Sheikh Rashid bin Saeed Crossing

Sarà il sesto ponte del Dubai Creek e, con i suoi 1,7 km di lunghezza e 205 metri di altezza, diventerà il ponte ad arco più grande del mondo. Il progetto porta la firma dello studio newyorchese FXFOWLE, vincitore del concorso di progettazione indetto dalla Roads & Transport Authority (RTA). Una volta ultimata - si prevede nel 2012 - la struttura si aggiungerà ai quattro ponti e al tunnel che consentono attualmente l’attraversamento del Dubai Creek. Due archi convergono al centro su un’isola artificiale. L’arco a ovest è lungo 667 metri e si innalza di 205 metri oltre il livello del mare. L’arco a est è lungo 560 metri e supera di 88 metri il livello del mare. Il nuovo ponte offrirà sei corsie di traffico per senso di marcia, due linee della metropolitana leggera, due percorsi pedonali (collocati sotto il ponte per proteggere i pedoni dal rumore e dal sole), un terminal traghetti, un anfiteatro ed un accesso multi-modale alla futura Opera House da realizzare su progetto di Zaha Hadid. “Il progetto trae ispirazione da molteplici elementi – spiega Sudhir Jambhekar di FXFOWLE – che evocano immagini simili, dall’elegante disegno delle adiacenti dune di sabbia, al ciclo lunare, al progetto della futura Opera House. Riteniamo che il nuovo ponte non sia mero collegamento tra zona commerciale e zona culturale, e che rappresenti bensì l’opportunità di realizzare un collegamento fisico ed emotivo tra le persone dando vita ad una nuova icona e ad un sistema di comunicazione tra la vecchia, la nuova e la futura Dubai”. English version Design Aspects Dubai is the leading city in the region in terms of technical development, construction innovation, and sustainable high quality growth. The west bridge of the Sixth Crossing at Dubai Creek is the world’s widest spanning arch bridge with an iconic arch rising 205m above sea level. The east bridge has a span of 560m. Together, they are therefore experienced as components of the global architectural composition with a continuously flowing form. The clear span of the bridge leaves the Creek unobstructed from structural elements and provides the highest possible flexibility for future water traffic development. The soaring arch, constructed in a spectacular manner and the use of modern, high performance materials for the whole project results in an innovative and iconic design that will be seen as the new landmark in the region. Technical Description Arch Bridges There are two arches with landings in front of the Opera Island Bridge the Creek. The western arch bridge spans over 667m and has a rise of 205m above sea level. The structure provides a 16m high navigation clearance. The eastern bridge has a span of 560m and the arch rises 88m above sea level. Both bridges accommodate 6 traffic lines in each direction, emergency sidewalks, 2 light rail lines and 2 pedestrian walkways. The walkways are situated below the bridge deck to protect pedestrians from sun and noise. The structural system of the bridges is the classical suspended deck arch bridge with the arch mainly under compression. The hangers are vertical and the arch has to resist compression and bending. The hangers are aligned with the inclined axis of the parabola defining the form of the arch. The complete bridge deck is arranged between two inclined arches. At the taller western span, the arches meet at the keystone thus creating sufficient resistance in transverse direction. The lower east span arch has the same transverse inclination and requires crossbeams to connect the two separate arches for sufficient transverse stability. The piers and arches form a continuous integral structure. The 4m deep composite bridge deck is 74m wide overall and spans in transverse direction from hanger to hanger. The transverse girder and the hangers are spaced 10m. The concrete deck slab forms together with the steel beams an effective composite system with an opening between the deck halves. The hangers are full locked grade cables with terminations at the bridge deck and adjustable terminations inside the arch for adjustment and re-tensioning. Each hanger consists of a twin cable for easy replacement and repair due to accidents. The removal of any two-hanger cables shall be possible. The bridge deck is supported by fixed and sliding elastomeric pot bearings. Hydraulic devices are used to resist horizontal movements during seismic events. The substructure of the arches consists of a thick pile cap with bored cast-in-place piles. Bridgeway Ramps The bridge approaches are concrete with a separate deck for each direction. The deck cross section is a multi-cellular concrete box. The span and depth may be modified according to local conditions. Depending on the number of lanes, the deck section is either a multi-cellular box or a simple box. There are two options for deck construction: 1. The bridge deck is erected in situ on scaffolding or with traveling formwork. 2. The bridge deck is erected with precast segments using a launching girder or the balanced cantilever method.