327 results on '"FWD"'
Search Results
152. En studie av luftfjädrade allhjulsdrivna lastbilar
- Author
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Andersson, Jacob and Danielsson, Fredrik
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AWD ,Dragbil ,Tractor ,Truck ,Teknik och teknologier ,Engineering and Technology ,Air Suspension ,Framhjulsdrift ,Lastbil ,Luftfjädring ,Allhjulsdrift ,FWD - Abstract
Currently, Scania is not offering full air suspended AWD trucks, which it seems to be a demand for. This study acts as a first step to fulfill this demand. Including, a benchmarking of what competitors offer as well as an investigation and an evaluation of Scania’s current suspension system. Moreover, a requirement specification and a concept generation for a front air suspension system on AWD trucks have been presented. Eight concept were generated, where two were chosen for further study of design, force analysis and roll gradient analysis. It was concluded that there is a market for this configuration, however, implementing it would require extensive design work. I nuläget erbjuder inte Scania luftfjädring för samtliga hjulaxlar på AWD lastbilar, vilket det tycks finnas ett kundbehov av. Denna studie agerar som ett initialt steg till att uppfylla detta kundbehov. Studien inkluderar inledningsvis en analys av vad konkurrenter erbjuder samt en undersökning och utvärdering av Scanias nuvarande fjädringssystem. Utöver det, har en kravspecifikation och en konceptgenerering för främre luftfjädring på AWD lastbilar presenterats. Åtta stycken koncept genererades, varav två stycken valdes för vidare studie av design, kraftanalys samt krängstyvhetsanalys. Slutsatserna var att det finns en marknad för denna typ av konfiguration, dock skulle det behövas omfattande designarbete för att implementera det.
- Published
- 2019
153. Comparison of static and dynamic strains of asphalt concrete pavement from FWD tests.
- Author
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Yun, Kyong-Ku
- Abstract
A series of Falling Wieght Deflectometer (FWD) tests is conducted on an instrumented asphalt concrete section on a test tract in the PACCAR Technical Center in Mount Vernon, Washington. Horizontal strain measurements are taken from strain gauges in pavement cores in Fall, Winter, late Spring and early Summer conditions. This paper presents results from the field tests and compares them with static and dynamic theoretical predictions using CEVRON and SAPSI computer programs respectively. CHEVRON is a well known pavement analysis computer program which uses static, linear, layered-elastic theory, and SAPSI is a computer program for the dynamic analysis of asphalt concrete pavements by the linear damped-elastic layer theory and the finite element method. The results indicate that static analysis using statically back-calculated layer moduli seems to be sufficient in analyzing FWD field tests, despite the fact that static back-calculation using FWD (dynamic) deflections will lead to “stiffened” elastic properties. Ninety percent of measured strains in October 1991 and in June 1992 were within ±10 percent error of their calculated values, versus 70 percent within ±20 percent error in February 1993. [ABSTRACT FROM AUTHOR]
- Published
- 1997
- Full Text
- View/download PDF
154. Pavimentos rodoviários flexíveis em Angola. Caracterização e aplicação de metodologias BIM
- Author
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Manico, Henderson Batista Pereira, Fontul, Simona, and Falcão, Maria João
- Subjects
Engenharia e Tecnologia::Engenharia Civil [Domínio/Área Científica] ,BIM ,pavimento flexível ,FWD - Abstract
As infraestruturas rodoviárias em serviço, dado o aumento das solicitações do tráfego, tanto em termos de carga por eixo como em termos de número de veículos, requerem medidas adequadas e um planeamento atempado de ações de manutenção e reabilitação. Devido à carga induzida pelo tráfego e aos fatores ambientais, ocorrem degradações graduais ao longo do tempo, causando problemas no desempenho e, uma redução na capacidade de carga do pavimento. Por este motivo, são realizadas campanhas de avaliação para analisar a condição do pavimento. No entanto, para aumentar a sua eficiência, procura-se implementar uma metodologia que reforce o seu desempenho e potencie o seu trabalho. Para tal, é aplicada a metodologia BIM que envolve a criação de uma representação digital das características físicas e funcionais de uma construção, baseando-se num conjunto de métodos que permite o controle da informação através de elementos paramétricos. Este trabalho baseia-se nos principais aspetos das campanhas de avaliação de pavimentos rodoviários, implementados a um caso de estudo de um pavimento em serviço, em que se tem em vista a modelação em 3D do mesmo num ambiente BIM onde se procura apresentar as potencialidades desta ferramenta no que diz respeito ao acompanhamento do estado do pavimento, desde a sua fase de projeto até à sua manutenção, em que se faz a monitorização dos valores de deflexão resultantes destas campanhas de avaliação estrutural com auxílio a um ensaio de carga não destrutiva utilizando o Defletómetro de Impacto (FWD). Tendo em vista, de uma forma mais intuitiva, perceber a evolução da estrutura do pavimento ao nível da camada de desgaste e fundação, quer ao nível da capacidade de carga das camadas, bem como o controle da quantidade de material utilizada no decorrer de uma reabilitação. Pretende-se, também, avaliar a aplicabilidade prática do conceito BIM implementado no caso de estudo, em que afigura-se a conceção de um modelo 3D onde se representa uma patologia bastante relevante, posteriormente faz-se um modelo do caso de estudo em que se em que se procura dar ênfase à definição dos elementos e à representação da informação através de metodologias mais expeditas e de cariz organizacional maior, as quais levam à otimização da infraestrutura, aumentando os níveis de segurança, qualidade e custo. Neste sentido, afigura-se com maior relevância compreender, à priori, as metodologias de inspeção e monitorização das infraestruturas existentes, e perceber de que forma os dados podem ser enquadrados para o estabelecimento de um modelo de registo da informação da construção numa base de dados estruturadas por objetos.
- Published
- 2018
155. Caracterização funcional e mecânica de um pavimento betuminoso permeável em troço experimental
- Author
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Santos, Tiago Da Silva and Almeida, Marisa Sofia Fernandes Dinis de
- Subjects
Mancha de Areia ,Pêndulo Britânico ,Pavimentos Permeáveis ,Engenharia e Tecnologia::Engenharia Civil [Domínio/Área Científica] ,Fwd - Abstract
Made available in DSpace on 2020-01-16T09:40:16Z (GMT). No. of bitstreams: 1 6499_14325.pdf: 2579657 bytes, checksum: ab74e3d82aefb0b6e8e2ce8e738ace00 (MD5) Previous issue date: 2018-11-13
- Published
- 2018
156. 高速道路舗装のマネジメントに資する舗装構造評価に関する基礎的研究
- Author
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Kazato, Takayuki, 小林, 潔司, 大津, 宏康, and 河野, 広隆
- Subjects
補修設計 ,劣化ハザードモデル ,舗装マネジメント ,舗装構造評価 ,FWD - Published
- 2018
157. Billionaire Richard Li's FWD to Raise $1.4 Billion, Weighs Hong Kong IPO.
- Author
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Baigorri, Manuel
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GOING public (Securities) ,BILLIONAIRES ,MARKET volatility - Abstract
While FWD had secured approval from the U.S. Securities and Exchange Commission to begin marketing the IPO to investors, the company decided to switch its venue to Hong Kong, they said. Keywords: 1735915DCN; 3682Z@CN; APO; ATH; DIDI; FWD; MPI@PM; PCGZ@HK; SCB@TB; ALLTOP; ASIA; BUSINESS; CHINA; COS; FIN; HK; INDUSTRIES; INS; MARKETS; STK; SVC; WORLD; WWTOP EN 1735915DCN 3682Z@CN APO ATH DIDI FWD MPI@PM PCGZ@HK SCB@TB ALLTOP ASIA BUSINESS CHINA COS FIN HK INDUSTRIES INS MARKETS STK SVC WORLD WWTOP (Bloomberg) -- Billionaire Richard Li's FWD Group Ltd. raised more than $1.4 billion in private placements with investors including an insurer backed by Apollo Global Management Inc. [Extracted from the article]
- Published
- 2021
158. Poppin' off: The Spinoff’s guide to summer Champagne and sparkling wine
159. This title is unavailable for guests, please login to see more information.
- Author
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Kazato, Takayuki and Kazato, Takayuki
- Published
- 2018
160. Correlation between Resilient Modulus (MR) of Soil, Light Weight Deflectometer (LWD), and Falling Weight Deflectometer (FWD)
- Author
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Park, Sung Soo, Bobet, Antonio, Nantung, Tommy E., Park, Sung Soo, Bobet, Antonio, and Nantung, Tommy E.
- Abstract
INDOT adopted the Mechanistic-Empirical Pavement Design Guide (MEPDG) beginning January 1, 2009, which is based on the FHWA Long Term Pavement Performance (LTTP) field study. The resilient modulus of the soil, MR, is required to implement the new design guide, as well as the pavement input parameters. The soil resilient modulus test requires special, expensive, equipment, significant time investment and effort, which has led researchers to develop MR prediction models and alternative methods to estimate the resilient modulus using non-destructive tests such as Falling Weight Deflectometer, FWD, Light Weight Deflectometer, LWD, and Dynamic Cone Penetrometer, DCP. The objectives of the project are geared toward a practical approach for pavement design procedures to effectively determine the soil resilient modulus for rehabilitation projects, targeting specifically untreated subgrade soils type A-6 and A-7-6. A total of four sites in Indiana were selected to conduct FWD, LWD, and DCP tests, as well as resilient modulus tests in the laboratory. In addition to the output from the four sites, additional data were collected from the data repository of INDOT which has geotechnical and pavement information. Extensive analysis and comparisons were done in an attempt at establishing relationships between the field tests and the laboratory results. The study showed the following: (1) high quality FWD tests conducted on top of the pavement can be used to estimate the subgrade MR, as long as site conditions and pavement layers thickness are well known; (2) the results of FWD tests on top of the subgrade are not reliable, as they are affected by the low confinement of the soils; and (3) LWD and DCP tests can be used to provide and assessment of the quality and uniformity of the subgrade, but do not provide reliable estimates of the stiffness of the subgrade.
- Published
- 2018
161. Development of an on-demand front wheel drive for Scania trucks
- Author
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Larsson, Filip, Dahlgren, Jonas, Larsson, Filip, and Dahlgren, Jonas
- Published
- 2018
162. Predicting the Remaining Service Life of Road Using Pavement Condition Index
- Author
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Arif Budiarto, Jolis Nainggolan, and Ary Setyawan
- Subjects
Engineering ,remaining service life ,Correlation coefficient ,business.industry ,Regression analysis ,General Medicine ,Pavement Condition Index ,road ,FWD ,Transport engineering ,Falling weight deflectometer ,Remaining life ,Service life ,Conventional PCI ,business ,Engineering(all) - Abstract
Numerous factors cause damage to the road so that the remaining service life of the existing pavement and long-term road maintenance are unpredictable. The aims of this paper are to evaluate the condition of the road performance and damages and to calculate the remaining service life of the pavement on East Line of South Sumatera, as well as examining the relationship between these two values. This research includes the evaluation of five sections of the route with a various damaged condition and detailed appraisal of road conditions using the Pavement Condition Index (PCI), while the prediction of the remaining service life using the deflection data acquiring from Falling Weight Deflectometer measurements. The correlation of PCI value and remaining life service, intellectually established, created regression model to obtain the relationship and the correlation coefficient. The outcomes demonstrated that the road segments I, II, III, IV, and V have a PCI value of 56.1 (good), 37.8 (poor), 9.3 (very good), 39.0 (poor), and 95.0 (excellent) respectively and the remaining service lives sequentially are 2.39 years, 0.65 years, 4.43 years, 0.11 years and 3.57 years. The correlation between the PCI value and the service life of the pavement is y = 4,1872ln (x) -14.728, with the correlation coefficient is 0.88 which strong level of relationship.
- Published
- 2015
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163. Warburg-Backed Hong Kong Firm That Uses AI for Drug Discovery Files for U.S. IPO.
- Subjects
DRUG utilization ,GOING public (Securities) ,ARTIFICIAL intelligence ,BILLIONAIRES ,STOCK prices ,BUSINESS enterprises - Abstract
LianBio, a biotechnology company with U.S. owners that does business primarily in China, priced its $325 million IPO last week, indicating that some companies may still be acceptable to regulators. R1ZP2LDWLU6G (Bloomberg) -- Insilico Medicine, a Hong Kong-based company that uses artificial intelligence to drive drug discovery, filed confidentially for a U.S. initial public offering last week, according to people familiar with the matter. Keywords: 1746950DHK; 18308Z; 20326Z; 4503@JP; 4581@JP; FWD; LIAN; SEQUOIA@BZ; AI; ALLTOP; ASIA; ASIATOP; BON; BUSINESS; CHINA; COS; DRG; FIN; GLOBALMACR; HEA; HK; INDUSTRIES; MARKETS; NORTHAM; STK; TEC; TOP; US; WORLD; WWTOP; WWTOPAS EN 1746950DHK 18308Z 20326Z 4503@JP 4581@JP FWD LIAN SEQUOIA@BZ AI ALLTOP ASIA ASIATOP BON BUSINESS CHINA COS DRG FIN GLOBALMACR HEA HK INDUSTRIES MARKETS NORTHAM STK TEC TOP US WORLD WWTOP WWTOPAS Insilico Medicine, a Hong Kong-based company that uses artificial intelligence to drive drug discovery, filed confidentially for a U.S. initial public offering last week, according to people familiar with the matter. [Extracted from the article]
- Published
- 2021
164. Sensitivity Analysis of Determining the Material Parameters of an Asphalt Pavement to Measurement Errors in Backcalculations.
- Author
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Tutka, Paweł, Nagórski, Roman, Złotowska, Magdalena, Rudnicki, Marek, and Cattaneo, Sara
- Subjects
- *
PAVEMENT testing , *FLEXIBLE pavements , *SENSITIVITY analysis , *MATERIALS analysis , *FATIGUE life , *MEASUREMENT errors , *ASPHALT pavements - Abstract
Nondestructive tests of road pavements are among the most widely used methods of pavement condition diagnostics. Deflections of road pavement under a known load are most commonly measured in such tests, e.g., with the use of falling weight deflectometer (FWD). Measured values allow to determine the material parameters of the road structure, corresponding to the obtained results, by means of backcalculations. Among the factors that impact on the quality of results is the accuracy of deflection measurement. Deflection basins with small differences of displacement values may correspond to significantly different combinations of material parameters. Taking advantage of them for mechanistic calculations of road pavement may eventually lead to incorrect estimation of the remaining fatigue life and then inadequate selection of pavement reinforcement. This study investigated the impact of measurement errors on the change of the obtained values of stiffness moduli of flexible road pavement layers. Additionally, the influence of obtained material parameters on the values of key pavement strain, and consequently on its design fatigue life was presented. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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165. Prototype of the Runway Monitoring Process at Smaller Airports: Edvard Rusjan Airport Maribor.
- Author
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Kovačič, Boštjan, Želodec, Damjan, and Doler, Damjan
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RUNWAYS (Aeronautics) ,AIRPORTS ,PASSENGER traffic ,PROTOTYPES ,AIR travelers ,TIME measurements - Abstract
The last 20-year announcement predicts a 3.5% increase in the number of yearly passengers which will result in the doubling of the number of passengers in air transport by 2037. Such anticipation indicates the need for efficient monitoring of airport infrastructure as the support of opportune and efficient maintenance works. The novelties of this article are a process model of maintenance and monitoring, suitable for smaller and less burdened airports, and the methodology of monitoring of runways by implementation of the geodetic and geomechanics falling weight deflectometer (FWD) method. In addition, the results confirm the assumption that a specific environment such as an airport allows for sufficiently reliable determination of deformation areas or areas of vertical deviations of runways in a relative short time period available for measurements by using geodetic methods only or by combining other methods; our research model includes the FWD method. With the research, we have also shown there is an interaction between deformations or areas of vertical deviations on the surface and anomalies in the runway lower constructure which will, hereinafter, allow the development of the prediction, creating a vertical deviations or deformation model. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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166. Billionaire Richard Li's FWD Files For $3 Billion IPO In U.S.
- Author
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Olsen, Robert
- Subjects
GOING public (Securities) ,BILLIONAIRES ,FINANCIAL planning - Abstract
FWD, the Asian insurer backed by Hong Kong billionaire Richard Li, has filed confidentially for an initial public offering in the U.S. [ABSTRACT FROM AUTHOR]
- Published
- 2021
167. Application of GPR and FWD in Assessing Pavement Bearing Capacity
- Author
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Josipa Domitrović, Tatjana Rukavina, and Răcănel, Carmen
- Subjects
Engineering ,elastic moduli ,TA1001-1280 ,business.industry ,gpr ,Pavement maintenance ,non-destructive testing ,General Medicine ,FWD ,GPR ,layer thickness ,Layer thickness ,Coring ,fwd ,Transportation engineering ,Falling weight deflectometer ,Structural condition ,Nondestructive testing ,Ground-penetrating radar ,Geotechnical engineering ,Bearing capacity ,business ,non - destructive testing - Abstract
The process of pavement maintenance and rehabilitation starts by collecting the data which will form the base for evaluation of pavement functional and structural condition. Collection of data can be performed by destructive and non-destructive testing. Usually preferred are the non-destructive methods, that do not damage the pavement, and the process of pavement evaluation is objective and repeatable. Non-destructive testing methods are becoming more and more popular, especially for assessing the structural condition of the pavement. Non-destructive testing by a Falling Weight Deflectometer (FWD) and the analysis of so collected data by the process of backcalculations is today the usual tool for assessing pavement bearing capacity. One of the basic input parameters for analysis of the data collected by FWD is pavement layers thickness. The practice in Croatia is to determine pavement layers thickness by coring. This destructive method affects pavement integrity, so the number of such tests should be kept to the minimum. By coring the accurate thickness of all pavement layers is obtained on specific point locations. Thus, numerous deviations in layer thickness remain unnoticed, and in the end, use of such data for the process of backcalculations does not provide ac urate values of layer moduli. Coring can be replaced with non-destructive method of testing by Ground Penetrating Radar (GPR), which provides continuous information on thickness of all pavement layers. The paper shows the method for assessing the bearing capacity of the pavement based on the data collected by FWD, GPR and coring. The calculation for layer moduli was performed by the ELMOD software, separately for the layers thickness data obtained by coring, and separately for the thickness obtained by GPR tests. Analysis and comparison of the results of calculated elasticity moduli obtained by using various methods for collecting layer thickness data were performed in the paper.
- Published
- 2013
168. Über den Zusammenhang von Tragfähigkeitsmessergebnissen mit mechanischen Modellgrößen bei Asphaltstraßen
- Author
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Plachkova-Dzhurova, Plamena Nedeva and Roos, R.
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ddc:690 ,bearing capacity ,Asphalt ,Rheologie ,rheological models ,Buildings ,FWD ,Tragfähigkeit - Abstract
Die Arbeit beschäftigt sich mit dem mechanischen Verformungsverhalten von Asphaltbefestigungen bei HWD-Messungen. Es werden mechanische Ansätze für die Berechnung des Krümmungsradius entwickelt, so dass untersucht werden kann, inwieweit der empirische Berechnungsansatz den Krümmungsradius im mechanischen Sinne beschreibt. Nach einer iterativen Rückrechnung der Materialparameter mit Hilfe von rheologischen Modellen wird der Krümmungsradius über ausgewählte mechanische Systeme berechnet.
- Published
- 2017
169. Case study of a structural evaluation of a flexible pavement located in the city of Bogotá, location of Bridge Aranda between av street 13 and 15, using non-destructive techniques and analysis of results obtained
- Author
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Ibague Novoa, Luis Fernando and Palomino, Cesar
- Subjects
Ensayos no destructivos NDT ,Non destructive essays ,MECANICA DE PAVIMENTOS ,Pavement evaluation ,Evaluación de pavimentos ,FWD ,PAVIMENTOS - Abstract
El presente trabajo, pretende documentar la metodología de evaluación estructural de un pavimento flexible utilizando equipos de auscultación no destructivos (NDT), tales como el deflectometro de impacto FWD y el georadar, aplicados con el método propuesto AASTHO – 93, comparado con otras metodologías de análisis como ROHDE y YONAAVE, así mismo, se muestra a manera de ejemplo un caso de estudio de evaluación realizada en un tramo de vía de la ciudad de Bogotá. This paper aims to document the methodology of structural evaluation of a Flexible flooring using non-destructive auscultation (NDT) equipment, such as Deflectometro of impact FWD and the georadar, applied with the proposed method AASTHO - 93, Compared to other analysis methodologies such as ROHDE and YONAPAVE. By way of example, an evaluation case study carried out on a section of the city from Bogota.
- Published
- 2016
170. Modélisation dynamique de la thermo-viscoélasticité des matériaux bitumeux : Application aux essais FWD sur les structures des chaussées
- Author
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Tautou, Rémi, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Université de Limoges, Christophe Petit, and Benoit Picoux
- Subjects
Méthode fréquentielle ,Thermo-viscoelasticity ,Frequency Method ,[SPI.GCIV.MAT]Engineering Sciences [physics]/Civil Engineering/Matériaux composites et construction ,Thermo-viscoélasticité ,FWD - Abstract
The diagnosis of the road fleet becomes a necessary step prior to themaintenance and the repair of pavement structures. The importance of a finer analysis of the results of the non-destructive testing methods can eventually achieve to cost and energy savings for the maintenance and construction. This phD thesis introduces a thermo-visco-elastic model for intersting the behavior ofbituminous pavement materials, using the complex modulus and damping from master curves. The resolution of the dynamic problem is performed thanks to a frequency approach. This approach is particularly applicable to a FWD test on which climatic variations are studied. In situ tests, carried out on two instrumented sites, are used to validate the model. The obtained of good results suggests the use of this model through a multi-criteria analysison deflection basins and of the records for the future development of a backcalculation dynamic model.; Le diagnostic du parc routier est une étape indispensable préalable à l'entretien et la réparation des structures de chaussées. L'importance d'une plus grande finesse de l'analyse des résultats issus des méthodes de contrôle non destructif peut permettre de réaliser, à terme, des économies sur les coûts et énergie mis en jeu lors de la maintenance et la construction. Ces travaux de doctorat présentent un modèle thermo-visco-elastique permettant d'intégrer le comportement des matériaux bitumineux composant une chaussée par l'utilisation du module et de l'amortissement complexe issu des courbes maitresses. La résolution du problème dynamique est réalisée à l'aide d'une approche fréquentielle. Cette approche est appliquée en particulier à un essai FWD sur lequel des variations climatiques sont étudiées. Des essais in situ, réalisés sur deux sites instrumentés, permettent de valider le modèle. Les bons résultats obtenus suggèrent l'utilisation de ce modèle à travers une analyse multicritère sur les bassins de déflexion et les historiques pour le développement futur d'un modèle de retro calcul dynamique.
- Published
- 2016
171. In-place evaluation of a limestone base course modulus, using a van-integrated falling weight deflectometer (FWD) and the GeoGauge (SSG)
- Author
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Pedro Andrade, Mário Quinta-Ferreira, Eduardo Fung, and Fernando Castelo Branco
- Subjects
Materials science ,pavement ,Modulus ,Stiffness ,Young's modulus ,GeoGauge ,all-in-aggregate ,Granular material ,FWD ,stiffness modulus ,Comparative evaluation ,Base course ,symbols.namesake ,Falling weight deflectometer ,base course ,symbols ,medicine ,Geotechnical engineering ,medicine.symptom ,Stiffness modulus ,Civil and Structural Engineering - Abstract
A comparative evaluation of the in-place stiffness modulus using a van-integrated falling weight deflectometer (FWD) and the GeoGauge (soil stiffness gauge – SSG) was done on a limestone all-in-aggregate (AIA), used in the base course of a highway pavement. The tests were done in two campaigns, one for each unbound granular layer of 0.15 m thickness, along 510 m, using five alignments. Considering the whole granular materials used, the dry unit weight (γd) is related with the stiffness modulus obtained with the SSG. The stiffness moduli obtained for the SSG and for the FWD in the same test point are not correlated. Considering as reference the equivalent modulus obtained with the FWD, the moduli computed for the 85th percentile with both the FWD and the SSG show a difference lower than 20%. These results emphasise the possible use of the SSG as a reliable procedure for stiffness modulus evaluation of unbound limestone bases.
- Published
- 2012
- Full Text
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172. Effect on Pavement Performance of a Subbase Layer Composed by Natural Aggregate and RAP
- Author
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Gabriele Tebaldi, Giacomo Betti, Alessandro Marradi, and Antonio Montepara
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Engineering ,Aggregate (composite) ,business.industry ,Performance Tests ,Track (rail transport) ,FWD ,Natural (archaeology) ,Subbase (pavement) ,Pavement engineering ,Asphalt pavement ,LWD ,RAP recycling ,General Materials Science ,Geotechnical engineering ,Layer (object-oriented design) ,business - Abstract
Reclaimed Asphalt Pavement (RAP) recycling in pavement engineering can be actually carried out by means of hot recycling and cold recycling. An additional option arise from mixing with natural aggregates to build the sub-base layer. This paper shows the first results of a research activity undertaken on a test track specifically constructed with the aim to analyze the effect on pavement performance of a sub-base layer mixture with 50% of natural aggregates and 50% of RAP. The investigation is based on LWD and FWD analysis, comparing results with those obtained on the subsequent section of the test track made by only natural aggregates.
- Published
- 2012
- Full Text
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173. Track Substructure Assessment using Non-Destructive Load Tests. A Portuguese Case Study
- Author
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Eduardo Fortunato, F. De Chiara, Simona Fontul, and D. Pereira
- Subjects
Railway line ,Engineering ,business.industry ,Structural engineering ,Sub-ballast ,Track (rail transport) ,Back-calculation ,FWD ,Fwd ,Back calculation ,Falling weight deflectometer ,Non destructive ,Track construction ,Substructure ,General Materials Science ,Structural evaluation ,business - Abstract
Comfort and safety are crucial aspects in a transport infrastructure project. Depending on axle loads and traffic speeds, parameters are established carefully in order to ensure a good quality in terms of geometry and bearing capacity during the entire infrastructure life cycle, preventing deterioration process. Nevertheless, maintenance actions have to be performed aiming to restore proper track condition. The quality control during the construction is an important factor that can evaluate the performance of materials. Nowadays, the materials are mainly characterised by their physical and mechanical properties, but there is an increased interest in developing performance based specifications that can provide more realistic information about the behaviour of the track during the life cycle. In order to achieve this task, non-destructive tests represent a good solution, as they are cost and time efficient. Among non-destructive loading equipment, one of the most efficient is the Falling Weight Deflectometer (FWD). In this research, FWD tests were undertaken during the construction of a new railway line 29 km long, at the top of the substructure and in different months. Based on the performed load tests, the structural modelling of the track was established through back-calculation, and the variation of the materials moduli for different testing campaigns was evaluated. The main results obtained are presented and analysed in this paper, as well as some considerations regarding FWD testing and interpretation. 8 4 9p DT/NIF 2012 29 a 31 de Outubro
- Published
- 2012
- Full Text
- View/download PDF
174. Preliminarni rezultati interpretacije dobljenih rezultatov FWD meritev na izbranih cestnih odsekih na Hrvaškem
- Author
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Cuculić, Marijana, Deluka-Tibljaš, Aleksandra, Pranjić, Ivana, Skender, Robert, Tollazi, T., Lipar, P., and Šemrov, D.
- Subjects
FWD ,nondestructive testing ,highway - Abstract
Pavement surface deflection measurements are usually conducted with different nondestructive testing methods. One of the most commonly used method is Falling Weight Deflectometer test (FWD), where an impulsive load is applied on pavement surface and the deflections are measured at a number of points radially distributed from the centre of falling weight. All the testing parameters are adjusted to correspond to the effect of loading due to standard axle on the investigated road. Laboratory for Transportation Engineering from Faculty of Civil Engineering Universi-ty of Rijeka in cooperation with Croatian Civil Engineering Institute (IGH) measured pavement deflections on the second longest and one of the most loaded Croatian highways A3 Bregana – Zagreb – Lipovac (E 70). This highwayis characteristic for a greater amount of heavy vehicle traffic whichis approximately 20% of total AADT and some highway sections were built 30 years ago, which were the reasons for the investigation of road’s structural capacity. In this paper part of the data collected with FWD test on one road section for both highway lanes will be presented. The aim is to interpret collected data for driving and passing lane for one highway section in Croatia.
- Published
- 2016
175. Preliminary results of FWD data interpretation on selected road section in Croatia
- Author
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Cuculić, Marijana, Deluka Tibljaš, Aleksandra, Pranjić, Ivana, Skender, Robert, and Družba za raziskave v cestni in prometni stroki Slovenije
- Subjects
FWD ,nondestructive testing ,highway - Abstract
Pavement surface deflection measurements are usually conducted with different nondestructive testing methods. One of the most commonly used method is Falling Weight Deflectometer test (FWD), where an impulsive load is applied on pavement surface and the deflections are measured at a number of points radially distributed from the center of falling weight. All the testing parameters are adjusted to correspond the effect of loading due to standard axle on the investigated road. Laboratory for Transportation Engineering from Faculty of Civil Engineering University of Rijeka in cooperation with Croatian Civil Engineering Institute (IGH) measured pavement deflections on the second longest and one of the most loaded Croatian highways A3 Bregana – Zagreb – Lipovac (E 70). This highway is characteristic for greater amount of heavy vehicle traffic which is approximately 20% of total AADT and some highway sections were built 30 years ago, which were the reasons for the investigation of road’s structural capacity. In this paper part of the data collected with FWD test on one road section for both highway lanes will be presented. The aim is to interpret collected data for driving and passing lane for one highway section in Croatia.
- Published
- 2016
176. Evaluation of Chemically Stabilized Subgrades with High Sulfate Concentrations
- Author
-
Kennedy, Kalub S.
- Subjects
- Civil Engineering, Geotechnology, Soil Sciences, Sulfate-induced heave, ettringite, thaumasite, subgrade stabilization, cement stabilization, lime stabilization, PSPA, DCP, FWD, LWD, SPT, XRD
- Abstract
This thesis evaluates natural and chemically stabilized subgrade soils from five project sites throughout Ohio. Three of the five project sites were historically known to have moderate to high sulfate concentrations in the natural soils (DEF-24-2.67-W, LAK- 2-7.76-W, MRW-71-3.17-N), while the other two sites were known to have little to no sulfate levels (CLA-70-13.98-W, CLI-73-6.52-E), and were used as controls. The main objective of the study was to compare in-situ and laboratory test results to determine if there were formations of ettringite or thaumasite in the soil, which can lead to sulfate heave and premature failure of pavement. Several field tests were performed such as PSPA, FWD, LWD, DCP, and SPT. Standard soil tests were performed on natural and chemically stabilized samples, such as gran size analysis, Atterberg limits, organic content, moisture content, and pH, as well as a chemical analysis comprising of neutralization potential, sulfate concentration, and X-ray diffraction (XRD). Analysis showed no major differences of moduli for pavement or soil layers between control and non-control. Results showed that sites where sulfates were known to exist, the chemically stabilized layers had sulfate concentrations greater than 3000 ppm and the pH was just barely greater than 10, which is an indication of concern for ettringite and thaumasite formation. However, the chemical analysis did not indicate formation of either mineral, therefore all conditions were not met.
- Published
- 2019
177. Investigation of in-situ strength of various construction/widening methods utilized on local roads
- Author
-
Sargand, S. M. and Sargand, S. M.
- Subjects
- Roads Widening Ohio., Road materials Evaluation. Ohio, Roads Design and construction. Ohio, Routes Élargissement Ohio., Routes Matériaux Évaluation. Ohio, Road materials Evaluation., Roads Design and construction., Roads Widening., Ohio.
- Abstract
This project goal was to develop and verify a low-cost, repeatable, non-destructive methodology to characterize the load carrying capacity of materials used in road widening and construction when established values are not available, and establish a range of structural coefficients and moduli for these materials. A total of 99 test sites were selected from 68 projects in seven participating counties across Ohio, which were grouped into five clusters. These sites included 19 different widening treatments. Each site was visited and tests were conducted and specimens gathered using the following techniques: Falling weight deflectometer (FWD), portable seismic properties analyzer (PSPA), light weight deflectometer (LWD), coring, and dynamic cone penetrometer (DCP). The data and specimens collected were used to measure layer thicknesses, the modulus, effective structural numbers, and layer coefficients applicable to each treatment. At least seven approaches were used to obtain these numbers from the data collected. The results were plotted in box plot and cumulative frequency format for each material and each analysis method. For each material, there is a wide variability of values both within one section and between different sections. There are many sources for this variability, however a range of numbers for moduli and layer coefficients can be identified for most treatments which can be utilized by local engineering personnel to design future projects. The procedure based on the Section 2.3.5 of the 1993 AASHTO pavement design guide using FWD data provided the best estimate of published layer coefficients. It is recommended the layer coefficients for the study materials estimated using this procedure be used. But note, the use of the coefficients in other areas without validation is not recommended. Accurate layer coefficients for multiple materials can only be determined by the construction of test sections and monitoring the performance under known loadings. For materials which will be widely used and the economics are justified, it is recommended test sections, with controls, be constructed at a common location to eliminate extraneous factors which confound the analysis.
- Published
- 2016
178. Effects of fine wood on macroinvertebrate drift in four boreal forest streams
- Author
-
Enefalk, Åsa, Bergman, Eva, Enefalk, Åsa, and Bergman, Eva
- Abstract
Most studies of stream wood have focused on pieces a parts per thousand yen0.1 m diameter. However, this approach may overlook an important feature of small streams, where wood < 0.1 m can constitute the majority of wood pieces. We examined the effect of fine wood (FW) on local drift of stream macroinvertebrates. The study was carried out at seven sites in four boreal forest streams, from early June to mid-August 2011. This was done by anchoring bundles of FW at each site and measuring drift upstream and downstream of each bundle. We hypothesized that FW would increase drift density, biomass and diversity of aquatic invertebrates. Ten weeks after FW addition, aquatic drift density was higher downstream than upstream of FW bundles, while drift biomass and drift diversity did not differ significantly downstream and upstream of FW.
- Published
- 2016
- Full Text
- View/download PDF
179. Active Filler's Effect on in-situ Performances of Foam Bitumen Recycled Mixtures
- Author
-
Betti, G., Airey, G., Jenkins, K., Marradi, Alessandro, and Tebaldi, G.
- Subjects
cement ,bearing capacity ,active filler ,Foam bitumen ,lime ,Foam bitumen, bearing capacity, FWD, active filler, lime, cement ,FWD - Published
- 2015
180. Application of Intelligent Compaction Technology for Estimation of Effective Modulus for a Multilayered Asphalt Pavement
- Author
-
Musharraf Zaman, Sesh Commuri, Fares Beainy, and Dharamveer Singh
- Subjects
Engineering ,Witczak Model ,business.industry ,Dynamic modulus of elasticity ,Mechanical Engineering ,Compaction ,Stiffness ,Modulus ,Structural engineering ,Hot-Mix Asphalt ,Fwd ,Asphalt pavement ,Mechanics of Materials ,Asphalt ,Dynamic modulus ,Calibration ,medicine ,Intelligent Compaction ,General Materials Science ,Geotechnical engineering ,medicine.symptom ,business - Abstract
In this paper, a procedure for estimation of effective modulus of a multilayered hot mix asphalt (HMA) pavement using intelligent compaction (IC) is investigated. The study is conducted during the construction of an interstate highway (I-35) in Norman, OK. A complete coverage of the level of compaction of each of the asphalt pavement layers was recorded using the intelligent asphalt compaction analyzer (IACA). The collected IACA data allow determination of the level of compaction (density) at any selected location, for each layer, and provided a set of global positioning system (GPS) coordinates. Calibration procedures have previously been tested and validated by the authors to estimate the density of different types of pavements from IACA data. In this paper, a different calibration procedure is used to measure the dynamic modulus instead of the density of a pavement using IACA. Considering the IACA estimated density, the dynamic modulus of each of the selected locations for an individual pavement layer was measured from laboratory developed master curves. Thereafter, an effective modulus of the three-layer pavement system was calculated for all of the selected locations using Odemark's method. The proposed technique was verified by conducting falling-weight deflectometer (FWD) tests at these selected locations. Analyses of the results show that the proposed intelligent compaction technique may be promising in estimating the effective modulus of the pavement layers in a non-destructive manner. In addition, the Witczak model was used to estimate moduli of each of the pavement layers. The comparison of the Witczak model with FWD revealed that the model over-predicted the modulus significantly.
- Published
- 2015
181. Falling Weight Deflectometer (FWD) tests on granular pavement reinforced with geogrids - Case study
- Author
-
Fowze, J S M, De Silva, N, Senanayake, K, Priyankara, N, Nawagamuwa, U, Kulathilaka, A, Rathnaweera, P, Gallage, Chaminda, Eom, TaeWoo, Barker, David, Ramanujam, Jothi, Fowze, J S M, De Silva, N, Senanayake, K, Priyankara, N, Nawagamuwa, U, Kulathilaka, A, Rathnaweera, P, Gallage, Chaminda, Eom, TaeWoo, Barker, David, and Ramanujam, Jothi
- Abstract
The use of geogrids in granular pavement layers could increase the modulus and the stiffness of granular layer and hence the required layer thickness can be reduced. Though, geogrids are being used in granular pavements to provide lateral restraint, bearing capacity, and membrane tension support, very limited studies have been carried out to investigate the effects of geogrids on modulus and stiffness of granular layer. In this study, two sections of a granular pavement were constructed: one with a geogrid at the bottom of the base layer and the other without a geogrid. Two sections were then tested using Falling Weight Deflectometer (FWD) and FWD results were analysed to determine the effect of geogrid on the overall modulus and stiffness of the granular pavement. The results suggested that the pavement section with geogrid has higher overall modulus and deflection ratio compared to the pavement section without geogrid.
- Published
- 2015
182. Nondestructive field assessment of flexible pavement and foundation layers
- Author
-
Hu, Jinhui and Hu, Jinhui
- Abstract
Falling weight deflectometer (FWD) and ground penetrating radar (GPR) are nondestructive test devices widely used by transportation agencies to assess pavement conditions. The two papers in this thesis evaluated the uncertainties associated with interpreting data from these devices and assessed potential applications. In the first paper, FWD tests were conducted on asphalt pavements with varying supporting conditions, and individual layer modulus values were estimated using forward-and back-calculation methods. Dynamic cone penetrometer (DCP) test device was used to independently measure individual layer penetration resistance (PR) values to compare with the estimate moduli values. Results indicated that the predicted subgrade moduli values from forward- and back-calculations are strongly correlated but produce slightly different values. The predicted asphalt and base layer moduli values from forward- and back-calculations, however, showed significant scatter. Comparison between DCP-PR and the predicted base and subgrade layer modulus yielded non-linear relationships. The relationships produced lower standard errors when only data from subgrade layer is considered. The relationships developed in this study fell within the upper and lower bounds of relationships documented in the literature. In the second paper, the efficacy of using a ground-coupled GPR system and a hand-held dielectric property measurement device to determine the asphalt and pavement foundation layer thicknesses is assessed. The actual pavement thicknesses were measured from pavement cores and foundation layer thicknesses were obtained using dynamic cone penetrometer (DCP) tests. Further, the viability of using GPR to detect moisture variations in the base layers is assessed. Tests were conducted on various asphalt pavement test sections built at a test site in Iowa with different foundation support and drainage conditions, and layer thicknesses. A comparative analysis of core measurements and asph
- Published
- 2015
183. Effekt av grusmängd och vältning för spårbildning på grusväg
- Author
-
Gustafsson, Oscar and Gustafsson, Oscar
- Abstract
Nybyggnation och underhåll av skogsbilvägar medför stora kostnader för skogsbruket. Georadar (GPR) är en teknik som kan användas för att läsa av en vägs struktur vilket ger ett möjligt tillvägagångssätt för att reducera kostnader vid upprustning av vägar. Detta genom att endast partier med sämre bärighet rustas upp och därmed läggs rätt mängd material på rätt ställe längs vägen. Alternativet är dagens subjektiva bedömning av åtgärdsbehov och godtycklig placering av grusmängd. Syftet med denna studie var att kvantifiera skillnader i spårbildning mellan 100 %, 75 % samt 50 % påförd materialmängd i överbyggnaden av total rekommenderad materialmängd för att uppnå bärighet motsvarande vägklass 3B, samt hur spårbildning i vägkroppen påverkas av vältning. Grusmängden för överbyggnaden dimensionerades med ledning från data insamlade med GPR och fallviktsmätare. Analysen grundade sig på inventering av sex block med vardera tre sträckor (50 meter långa) samt en referenssträcka (30 meter lång), för vilka materielmängd samt behandling skiljde sig åt. Vägytan mättes dagligen inom blocken under en fem-dagarsperiod då vägen belastades av virkestransporter. Den skogsbilväg studien genomfördes på hade en undergrund av normalmorän. Ingen signifikant skillnad mellan vältade eller ovältade sträckor uppvisades. Inga signifikanta skillnader uppvisades heller mellan sträckorna med olika materialnivåer. Det maximala spårdjupet som registrerades uppgick till 87 mm, medelvärdet för spårbildningen var 23 mm. Dessa resultat tyder på att den materialmängd som påförs överbyggnaden vid upprustning av en väg kan reduceras, om vägen har en undergrund av normalmorän, utan att spårbildning vid trafikering blir besvärande vid förhållanden liknande de för denna studie. Detta innebär en stor teoretisk besparingspotential för SCA Skog, då den rådande rekommendationen för materialmängd för att uppnå B-bärighet är 1630 ton/km, vilket innebär en materialkostnad om ca 100 000 kr/km. Ytterligare studier krävs, Construction and maintenance of forest roads are costly for the forest industry. Ground Penetrating Radar (GPR) is a technique for reading the road structure, which is a possible approach to reduce the cost of road upgrades. This by simply placing gravel on stretches with lower bearing capacity, and thereby adding the right amount of material in the right place along the way. The alternative is today's subjective assessment of the need for action and arbitrary placement of gravel lot. The purpose of this study was to quantify differences in rutting between 100 %, 75 % and 50 % applied gravel amount on the superstructure. These amounts were based on the total recommended amount of material to achieve buoyancy corresponding to road bearing class 3B, and how rutting in the road structure is affected by overturning. Gravel amount for the superstructure was designed with guidance from the data collected with the GPR and a falling weight deflect meter. The analysis was based on the inventory of six blocks, each with three sections (50 meters long) and a reference section (30 meters long), where the road surface was measured daily for five days of timber load transport. The study was conducted on a subgrade of normal moraine No significant difference between overturned or not overturned distances where exhibited. Neither was significant differences demonstrated between sections with different material amounts. The maximum rut depth recorded was 87 mm; the mean of rutting was 23 mm. These results suggest that the amount of material applied to the superstructure at the improvement of a road can be reduced if the road has a subgrade of normal moraine, rutting was not troublesome for traffic on any section. This is a significant theoretical savings potential for SCA Skog, since the current recommendation for the amount of material to achieve the B-bearing capacity is 1630 tons / km, which means a material cost of approximately 100.000 SEK / km. Further studies are required to
- Published
- 2015
184. Bituminous mixtures application in railway sub-ballast layer
- Author
-
Chiara, F., Fontul, S., Paixão, A., Andrea, A., and Prof. A. K. Nokalides
- Subjects
Bituminous mixture ,Sub-ballast ,Structural modelling ,Fwd - Abstract
The increasing of loads and traffic speed of the railways requires a better infrastructure, in order to enable the operation in optimal condition and less traffic interruptions due to maintenance actions. At the same time, the natural resources for the material generally used in the sub-ballast layer, namely the granite are limited, taking into account that the requirements in terms of stiffness and wearing resistance are very high. The bituminous mixtures can represent a good alternative to this traditional material. They enable the decreasing of sub-ballast thickness, better impermeability, better behaviour under the lorry traffic during construction and an improvement of the infrastructure stiffness and its continuity along the railway that results in less maintenance works. In this study two different structures are compared, one with granular material and the other one with bituminous material as sub-ballast layers. Falling Weight Deflectometer (FWD) tests were performed in order to establish the structural model. The back-calculation was made using both linear elastic and finite difference method. The results obtained so far are presented in this paper, together with some proposals for future developments. PTDC/ECM/70571/2006 - Optimisation of High-Speed Railway Track Using Bituminous Sub-ballast 9 0 768p-777p DT/NIF 2011 1 a 3 de Junho
- Published
- 2011
185. Bituminous mixtures application in railway sub-ballst layer
- Author
-
DE CHIARA, Francesca, Fontul, S., Paixao, A., and D'Andrea, Antonio
- Subjects
Bituminous mixtures ,sub-ballast ,FWD ,Structural modelling - Published
- 2011
186. Análise comparativa de metodologias para avaliação das condições de fundação de pavimentos rodoviários
- Author
-
Tangarrinha, João André Custódio and Quaresma, Luís
- Subjects
Módulo de deformabilidade ,Fundação de pavimentos ,ECP ,Plataforma ,FWD - Abstract
Dissertação para obtenção do Grau de Mestre em Engenharia Civil – Perfil de Construção As características da fundação são essenciais para o bom comportamento do pavimento, para a circulação efectuada em fase de obra e para impedir a ascensão da água por capilaridade, quer a curto quer a longo prazo. O objectivo do presente trabalho é apresentar propostas para melhorar os procedimentos para classificação de plataformas de fundação de pavimentos. Estas propostas incidem sobre a tradicional forma de classificar plataformas com base em tabelas, que em Portugal corresponde ao ―Manual de concepção de pavimentos para a rede rodoviária nacional‖ da JAE (1995). Foi também analisado uma tendência mais recente de classificação de plataformas com base em ensaios de carga realizados em fase de obra. Apresentam-se sugestões para uma metodologia baseada neste tipo de procedimento. Os ensaios de carga analisados foram o FWD e o ECP.
- Published
- 2011
187. Local calibration of the MEPDG prediction models for pavement rehabilitation and evaluation of top-down cracking for Oregon Roadways
- Author
-
Rahman, Md Shaidur and Rahman, Md Shaidur
- Abstract
The Oregon Department of Transportation (ODOT) is in the process of implementing the recently introduced AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) for new pavement sections. However, the vast majority of pavement work conducted by ODOT involves rehabilitation of existing pavements. Hot mix asphalt (HMA) overlays are the preferred rehabilitation treatment for both flexible and rigid pavements in Oregon. However, like new work sections, HMA overlays are also susceptible to fatigue cracking (alligator cracking and longitudinal cracking), rutting, and thermal cracking. Additional work was therefore needed to calibrate the design process for rehabilitation of existing pavement structures. 38 pavement sections throughout Oregon were included in this calibration study. A detailed comparison of predictive and measured distresses was made using the MEPDG released software Darwin M-E (Version 1.1). It was found that Darwin M-E predictive distresses did not accurately reflect measured distresses, calling for a local calibration of performance prediction models was warranted. Four distress prediction models (rutting, alligator cracking, longitudinal cracking, and thermal cracking) of the HMA overlays were calibrated for Oregon conditions. A comparison was made between the results before and after the calibration to assess the improvement in accuracy of the distress prediction models provided by the local calibration. While the thermal cracking model could not be calibrated, the locally calibrated models of rutting, alligator cracking, and longitudinal cracking provided better predictions with lower bias and standard error than the nationally (default) calibrated models. However, there was a high degree of variability between the predicted and measured distresses, especially for longitudinal cracking, even after the calibration. It is believed that there is a significant lack-of-fit modeling error for the occurrence of thermal cracks. The Darwin M-E calibrated m
- Published
- 2014
188. BLUEPRINT SUPPORT PLEDGED
- Subjects
FWD ,Business ,Business, international ,Food and beverage industries - Abstract
The country's top brewers, cider makers and wholesalers have pledged to continue supporting the Take Home Blueprint next year. The Blueprint, developed by the Federation of Wholesale Distributors, was launched [...]
- Published
- 2000
189. Development of a Structural Index as an Integral Part of the Overall Pavement Quality in the INDOT PMS
- Author
-
William Flora, Kumares C. Sinha, and Ghim Ping Ong
- Subjects
Engineering ,business.industry ,Pavement management ,Falling Weight Deflectometer ,Pavement maintenance ,Pavement Management ,System monitoring ,Civil Engineering ,Civil engineering ,FWD ,Transport engineering ,Pavement engineering ,Falling weight deflectometer ,Deflection (engineering) ,Pavement Structural Strength ,Asset management ,Asset Management ,business ,SPR-3062 ,Size effect on structural strength - Abstract
Transportation agencies spend billions of dollars annually on pavement maintenance and rehabilitation to meet public, legislative, and agency expectations. Knowledge of the structural condition of a highway pavement is crucial for pavement management at both the network level and the project level, particularly when the system monitoring, evaluation, and decision-making are to be made in a context of multiple criteria that include structural condition. A key aspect of the performance criteria for multiple criteria decision making is that the criteria must be amenable to scaling so that it can be duly incorporated in the overall utility function. The main objectives of this research study are: 1) To develop a pavement structural strength index (SSI), scaled logistically from zero to a 100, based on the falling weight deflectometer (FWD) deflection measurements; 2) To formulate SSI in such a manner to be used as an index or employ the value of “100 – SSI” as a deduct value from pavement distresses surface index; and 3) To develop models by which the SSI could be estimated given functional class, age, and drainage condition wherever deflection measurements are not available. Extensive literature review of existing information related to pavement structural capacity assessment was conducted. Necessary data was collected from the Indiana Department of Transportation (INDOT) pavement management databases and deflection measurements available at INDOT Research and Development for both project and network levels. Information from INDIPAVE (a database that includes data on weather conditions, highway classification, traffic, and other information at over 10,000 one-mile pavement sections in the State of Indiana) were also employed. Weather information was also collected from the Indiana State Climate Office. The data includes information on 12,250 road sections from 1999 to 2007. Data was classified by pavement surface type (whether it is asphalt or concrete) and system classification (whether it is an interstate, a non-interstate but part of the national highway system (NHS), or a non interstate and not a part of the national highway system (non-NHS).
- Published
- 2010
- Full Text
- View/download PDF
190. Use of FWD Deflection Basin Parameters (SCI, BDI, BCI) for Pavement Condition Assessment
- Author
-
Andrus Aavik and Ott Talvik
- Subjects
Engineering ,base curvature index (bci) ,lcsh:TE1-450 ,Rut ,Modulus ,limit value ,Young's modulus ,Curvature ,lcsh:TG1-470 ,symbols.namesake ,lcsh:Bridge engineering ,Deflection (engineering) ,Geotechnical engineering ,Bearing capacity ,lcsh:Highway engineering. Roads and pavements ,surface curvature index (sci) ,Civil and Structural Engineering ,business.industry ,FWD ,deflection basin ,surface curvature index (SCI) ,base damage index (BDI) ,base curvature index (BCI) ,Building and Construction ,Structural engineering ,Subgrade ,base damage index (bdi) ,fwd ,Falling weight deflectometer ,symbols ,business - Abstract
Current research studies relationship between Falling Weight Deflectometer (FWD) deflection basin parameters and road pavement structural condition indicators, such as fatigue cracking and permanent deformations induced by low bearing capacity of pavement, and pavement equivalent E modulus (Eeq). The primary aim of the research was to develop limit values for deflection basin parameters: surface curvature index (SCI), base damage index (BDI) and base curvature index (BCI). Analyses of data derived from the Estonian Road Databank disproved the hypothesis of relationship between deflection basin parameters and pavement defects or rutting. Deflection basin parameters and back-calculated Eeq were found to be in good correlation. Strong relationships were found between upper layers indicators (SCI and BDI) and Eeq. Relationship between subgrade indicator BCI and Eeq, found in the research, was not very strong. Based on the aforementioned relationships, and the required min equivalent modulus of particular pavement, the equations to determine the limit values of deflection basin parameters for different types of pavements were developed. As the statistical analyses of such extensive database have been done for the first time in Estonia, the determined limit values have to be evaluated in practice and, if needed, corrected.
- Published
- 2009
191. Temperaturkorrektur von mit dem Falling-Weight-Deflectometer gemessenen Deflexionen auf Asphaltbefestigungen
- Author
-
Jansen, Dirk and Straube, Edeltraud
- Subjects
Falling-Weight-Deflectometer ,ddc:620 ,Fakultät für Ingenieurwissenschaften » Bauwissenschaften » Bauingenieurwesen » Straßenbau und Verkehrswesen ,ddc:625 ,FWD ,Tragfähigkeit - Abstract
Die mit dem Falling-Weight-Deflectometer (FWD) auf Asphaltstraßen gemessenen Oberflächendeflexionen werden erheblich von der Temperatur der Asphaltschichten beeinflusst. Um vergleichbare Ergebnisse bei der Auswertung der Messergebnisse zu erhalten, muss die Temperatur der Asphaltschichten berücksichtigt werden, indem beispielsweise die gemessenen Deflexionen auf eine Standardoberbautempera¬tur umgerechnet werden. Für diese so genannte Temperaturkorrektur existiert in Deutschland derzeit nur eine Funktion, die aus einem Ansatz für die Temperaturkorrektur von Messungen mit dem Benkelman Balken abgeleitet wurde. International existierende Ansätze können teilweise nicht übertragen werden, da sie an meist sehr viel dünneren Oberbauten, als sie in Deutschland üblich sind, hergeleitet wurden. Die Promotionsarbeit hatte zum Ziel, einen Ansatz für die Temperaturkorrektur von FWD Messungen in Deutschland zu erarbeiten. Hierzu wurden zunächst zwei bestehende Streckenabschnitte mit Temperatursensoren in den Asphaltschichten instrumentiert, die seit April 2007 kontinuierlich die Asphalttemperaturen in verschiedenen Tiefen aufzeichnen. FWD Messungen im Bereich dieser Messstationen und an weiteren 20 Streckenabschnitten bei verschiedenen Temperaturen und verschiedenen Jahreszeiten, meteorologische Daten sowie die Ergebnisse aus Bohrkernuntersuchungen unterstützten den Prozess. For the design of pavements it is important to know the bearing capacity of the pavement. The bearing capacity can be derived from deflection measurements by a Falling-Weight-Deflectometer (FWD). The deflections out to about 500 mm from the load centre on asphalt pavements are strongly influenced by the temperature of asphalt layers. To get comparable results, the measured deflections have to be corrected to a reference temperature. In Germany there exists only a function for the temperature correction which was developed for Benkelman Beam measurements. The transfer of this function to FWD deflections is not possible. Internationally existing algorithms often cannot be transferred, because of differing climatic conditions and construction principles in Germany. The aim of the research project was to develop a function for temperature correction of FWD deflections which is suitable for conditions in Germany. For this, two existing asphalt pavements were instrumented with temperature sensors in the asphalt layer, which continuously log the asphalt temperatures since April 2007. The thickness of the asphalt layer is 28 cm and 20 cm respectively. In each pavement 8 sensors are arranged from surface to bottom. FWD deflection bowls will be measured on the instrumented test sections at different temperatures and seasons. In addition 20 more test sections with different thicknesses and asphalt materials will be measured by FWD at different temperatures and seasons. All pavements are in very good condition because they were built in recent years. Meteorological data and results from drill core evaluations make the analysis complete. A partial goal of the research project is to develop a draft for a manual for measuring the asphalt layer temperatures during FWD measurements.
- Published
- 2009
192. Mechanistic-based field evaluation of pavement foundation
- Author
-
Nazarian, Soheil, Correia, A. Gomes, and Universidade do Minho
- Subjects
Mechanistic approach ,Pavement foundation ,Field tests ,FWD - Abstract
For the last few decades, practitioners have understood the importance of the properties of pavement foundation layers on the performance of rigid and flexible pavements. With the pavement community’s widespread interest in implementing a new mechanistic empirical pavement design program (ME-PDG), the importance of accurately quantifying the stiffness and thickness of the foundation layers has become even more critical., ASCE, Geo Institute, Soy Ink
- Published
- 2009
193. Mechanistic Evaluation of Rubblized PCC Pavements
- Author
-
Ji, Yigong
- Subjects
subgrade modulus ,Structure Number ,SPR-2415 ,Layer Coefficients ,Non-destructive testing ,rubblization pavement ,Civil Engineering ,FWD - Abstract
This report presents a mechanistic approach and procedures for determining layer coefficients to characterize the in-situ behaviors of rubblized pavements. This procedure was developed based on the 1993 AASHTO Pavement Design Guide utilizing Falling Weight Deflectometer (FWD) testing and in-place simulation using back-calculation layer modulus. In order to evaluate the rubblized pavement systematically, twelve constructed pavement sections were extensively tested by FWD annually after construction. The FWD data was processed using the proposed mechanistic procedure. In addition, statistical analysis was conducted to compare the pavement structure parameters each year, including layer coefficient and in-situ resilient modulus using Analysis of Variance (ANOVA) and Z-tests. In the ANOVA, the comparison of the structure capacities derived from the field FWD tests with those from the mechanistic procedure supports the null hypothesis, which concluded there is no difference between the structural numbers from these two methods. Also, statistically, the layer coefficients in each year are significantly different. The in-situ resilient moduli for each year varied significantly. The results from Z-test show that for Hot Mixed Asphalt (HMA) layers, the layer coefficient confidence interval could be as high as 0.70 and also as low as 0.38. For the base layers, the layer coefficient confidence interval could be as high as 0.25 and also as low as 0.16. A layer coefficient of 0.42 is recommended for HMA and 0.22 for rubblized layer for the design of HMA overlay on rubblized PCC pavement.
- Published
- 2009
- Full Text
- View/download PDF
194. Ocjena nosivosti kolničke konstrukcije (strukturalni kapacitet) autoceste A3, Bregana - Zagreb - Lipovac, dionica Oprisavci - Spačva
- Author
-
Rukavina, Tatjana and Ožbolt, Marko
- Subjects
strukturalni kapacitet ,ocjena ,FWD ,GPR ,ELMOD6 - Abstract
Za potrebe ocjene stanja nosivosti kolničke konstrukcije (strukturalnog kapaciteta) provedena su na autocesti A3, Bregana-Zagreb-Lipovac, dionici Oprisavci-Spačva mjerenja defleksija uređajem s padajućim teretom (FWD) kao i nerazorno kontinuirano snimanje debljina pojedinih slojeva kolničke konstrukcije a u cilju što točnije interpretacije rezultata mjerenja defleksija. Programom ELMOD6 provedena je interpretacija rezultata mjerenja te je korištenjem računalnog programa BISAR te BANDS-PC ocjenjeno stanje kolničke konstrukcije.
- Published
- 2009
195. Methode zur Klassifizierung von Tragfähigkeitsmessergebnissen des Falling Weight Deflectometers bei Asphaltbefestigungen
- Author
-
Chakar, Thomas and Roos, R.
- Subjects
ddc:690 ,Substanzbewertung ,Erhaltung ,Zustandserfassung ,Buildings ,FWD ,Tragfähigkeit - Abstract
Mit dem Falling Weight Deflectometer können Tragfähigkeitsmuster als Merkmal für die strukturellen Gegebenheiten einer Straßenkonstruktion erfasst werden. Zur Bewertung dieser Tragfähigkeitsmuster (Deflexionsmulden) wurde durch Generierung theoretischer Deflexionsmulden eine bereits vorhandene Datenbank erweitert und dieser Datenbestand klassifiziert. Durch den Einsatz von Künstlichen Neuronalen Netzen wurde außerdem eine pragmatische Anwendung des klassifizierten Datenbestandes dargestellt.
- Published
- 2009
- Full Text
- View/download PDF
196. Ocjena nosivosti kolničke konstrukcije (strukturalni kapacitet) autoceste A3, Bregana - Zagreb - Lipovac, dionica Slavonski Brod zapad - Slavonski Brod istok
- Author
-
Rukavina, Tatjana
- Subjects
strukturalni kapacitet ,ocjena ,FWD ,GPR ,ELMOD6 - Abstract
Za potrebe ocjene stanja nosivosti kolničke konstrukcije (strukturalnog kapaciteta) provedena su na autocesti A3, Bregana-Zagreb-Lipovac, dionici Slavonski Brod zapad - Slavonski Brod istok mjerenja defleksija uređajem s padajućim teretom (FWD) kao i nerazorno kontinuirano snimanje debljina pojedinih slojeva kolničke konstrukcije a u cilju što točnije interpretacije rezultata mjerenja defleksija. Programom ELMOD6 provedena je interpretacija rezultata mjerenja te je korištenjem računalnog programa BISAR te BANDS-PC ocjenjeno stanje kolničke konstrukcije.
- Published
- 2008
197. Ocjena nosivosti kolničke konstrukcije (strukturalni kapacitet) autoceste A3, Bregana - Zagreb - Lipovac, dionica Slavonski Brod - Oprisavci
- Author
-
Rukavina, Tatjana and Ožbolt, Marko
- Subjects
strukturalni kapacitet ,ocjena ,FWD ,GPR ,ELMOD6 - Abstract
Za potrebe ocjene stanja nosivosti kolničke konstrukcije (strukturalnog kapaciteta) provedena su na autocesti A3, Bregana-Zagreb-Lipovac, dionici Slavonski Brod - Oprisavci mjerenja defleksija uređajem s padajućim teretom (FWD) kao i nerazorno kontinuirano snimanje debljina pojedinih slojeva kolničke konstrukcije a u cilju što točnije interpretacije rezultata mjerenja defleksija. Programom ELMOD6 provedena je interpretacija rezultata mjerenja te je korištenjem računalnog programa BISAR te BANDS-PC ocjenjeno stanje kolničke konstrukcije.
- Published
- 2008
198. Kontrollmetoder för aktiv design på obundna granulära material
- Author
-
Pinotti, Jacob, Forsberg, Alex, Pinotti, Jacob, and Forsberg, Alex
- Abstract
Today a newly built road has high standards on the bearing capacity; it should withstand the rigors of heavy traffic. To test the roads ability to cope with the oversized strain we use heavy and light weight case, static plate load or YPK (Wide area compaction control) as a control for bearing capacity. The method is used to measure the roads E-module, which is a measurement of the bearing capacity. To understand the term ”bearing capacity”, knowledge from other fields must be gathered. Fields such as geotechnology, road construction, packing, checking and deformation. In the current situation the roads are not optimized for its purpose along the entire route. This because the bearing capacity may be varied, which means that certain parts of the road can break before others. With an active design the road is constructed in places according to the bearing capacity. This results in a more even life expectancy of the entire route. A field trial was made during April of 2012 in Gislaved on the reconstruction of one existing road and a new development outside of Gislaved. Heavy weight case and plate loading tests was made on the sub base. The most emphasis was made on checking the bearing capacity and the degree of compaction in the roads construction to see if there is any connection between static plate load and heavy weight case. The test results was also used to conduct an active design of the road using a specialized computer program to calculate the thicknesses required for the bound material. Comparisons with the normal sections have shown that the road will cope with the set traffic load and that the active design contributes to a more even life expectancy along the entire route. An evaluation of old and new results have shown benefits with heavy weight case compared to using a plate load. Heavy fall weight is a fast and informative method of controlling bearing capacity and packing. Keywords: Bearing capacity, FWD, PLT, packing, checking and active design.
- Published
- 2012
199. Development of a Structural Index as an Integral Part of the Overall Pavement Quality in the INDOT PMS
- Author
-
Flora, William Frederick, Ong, Ghim Ping (Raymond), Sinha, Kumares C., Flora, William Frederick, Ong, Ghim Ping (Raymond), and Sinha, Kumares C.
- Published
- 2010
200. Non-Destructive Estimation of Pavement Thickness, Structural Number and Subgrade Resilience along INDOT Highways
- Author
-
Karen Zhu, Dwayne Authur Harris, Samy Noureldin, and Shuo Li
- Subjects
International Roughness Index ,Engineering ,effective structural number ,factory of safety ,Data collection ,reliability ,Cost effectiveness ,business.industry ,GPR ,layer coefficients ,deflection ,Pavement management ,Subgrade ,Civil engineering ,Civil Engineering ,FWD ,SPR-2408 ,Transport engineering ,Pavement engineering ,Falling weight deflectometer ,backcalculation of layer moduli ,remaining life ,Ground-penetrating radar ,pavement layer thickness ,business - Abstract
Nondestructive testing has become an integral part for evaluation and rehabilitation strategies of pavements in recent years. Pavement evaluation employing the Falling Weight Deflectometer (FWD) and the Ground Penetrating Radar (GPR) can provide valuable information about pavement performance characteristics and be a very useful tool for project prioritization purposes and estimation of construction budget at the network level. FWD deflection testing is an accurate tool for determining pavement structural capacity and estimating the required thickness of overlays and hence is an accurate tool for planning for or estimating required current and future construction budgets. GPR is the only tool that a highway agency may use to develop an inventory of pavement layers thicknesses in the most efficient manner possible. By estimating pavement layer thicknesses and stiffness properties more reliable projections of network rehabilitation strategies and needs can be established, thus resulting in cost effective use of available funds. Traditional obstacles for the use of FWD and GPR in pavement evaluation at the network level used to be expenses involved in data collection, limited resources and lack of simplified analysis procedures. This report presents Indiana experience in pavement evaluation with the FWD and GPR at the network level. A network level FWD and GPR testing program is implemented as a part of a study to overcome those traditional obstacles. This testing program included Interstate Highways I-64, I-65, I-69, I-70 and I-74 and a number of U.S. Roads and State Routes. It is concluded that network level testing employing the FWD and GPR is a worthwhile, technically sound program that will provide a baseline of structural capacities of in–service pavements in Indiana. Periodical generation of necessary data will be useful for determining how best to quantify structural capacity and estimate annual construction budget. FWD data on 2200 lane miles of the Indiana Department of Transportation (INDOT) network is recommended annually for network level pavement evaluation. Only three FWD tests per mile are recommended. This amount of testing can easily be conducted in one testing season. The information collected will allow the equivalent of 100% coverage of the whole network in 5 years. GPR data is recommended to be collected once every 5 years (if another thickness inventory is needed), after the successful network thickness inventory conducted in this study. GPR data collection is also recommended at the project level and for special projects. Both FWD and GPR data is recommended to be used as part of the pavement management system (together with automated collected data of international roughness index, IRI, pavement condition rating, PCR, rut depth, pavement quality index, PQI, and skid resistance).
- Published
- 2005
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