Drift人行桥

设计师Volkan Alkanoglu设计的木钢人行桥已经完成，将于2021年夏天在德克萨斯州沃斯堡安装。项目是即装即用的一个创新例子，这是一种新兴的可持续和可负担的设计策略，建议在现场以外的地方建造基础设施元素，并将其放置在适当的位置。

Drift, a timber-and-steel pedestrian bridge by designer Volkan Alkanoglu, has been completed and will be installed in Fort Worth, TX in Summer 2021. Fabricated off site with a projected installation time of just a few hours, Drift is an innovative example of plug-and-play urbanism, an emerging sustainable and affordable design strategy that proposes building infrastructural elements off site and dropping them into place.

由沃斯堡市的公共艺术项目委托，项目跨越了公共艺术、公民设计、建筑和基础设施。一方面，它是一个由社区驱动的、特定地点的项目，旨在弥合一个社区的两半及其各自的公园系统之间的物理鸿沟--一条小溪。另一方面，所采用的制造和安装技术可以应用于广泛的社区和使用情况。

Commissioned by the City of Fort Worth’s Public Art Program, Drift straddles public art, civic design, architecture, and infrastructure. On one hand, it is a community-driven, site-specific project created to bridge a physical divide—a creek—between two halves of one neighborhood and their respective park systems. On the other, the fabrication and installation techniques employed can be applied to a wide range of communities and use cases.

项目了回应沃斯堡公共艺术的要求，在沃斯堡的南山住宅区建造一座横跨小溪的人行桥，以加强三一河步道系统沿线许多社区的连接。历史上，在七个街区内，没有地方可以跨越80英尺宽的涵洞。Alkanoglu实施了三个中心设计原则。1）使用可持续材料，尽量减少对现场自然栖息地的影响；2）通过创新设计和项目物流降低项目成本；3）创造地方感，连接社区。预算为37.5万美元--对于这种规模的基础设施项目来说，这是一个相当小的数字。

Alkanoglu began conceptualizing Drift in response to a brief from Fort Worth Public Art for a pedestrian bridge spanning a creek in the South Hills residential neighborhood of Fort Worth that would enhance connectivity of the many communities along the Trinity River Trail System. Historically, there had been no place to cross the 80-foot-wide culvert for seven blocks. Alkanoglu implemented three central design principles: 1) Use sustainable material and minimize impact on natural habitat on site; 2) Reduce project cost through innovative design and project logistics; 3) Create a sense of place and connect the community. The budget was $375,000—a fairly slim sum for an infrastructure project of this scale.

项目从三个入围方案中脱颖而出，从Westcreek场地及其周边环境中获得了最初的灵感。根据不同的季节，溪床从一个流动的容器转变为一个充满浮木和砍伐的植物的干燥盆地。这一转变过程以及反映这一过程的浮木和植物，推动了桥梁的材料色调和形式。中世纪现代牧场风格的住宅充斥着小河两岸的社区，这也提供了素材。Alkanoglu在桥和社区的主要建筑之间画了一条线，他参考了模制胶合板的创新，如Ray和Charles Eames的腿部夹板，这些夹板与住宅在同一时代制造。

Alkanoglu’s design for Drift, which was selected among three finalist proposals, drew initial inspiration from the Westcreek site and its immediate surroundings. Depending on the season, the creek bed shifts from a container for flowing water to a dry basin filled with driftwood and felled plants. This process of transformation—and the driftwood and plant life that reflect it—drove the bridge’s material palette and form. The mid-century modern ranch style homes that fill the neighborhoods on either side of the creek also offered fodder. Drawing a line between the bridge and the neighborhoods’ dominant architecture, Alkanoglu looked to molded plywood innovations, such as Ray and Charles Eames’ leg splint, made during the same era as the homes.

由此产生的62英尺长的桥类似于光滑、弯曲的浮木树枝或弓形的弯曲木夹板，在小河上划出弧线，在社区的两个部分之间提供行人连接。从其他角度看，它松散地指的是船体，有一个凸起的船底和一个凹陷的船体，里面有一条通道、长椅和栏杆。独特的是，这些元素都被构建在一个单一的形式中，其中不规则的起伏和曲线被设计为坐和支撑。这一创新也从Eames的夹板中获得了灵感，"在那里，每个功能都发生在一个单一的数字中，"Alkanoglu解释说。嵌入长椅是Alkanoglu创造场所的一种手段。有了它们，项目成为一个沉思、娱乐和交流的空间，而不仅仅是一个通道或寻路机制。

The resulting 62-foot-long bridge resembles a smooth, curving branch of driftwood or a bowed bentwood splint, arcing over the creek and providing pedestrian connectivity between two parts of a neighborhood. From other angles it refers loosely to the hull of a ship, with a convex underbelly and a concave hull containing a pathway, benches, and railings. Uniquely, these elements are all built into a single form, where irregular undulations and curves are engineered for sitting and support. This innovation also draws inspiration from Eames’ splint, “where every function occurs within a single figure,” explains Alkanoglu. Embedding the benches was a means of placemaking for Alkanoglu. With them, Drift becomes a space for contemplation, recreation, and communing, rather than just a thruway or wayfinding mechanism.

虽然Alkanoglu最初设想只用交叉层压木材来制造桥梁，但预算的限制促使他采取不同但同样创新的策略。他和一个工程师团队从造船技术中得到启发，开始使用钢制衔铁，但偏离了传统，用数控切割和翻转铣削的木板覆盖它，这是计算设计的产物。通过这种方式，每块木板都是定制的，然后堆叠成一个大型的、体积大的、起伏的形式。

While Alkanoglu originally envisioned fabricating the bridge solely from cross-laminated timber, budgetary constraints encouraged a different but equally innovative strategy. Taking a cue from shipbuilding techniques, he and a team of engineers began with a steel armature, but veered away from tradition by cladding it with CNC-cut and flip-milled timber planks—a product of computational design. In this way, each plank is custom cut, then stack-laminated into one large, volumetric, undulating form.

这种技术适应了大桥独特的起伏形式，满足了设计师和客户对可持续设计策略的共同兴趣。木材是一种可通过可持续森林管理计划获得的可再生资源，是最有效和最生态的建筑材料之一。使用翻转式铣削木板也支持了阿尔卡诺格鲁对即装即用的城市主义的兴趣。"通过这种方式，桥梁可以在现场外制作，由任何超大型卡车作为一个整体运输到现场，然后用起重机吊装到位，"他说："我们的城市迫切需要在各个层面上进行升级，即插即用的城市主义是一种经济上可行的方式，可以在异地生产中等规模的基础设施，并将其交付给城市环境。我们可以利用计算设计方面的进步来实现高效和创新"。

This technique accommodated the bridge’s unique, undulating form and met the designer and client’s shared interest in sustainable design strategies. A renewable resource available through sustainable forest management programs, wood is one of the most efficient and ecological building materials. The use of flip-milled planks also supported Alkanoglu’s interest in plug-and-play urbanism. “In this way, the bridge could be fabricated off site, transported to the location by any oversize truck as one piece, and lifted into place with a crane,” he says. “Our cities urgently need upgrades on all levels, and plug-and-play urbanism is an economically feasible way to produce mid-scale infrastructure offsite and deliver it to its urban context. We can leverage advancements in computational design to be efficient and innovative.”

This process reduces on-site installation time and greatly minimizes disruption to the surrounding community and impact on the creek habitat’s natural vegetation. Additionally, Alkanoglu paired the craned-in bridge with low impact piers on either side of the bank, and a rip-rap drainage system to create minimum footprints for the bridge foundation. “While stitching the urban neighborhood fabric back together, Drift also offers social and ecological opportunities for the local community through use of sustainable principles, which can alter our collective understanding of the built environment,” says Alkanoglu.

Project: Drift Bridge

Design: Volkan Alkanoglu, Portland, OR

Client: City of Fort Worth, Fort Worth Public Art Program

Public Art Manager: Anne Allen

Design Development and Fabrication: Ignition Arts LLC, Indianapolis, IN; Brownsmith Studios,

Bloomington, IN

Structural Engineering: CMID Engineers, Indianapolis, IN

GeoTechnical Engineering: Alpha Testing, Fort Worth, TX

Material Testing: Simpson, Gumpertz & Heger Inc., Cambridge, MA

Concept Engineering: AKT II, London, UK

Photo Credit: Jennifer Boomer