An Illustrated Guide for Monitoring and Protecting Bridge Waterways Against Scour - Project TR-515 - Final Report, March 2006

This report is a well illustrated and practical Guide intended to aid engineers and engineering technicians in monitoring, maintaining, and protecting bridge waterways so as to mitigate or prevent scour from adversely affecting the structural performance of bridge abutments, piers, and approach road embankments. Described and illustrated here are the scour processes affecting the stability of these components of bridge waterways. Also described and illustrated are methods for monitoring waterways, and the various methods for repairing scour damage and protecting bridge waterways against scour. The Guide focuses on smaller bridges, especially those in Iowa. Scour processes at small bridges are complicated by the close proximity of abutments, piers, and waterway banks, such that scour processes interact in ways difficult to predict and for which reliable design relationships do not exist. Additionally, blockage by woody debris or by ice, along with changes in approach channel alignment, can have greater effects on pier and abutment scour for smaller bridges. These considerations tend to cause greater reliance on monitoring for smaller bridges. The Guide is intended to augment and support, as a source of information, existing procedures for monitoring bridge waterways. It also may prompt some adjustments of existing forms and reports used for bridge monitoring. In accord with increasing emphasis on effective management of public facilities like bridges, the Guide ventures to include an example report format for quantitative risk assessment applied to bridge waterways. Quantitative risk assessment is useful when many bridges have to be evaluated for scour risk and damage, and priorities need to be determined for repair and protection work. Such risk assessment aids comparison of bridges at risk. It is expected that bridge inspectors will implement the Guide as a concise, handy reference available back at the office. The Guide also likely may be implemented as an educational primer for new inspectors who have yet to become acquainted with waterway scour. Additionally, the Guide may be implemented as a part of process to check whether existing bridge-inspection forms or reports adequately encompass bridge-waterway scour.

Monitoring of the Launched Girder Bridge over the Iowa River on US 20, March 2004

The objective of the study presented in this report was to document the launch of the Iowa River Bridge and to monitor and evaluate the structural performance of the bridge superstructure and substructure during the launch. The Iowa Department of Transportation used an incremental launching method, which is relatively unique for steel I-girder bridges, to construct the Iowa River Bridge over an environmentally sensitive river valley in central Iowa. The bridge was designed as two separate roadways consisting of four steel plate girders each that are approximately 11 ft deep and span approximately 301 ft each over five spans. The concrete bridge deck was not placed until after both roadways had been launched. One of the most significant monitoring and evaluation observations related to the superstructure was that the bottom flange (and associated web region) was subjected to extremely large stresses during the crossing of launch rollers. Regarding the substructure performance, the column stresses did not exceed reasonable design limits during the daylong launches. The scope of the study did not allow adequate quantification of the measured applied launch forces at the piers. Future proposed esearch should provide an opportunity to address this. The overall experimental performance of the bridge during the launch was compared with the predicted design performance. In general, the substructure design, girder contact stress, and total launching force assumptions correlated well with the experimental results. The design assumptions for total axial force in crossframe members, on the other hand, differed from the experimental results by as much as 300%.

Evaluation of a Bridge Constructed using High Performance Steel, May 2006

Of the approximately 25,000 bridges in Iowa, 28% are classified as structurally deficient, functionally obsolete, or both. Because many Iowa bridges require repair or replacement with a relatively limited funding base, there is a need to develop new bridge materials that may lead to longer life spans and reduced life-cycle costs. In addition, new and effective methods for determining the condition of structures are needed to identify when the useful life has expired or other maintenance is needed. Due to its unique alloy blend, high-performance steel (HPS) has been shown to have improved weldability, weathering capabilities, and fracture toughness than conventional structural steels. Since the development of HPS in the mid-1990s, numerous bridges using HPS girders have been constructed, and many have been economically built. The East 12th Street Bridge, which replaced a deteriorated box girder bridge, is Iowa’s first bridge constructed using HPS girders. The new structure is a two-span bridge that crosses I-235 in Des Moines, Iowa, providing one lane of traffic in each direction. A remote, continuous, fiber-optic based structural health monitoring (SHM) system for the bridge was developed using off-the-shelf technologies. In the system, sensors strategically located on the bridge collect raw strain data and then transfer the data via wireless communication to a gateway system at a nearby secure facility. The data are integrated and converted to text files before being uploaded automatically to a website that provides live strain data and a live video stream. A data storage/processing system at the Bridge Engineering Center in Ames, Iowa, permanently stores and processes the data files. Several processes are performed to check the overall system’s operation, eliminate temperature effects from the complete strain record, compute the global behavior of the bridge, and count strain cycles at the various sensor locations.

An Integral Abutment Bridge with Precast Concrete Piles, May 2007

The use of precast, prestressed concrete piles in the foundation of bridge piers has long been recognized as a valuable option for bridge owners and designers. However, the use of these precast, prestressed concrete piles in integral abutment bridges has not been widespread because of concerns over pile flexibility and the potential for concrete cracking and deterioration of the prestressing strands due to long-term exposure to moisture. This report presents the details of the first integral abutment bridge in the state of Iowa that utilized precast, prestressed concrete piles in the abutment. The bridge, which was constructed in Tama County in 2000, consists of a 110 ft. long, 30 ft. wide, single-span PC girder superstructure with a left-side-ahead 20º skew angle. The bridge was instrumented with a variety of strain gages, displacement sensors, and thermocouples to monitor and help in the assessment of structural behavior. The results of this monitoring are presented, and recommendations are made for future application of precast, prestressed concrete piles in integral abutment bridges. In addition to the structural monitoring data, this report presents the results of a survey questionnaire that had been mailed to each of the 50 state DOT chief bridge engineers to ascertain their current practices for precast, prestressed concrete piles and especially the application of these piles in integral abutment bridges.

Análisis del comportamiento de los resultados en 'full' y 'direct costing'

In this paper we perform a mathematical analyse of profits and losses indirect and full costing. They are compared in different situations, mainlythe utilisation of productive capacity and the existence of beginninginventories. Direct costing was conceived as a system of cost accountingwhich would show profits as a function of sales. In full costing profitsdepend on available combinations of sales, production, costs of beginninginventories, etc., and information displayed in financial statements displayappears incongruent. Differences in profits with full and direct costingincrease when full costing allocates fixed costs according to normalproduction, in some cases differences, and financial statements would showmore incongruent performance. It is concluded about the importance thatprofit and loss statement expresses profits in both costing systems.

Full insurance, asymmetric information and genetic testing

This paper extends previous resuls on optimal insurance trading in the presence of a stock market that allows continuous asset trading and substantial personal heterogeneity, and applies those results in a context of asymmetric informationwith references to the role of genetic testing in insurance markets.We find a novel and surprising result under symmetric information:agents may optimally prefer to purchase full insurance despitethe presence of unfairly priced insurance contracts, and other assets which are correlated with insurance.Asymmetric information has a Hirschleifer-type effect whichcan be solved by suspending insurance trading. Nevertheless,agents can attain their first best allocations, which suggeststhat the practice of restricting insurance not to be contingenton genetic tests can be efficient.

O Dualismo Cultural: os Luso-Caboverdianos entre a Escola a Família e a Comunidade (Estudo de Caso)

A tese que ora findamos visa a obtenção do grau de doutora em Educação, na Especialidade de Desenvolvimento Curricular, pelo Departamento do Currículo e Tecnologia Educativa, do Instituto de Educação e Psicologia, da Universidade do Minho. Intitulado o dualismo cultural: os luso-caboverdianos entre a escola, a família e a comunidade, o presente estudo centra-se numa abordagem crítica da escolaridade básica obrigatória, no qual procurámos compreender e explicar as condições de realização deste nível de ensino pelos jovens de ascendência caboverdiana, nascidos em Portugal, na qualidade de sujeitos biculturais em consequência da simbiose das culturas caboverdeana e portuguesa. Isto para concluirmos se na oferta do serviço educativo e de formação estão acautelados os seus direitos de cidadania e de participação na sociedade em que se encontram inseridos e a que pertencem de facto. Nesta investigação foi fundamental analisar a oferta de educação básica, entender as representações de alunos lusocaboverdeanos acerca da sua identidade cultural e das suas percepções sobre a formação académica que recebem; reconhecer representações e percepções de professores acerca da realidade educativa portuguesa, o enquadramento da multiculturalidade e a docência em turmas com alunos luso-caboverdianos, e compreender as percepções de pais e encarregados da educação caboverdeanos acerca da realidade educativa portuguesa e do enquadramento dos seus filhos na escola, para perceber se o insucesso educativo dos luso-caboverdeanos está relacionado com a condição de aluno “culturalmente diferente” ou se tem a sua origem na escola e no currículo da escolaridade obrigatória e, assim, contribuir com subsídios teóricos e práticos para o aprofundamento da problemática da multiculturalidade em Portugal, com vista à sua potenciação e normalização no sistema educativo. Estando perante uma sociedade de formação multicultural reafirmada com a colonização, justifica-se, em Portugal, a preocupação com a temática da diversidade cultural nas políticas educativas, resultante da consciencialização da manifestação da diversidade cultural no contexto escolar, podendo a sua omissão constituir num factor de insucesso educativo. Por isso, integramos nesta investigação matérias como: uma conceptualização do multiculturalismo com vista a questionar e clarificar os conceitos e as perspectivas inerentes a este fenómeno. Uma tentativa de desocultar para perceber o conteúdo simbólico e os porquês das políticas de integração das minorias etnicoculturais que, ao que parece, nos tempos que correm, por quase toda a parte, se converteram numa prioridade absoluta e inadiável. Estabelecemos uma ponte entre a génese do campo curricular e a construção de um currículo multi e/ou intercultural, merecendo devida atenção as tendências que dominam as discussões e a produção científica actuais nestes domínios. Problematizámos o currículo e identidade na escolaridade obrigatória nas dimensões inserção sociocultural, promoção da igualdade de sucesso educativo e inclusão dos sujeitos e o currículo e a educação para o exercício da cidadania numa escola que se quer plural. Neste último debatemos o conteúdo político da educação para a cidadania, as políticas educativas e curriculares e a escolaridade básica obrigatória como uma proposta que continua em aberto, por isso, passível de adequação às necessidades de uma educação da e para a diversidade. Procurámos fazer uma análise das políticas de integração socioeducativa da diversidade cultural, com destaque para o quadro legal que regula a integração das minorias étnicas na escola básica portuguesa, com particular incidência sobre as crianças pertencentes à comunidade caboverdeana nascidas em território português, procurando concluir acerca da existência, ou não, de posições e opções de políticas educativas concretas face à necessidade de dar prosseguimento à educação multicultural neste contexto. Tratou-se de uma investigação qualitativa holística, que permitiu desenvolver compreensões profundas dos fenómenos a partir das evidências reunidas, do estudo das representações dos sujeitos sobre quem recaem os resultados da investigação, mas também de sujeitos que, assim como o meio envolvente, estabelecem uma relação indirecta com os mesmos resultados. Circunscrito a um estudo de caso, a reflexão e a partilha de conhecimento e informações possibilitou desenvolver uma compreensão sobre a problemática estudada. Dos resultados obtidos, destacámos aqui que, em Portugal, apesar da absorvência da diversidade cultural nas política educativa, não se concretizou, ainda, uma proposta que, na prática, crie a reciprocidade entre as questões etnicoculturais e o sucesso e/ou insucesso educativos das minorias em educação com ganhos decisivos no combate ao insucesso e ao abandono escolar. Continua-se a desenvolver uma educação igualitarista monocultural pela via da homogeneização curricular, assente na noção de que povos e grupos podem estar em condições de igualdade se reunidos numa cultura comum. Aparentemente sob pilares democráticos, esta educação multicultural segue a concepção liberal associando essencialismo, universalismo e igualitarismo, resultando num propósito civilizacional excludente das minorias etnicoculturais. As conclusões chegadas permitem-nos defender a dessacralização do currículo nacional comum e uniforme e a defesa de uma proposta curricular baseada numa cultura científica global e necessária, de acordo com as faixas etárias e níveis de ensino, com campos de integração obrigatória de conteúdos territorializados alicerçados no interculturalismo como estratégia promotora da interacção crítica e solidária entre diferentes sujeitos e grupos culturais, permissiva da construção de identidades próprias e da confissão da diferença cultural, associada ao intraculturalismo como uma via permeabilizadora da educação democrática como garante da cidadania plena a todos os indivíduos, como condição fundamental para o estabelecimento das condições de igualdade e de garantia de sucesso em educação.

High Performance Concret Bridge Deck Overlays for County Bridges, October 2007

The Iowa Method for bridge deck overlays has been very successful in Iowa since its adoption in the 1970s. This method involves removal of deteriorated portions of a bridge deck followed by placement of a layer of den (Type O) Portland Cement Concrete (PCC). The challenge encountered with this type of bridge deck overlay is that the PCC must be mixed on-site, brought to the placement area and placed with specialized equipment. This adds considerably to the cost and limits contractor selection. A previous study (TR-427) showed that a dense PCC with high-range water reducers could successfully be used for bridge deck overlays using conventional equipment and methods. This current study evaluated the use of high performance PCC in place of a dense PCC for work on county bridges. High performance PCC uses fly ash and slag to replace some of the cement in the mix. This results in a workable PCC mix that cures to form a very low permeability overlay.

The debates of the Constitutional Convention of the state of Iowa, assembled at Iowa City, Monday, January 19, 1857. Being a full and complete report of the debates and proceedings, by authority of the Convention; accompanied, for purposes of reference, by a copious index of subjects, and remarks of members thereon. W. Blair Lord, reporter.

The two volume record of the debates that occured during the thirty-nine days it took to draft the third constitution of the State of Iowa.