Papers

This article is a comprehensive Book review of the "Handbook of Transport Economics" (904 pages) by A. de Palma, R. Lindsey and E. Quinet, published in 2011 by Edward Elgar, Cheltenham, UK, ISBN: 978 1 84720203 1.

This paper concerns the design of bridge construction equipment (BCE). First an extensive design review of existing standards and codes of practice published in the USA and Europe is presented. A comparison is given concerning the design principles used, the design rules specified concerning structural analysis, types of loads, load combinations and safety factors. Additionally, discussion is presented about design verification procedures specified for steel members, connections, bearings and mechanical equipments. Following, a summary of the design guidance available in other documents, namely recent scientific textbooks, papers and reports, is presented, and failure examples are used to describe some critical enabling and triggering events. The paper also discusses some difficult challenges in the design of BCE, often found to be not completely addressed in existing codes, when compared with the design of permanent structures. The applicability of existing codes to the design of BCE is discussed. Recommendations for the adoption of a risk-based design framework to BCE are then presented.

Currently, there is strong pressure to use industrial byproducts and recycled materials in the construction of transportation infrastructure and geotechnical works. The reuse of these materials positively affects the environment by reducing deposits and preserving raw materials. The related geotechnical, geoenvironmental, economical, and social issues should be addressed so that these materials can be used in construction to provide sustainable development. This paper presents a study of all of these aspects and focuses on Portuguese electrical arc furnace steel slag. A huge laboratory research program was carried out that addressed four elements of geotechnical and geoenvironmental behavior: ultimate strength under monotonic loading, resilient behavior (stiffness), susceptibility to permanent deformation due to repeated loading, and leachability. These test results were compared with those from the empirical tests used in the national specifications for embankments and structural layers of transportation infrastructures. It was concluded that performance-based laboratory test results show much better material performance than the results based on empirical tests (Los Angeles and micro-Deval). Furthermore, this material shows better mechanical performance than in the mechanical tests of natural unbound granular materials used in road construction. Additionally, leaching test results show that this byproduct is inert, which caused it to become known as “inert steel aggregates for construction” (ISAC). These laboratory conclusions were validated in a full-scale field trial by end performance testing (using devices that measure in situ stiffness through spot tests and continuous monitoring, as well as lysimeters to measure leaching values). This field trial involved raw materials and ISAC. A final remark is made about some socioeconomic aspects that should be taken into account in decision making regarding the use of ISAC in public works.

Currently, there is strong pressure to use industrial byproducts and recycled materials in the construction of transportation infrastructure and geotechnical works. The reuse of these materials positively affects the environment by reducing deposits and preserving raw materials. The related geotechnical, geoenvironmental, economical, and social issues should be addressed so that these materials can be used in construction to provide sustainable development. This paper presents a study of all of these aspects and focuses on Portuguese electrical arc furnace steel slag. A huge laboratory research program was carried out that addressed four elements of geotechnical and geoenvironmental behavior: ultimate strength under monotonic loading, resilient behavior (stiffness), susceptibility to permanent deformation due to repeated loading, and leachability. These test results were compared with those from the empirical tests used in the national specifications for embankments and structural layers of transportation infrastructures. It was concluded that performance-based laboratory test results show much better material performance than the results based on empirical tests (Los Angeles and micro-Deval). Furthermore, this material shows better mechanical performance than in the mechanical tests of natural unbound granular materials used in road construction. Additionally, leaching test results show that this byproduct is inert, which caused it to become known as “inert steel aggregates for construction” (ISAC). These laboratory conclusions were validated in a full-scale field trial by end performance testing (using devices that measure in situ stiffness through spot tests and continuous monitoring, as well as lysimeters to measure leaching values). This field trial involved raw materials and ISAC. A final remark is made about some socioeconomic aspects that should be taken into account in decision making regarding the use of ISAC in public works.

A few years ago, it began in Portugal the development of buildings fire risk analysis model, named MARIE, composed by eleven partial models according to the factors taking influence on that risk, having the model for the building egress (MEE), constituted by the building description model (MDE) and the occupants’ movement model (MMO), already been completed. During MMO development, and due to the absence of national data allowing the characterization and quantification of people’s movement kinematic aspects on adverse environments boosting building evacuation, as stated on fire emergency situations, it was adopted Predtechenskii & Milinskii (P & M) mathematical relations. MEE is, nowadays, being improved, regarding both MDE and MMO. These improvements affecting MMO are related, in one hand, with the occupants’ behaviour, and, in the other hand, with the possibility of application to staircases of the mathematical relations of velocity and flow with density deduced by Predtechenskii & Milinskii. Therefore, several evacuation drills performed at the University of Coimbra Campus were filmed and analysed, where 321 people were involved, in order to obtain the expressions describing the movement in stairs, and later comparing them with P & M’s expressions.

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A relevant parameter for estimating discontinuity shear strength is the basic friction angle, usually derived from different types of tilt tests. However, the tilt tests described in the literature produce varying basic friction angle values. From a large number of different types of tilt tests on different kinds of rocks, it was possible to conclude that the mechanisms of sliding along cylinder generatrixes and planar surfaces are quite different, and that tests based on sliding along generatrixes are not appropriate for determining reliable basic friction angle values for discontinuity planes. Tests on small specimens are also not recommended, for geometry reasons and because ensuring reliable stress conditions is difficult. To quantify the natural variability in tilt testing, large specimens of the same granite were tested. The results revealed coefficients of variation for the basic friction angle in the range of 5–10 %, a variability which is no greater than that found for other rock mechanics parameters. This observation enables to forward some recommendations concerning the appropriate number of tests needed to obtain reliable results.

O escoamento em torno de um cilindro circular de comprimento infinito para números de Reynolds de 10 até 300 é investigado utilizando um método de resolução totalmente acoplado, resolvendo assim simultaneamente todas as equações discretas. O modelo numérico incorpora ainda um método de solução pouco convencional em que a equação da continuidade é resolvida na sua forma original (i.e. não há reconstrução de uma equação de pressão). O estudo cuidadoso dos esforços de arrasto e de sustentação, da pressão de base e do número de Strouhal é realizado em regime laminar e bidimensional em função da resolução e da extensão do domínio de cálculo. Resultados assimptóticos são obtidos aumentando a dimensão do domínio computacional de 20 até 4800 diâmetros do cilindro. É assim verificado que em contraste ao número de Strouhal, os esforços e a pressão de base são muito mais dependentes da resolução da malha e ainda mais da dimensão do domínio computacional.

Habitar é viver a cidade, seja como sítio de habitar, seja como espaço próprio de actividades urbanas específicas e desejavelmente estimulantes, e o lugar comum, mais fulcral e estratégico, deste quadro do habitar é o percurso da rua à casa e da casa à rua, um percurso que deve proporcionar agradabilidade, um certo sentido de surpresa estimulante e interessantes e adequadas condições de pormenorização; características estas que devem definir a identidade e a positiva singularidade de cada sítio urbano e habitacional.

Este trabalho aborda as complementaridades e contrariedades da invenção do bairro da Mouraria, em Lisboa. Foca-se as tentativas de (re)invenção do bairro através de propostas de intervenção técnica e urbanística que fixam valores e representações, e símbolos urbanos identitários, sobretudo incrementados em torno das ideias de cidade ‘plural’ e ‘cultural’. Explora-se a hipótese de que a ambiguidade e a ambivalência, como as interconexões entre processos de emblematização e de estigmatização territorial, são centrais na interpretação da realidade ‘polifónica’ que é o bairro.