Drift 人行桥丨美国丨Volkan Alkanoglu

该项目是一座由设计师Volkan Alkanoglu设计的木钢人行桥，现已完工并于今年夏天安装在得克萨斯州的沃斯堡。该桥是即插即用城市规划的创新范例，采取异地建造基础构件并现场安装的可持续经济策略。Drift人行桥属于沃斯堡公共艺术项目，涉及公共艺术、城市设计、建筑和基础建设。一方面，它由社区主导、定点安装，在社区的两部分及其各自的公园系统之间建立起物理连接。另一方面，它所采用的制造和安装技术可以广泛应用于社区及其他案例。

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. 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 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.

▼桥梁鸟瞰，aerial view © Peter Molick

▼鸟瞰局部，partial view © Peter Molick

Alkanoglu实施三大设计原则：1) 使用可持续材料，尽量减少项目对基地自然环境的影响；2) 通过创新设计和工程物流降低成本；3) 创造场所感并连接社区。

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.

▼设计原则，design principles © Volkan Alkanoglu

Alkanoglu的桥梁设计最终在三个方案中脱颖而出，最初的灵感来自于基地Westcreek和周边环境。随着季节变化，这里的河床从充满水的容器变成布满浮木和砍伐木的干旱凹地。这一转变过程及反映这一过程的浮木和植物影响了桥梁材料的色调和形式，遍布小溪两侧社区的中世纪现代牧场风格房屋也为此带来灵感。Alkanoglu借鉴由伊姆斯夫妇设计的腿夹板，着眼于模压胶合板的创新。

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. Alkanoglu looked to molded plywood innovations, such as Ray and Charles Eames’ leg splint.

▼桥梁外观，appearance © Jennifer Boomer

由此诞生的62英尺（约19米）长的桥梁如同平滑的浮木枝和弯曲的木夹板，在小溪上形成曲线造型，为社区的两部分提供人行连接。从其他角度看，它仿佛外凸内凹的船体，带有走道、长椅和栏杆，这些元素都被整合在单一形体中，不规则的起伏和曲线造型专为座椅和支座设计。Alkanoglu将长椅嵌入桥梁内部，使桥梁变成沉思、娱乐和交流的空间，而不仅仅是一个通道或交通设施。

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. 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.

▼62英尺（约19米）长的桥梁，62-foot-long bridge © Jennifer Boomer

▼曲线造型，curving figure © （上）Jennifer Boomer, （下）Peter Molick

▼桥梁内部，inside view © Jennifer Boomer

▼一体式走道、长椅和栏杆 © Jennifer Boomer integrated pathway, benches, and railings

▼使用场景，usage scenario © Peter Molick

▼细部，details © Jennifer Boomer

Alkanoglu最初设想仅用交叉层积材建造桥梁，但预算限制使他采取不同但同样具有创新性的策略。他从造船技术中汲取灵感，和工程师团队从钢骨架开始建造，并且通过用数控切割和旋转铣刨板包覆骨架来摆脱传统。通过这种方式，每块木板都是定制切割的，然后堆叠成体积庞大的、起伏的外形。

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. In this way, each plank is custom cut, then stack-laminated into one large, volumetric, undulating form.

▼剖面详图，details © Volkan Alkanoglu

这种技术适用于桥梁独特的起伏外形，并满足设计师和客户对可持续设计策略的共同兴趣。木材这种可再生资源可以通过可持续森林管理计划获得，是最高效、最生态的建筑材料之一。旋转铣刨板的使用支撑了Alkanoglu对即插即用城市规划的兴趣。他说：“通过这种方式，桥梁可以异地制造，用大型卡车整体运输至现场，然后用起重机起吊至指定位置。我们的城市迫切地需要在各个层面进行提升，即插即用城市规划是一种经济可行的方式，可以异地生产中型基础设施并运输到城市环境中。我们可以利用计算机设计的进步来实现高效与创新。”

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.”

▼异地制造，offsite manufacture © Volkan Alkanoglu

▼现场安装，site installation © Volkan Alkanoglu

这一过程减少了现场安装的时间，并最大限度地减少了对周围社区的干扰以及对小溪自然植被的影响。此外Alkanoglu将吊入式桥梁与堤岸两侧的低冲击桥墩和碎石排水系统搭配，从而减少桥梁基础的占地面积。Alkanoglu说：“Drift人行桥不仅将城市社区结构重新拼接在一起，而且通过可持续原则为当地社区提供社会和生态发展机遇，改善人们对人造环境的集体理解。”

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.

▼桥梁俯瞰，top view © Peter Molick

虽然Drift人行桥是Alkanoglu的第一个基础设施项目，但它与设计师对城市设计的持续参与密切相关。他解释道：“Drift人行桥可以追溯至过去的项目，例如Public Figure和CloudScape，它们的造型富有表现力，同时又允许人们参与其中。我对这些作品在社交环境中的作用很感兴趣。我的作品始终希望设计能够增进人们彼此互动、支持和交流的方式。”

While Drift is Alkanoglu’s first infrastructure project, it connects to the designer’s ongoing engagement with civic design. “Drift connects back to past projects like Public Figure and CloudScape—they’re very expressive figures, but they can all be occupied or engaged with,” he explains. “I’m interested in what these pieces can do in a social setting. Embedded in my work is always the hope that design can enhance how we interact, support and communicate with each other.”

▼桥梁、环境与人，bridge, environment and people © Peter Molick

Project Credits: Design: Volkan Alkanoglu, Portland, OR Client: City of Fort Worth, Fort Worth Public Art Program Public Art Manager: Anne Allen 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