hiroshima peace broer

Hiroshima Peace Bridge

hiroshima-peace-bridge---rendering-(5).jpg

fakta

Hiroshima Peace bro
Bjælkebro

Hiroshima, Japan 

Konkurrence: 2008
2. præmie

Total længde: 84m
Maksimal dækdybde: 1,8m
Minimum dækdybde: 0,5m
Dækkets bredde: 6,5m 

Bygherre: Hiroshima kommune
Arkitekt: DISSING+WEITLING architecture
Ingeniør: Buro Happold (UK)

Visualiseringer: DISSING+WEITLING architecture

facts

Hiroshima Peace Bridges
Propped-up cantilever pedestrian bridge

Hiroshima, Japan

Competition: 2008
2nd place

Total length: 84m
Maximum deck depth: 1.8m
Minimum deck depth: 0.5m
Deck width: 6.5m

Client: Municipality of Hiroshima
Architect: DISSING+WEITLING architecture
Engineer: Buro Happold (UK)

Renderings: DISSING+WEITLING architecture

Hiroshima Peace broer

Konkurrencen om de to gangbroer over Motoyasu-gawa floden var en vigtig del af fornyelsen af Hiroshimas Peace Boulevard og skulle etablere en vigtig forbindelse til Peace Memorial Parken. Man ønskede, at gangbroerne skulle være i harmoni med det omkringliggende, heriblandt den eksisterende bro, Motoyasu-gawa floden og Peace Memorial Parken.

DISSING+WEITLING architecture mente, at den eksisterende bros dramatiske design ikke skulle gentages, og valgte dermed et klart og enkelt design, der skulle være æstetisk tiltalende set fra bredden og i vandspejlet. 

Da man ikke ønskede, at gangbroerne skulle konkurrere eller hindre udsigten til Peace Memorial Parken, Atomic Bomb Dome og Heiwa-Ohashi broen, valgte DISSING+WEITLING architecture at placere den bærende konstruktion under dækket og gjorde elementerne over dækket transparente heriblandt håndlisterne.

Broens konstruktion bestod af en udkraget bjælke, der var understøttet af en pille. Formen på broen var en afspejling af, hvorledes kræfterne løb i konstruktionen. Ståldrageren, der fungerede som en torsionscelle, var udkraget fra den centrale pille. Drageren var dybest over pillen og blev reduceret i højden mod hver ende. Pillens tilspidsede form muliggjorde maksimal stabilitet af drageren med mindst mulig blokering af vandgennemstrømningen. Den øverste del af den hvælvede pille var i stål mens dens nederste del var beton.

DISSING+WEITLING architecture, med inspiration fra japansk arkitektur og design, fremhæver skønheden ved det enkle og omhyggelig detaljering. Broen er formgivet med kassedragerens varierende tværsnit med de vredne planer, der giver broen et let og elegant udtryk. Formen er uden vindskæve planer og dermed let at formgive og bygge. Dragerens tværsnit er forskudt fra broens tværsnit, hvilket gør svejsning fra ydresiden muligt og fremhæver de roterede, tvistede planer. Ståloverfladerne skulle have en malet overflade i en lys næsten hvid farve. 

Dækkets asfalt, der indeholder små metalstykker, reflekterer dagslyset og broens belysning om natten, hvilket resulterer i, at passagen over floden opfattes som at gå på lys. Belysningen, der er indbygget i håndlisterne, skaber et bånd af lys, der leder forgængere og cyklister sikkert over Motoyasu-gawa floden.

Heiwa-Ohashi broerne er et led i det grønne bånd, der karakteriserer Peace Boulevarden og markerer indgangen til Peace Memorial Parken. DISSING+WEITLING architecture fortsatte det grønne bånd ved at etablere et grønt byområde med et hævet landskab, der optimerer udsigten for fodgængere og cyklister.

Designet af de grønne områder minimerede omplantningen af eksisterende træer og respekterede mindesmærker og monumenter i området. 

 

Hiroshima Peace bridges

The Heiwa-ohashi Pedestrian Bridge Design Proposal Competition asks for two bridges. A dramatic statement is not suited for being repeated and would be out of context. Our proposal is of a serene and restrained quality - aesthetically pleasing in the overall view, from the Motoyasu-gawa River surface and the green spaces on either shore.

The Heiwa-ohashi Pedestrian Bridges are a key part of the renewal of Peace Boulevard. The bridges will have an important function providing access for many visitors to the Peace Memorial Park. The new pedestrian bridges must harmonize with the existing bridge, the Isamu Noguchi handrails, the Motoyasu-gawa River, Peace Memorial Park and the surrounding area.

The Heiwa-ohashi Pedestrian Bridges are not to compete with the Peace Memorial Park nor obstruct the view of both the Atomic Bomb Dome and the railings of the Heiwa-ohashi Bridge. We have hence placed the load bearing structure below deck and made the above deck as transparent as possible with cantilevered glass handrails. The image of the proposed Heiwa-ohashi Pedestrian Bridge is one of a Crane Bird standing in the Motoyasu-gawa River with its outstretched wings gently touching the river banks.

The bridge is structurally a propped-up cantilever bridge. The shape of the bridge is a reflection of the flow of forces in the structure. The steel girder, acting as a torsion box, is cantilevered from the central pier. The girder is deepest above the peer and thins out towards each end. The tapering of the pier ensures maximum stability for the girder and minimum obstruction of the water flow. The upper part of the warped pier is in steel the lower in concrete.

The project reflects the best in Japanese architecture and design - simplicity and careful detailing - and in so paying the utmost respect to the Peace Memorial Park. The bridge is carefully crafted with the box girder's varied cross section with twisted planes giving it a sweeping, airborne (lightweight) elegance. The shape having no double curved planes is easy to construct. The girder diaphragms protrude slightly providing for easy welding from the outside and enhancing the shape of the rolled, twisted planes. All steel will have a paint protection system applied in a light, almost white colour.

The pedestrian will experience the crossing of The Motoyasu-gawa River as walking on light. The Bridge has bituminous asphalt decking with a sparkling metallic aggregate reflecting light at day and night time. At night time the bridge is lit up from small cylindrical fibre optical lights cast in the decking material. The light sources for the fibres are provided at both ends from fixtures built into the deck and sealed off from the girder. Service access is provided from above. The toughened and laminated glass handrails has extruded, anodized aluminium handrails with built in light fixtures creating a ribbon of light across the river providing safety for pedestrians and cyclists.

The abutments are built into the ground in order to maintain the prominent key sides. They are equipped with man-holes for inspection access. The Peace Boulevard traverses five arms of the Ota River is one of the most important arteries of the city. The Boulevard is lined by rows of trees forming green bands. The Heiwa-ohashi Bridges new pedestrian bridges belong to the green bands and mark the entrance to the Peace Memorial Park. We have designed the areas around the bridges as a continuation of the green bands - an urban area with green, very slightly elevated, landscape triangles that direct the flow of pedestrians and bicycles without obstructing the thier views.

The green areas are designed to minimize transplanting of existing trees and interference with memorial stone tablets and monuments. The triangles, defined by a low, vertical untreated steel plate edge, will have grass covering, trees and tall, slim posts with focused spot lighting fixtures illuminating walkways, cycle paths and the green areas. Pavement on cycle and walk ways is to be granite in a light colour. Cycle ways will be clearly marked on the paving. Whereas the shape of the new pedestrian bridges is generated by shifting straight lines forming a warped plane the plan of the green triangles resembles origami figures. The total image is one of the Crane and the paper folds.