Papers by Antonio Adao da Fonseca
Géotechnique, 1997
In the north-western region of Portugal residual soils from granite are dominant. Their porous ce... more In the north-western region of Portugal residual soils from granite are dominant. Their porous cemented structure leads to a complex geotechnical behaviour, quite distinct from that of transported soils with a similar grain size distribution. The paper describes some of the studies carried out at an experimental site on which a fairly homogeneous saprolitic soil 6m thick was encountered. These studies included: (i) a full-scale load test of a circular concrete footing (1·20m diameter), under carefully controlled conditions and with extensive monitoring; (ii) in situ testing techniques (SPT, CPT, SBPT, CH) and (iii) laboratory testing on high-quality block samples, including triaxial tests with local strain measurement. The discussion is concentrated on the interpretation of the pressure—settlement curve from the footing load test, for a range of pressures typical of working conditions, by means of linear and non-linear elastic analyses based on stiffnesses from the laboratory and in...
<u>Footbridge 2008 - Footbridges for Urban Renewal</u>, Third International Conference on Footbridges, 2-4 July 2008, Porto, Portugal, 2008
... Recently, that land was allocated to parkland with several social, leisure and cultural equip... more ... Recently, that land was allocated to parkland with several social, leisure and cultural equipments, and crossing from one margin to the other is now a very pleasant promenade along the footbridge named after Prince Pedro and Lady-in-Waiting Ines, who were ... Ponte da Europa ...
<u>Footbridge 2008 - Footbridges for Urban Renewal</u>, Third International Conference on Footbridges, 2-4 July 2008, Porto, Portugal, 2008
<u>Footbridge 2008 - Footbridges for Urban Renewal</u>, Third International Conference on Footbridges, 2-4 July 2008, Porto, Portugal, 2008
WIT Transactions on the Built Environment, Feb 24, 1999
A comparison is made between the cost minimization of a truss with variable cross-sectional dimen... more A comparison is made between the cost minimization of a truss with variable cross-sectional dimensions and fixed geometry (sizing) and the same problem with variable nodal coordinates (shape optimization). Both problems can be formulated as a mathematical program that comprises both structural analysis and design. When this integrated formulation is used, the number of variables in the mathematical program is usually large and an efficient algorithm is required. In this paper the shape optimization problem is solved by a second-order algorithm called NEWTOP that is based on the Lagrange-Newton method. The expressions that define the mathematical program are parsed and their first and second derivatives are symbolically determined and evaluated by the computer program. With the NEWTOP code, problems with more than 4 000 independent design variables and 20 000 constraints have already been successfully solved. The solution of a large variety of structural optimization problems has shown that this code is robust, efficient and very accurate. A simple shape optimization example and a bridge design problem are presented. The latter corresponds to a steel pedestrian bridge with eight spans and constant height. Sizing and shape optimization of one of the central spans are performed and compared.
<u>Footbridge 2008 - Footbridges for Urban Renewal</u>, Third International Conference on Footbridges, 2-4 July 2008, Porto, Portugal, 2008
Bridges overcome obstacles, open passageways and provide the way to the other side. Bridges unite... more Bridges overcome obstacles, open passageways and provide the way to the other side. Bridges unite territories and people separated by water or topographic barriers. Bridges are man-made objects in the landscape scenery. Bridges are always points of reference. Road and railway bridges bring about social and economic development. Road and railway bridges grant more efficient travel. Road and railway bridges are made to go along. Often, road and railway bridges are not perceived. Road and railway bridges are for all but belong to no one. Many people hardly notice road and railway bridges. Footbridges bring about quality of life. Footbridges offer opportunities to meander above ground or water, to take pedestrians away from the busy traffic in urban areas and to offer unexpected views and enjoyment of the landscape, whether built or natural. Footbridges provide meeting points. Footbridges are perceived and touched by the individual pedestrian. Footbridges are for all but belong to each pedestrian. Footbridges may attract pedestrians. Footbridges may frighten people. Definitely, footbridges are playing a central role in the urban renewal and pedestrian safety demanded by modern society, which is more and more sensitive to the needs of the elderly, of the physically handicapped, of the pregnant women and of the infants. 2. FOOTBRIDGES-design concept Footbridges may be regarded as large sculptures with practical purpose and severe structural requirements, but they should not be designed as sculptures are. Footbridges are to be used by human beings and their size and applied loads imply that structural demands are dominant. Therefore, beauty and elegance in the architectural concept must spring from efficiency in the structural design. And structural efficiency requires simplicity and purity of structural form and of their structural components. It should be clear to all involved that the achievement of natural harmony between the beauty of architectural and structural concept, the physical configuration of the local landscape and the social attractiveness and usefulness of footbridges require a fusion of all the various issues, whether social, artistic or technical. Unfortunately, that is not the view and understanding of many of those holding the initiative and authority to build footbridges. The belief that footbridges overflying streets, roads or motorways, even if in urban areas, need only to be there at a minimum cost has proved to be shortsighted and ignores responsibility towards the built environment and the aesthetic, cultural and emotional dimensions of human beings. Pedestrians disregard those footbridges and seem to prefer to endanger life when crossing busy traffic roads. Preferably, footbridges should be located and stretched along the natural walkway of pedestrians, who should derive pleasure from their use, never implying the walk of a much longer distance. When possible, pedestrians should be led naturally into the footbridge, well before pedestrians are at the edge of the road to be crossed. The setting of footbridges in parks or in open land is much easier and, although these footbridges are seen by less people, they tend to be better designed, as if the natural environment is regarded as deserving more esteem than the built environment.
<i>Footbridge 2014 - Past, Present & Future</i>, London, 16-18 July 2014, 2014
Available from British Library Document Supply Centre- DSC:D70217/81 / BLDSC - British Library Do... more Available from British Library Document Supply Centre- DSC:D70217/81 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
This paper describes the experience of working together with architects in the design of footbrid... more This paper describes the experience of working together with architects in the design of footbridges where aesthetics and structural efficiency are intrinsically linked. It is quite common to say that the deep understanding of the function and the location (physical and human environment) dictate the form of a bridge. In the specific cases presented in the paper, the particularities of several footbridges where the main advantages of their structural behaviour came from the symbiosis between architectural and structural conception, are emphasized. In some details, it can be said that the aesthetic choices intuited the good structural behaviour. As in other cases, it was the structural optimization that became the reason of the aesthetic options. Several examples are listed to illustrate this story where global structural response (longitudinal and transversal), static and dynamic behaviour, stiffness and resistance, cross section definition and structural material choice are discussed. Aesthetics of the given examples result from architectonic concepts that reflect structural demands and physical laws and that aim at optimized structures.
Footbridge 2022, Madrid: Creating Experience, Aug 20, 2022
At a time when the formal excesses and the ornamental delusions seem to be the rule in footbridge... more At a time when the formal excesses and the ornamental delusions seem to be the rule in footbridge design, this paper describes the experience of “going back to simplicity” in the global conception and design of footbridges where aesthetics, environmental integration, structural efficiency and economy are naturally interrelated. Generally, the structural solution results from the confluence of a variety of factors: the distance to be overcome and the intermediate supports to be considered, the function to be performed by the bridge, the structural materials to be employed, the free widths and heights to be considered and the construction methodology to adopt. In bridges, the structural solution is the paramount factor of its global conception, very much dictated by the location (physical and social context). Obviously, the search for efficiency results many times from the symbiosis between architectural (form) and structural ideas. For the “Vila do Conde” footbridge, both the landscape and the historical and cultural surroundings invited the conception to be as pure and clean as possible, with no structural elements above the bridge deck.
Ao longo da última década têm sido desenvolvidos vários trabalhos de investigação, desenvolviment... more Ao longo da última década têm sido desenvolvidos vários trabalhos de investigação, desenvolvimento e aplicação na área do pré-esforço orgânico. Este processo foi particularmente dinamizado a partir de 2005, data na qual foi realizada a primeira aplicação à escala real, no processo construtivo de uma ponte no Norte de Portugal, com resultados surpreendentes. Este artigo faz um resumo histórico desse processo de investigação e desenvolvimento, ilustrando e caracterizando os aspectos fundamentais das soluções para a construção de pontes em concreto que esta nova tecnologia viabiliza.
SUMÁRIO Este trabalho aborda sucintamente o "estado da arte" dos sistemas de control ac... more SUMÁRIO Este trabalho aborda sucintamente o "estado da arte" dos sistemas de control activo e enuncia os conceitos envolvidos em novas aplicações deste tipo de soluções, nomeadamente com vista ao control do comportamento pseudo-estático de estruturas. Apresenta também uma metodologia para concretizar as referidas aplicações, e discute os problemas de dimensionamento face às novas variáveis envolvidas. Para concretizar a metodologia proposta e para salientar as potencialidades dos sistemas em causa, inclui ainda um exemplo numérico. Finalmente, sintetizam-se as dúvidas imergentes deste tipo de problemas estruturais, apontam-se soluções para a sua resolução e descrevem-se algumas potencialidades desta área da Engenharia Estrutural. ABSTRACT The "state of art" of active control systems is mentioned briefly, and concepts implied in new applications, as it is the case of psuedo-static control of structures, are presented. A methodology developed for these applications...
SUMÁRIO Este trabalho descreve várias aplicações de pré-esforço orgânico. As suas características... more SUMÁRIO Este trabalho descreve várias aplicações de pré-esforço orgânico. As suas características são salientadas e apresenta-se o espaço previlegiado de aplicação do sistema proposto. A ilustração dos aspectos essenciais é conseguida com a apresentação de exemplos numéricos. Com base nos resultados obtidos é sugerida a aplicação de pré-esforço orgânico na reabilitação e reforço de pontes, constatando-se ser uma solução com potencialidades relevantes. ABSTRACT This paper describes several cases of organic prestressing. Main features are emphasised and specific benefits of the system are set. This is achieved by means of numerical examples. Results are used to suggest the application of organic prestressing to the rehabilitation and strengthening of bridges, which shows to be a technique of high potential. 1 -INTRODUÇÃO Nos últimos anos têm vindo a ser desenvolvidos e aplicados diversos sistemas de controlo activo em estruturas. Esta área de investigação tem revelado prometedoras pot...
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Papers by Antonio Adao da Fonseca