荷蘭埃因霍溫市的Heerbaan和Meerenakkerweg路口上懸浮著一座“飛碟”式橋梁，這就是世界上首座環(huán)形自行車專用天橋。荷蘭是世界著名的自行車城市，除了民眾自覺騎自行車是對自然環(huán)境愛護的體現(xiàn)外，政府與民間對單車客的支持與配合亦不在話下，為讓民眾能安全無礙的騎車穿越繁忙的公路，ipv Delft在Eindhoven的一條高速公路上興建了一座供自行車騎乘的高架橋Hovenring，它的功用不只在平日的交通運輸，也是假日民眾騎車休憩的去處，而整座具有設計感的建筑在落成后，更成為當?shù)匦碌貥?。這座自行車天橋每天幫助超過5000名自行車騎車人安全通過有2.5萬輛汽車行駛的交通要道。
這里曾經(jīng)是一個平交路口，隨著附近的發(fā)展，人流車流的不斷激增，政府不得不邀請荷蘭橋梁專家ipv Delft提出解決方案。圓形斜拉橋似乎是最好的選擇。整座環(huán)島橋包括一個70米的中央塔、24條鋼纜、和約1000噸鋼材制作的橋面，24條鋼纜均勻的連接到圓橋內側、與地面的M形支架一道確保著橋梁的安全穩(wěn)定。
Like a flying saucer, the steel bridge hoovers above the Heerbaan/Meerenakkerweg intersection, its impressive pylon marking the entrance way to the cities of Eindhoven and Veldhoven. There used to be a level crossing here, but the development of a nearby housing estate meant the intersection needed changing in order to cope with growing traffic. As Eindhoven City Council refrains from cyclist underpasses and didn’t want a level crossing roundabout either, they asked Dutch bridge specialist ipv Delft to look at possible solutions. A circular cable-stayed bridge soon appeared to be the best option.
Structure
The bridge comprises a 70-metre high pylon, 24 steel cables and a circular bridge deck and is made out of circa 1.000 tons of steel. The cables are attached to the inner side of the bridge deck, right where the bridge deck connects to the circular, concrete counter weight. This way, torsion within the 72-metre diameter bridge deck is prevented.To ensure stability, concrete was added to sections of the bridge deck as well. The M-shaped supports near the approach spans also ensure stability.Soon after the pylon was put in place, the cables started vibrating visibly.
Vibrations like these (caused by the wind) are nearly impossible to predict. After extensive research by structural experts, two types of dampers (high frequency and low frequency) were attached to the cables, solving the vibration issues.
One of the challenges of the design process was the spacial integration. The existing infrastructure and buildings set the boundaries for the grades of the slopes leading up to the roundabout. As space was limited, it was decided to lower the ground level of the intersection underneath by a metre and a half, allowing for a comfortable slope for pedestrians and cyclists.
TAILOR-MADE
The design and building process offered many technical challenges as well. Ipv Delft had a very clear view of what the bridge should look like: little more than a thin circular bridge deck and a powerfully shaped pylon. Amongst other things, this meant the standard way of attaching cables to the pylon wouldn’t suffice, as it would result in a bulk of steal near the pylon top. Therefore, a tailor-made solution was designed. The same applies to the M-shaped supports near the span bridges.
Lighting design
Befitting Eindhoven’s identity as the ‘City of Light’ (Eindhoven is home to the Philips company), ipv Delft also made a lighting design for the Hovenring. One of its main elements is integrated into the circular deck. The space in between counter weight and deck has been fitted with aluminum lamellas, translucent sheeting and tube lighting, which results in a clearly visible ring of light at night. Together with the illuminated pylon, the ring of light ensures the bridge’s spectacular appearance at night.
The functional lighting is integrated into the railing, where LED-lighting illuminates the bridge deck and ensures facial recognition of the bridge users at the same time. Lights attached to a cable framework in between pylon and bridge deck and to the inner surface of the circular counterweight illuminate the intersection underneath.Both day and night, the pylon bridge is a true eye-catcher, spectacular in its simplicity.
在我們國家，騎自行車上班的人少得可憐，周末的時候稀稀疏疏的可以看到幾個自行車愛好者，騎著越野自行車在寬大的機動車馬路上擠。在我們擁擠的城市里，騎自行車似乎成為了一件奢侈的運動項目。荷蘭國還有專屬的自行車道路，甚至還有專屬的自行車環(huán)島高架橋，道路照明設計不比機動車道路的差。上班的時候騎著自行車，告別擁擠的公交，空閑的夜晚，也可以牽著愛騎來到這里欣賞城市夜景燈光設計，雖然能夠聽到橋底下傳來的汽車引擎做聲，但是這里是屬于自行車的。
In the summer of 2012, design office IPV Delft realized one of its most talked about cycle bridges to date: The Hovenring in the Dutch city of Eindhoven. The cable-stayed bridge offers cyclists and pedestrians an exciting crossover. With its impressive 70-metre pylon, 72 meter diameter, thin deck and conspicuous lighting, the cyclist roundabout is a new landmark for the city. Like a flying saucer, the steel bridge hoovers above the Heerbaan/Meerenakkerweg intersection, its impressive pylon marking the entrance way to the cities of Eindhoven and Veldhoven.
號外：位于上海陸家嘴的環(huán)形人行天橋 Circular Pedestrian Bridge in Lujiazui, China
