Papers

Apresenta-se uma panorâmica geral sobre os principais problemas relacionados com a fisiografia costeira e as principais técnicas de protecção da orla costeira. Referem-se os processos físicos responsáveis pela dinâmica sedimentar, e os principais problemas a ela associados que afectam praias e embocaduras de estuários e lagunas. As soluções mais comuns para este tipo de problemas são depois revistas de forma crítica. Finalmente, três casos de estudo são utilizados para exemplificar problemas e soluções, e, simultaneamente, ilustrar abordagens seguidas em estudos de engenharia: uma praia encaixada em erosão (praia de Hac-Sá, República Popular da China), um sistema no Rio de Janeiro, Brasil, composto por uma praia arqueada (praias de Leblon, Ipanema e Arpoador), um canal e uma laguna com problemas simultâneos de erosão e assoreamento e uma embocadura lagunar com problemas de assoreamento e de estabilidade (Lagoa de Óbidos, Portugal).

Performance assessment (PA) of urban infrastructure services, mainly in the case of water systems, is becoming a major issue worldwide. Therefore, in the last decade, the need for a clear definition of management objectives of water services and the subsequent need to monitor goals achievement have led to the development of some initiatives to tackle the evaluation of the efficiency of those services, their main aim being the definitin of systems of performance indicators. However, these PA systems are strongly oriented by a management/economic perspective and technical aspects have often been ignored. In addition, none of them has specifically addressed the drinking water treatment. This paper presents a proposal for a PI system that applies to drinking water treatment facilities as a part of a standardised methodology for performance assessment. In total, ca.80 PI have been define and classified according to seven evaluation domains, namely: treated water quality; plant reliability; use of natural resources and raw materials; by-products management; safety; human resources; and, economical and financial resources.

Em muitas utilizações, especialmente em ambientes húmidos ou expostos à chuva, o risco de degradação da madeira depende em grande medida das disposições construtivas adoptadas, no que se refere à pormenorização e ao cuidado na realização das ligações. A absorção e retenção de água pela madeira podem ocasionar o seu inchamento e ataque por insectos como as térmitas subterrâneas, ou a instalação e o desenvolvimento de fungos causadores de manchas ou de podridão. A variação das condições ambientais provoca ainda empenos e fendas. Compreende-se assim a importância da pormenorização para o desempenho e a durabilidade das estruturas de madeira, no sentido de limitar o acesso da água à madeira, promover a sua eliminação rápida e/ou minimizar as suas consequências. Também a escolha de materiais e a execução podem comprometer de forma drástica a qualidade e a durabilidade das estruturas, referindo-se adiante alguns aspectos relacionados com as ligações.

In this study, we simulate and compare ground motion shaking in the city of Lisbon and surrounding counties (metropolitan area of Lisbon (MAL)), using two possible earthquake models: the onshore source area of Lower Tagus Valley, M5.7 and M4.7 and the offshore source area, Marques de Pombal Fault, M7.6, one of the possible source of the 1755 Lisbon earthquake. The stochastic and a new hybrid stochastic-deterministic approach (DSM) are used in order to evaluate the ground shaking and to characterize its spatial variability. Results are presented in terms of response acceleration spectra (PSA) and peak ground acceleration (PGA) with respect to bedrock and surface. Site effects are evaluated by means of equivalent stochastic non-linear one-dimensional ground responses analysis, performed for a set of stratified soil profile units properly designed to cope with the soil site conditions of MAL region. A sensitive study is carried out using different input parameters and different approaches in order to give the basic information to evaluate the range of uncertainty in seismic scenarios.

In this study, we simulate and compare ground motion shaking in the city of Lisbon and surrounding counties (metropolitan area of Lisbon (MAL)), using two possible earthquake models: the onshore source area of Lower Tagus Valley, M5.7 and M4.7 and the offshore source area, Marques de Pombal Fault, M7.6, one of the possible source of the 1755 Lisbon earthquake. The stochastic and a new hybrid stochastic-deterministic approach (DSM) are used in order to evaluate the ground shaking and to characterize its spatial variability. Results are presented in terms of response acceleration spectra (PSA) and peak ground acceleration (PGA) with respect to bedrock and surface. Site effects are evaluated by means of equivalent stochastic non-linear one-dimensional ground responses analysis, performed for a set of stratified soil profile units properly designed to cope with the soil site conditions of MAL region. A sensitive study is carried out using different input parameters and different approaches in order to give the basic information to evaluate the range of uncertainty in seismic scenarios.

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This article describes the dynamical behavior of free-standing block structures under seismic loading. A comprehensive experimental investigation has been carried out to study the rocking response of four single blocks of different geometry and associations of two and three blocks. The blocks, which are large stones of high strength blue granite, were subjected to free vibration, and harmonic and random motions of the base. In total, 379 tests on a shaking table were carried out in order to address the issues of repeatability of the results and stability of the rocking motion response. Significant understanding of the rocking motion mechanism is possible from the high quality experimental data. Extensive experimental measurements allowed to discuss the impulsive forces acting in the blocks and the three-dimensional effects presented in the response.

The main objective of the use of very fine red clay ceramic waste in rendering mortars is the reduction in the primary binder (cement) content made possible by the potential pozzolanic effect of this recycled material, with very clear environmental benefits in the reduction of overly-high energy consuming cement and economic benefits in the potential reduction of the cost of mortars. This paper presents an experimental program where ceramic waste crushed to very fine particles was used to partially replace cement in mortars manufacturing, acting as a secondary binder. A large number of tests of the most relevant characteristics of various mortars in which this principle was applied were performed and compared with the results of the same tests in a reference rendering mortar with no ceramic fines (and no reduction of the cement content). The results are most promising both from a performance-based and an environmental point of view.

O presente trabalho apresenta uma formulação analítica do cálculo dos deslocamentos (rotação, flecha e deslocamento axial) de uma secção transversal qualquer dum elemento estrutural de barra plano (viga ou coluna-viga, p. ex.) de secção rectangular, de aço, submetido a uma força axial constante e a um momento flector em cada uma das suas extremidades. As equações apresentadas fornecem um método de cálculo não linear expedito e exacto, alternativo aos métodos clássicos das “rótulas plásticas” ou da “zona plástica”, e constituem uma base para o posterior desenvolvimento de outros métodos analíticos de cálculo não linear com aplicações mais alargadas, nomeadamente para o cálculo das matrizes de flexibilidade ou de rigidez elastoplástica destes elementos, ou de elementos estruturais de barra com outros tipos de secções transversais (perfis em I ou secções tubulares rectangulares, por exemplo).

double-skin façades (DSF) areused as an architectural solution to improve indoor comfort being characterized by having at least two membranes between the indoor occupied space and the exterior environment, separated by ana ir gap where the shading devices lie. The pressure within he gap plays an important role on i) the glazing structural safety; ii) te sahft ventilation, in particular if a natural ventilation scheme is implemented, but also to promote an efficient gap air change, and; iii) the safety of the maintenence satff, especially when windows may be opened to the interior.Although there are several DSF typologies only the multi-storey case, where no horizontal or vertical partitioning exists between the two skins, will be analised in this paper. Nevertheless, there are still a number of possible layouts for multi-storey DSF that might impose different pressure distributions within the gap. This paper refers to a set of wind tunnel tests made over a building model wit different multi-storey DSF layouts - from open an all edges to fully lateral closure and from naroow to wide gap depths, for an extented range of wind directions. The experimental data showed a layout dependent inner wall pressure distribution that may be considered different from the unsheltered building.