The Line Of Arch

Arch Flanagan, 91, is a retired school teacher. In 1943, as a sergeant in the Australian Army, he was forced to labor on the infamous Burma Railway upon which it is said one man died for every sleeper laid. In the 50 years since, Arch has written four separate pieces reflecting on the experience, two short stories, a memoir and an obituary for his commanding officer, Sir Edward "Weary" Dunlop. Martin Flanagan is a poet, writer and a journalist and is the fourth of Arch's six children.

Modern structural engineering surprises us with the mastery and certainty with which it plans and carries out daring projects, such as the most recent metal or concrete bridges, whether they be suspension or arch bridges. On the other hand, little is yet known about the state of knowledge of construction science and techniques which, well before the arrival of modern methods based on the mechanics of deformable continua, made it possible in the past to erect the vaulted masonry structures rthat we have inherited. The fact that these have lasted through many centuries to our time, and are still in a fairly good state of conservation, makes them competitive, as far as stability and durability are concerned, with those constructed in other materials. Although it is known that the equilibrium of the arch is guaranteed by any funicular whatsoever of the loads, contained inside the profile of an arch, finding the unique solution is not such a certainty. In other words, the problem of the equilibrium of vaulted structures is 'Poleni's problem', the one for which the Venetian scientist was able to give an exemplary solution on the occasion of the assessment of the dome of St. Peter's. Arch Bridges focuses on the main aspects of the debate about the masonry arch bridge: History of structural mechanics and construction, theoretical models, analysis for assessment, numerical methods, experimental and non-destructive testing, maintenance and repair are the topics of the Conference. The breadth and variety of the contributions presented and discussed by leading experts from many countries make this volume an authoritative source of up-to-date information.

Introductory technical guidance for civil engineers interested design of concrete arch dams. Here is what is discussed: 1. GENERAL DESIGN PROCESS 2. LEVELS OF DESIGN 3. PROCEDURE 4. MANUAL LAYOUT 5. PRELIMINARY STRESS ANALYSES 6. EVALUATION OF RESULTS 7. IMPROVEMENT OF DESIG 8. PRESENTATION OF DESIGN LAYOUT 9. COMPUTER-ASSISTED LAYOUTS.

Les ponts en arc font actuellement face au double défi de protéger leur patrimoine et de rivaliser avec d'autres formes plus récentes de structures. La conservation des ponts en arc implique de multiples impératifs : une politique saine d'inspection et de suivi, des méthodes précises d'investigation, une évaluation fiable et un éventuel diagnostic, des moyens efficaces de maintenance, de réparation, de renforcement et d'élargissement. Pendant que des ouvrages existants sont réparés et revalorisés, de nouveaux ponts en arc, de -nies traditionnelles et à " l'échelle humaine ", continuent à se construire, en utilisant des matériaux et procédés améliorés et rentables, assurant longévité et respect de l'environnement. Au premier plan de cette continuité, les concepteurs des ponts en béton, dans les hémisphères Nord et Sud, s'efforcent avec succès de réaliser des portées en arc de plus en plus longues, frôlant les 400 mètres dans les années 1980. Récemment, sur d'autres sites spectaculaires, des records de portées ont été battus par trois ponts en arc respectivement en pierre, en béton, en tubes d'acier remplis de béton. Une telle avancée ne manquera pas d'inciter les ingénieurs à rechercher des formes d'arc encore plus audacieuses et élégantes. Sur le large éventail des thèmes proposés, de nombreux auteurs, de plus de vingt-cinq pays, ont apporté des contributions majeures rappelant que les ponts en arc n'ont rien perdu de leur actualité et que, malgré les leçons assimilées de leur prestigieux héritage, leur conception stimule toujours la créativité des ingénieurs et des architectes. Ces contributions sont réunies dans le présent volume édité à l'occasion de la Troisième Conférence internationale sur les Ponts en Arc, tenue à Paris en septembre 2001. Arch bridges face at present the double challenge of protecting their heritage and competing with other more recent structural forms. The conservation of the arch bridge heritage successively requires sound inspection and monitoring policies, accurate investigative methods, reliable assessment and eventual diagnosis, efficient means for maintenance, repair, strengthening and widening. While existing structures are being repaired and upgraded, new arch bridges, of traditional forms and on a "human scale", continue to be constructed, using improved and cost-effective materials and procedures, ensuring longevity and respect for the environment. In the forefront of this continuity, concrete bridge designers, in the northern and southern hemispheres, have successfully been striving for ever larger arch spans, closely approaching 400 m in the 1980's. Lately, at other spectacular sites, span records were beaten in three arch bridges respectively using stone, concrete and slender concrete-filled steel tubes. This breakthrough may encourage engineers to seek more daring and elegant forms of arch. On the broad spectrum of the suggested topics, numerous authors, from more than twenty-five countries, have recently offered major contributions, reminding that arch bridges have nothing lost of their appeal and that, for all the lessons learnt from their prestigious heritage, their design still simulates the creativity of engineers and architects. These contributions are put together in the present volume edited on the occasion of the Third International Arch Bridge Conference held in Paris in September 2001.