**Computational Design And Engineering Of**

**Tensioned Formworks For Concrete Shells**

**Instructor: **Prof. Philippe Block | Tom Van Mele

**TA****:**** **Xiao ZHANG

**Students: **Keerthana Udaykumar | Eleni Maria Skevaki | Chaoyu Du | Lee Chinghan | Tan Ying Yi | Ke Liu | Di Ge | Dan Luo | Haotian Xu | Qiang Cui | Yihao Hu | Yumeng Zhang | Cong Wang | Nikolas Arvanitopoulos | Escudero Gongora jesus | Shuoyong Yang | Rui Liu | Kan Lin | Haoyu Liu | Xuan Liu | Qingfeng Yang | Jian Yan

DigitalFUTURES 2019 Summer Workshop “Architectural Intelligence”, has ended up with great success. In Group1, Prof. Philippe Block and Dr. Tom Van Mele, University of ETH, has led 22 students from universities across the world to explore new dimensions in architecture with the theme of ” **Computational Design and Engineering of Tensioned Formworks for Concrete Shells**”, which aims to explore the application prospects and workflow of advanced computational design method and die construction technology in the design and construction of large-scale building components. Besides， we would give special thanks to the members from ‘International Undergraduate Competition” for their persistence and dedication.

**Part1：**

**Background**

**Graphic Statics in Catenary Model**

**“Why is the shape found by the catenary inverted to the arch?”**Because the “rope” can only bear tension, the force in the rope must follow the rope. By inverting the whole shape and replacing the flexible rope with a rod, the decomposition direction of the force can remain unchanged. Therefore, if there are enough subdividing points in the whole device, it will be closer to the acceptance form under uniform gravity load. This process is called

**“Form Finding”.**The shape found is called

**“compression only”**arch.

**Graphics Static in Catenary Mesh**

**“Horizontal Equilibrium”**. After theHorizontal Equilibrium and fixed, the whole device makes

**“Vertical Equilibrium”**, enlarges the force points in equal proportion, and carries out Z-direction shape finding under the premise of maintaining the plane direction unchanged; therefore, no matter the force of each point is 5N or 100N, the plane Equilibrium preserves it after the static setting forever.

**Part2：**

**Workflow**

**（1）Introduction and installation of Compas platform**

**（2）FOFIN (Form Finding)**

**Step1:**

**Run the**

**‘**

**FOFIN_init**

**‘**command to find the FOFIN python library in your computer and call it into Rhino.

**Step2:**

**Run**

**“**

**FOFIN_from**

**“**to load the object to be typed. The “.jason” file is the most important file format in the work camp. It is the coordinates of each point in the grid system. User organizes Rhino model through the instruction set, forming three kinds of pickable geometries: ‘point, line, and face’.

**Step3**

**:**

**‘**

**FOFIN_select**

**‘**and

**‘**

**FOFIN_attributes**

**‘**work cooperatly. ‘Select’ is used for fast selection of elements (points, lines, surfaces) on the geometry. Multiple lines and points can be selected at one time separately according to the direction of U/V of the grid and the boundary continuously. ‘Attributes’ can set degree of anchorage at each point and degree of tension in each line.

**Step4:**

**‘**

**FOFIN_run**

**‘**is a comprehensive operator, finding statically determinate form of mesh space under the corresponding conditions. After Form-finding, designers can repeat the third step, making iterative optimization.

**‘**

**FOFIN_settings**

**‘**can show direction and size of the stress on each structural unit, such as anchor point and rope.

**‘**

**FOFIN_save**

**“**stores the found form as geometric information with the data, which can be adjusted the next time.

**（3）Cable network system analysis**

**“**

**vertex_normal**

**“**instruction relates to computer graphics, which can be referred to description of the COMPAS official website.

**For Example**:

As**“****vertex_normal****”**command for example ，This command is to find the roemal vector for vertex on mesh，Here is how it works!

**Step1: **Let’s open COMPAS website

（https://compasdev.github.io/main/tutorials/networks.html）

**Step2:** Through the website, we search **“****vertex_normal****”**, and it shows：Return the normal vector at the vertex as the weighted average of the normals of the neighboring faces. Here，the weighted average means the length of the vector has something to do with the area of the faces，The bigger the area of the face is, the more it will pull the vector of the vertex .

**Step3:**Here, we take the four meshes on the model as an example. Firstly, we find thecenter points of four meshes in the blue part, whose coordinates are “average of four vertex coordinates”. Secondly, four sides are divided into four triangles according to the center point (Fig. 2). Four face plane normal vectors are solved, and their area quadrature with normal vectors (in Figure 3, the length of the normal vectors of each triangle is different), and the final sum of the vectors is displayed at the vertex of the mesh (Figure 3).

As shown in the code above, the points where **‘****is anchor****’** is true in **‘****FOFIN_attributes-vertices****’** are firstly colored. Then designers make sure the starting point, end point and the scale of vector. The figure below is the result after solving.

**（4）Production and construction of PVC film**

**（5）Pouring simulation and construction**

**The final proportion of concrete :**1. Cement: 50kg2. Sand: 50kg

3. Water: 20.0-24kg

4. 2mm Glass Fiber: 1000g（1kg）

5. Secret White Powder: 25g

6. Plasticizer：1000g（1kg）

**（6）Concrete watering and demoulding**

**Welcome to**

**DigitalFUTURES 2019 Exhibition!**

**DigitalFUTURES Shanghai 2019**

**Host**Tongji University

Co-organizers

ASC-CCD

ASC-VACS

Education Committee of Digital Technologies in Architecture

Tongji Architectural Design (Group) Co., Ltd.

**Organizer**

College of Architecture and Urban Planning, Tongji University

Shanghai Digital Fabrication Engineering Technology Center

**Partners**

Tongji Undergraduate School (TUS)

**Support**

Fab-Union

DADA

Trendzone Construction Decoration Group Co.,Ltd.

**Media**

Architectual Journal| Time+Architecture | World Architecture | Architecture China | Journal of Human Settlements in West China | South Architecture | Architecture Technique | Architectural Practice | Position | gooood | ArchDaily | Dezeen