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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Truck Size and Weight Analysis for the Development of a European Bridge Formula

Moshiri, Maryam January 2011 (has links)
The research analyzes the bridge load stress effects resulting from international bridge formulae and truck size and weight regulations in Europe. This is done with a view to identifying issues that may need to be considered in the development of a European Bridge Formula (EUBF) conforming to European Directive truck configurations for the regulation of truck size and weight limits associated with international travel between European Union (EU) member states. The level of efficiency of bridge formulae vary depending on the design criteria used in the development of the formula, the compatibility to the jurisdiction’s infrastructure and truck fleet characteristics, and the method of implementation as part of the regulation and by operators in the trucking industry. The EUBF should limit imposed critical bending moment and shear stresses on single and continuous span bridges of varying lengths (5, 20, and 50 metres) in accordance to design live loads specified in the Eurocode. The analysis of bridge load effects imposed by European Directive truck configurations in this research, provide the basis for the development of a EUBF.
2

Truck Size and Weight Analysis for the Development of a European Bridge Formula

Moshiri, Maryam January 2011 (has links)
The research analyzes the bridge load stress effects resulting from international bridge formulae and truck size and weight regulations in Europe. This is done with a view to identifying issues that may need to be considered in the development of a European Bridge Formula (EUBF) conforming to European Directive truck configurations for the regulation of truck size and weight limits associated with international travel between European Union (EU) member states. The level of efficiency of bridge formulae vary depending on the design criteria used in the development of the formula, the compatibility to the jurisdiction’s infrastructure and truck fleet characteristics, and the method of implementation as part of the regulation and by operators in the trucking industry. The EUBF should limit imposed critical bending moment and shear stresses on single and continuous span bridges of varying lengths (5, 20, and 50 metres) in accordance to design live loads specified in the Eurocode. The analysis of bridge load effects imposed by European Directive truck configurations in this research, provide the basis for the development of a EUBF.
3

Evaluation of a new bridge formula for regulation of truck weights

Contractor, Yateesh Jaykishan 01 November 2005 (has links)
The current bridge formula, Federal Bridge Formula B (BFB), established in 1974 to protect bridges against excessive overstress, is very restrictive on long combination vehicles due to an 80,000 lb gross vehicle weight limit. Without this limit the formula will not be able to protect bridges in the cases of longer trucks. A formula developed by the Texas Transportation Institute (T.T.I.) called the TTI-HS20 Formula addresses these issues. This formula, developed especially for bridges designed for the HS-20 truck, eliminates the need for the 80,000 lb limit. A generic formula developed to protect H15 and HS-20 bridges (James et al., 1986) was evaluated in a previous study (James and Zhang, 1991). The approach to evaluating the TTI-HS20 Formula follows the approach outlined in James and Zhang, 1991. Information was collected on two important elements: a set of test bridges representative of the lightest continuous bridges, and a set of test truck configurations representative of real truck traffic with a focus on long combination vehicles. Critical weights of the selected trucks for the representative bridges are calculated and plotted against the TTI-HS 20 formula and other proposed formulas. A final recommendation as to whether this formula should be adopted nationwide is made.
4

Aplicação da teoria da confiabilidade na obtenção de limites para o peso de veículos de carga em pontes de concreto / Development of truck weight limits for concrete bridges using reliability theory

Ferreira, Luciano Maldonado 29 May 2006 (has links)
O aumento nos limites de pesos estabelecidos pela legislação brasileira e o surgimento de novas combinações de veículos de carga nos últimos anos tornam necessária a verificação da segurança estrutural das pontes quando submetidas ao tráfego real. Este trabalho verifica o desempenho das obras de arte sob jurisdição do DER-SP através do índice de confiabilidade 'beta' e obtém limites para o peso de caminhões de modo a não comprometer sua integridade estrutural. São consideradas as superestruturas das pontes em concreto armado ou protendido, classes 36 e 45. Verifica-se o estado limite último nas seções transversais mais solicitadas por momento fletor positivo e negativo. No caso de pontes em concreto protendido, acrescenta-se o estado limite de formação de fissuras. Para a representação do tráfego real, é desenvolvido um modelo de carregamento móvel com base em pesagens de caminhões efetuadas em rodovias do estado de São Paulo. Admite-se a presença simultânea de veículos sobre a ponte e diferentes relações entre seus pesos. Os parâmetros estatísticos da resistência são determinados através da técnica de Monte Carlo. Apresenta-se os limites de peso em forma de equações, denominadas ECPLs (equações comprimento-peso limite), aplicáveis a quaisquer grupo de eixos consecutivos. Os resultados indicam restrições à circulação de algumas composições, especialmente ao rodotrem de 740 kN e 19,80 metros de comprimento. Considerando-se apenas o estado limite de serviço, as obras de arte classe 45 apresentam menores limites de peso devido à ponderação de ações durante o projeto / The increase in gross weight limits allowed by Brazilian legislation and the appearance of new truck configurations in last years require the assessment of bridges structural safety when submitted to real traffic. This thesis verifies the performance of the bridges under DER-SP jurisdiction using the reliability index 'beta' and obtains truck weight limits in order to guarantee its structural integrity. The superstructure of reinforced and prestressed concrete bridges, classes 36 and 45, is considered. The ultimate limit state is verified in cross sections submitted to critical positive and negative bending moments. In case of prestressed bridges, the tension limit state in concrete is added. To represent the real traffic, a live load model is developed based on weighting data collected from stations located at highways of the state of Sao Paulo. Multiple presence of vehicles over the bridge and different relations between weights are admitted. The statistical parameters of resistance are determined using the Monte Carlo technique. The gross weight limits are presented in the form of equations, known as bridge formulas, to be applied on any group of two or more consecutive axles. The results indicate restrictions to the traffic of some vehicles, especially the 740 kN and 19,80 meters length roadtrain. Considering only the serviceability limit state, bridges class 45 exhibit lower weight limits due to the load factors recommended by the code during design
5

Aplicação da teoria da confiabilidade na obtenção de limites para o peso de veículos de carga em pontes de concreto / Development of truck weight limits for concrete bridges using reliability theory

Luciano Maldonado Ferreira 29 May 2006 (has links)
O aumento nos limites de pesos estabelecidos pela legislação brasileira e o surgimento de novas combinações de veículos de carga nos últimos anos tornam necessária a verificação da segurança estrutural das pontes quando submetidas ao tráfego real. Este trabalho verifica o desempenho das obras de arte sob jurisdição do DER-SP através do índice de confiabilidade 'beta' e obtém limites para o peso de caminhões de modo a não comprometer sua integridade estrutural. São consideradas as superestruturas das pontes em concreto armado ou protendido, classes 36 e 45. Verifica-se o estado limite último nas seções transversais mais solicitadas por momento fletor positivo e negativo. No caso de pontes em concreto protendido, acrescenta-se o estado limite de formação de fissuras. Para a representação do tráfego real, é desenvolvido um modelo de carregamento móvel com base em pesagens de caminhões efetuadas em rodovias do estado de São Paulo. Admite-se a presença simultânea de veículos sobre a ponte e diferentes relações entre seus pesos. Os parâmetros estatísticos da resistência são determinados através da técnica de Monte Carlo. Apresenta-se os limites de peso em forma de equações, denominadas ECPLs (equações comprimento-peso limite), aplicáveis a quaisquer grupo de eixos consecutivos. Os resultados indicam restrições à circulação de algumas composições, especialmente ao rodotrem de 740 kN e 19,80 metros de comprimento. Considerando-se apenas o estado limite de serviço, as obras de arte classe 45 apresentam menores limites de peso devido à ponderação de ações durante o projeto / The increase in gross weight limits allowed by Brazilian legislation and the appearance of new truck configurations in last years require the assessment of bridges structural safety when submitted to real traffic. This thesis verifies the performance of the bridges under DER-SP jurisdiction using the reliability index 'beta' and obtains truck weight limits in order to guarantee its structural integrity. The superstructure of reinforced and prestressed concrete bridges, classes 36 and 45, is considered. The ultimate limit state is verified in cross sections submitted to critical positive and negative bending moments. In case of prestressed bridges, the tension limit state in concrete is added. To represent the real traffic, a live load model is developed based on weighting data collected from stations located at highways of the state of Sao Paulo. Multiple presence of vehicles over the bridge and different relations between weights are admitted. The statistical parameters of resistance are determined using the Monte Carlo technique. The gross weight limits are presented in the form of equations, known as bridge formulas, to be applied on any group of two or more consecutive axles. The results indicate restrictions to the traffic of some vehicles, especially the 740 kN and 19,80 meters length roadtrain. Considering only the serviceability limit state, bridges class 45 exhibit lower weight limits due to the load factors recommended by the code during design

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