중국 톈먼(天門) 미래의 현수식 피에조 일렉트릭 펜듈럼 보행교 Piezoelectric Pendulum Bridge in Loudi Shi

Piezoelectric Pendulum Bridge in Loudi Shi

Futuristic Concept Suspension Structure in China – design by Margot Krasojević Architects

21 Nov 2019

Piezoelectric Pendulum Bridge

Design: Margot Krasojević Architects

Location: Tianmen, Loudi Shi, China

Piezoelectric Pendulum Bridge Loudi Shi

Piezoelectric Pendulum Bridge is a suspension footbridge in Tianmen, China, that spans two mountains, and its design simulates that of the surrounding snow-capped mountain landscape. Further, it responds to the cloud-edge effect, capturing direct and reflected light to increase solar energy production.

중국 톈먼(天門) 미래의 현수교 피에조 일렉트릭 펜듈럼 보행교 마고 크라소제비치 건축회사 디자인     피에조 일렉트릭 펜듈럼 대교는 두 개의 산에 걸쳐 있는 중국 톈먼(天門)에 있는 현수교로, 주변의 눈 덮인 산악 지형을 모사하고 있다. 게다가, 그것은 태양 에너지 생산을 증가시키기 위해 직접적이고 반사된 빛을 포착하면서 구름의 가장자리 효과에 대응한다. *피에조 일렉트릭(Piezoelectric) 압전 어떤 물질은 기계적으로 스트레스를 받으면 전위를 발생시킨다. 기계 에너지를 작은 전기(또는 그 반대)로 변환하는 이러한 능력을 압전 효과라고 하며, 공학자들은 수년 동안 그것을 이용해 왔다. 흐린 날에는 태양 전지판이 확산된 빛과 반사광을 흡수해 태양 에너지에 최대한 노출될 수 있다. 게다가, 그것의 캐노피는 클랩되고 광전지와 압전 셀이 내장된 매우 반사적인 탄소 섬유 복합체로 제작된다. 보행자들은 구름의 단절과 수평선 확장을 예상하면서 날씨에  따라 변하는 뷰를 갖고 있다. 그 다리는 지상 195m 높이에 서 있는데, 거기서 디자인은 구름과 환경 속에서 그것을 위장하는 착각을 일으킨다. 정적인 평형 균형과 균형 균형을 유지하는 것은 구조적 중요성이 있는데, 그 높이는 요소에 대한 노출과 함께 설계할 불안정한 환경을 만들어 내기 때문이다. 또한 회전 관성은 일차적인 관심사항이며, 흔들리는 캔틸레버 보행로 길이를 통합하면 구조물이 안정될 뿐만 아니라 줄타기 보행자의 경험처럼 경직되지 않고 관성의 순간을 증가시킨다. 디자인은 부드럽게 움직이며, 이는 상향 공기의 움직임과 구름 형성에 대한 안무된 반응으로 보행자들에게 장관을 연출할 뿐만 아니라 때로는 위협적일 수 있는 현장의 바로 그 본성에 대한 노출을 제공한다. 또한, 교량을 안정적인 수평 위치로 복원하기 위해 천천히 그리고 방법적으로 흔들리는 캔틸레버 요소에 의해 균형이 유지되고 제어된다. 이와 관련하여 설계 영감에는 현수된 펜듈럼과 유사한 접이식 푸시 인형이 있는데, 이 인형은 교량의 자연적인 움직임으로 인해 긴장의 상태에 있을 때 관성의 순간을 유지함으로써 교량의 주 골격을 중심으로 회전하는 것을 충분히 방지할 수 있을 만큼 구조물을 조이고 구속한다. 흥미롭게도, 이 다리의 경험은 메콩 강 위에 매달려 있는 밧줄 다리의 영향을 받아, 강을 건너는 보행자들이 그들 자신의 안전을 더 책임지게 된다. 하지만, 이것은 극단적인 경험이고, Margot Krasojevich Architects는 이 디자인이 보행자를 위협하거나 지지하지 않는 것을 믿는다. 황기철 콘페이퍼 에디터 큐레이터 Ki Chul Hwang, conpaper editor, curator

edited by kcontents

On cloudy days, its solar panels absorb diffused as well as reflective light, so that this bridge can achieve maximum exposure to solar energy. Moreover, its canopy is clad and fabricated with a highly reflective shifting carbon-fibre aluminium composite embedded with photovoltaic and piezoelectric cells.

 

Pedestrians have a birds-eye aerial view that changes with the weather, anticipating cloud-breaks and expanding horizon lines. The bridge stands at a height of 650 feet above the ground, wherein the design creates an illusion to camouflage it amidst the clouds and environment.

Maintaining static equilibrium balance and counterbalance is of structural importance, as the height, along with the exposure to elements, creates an unstable environment to design for.

Additionally, rotational inertia is of primary concern, and integrating swinging cantilevered walkway lengths stabilises the structure as well as increases the moment of inertia without making it rigid, rather like the experience of a tightrope walker. The design moves and sways gently, which is a choreographed response to the upward air movement and cloud formation, offering pedestrians with not only spectacular views but also exposure to the very nature of the site, which can be intimidating at times.

Further, two interlaced footpaths are suspended from the structural axes of rotation, which dislocate and shift to rebalance the bridge, thus allowing for a safe crossing. Significantly, the canopy structure fragments in order to recalibrate the shifting weights, along the bridge’s cross-section, in a more efficient manner. This counterbalance is directed by the bridge’s pendulum weights suspended beneath the structure, which tighten and shift to restore equilibrium and maintain structural stability.

Moreover, balance is retained and controlled by the cantilevered elements that swing slowly and methodically to reinstate the bridge to a stable horizontal position. Design inspirations in this regard include a collapsible push puppet similar to the suspended pendulums, which when in tension due to the bridge’s natural movements, tighten and restrain the structure, enough to prevent it from revolving around its main frame, by retaining the moment of inertia. Interestingly, the experience of the bridge was influenced by that of a rope bridge suspended over the river Mekong, which makes pedestrians crossing it more responsible for their own safety. However, this is an extreme experience, and Margot Krasojević Architects believe in one wherein the design does not intimidate or patronise the pedestrian.

The canopy’s dislocating fragments are clad with a carbon-fibre reinforced aluminium composite, which is lighter than aluminium for its weightlessness and is flexible enough for the cantilevered movements yet stronger than steel. This helps in limiting wear and tear, in addition to providing stability through 45-degree torsions and adapting to the external forces of the cantilever frames’ movements, whilst accommodating complex shifting shapes.

In addition, a motion capture system, sandwiched between the primary and tertiary structure, records the canopy movements, choreographing the synchronicity between the edge cloud cover, solar panels and footpath walkways made from steel-framed sections lined with rubber, to absorb unnecessary load-bearing changes arising due to the bridge retaining horizontal inertia. Self-healing polymers have been used to support internal mechanisms and slide surfaces seamlessly, to transfer loads between separating canopy elements and skeleton frames. Moreover, the canopy’s structural deformity under load has a series of polymer sheaths in between the separating elements that protect the design from wear and tear, similar to a plane’s wing.

 

The canopy also shifts with passing clouds, revealing glimpses of the horizon and views visible only for a minute and lost in the next. A patchwork of visual context is also present, similar to the patchwork canopy of elements not too dissimilar from clouds or kites that swivel and shift, attempting to capture as much cloud-edge solar energy as possible. Light levels are monitored using sensors across the cross-section of the bridge, which anticipate a break in cloud cover to expose the beautiful natural surrounding landscapes in the process – a choreography between nature and technology, a dance simulating the co-existence of natural and artificial phenomena.

This project was partly designed in 2015 and is currently in the process of being technologically revised, to be more dynamic and energy-efficient. Like mountain climbers, the people crossing this bridge are exposed to the elements and to the true nature of its surroundings. A turbulent and dangerous beauty, the environment is threatening yet awe-inspiring in the same breath. Further, this bridge moves with air currents, similar to a kite or aeroplane wing, allowing us to relate with our environment more honestly and less submissively. It is noteworthy that using harnesses while crossing this bridge is optional.

The shifting canopy elements resemble solar kites embedded with photovoltaic cells; these are lightweight, durable, non-corrosive and highly reflective, thus creating a continuous surface cantilevered from the primary axial structure. Additionally, these solar kites are CNC fabricated and can be positioned in several configurations, depending on the structural frame. Lightweight yet durable, these canopy elements split apart and can be easily locked into position. For a static surface canopy, they are laser cut sections that can be repositioned as well as replicated for other sites and programmatic uses. The materials used and the building techniques employed in this pendulum bridge reflect progressive engineering applied in aviation, particularly when dealing with the context’s fluid environmental dynamics and maintaining the structure’s integrity.

Digital fabrication is an essential construction technique employed in this project; all elements can be replicated and replaced cost-effectively, and they can be adapted to different scales, ranging from workshop model to site. The bridge also generates electrical power, making it easier to structurally maintain it by keeping these fabrication tools on site. Moreover, the bridge is self-motorised with direct and cloud-edge solar power, which generates enough electricity to animate, float and mechanically move the structure in order to restore balance by shifting dynamic loads, rather like a hang glider only with an external power source.

Applying semi-conductor piezoelectric crystal cells as a gate voltage to the design, by embedding them within the canopy and walkway, generates electricity through resistance. When mechanical pressure is exerted on these elements (for example, as pedestrians walk across the bridge or environmental mechanical dynamics alter the direct pressure on the fragmented canopy), the piezoelectric cells change the resistance, thereby generating and releasing direct electrical current to the motor in order to move the structure. This type of electronics maximises the efficiency of generating power, as a direct response to instability in design and context. To summarise, the piezoelectric pendulum bridge uses a natural equilibrium to monitor and capture electrical energy from either solar or mechanical movement, whilst trying to stabilise the momentum of inertia, so that it can function safely as a footpath and observation deck. The dual nature of its design responds directly to its immediate context, which provokes the nature of its program, sustainability and appropriation.

Piezoelectric Pendulum Bridge, Loudi Shi – Building Information

Architect & Project Manager: Margot Krasojević

Visuals: Margot Krasojević

Piezoelectric Pendulum Bridge in Loudi Shi, China images / information received 211119 from v2com newswire

Location: Loudi Shi, China