in large cities, limiting
assessment in more remote locations. Usually, these stations can measure several types of
pollutants, such as NOx, SO2, CO2, particulate matter, among others, and the meteorological
conditions, for example temperature, relative humidity, wind speed and direction , etc.
Another method to evaluate the performance in field studies is to use passive sampling. The
passive sampling approach is a low-cost, non-electrical, and simplified solution for the
distribution of samples. The principle of the passive sampler involves gas collection through the
diffusion of atmospheric air, which enters the device through one of its ends, travels through the
body of the sampler (in the form of a tube) until it reaches its other end, which is sealed and
contains a filter paper previously impregnated with a specific absorbent solution designed to react
with the targeted pollutant to be collected.
Measurement of photocatalytic efficiency is crucial in determining the performance of
photocatalytic pavements and their impact on air quality. Thus, this study aims to provide a
comprehensive elucidation of how to evaluate the photocatalytic efficiency of photocatalytic asphalt pavements functionalized with TiO2 nanoparticles through various methods,
encompassing laboratory approaches and field studies.This research was funded by FCT: NanoAir PTDC/FISMAC/6606/2020,
MicroCoolPav EXPL/EQU-EQU/1110/2021, UIDB/04650/2020,
UIDB/04029/2020, 2022.00763.CEECIND and 2023.02795.BD. Also, it was
funded by FUNCAP: MLC-0191-00144.01.00/22 and CNPq: 404978/2021-5 –
Chamada CNPq/MCTI/FNDCT Nº 18/2021.
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