Eleutherna Bridge The Eleutherna Bridge is an ancient

Eleutherna Bridge • • • The Eleutherna Bridge is an ancient Greek corbel arch bridge near the Cretan town of Eleutherna, Greece. [1] The well-preserved structure has a single span of 3. 95 m, which is quite large for a false arch. The opening is cut from the unmortared limestone blocks in the shape of an isosceles triangle, the height of which is 1. 84 m. The overall length of the bridge measures 9. 35 m. Its width varies from 5. 1 to 5. 2 m, with the structure converging slightly towards its center point above the arch (5. 05 m width there). The height is between 4 and 4. 2 m. The bridge which is still in use was first described by the Englishman T. A. B. Spratt in his Travels and Researches in Crete, after he had paid a visit to the site in 1853. At the time, another ancient bridge with a triangular arch was still standing a few hundred metres away, but, judging from a later report, was destroyed some unknown time before 1893. While there is general agreement that the two bridges of Eleutherna date to the pre-Roman period, a more precise dating is hampered by the lack of proper finds. According to Nakassis, the extant bridge was built sometime during the Hellenistic period, [ while the Italian scholar Galliazzo dates the construction more precisely to the end of the 4 th or beginning of the 3 rd century BC.

Eleutherna Bridge • Carries Footpath to Eleutherna Crosses Confluence of Pharangitis and Chalopota streams Locale Prines, Crete, Greece Design Corbel arch bridge Material Limestone Total length 9. 35 m Width 5. 05− 5. 2 m Height 4− 4. 2 m Longest span 3. 95 m Number of spans 1 Construction end Hellenistic period Coordinates 35° 20′ 17″N 24° 40′ 15″E

Arch Bridge Nagasaki. Meganebashi

The Alcántara Bridge, Spain (built 103 -106 AD) • Ρωμαϊκά τοξωτά γεφύρια

Segovia Aqueduct (c. 100 AD)/File: Acueducto. Segovia edit 1. jpg Ρωμαϊκά τοξωτά γεφύρια

Richmond Bridge /Panorama Richmond Bridge, oldest operational bridge in Australia (1825)

In China, the oldest existing arch bridge is the Zhaozhou Bridge • of 605 AD, which combined a very low span-to-rise ratio of 5. 2: 1, with the use of spandrel arches (buttressed with iron brackets). The Zhaozhou Bridge, with a length of 167 feet (51 m) and span of 123 feet (37 m), is the world's first wholly stone open-spandrel segmental arch bridge, allowing a greater passage for flood waters. • In more modern times, stone and brick arches continued to be built by many civil engineers, including Thomas Telford, Isambard Kingdom Brunel and John Rennie. A key pioneer was Jean-Rodolphe Perronet, who used much narrower piers, revised calculation methods and exceptionally low span-to-rise ratios. Different materials, such as cast iron, steel and concrete have been increasingly used in the construction of arch bridges.

File: Bridge Alcantara. JPG The Alcántara Bridge, Spain (built 103 -106 AD)

The Alcántara Bridge, Spain (built 103 -106 AD)

Segovia Aqueduct (c. 100 AD)/ : Acueduc/ to/ Segovia/

Devil's bridge, Céret, /France (1341)/ Pont du Diable • In medieval Europe, bridge builders improved on the Roman structures by using narrower piers, thinner arch barrels and lower span-rise ratios on bridges. Gothic pointed arches were also introduced, reducing lateral thrust, and spans increased as with the eccentric Puente del Diablo (1282). Στη μεσαιωνική Ευρώπη, οι οικοδόμοι γεφυριών βελτιώθηκαν στις ρωμαϊκές δομές, χρησιμοποιώντας στενότερες προβλήτες, λεπτότερα βαρέλια καμάρας και χαμηλότερες τιμές ανοίγματος άνοδο σε γέφυρες. Puente del Diablo (1282). ΓΟΤΘΙΚΑ οξυκόρυφα τόξα Εισήχθησαν επίσης, μείωση πλευρική ώθηση, και τα ανοίγματα αυξήθηκαν με τον εκκεντρικό Puente del Diablo (1282).

The 14 th century in particular saw bridge building • reaching new heights. Span lengthes of 40 m, previously unheard of in the history of masonry arch construction, were now reached in places as diverse as Spain (Puente de San Martín), Italy (Castelvecchio Bridge) and France (Devil's bridge and Pont Grand) and with arch types as different as semi-circular, pointed and segmental arches. The bridge at Trezzo sull'Adda, destroyed in the 15 th century, even featured a span length of 72 m, not matched until 1796.

Constructions such as the acclaimed Florentine segmental arch bridge Ponte Vecchio (1345) • combined sound engineering (span-to-rise ratio of over 5. 3 to 1) with aesthetical appeal. The three elegant arches of the Renaissance Ponte Santa Trinita (1569) constitute the oldest elliptic arch bridge worldwide. Such low rising structures required massive abutments, which at the Venetian Rialto bridge and the Fleischbrücke in Nuremberg (span-to-rise ratio 6. 4: 1) were founded on thousands of wooden piles, partly rammed obliquely into the grounds to counteract more effectively the lateral thrust.

arch bridge Ponte Vecchio(1345) Constructions such as the acclaimed Florentine segmental arch bridge Ponte Vecchio (1345) combined sound engineering (span-to-rise ratio of over 5. 3 to 1) with aesthetical appeal. The three elegant arches of the Renaissance Ponte Santa Trinita (1569) constitute the oldest elliptic arch bridge worldwide. Such low rising structures required massive abutments, which at the Venetian Rialto bridge and the Fleischbrücke in Nuremberg (span-to-rise ratio 6. 4: 1) were founded on thousands of wooden piles, partly rammed obliquely into the grounds to counteract more effectively the lateral thrust.

The Ponte Vecchio, Florence, Italy (1345)/Firenze. Ponte Vecchio Κατασκευές όπως η περίφημη της Φλωρεντίας τμηματική γέφυρα αψίδα Ponte Vecchio (1345),

/8/ Vradeto stairway, Zagori, Greece. was taken by the photographer nenia on 25 May 2009, /8/ Vradeto stairway, Zagori, Greece. is next to Vradéton and is located in Epirus, Greece.