摇摆桥 · 伦敦水晶宫公园的仿生“硬骨鱼”桥梁设计丨英国伦敦丨Tonkin Liu

项目坐落于伦敦水晶宫公园恐龙岛，公园的独特环境，以及对安全通道的需求，激发了摇摆桥的设计灵感。设计团队Tonkin Liu数十年来一直受到仿生学研究的启发，而本项目则在该基础上展现出三个具体的创新方向，分别表现在：1. 通过桥身的旋转摆动来连接两岸；2. 运用波形几何结构增强桥身强度；3. 桥梁梳形伸缩缝施工工艺。

The unique circumstances of the Crystal Palace Park Dinosaur Islands and the need for a secure crossing inspired the structural artwork of Swing Bridge. Informed by Tonkin Liu team’s decade-long immersion in biomimetic studies, the project delivers three specific innovations: swinging to access the banks, undulating geometry for structural strength, and the comb construction technique.

▼由林间看桥梁，viewing the bridge from the woods ©Tonkin Liu

▼桥梁与附近的恐龙雕塑，the bridge and the dinosaur sculpture nearby ©Tonkin Liu

水晶宫公园恐龙岛拥有167年历史，岛上的混凝土恐龙雕塑被列为I级保护文化遗产，这些雕塑生动地呈现出在深地质时代因世界毁灭而灭绝的动物们。研究小组因此希望以这座桥的位置来标记出史前时间序列的开始，如同一个讲述生物进化进程的序章，同时“史前硬骨鱼”般的外观形态也反过来引起了人们对恐龙的前身的联想，进一步点明了岛上描绘的进化时间轴。

The 167-year-old, Grade I Listed concrete Dinosaur sculptures were configured to depict extinct animals in the lost worlds of deep geological time. The team chose the bridge’s location to mark the start of this sequence, helping to tell a story of evolution, which in turn inspiring the reference to the prehistoric bony fish, the precursor to the Dinosaurs and the evolutionary timeline depicted on the islands.

▼桥梁整体概览，overall of the bridge ©Tonkin Liu

▼雪景，snow day view ©Tonkin Liu

为了保护通往恐龙岛的通道，桥身被设计在水中，只有在供教育和维修使用时才能与陆地相连。整个桥身仅由水中央的一个中心基础结构支撑，这种设置避免了项目对大型保护屏障装置的需求，同时使桥梁与恐龙雕塑保持了一定的距离。当不使用时，这座桥又巧妙地转变成一座漂浮在公园水景中的雕塑艺术品。

To protect access to the Dinosaur Islands, the bridge has been designed to remain in the water and only make its connection to land when access is given for education and for maintenance. This negates the need for a large protective barrier, keeps its distance from the Dinosaurs, and requires only one central foundation. Crystal Palace Park in turn enjoys, when the bridge is not in use, a sculptural artwork floating in water.

▼人与桥梁的互动，interaction between people and the bridge ©Tonkin Liu

桥身结构的每个组成部分都呈现出严谨的几何形态，赋予了桥梁足够的强度。三角脊柱梁将荷载传递到中心轴承，这种结构形式是经过最小弯矩计算而特别定制的。甲板的骨架结构从主梁中延伸出来，与梁架融为一体。桥身最宽以及最高的地方坐落在中心支撑上，保证了整体桥身的强度与稳定性。此外，设计师还通过优化几何形状来增强结构的强度，从而实现了最小的钢板厚度。

Form gives strength through geometry in each of the component of the structure. A triangular spine beam delivers load to the central bearing, its tailored form is minimised in response to the bending moments. The skeletal deck structure projects out from the beam’s backbone like form. The bridge form gains overall strength from being widest and tallest over its central support. Minimal thickness of the steel sheet is achieved by optimising resistance through the geometry.

▼宛如硬骨鱼的桥梁外观，the bony fish appearance of the bridge ©Tonkin Liu

▼桥身细部，detail of the bridge ©Tonkin Liu

▼扶手细部，detail of the handrail ©Tonkin Liu

在硬骨鱼的进化过程中，起伏的身体形态与运动方式为其产生了前进的动力。本项目则以此为灵感，将人们推拉扶手时产生的动力荷载传导至起伏的栏杆和甲板上。栏杆沿着起伏甲板的长度前后倾斜，外部起到支撑作用，内部则起到束缚作用。多个弯曲并焊接在一起的叉状件如同车轮中的辐条一般相互作用，既形成了起伏的桥梁形态又满足了桥身的横向刚度。精心的设计与严谨的计算使摇摆桥的振荡频率与振幅都保持在最佳的范围内。

In the evolution of the first bony fish, an undulating movement produces a force that propels it forward. The undulating form of the balustrade and deck resists forces applied to the handrail through a push-pull action. The balusters lean backward and forward along the length of the undulating deck, the outer acting as a strut and the inner acting as a tie. The multiple bent and welded prongs act together like spokes in a wheel to give the undulating form lateral stiffness. The frequency and pitch of the oscillation have been engineered to find the optimum form.

▼吊装过程，installation ©Tonkin Liu

▼3d效果图，3d rendering ©Tonkin Liu

▼桥梁旋转运动示意图，Diagram of bridge rotation motion ©Tonkin Liu

▼平面图，plan ©Tonkin Liu

▼剖面图，section ©Tonkin Liu

Project size：8 m2 Completion date：2020 Project team：Main Contractor, Fabricator, and sub-structure design：Cake Industries Design：Tonkin Liu Structural Engineer：ARUP