上海 3D 打印最大混凝土步行桥启用，智能建造助力转型

2019年1月12日，目前全球最大规模的混凝土3D打印步行桥在上海宝山智慧湾落成。该工程由清华大学（建筑学院）-中南置地数字建筑研究中心徐卫国教授团队设计研发、并与上海智慧湾投资管理公司共同建造。

On January 12, 2019, the world’s largest concrete 3D printed pedestrian bridge was completed in the Wisdom Bay Industrial Park, Baoshan District, Shanghai. The project was designed and developed by the team of Professor Xu Weiguo from Tsinghua University (School of Architecture) – Zoina Land Joint Research Center for Digital Architecture, and was jointly built with Shanghai Wisdom Bay Investment Management Company.

▼3D打印桥鸟瞰及周边环境，aerial view of 3D printed pedestrian bridge and the surroundings

▼3D打印桥概览，view of the 3D print bridge

该步行桥全长26.3米，宽度3.6米，桥梁结构借取了中国古代赵州桥的结构方式，采用单拱结构承受荷载，拱脚间距14.4米。在该桥梁进入实际打印施工之前，进行了1:4缩尺实材桥梁破坏试验，其强度可满足站满行人的荷载要求。

The length of the pedestrian bridge is 26.3 meters and the width is 3.6 meters. The bridge’s structure is inspired by the ancient Anji Bridge in Zhaoxian, China. It adopts the structure of a single arch to bear the load, and the distance between the abutments is 14.4 meters. Before the bridge’s printing process, a 1:4 scale physical model was built to carry out the structure failure testing, which proved the bridge’s strength can meet the load requirements of holding pedestrians crowding over the whole bridge.

▼桥的强度可以满足站满行人的荷载要求，the bridge’s strength can meet the load requirements of holding pedestrians crowding over the whole bridge

该步行桥的打印运用了徐卫国教授团队自主开发的混凝土3D打印系统技术，该系统由数字建筑设计，打印路径生成，操作控制系统，打印机前端，混凝土材料等创新技术集成，具有工作稳定性好、打印效率高、成型精度高、可连续工作等特点。该系统在三个方面具有独特的创新性并领先于国内外同行，第一为机器臂前端打印头，它具有不堵头、且打印出的材料在层叠过程中不塌落的特点；第二为打印路径生成及操作系统，它将形体设计、打印路径生成、材料泵送、前端运动、机器臂移动等各系统连接为一体协同工作；第三为独有的打印材料配方，它具有合理的材性及稳定的流变性。

▼从东侧俯视桥面，aerial view from the east

The printing of the bridge uses the 3D printing concrete system independently developed by Professor Xu Weiguo’s team. The system is integrated with innovative technologies such as digital architectural design, printing path generation, operation control system, printing tool, concrete material, etc. It has the characteristics of high printing efficiency, high molding precision and high constancy in prolonged work. There are three main innovation points of the system, taking the leading position in this field internationally. The first is the printing tool of the robot arm, which avoids plugging in extrusion process and collapse during the material’s layer stacking; For the print path generation and operating system, it integrates form design, print path generation, material pumping, printing tool’s movement, robot arm movement and other systems to work together; the third is a unique printing material formula, which has reasonable performance and stable rheology.

▼桥面西侧局部，detail on the west side

▼桥梁细部，detail of the bridge

整体桥梁工程的打印用了两台机器臂3D打印系统，共用450小时打印完成全部混凝土构件；与同等规模的桥梁相比，它的造价只有普通桥梁造价的三分之二；该桥梁主体的打印及施工未用模板，未用钢筋，大大节省了工程花费。步行桥的设计采用了三维实体建模，桥栏板采用了形似飘带的造形与桥拱一起构筑出轻盈优雅的体态横卧于上海智慧湾池塘之上；该桥的桥面板采用了脑纹珊瑚的形态，珊瑚纹之间的空隙填充细石子，形成园林化的路面。

All of the concrete components of this bridge are printed with two robotic arm 3D printing systems in 450 hours. Compared with conventional bridge of similar size, its cost is only two-thirds of the latter one; This is mainly because that the printing and construction of the bridge’s main body did not use any templates or reinforcing bars, saving costs significantly.The design of the pedestrian bridge adopts three-dimensional solid modeling. The bridge handrails are shaped like flowing ribbons on the arch, forming a light and elegant posture lying on the pond of Shanghai Wisdom Bay. The pavements of the bridge are generated from the form of brain corals, and white pebbles are filled in the voids of the pattern.

▼打印过程，print process of the bridge

▼打印栏板，print the bridge handrails

▼打印桥面，print the bridge pavements

▼桥面图案，pavement details

▼图案细部，detail of the pattern

该步行桥桥体由桥拱结构、桥栏板、桥面板三部分组成，桥体结构由44块0.9*0.9*1.6米的混凝土3D打印单元组成 ，桥栏板分为68块单元进行打印，桥面板共64块也通过打印制成。这些构件的打印材料均为聚乙烯纤维混凝土添加多种外加剂组成的复合材料，经过多次配比试验及打印实验，目前已具有可控的流变性满足打印需求；该新型混凝土材料的抗压强度达到65MPa，抗折强度达到15MPa。该桥预埋有实时监测系统，包括振弦式应力监控和高精度应变监控系统，可以即时收集桥梁受力及变形状态数据，对于跟踪研究新型混凝土材料性能以及打印构件的结构力学性能具有实际作用。

The pedestrian bridge consists of three parts: the arch structure, the handrails and the pavements. The bridge structure contains 44 hollow-out 3D printed concrete units in the size of 0.9*0.9*1.6 meters; the handrails and pavements are also divided into 68 and 64 units for printing respectively. The printing materials of these components are all composite materials composed of polyethylene fiber concrete with various admixtures. After repeated ratio test and printing experiments, it has controllable rheology to meet printing requirements; the pressure resistance strength of the new concrete material reaches 65 MPa and the flexural strength reaches 15MPa. The bridge is embedded with real-time monitoring system, including vibrating wire stress sensors and high-precision strain monitoring system, which can collect the force and deformation data of the bridge in real time. They will have practical effect on tracking the performance of new concrete materials and the structural mechanical properties of printing components.

▼结构试验，structure test

随着我国人口红利的消失，建设工程对于劳动力的需求将越来越供不应求，智能建造将是解决这问题的重要渠道，它将推动我国建筑工业的转型升级，3D打印作为智能建造的一种重要方式，将对工程建设的智能化发展发挥重要作用。

With the disappearance of China’s demographic dividend, the demand for labor in construction projects will be deficient increasingly. Intelligent construction will be an important channel to solve this problem. It will promote the transformation and upgrading of China’s construction industry. As an important part of intelligent construction, 3D printing will play an important role in the intelligentize development of engineering construction.

▼夜景，night scene

虽然在3D混凝土打印建造方面存在着许多需要解决的瓶颈问题，该领域技术研发及实际应用的竞争也日益激烈，国际国内具有相当多的科研机构及建造公司一直致力于这方面的技术攻关，但还没有真正将这一技术用于实际工程。该步行桥的建成，标志着这一技术从研发到实际工程应用迈出了可喜的一步，同时它标志着我国3D混凝土打印建造技术进入世界先进水平。

Although there are many bottlenecks that need to be solved in 3D printing concrete construction, the competition in research and practical application of this field is becoming increasingly fierce. There are quite a few research institutions and construction companies in the world that have been committed to technical research in this area, but these technologies have not been used in actual engineering. The completion of the pedestrian bridge marks a gratifying step for this technology from research and development to practical engineering applications. At the same time, it marks the entry of China’s 3D concrete printing and construction technology into the world’s advanced level.

▼平面，plan

▼剖面，section

团队：清华大学（建筑学院）-中南置地数字建筑研究中心

徐卫国，孙晨炜，王智，高远，张智龄，邵长专等

Design Team: Tsinghua University (School of Architecture) – Zoina Land Joint Research Center for Digital Architecture;

XU Weiguo, SUN Chenwei, WANG Zhi, GAO Yuan, ZHANG Zhiling, SHAO Changzhuan, etc.