Bamboo_img_02

Shanghai Bamboo Pavilion

Shigeru Ban Architect

2018

Feasibility studies for reciprocal frame structure from planar materials

Shanghai Bamboo Pavilion at Tonji University

The reciprocal frame structure was constructed in collaboration by Ban Laboratory at Keio University, Japan and Tonji University, China. A computational model was created to better understand the behavior of this structure before construction.

Several challenges were identified at the beginning of the study. Rectangular cross-section of materials prevent prefect assumption of tangency between frame element in compare to other research using tubular element. A shallow dome structure, thick material and a pre-determined engagement length require large deformation of frame elements and internal strain. Rectangular projection on the spherical geometry led to high eccentricity of surface subdivision.

 

The circle-tangent model was created initially to replicate results from previous research and the bend-conform model was created specifically for this project. Both adopt a simple gradient-decent optimization to calculate proper engagement length/deformation to achieve perfect contact between frame element.

Project Team: Harano Yasunori(SBA), Jun Fujisaki(SBA), Anthony Chu(SBA)

Ref: Parigi, D. “Advances in Design and Fabrication of Free-Form Reciprocal Structures.” Structures and Architecture, 2016, pp. 290–297., doi:10.1201/b20891-37.

Methodology

1. Spherical Dome

2. Subdivision with singularity

3. Mesh Relaxation with constant edge length

4-1. Circle-Tangent

4-2. Bend-Conform

Bamboo_Method_tangent
Bamboo_Method_bend

Frame element is bent until frame element touch properly. 

Circle radius is increase/ decrease iteratively until frame elements touch.

Pre-optimization

Member location determined by original mesh vertices and not touching.

Optimized

Members with modified engagement length now fully tangent to each other.Median difference to target > 0.0002%

Curvature Adaptation
Adapt to Surface Curvature

Engagement length adapt to varying surface curvature, allowing the approximation of an reciprocal frame structure to free form shell geometry. Spikes showing deviation from target distance.

Artboard 1.png

Parigi, D. “Advances in Design and Fabrication of Free-Form Reciprocal Structures.” Structures and Architecture, 2016, pp. 290–297., doi:10.1201/b20891-37.