NuBlock Design Report by Erin Hunt and Yaxuan Liu

Interface Design: Interigating Material Perceptions

NuBlock

Professor: Sawako Kajima

Students: Erin Hunt and Yaxuan Liu

Objective

Our project NuBlock brings a modern and aesthetic update to an

architectural and structural elementary unit—brick. With its innovative

water-soluble formwork, this project can create lighter concrete bricks

through a gradient of variable porosities with intricate geometries and

infinite customizability. Thanks to its customizability, NuBlock’s porosity

can directly relate to its location’s structural need. In areas where greater

structural stiffness is required the block is denser and vice versa. The goal is

to minimize the quantity of material necessary through formal optimization

while maintaining its structural performance and decreasing the embodied

carbon latent in concrete fabrication.

NuBlock | Hunt + Liu

3

Module: Block

We chose to investigate bricks and masonry blocks because of their:

1. Inherent scale to a person

2. Ease for transportation

3. They are very versatile and can be used to approximate intricate

geometries

Scale Ease of Transport Versatility

(Left) https://mindfulstoic.net/mindful-walking/

(Middle) https://lectura.press/en/picture/brick-handling-with-hyster/44962

(Right) https://sydneyuncovered.com/the-goods-line/


5

Formwork Material: Polyvinyl Alcohol

Polyvinyl Alcohol (PVA) is a biodegradable, water-soluble polymer that is

used in 3D printing as a support structure for a second 3D print material.

When exposed to water it will dissolve. This material is what is used to hold

the detergent in pods and are the composition of glue sticks.

PVA Formwork

For this project PVA was used as a primary print material for use as

concrete formwork. As formwork, it has allowed for the creation of concrete

components with hollow parts, undercuts, as well as other scenarios in

which removing or breaking the formwork would be impossible without

breaking the cast. Typically, casting complex forms in concrete requires

large and multipart formwork but, with PVA, a single mold can be used as

shown in the diagram on this slide. The PVA formwork at left would dissolve

leaving the intricate block at right.

Rockite Cast


7

Brick Design Logic

The brick was based off hexagonal sphere packing. The cell size determined the density of the

spheres which allowed for varying porosities. The angle of the sphere array can be changed to allow

for varying direction of porosity that can augment the view or the lighting. The spheres were used

to remove material from a block. An exterior boundary remained on four sides to make the module

more legible once populated on a structure.

Creation of a Hexagonal Grid

Separation of Points

Moving one set of Points in the Z

Axis Distance

Use the Obtained Points as the

Spheres’ Centroids

Linear Array of Spheres

Rotating Spheres about the YZ

Plane and Creating Block Bounds

for the Interior and Exterior

Differencing the Spheres from the

Interior Bounds

Differencing the Spheres from the

Exterior Bounds

Inputs

Hex Cell Size

Length (X Axis)

Width (Y Axis)

Input

Z Axis Move Distance

Input

Sphere Radius

Input

Array Count

Input

Angle


9

Case Studies

Two case studies were investigated using very different structures to

showcase NuBlock’s versatility. These two studies were a staircase core and

a shell structure.


11

1

6

2

Brick Types

7

Ten brick types were designed with a gradient porosity. The depth of the

bricks range from eight to twelve centimeters from the most porous to the

least porous.

3

8

4

9

5

10


13

Corner Block

A corner block was designed to aid in turning the corner without losing

porosity.


15

Mapping Method

In order to map NuBlocks according to the stiffness map from finite element

analysis and optimization, a grid was populated onto the surface and used

to sample the UV tangents (and/or contour line tangents), and stiffness map

brightness, which are used to determine the block orientation and type. The

selected bricks are mapped onto the surface so that their centroids are at

the corresponding grid points.

Brightness: 0.98

Type 10 NuBlock


17

9 meters

3 meters

1 meters

3D Model

Structure FEA Analysis

The staircase core case study started with a finite element analysis in

Millipede, a plugin for McNeel’s Grasshopper, of the structure. The

3D model at left was translated into a shell model to be analyzed and

optimized. The staircase wraps about the three-by-three-meter masonry

core which is nine meters tall. The model on the right shows the model that

was input into Millipede. The structural load is represented in pink. The stair

is loaded with five-thousand newtons per square meter with a safety factor

of three while the roof load is two-thousand newtons per square meter and

a safety factor of five. The blue denotes the support structure.

Shell Model

FEA Model


19

FEA Result (Stiffness)

FEA Optimization

The diagrams at right denote the stiffness map from the FEA optimization.

The white areas are where the most structural stiffness is desired while the

least is required in the black areas. The rightmost diagram is an unrolled

stiffness map of the three-by-three-meter masonry core.

3 meters

9 meters

12 meters

UnRolled FEA


21

Brick Mapping

The renders at right show the blocks mapped onto the structure according

to the FEA optimization result. Solid blocks were placed in areas where the

floating stair is mounted.

Wall 1 Wall 2 Wall 3 Wall 4


23

Concrete Block

Steel Plate

Steel Support

Timber Cladding

Section

Staircase Design Standard Tread

A stair was designed to be subtle and complement the block, with the

intention of not taking away focus from the porous concrete blocks. The

stair’s steel support assembly was designed using Finite Element Analysis.

This analysis allowed for the development of a rectangular extrusion steel

support. This support would be cast into the concrete blocks. The steel

support would be clad with a steel plate and timber.

Timber Cladding

Steel Plate

Steel Support

Isometric


25

Timber Cladding

Steel Plate

Staircase Design Corner

The corner landing follows the same structural and material logic as the

standard treads.

Steel Support

Concrete Block


27

Isometric

Plan

Elevations


29

Close-Up Speculative Rendering


31

View at the Staircase Base


33

View at the Second Level


35

Blocks can be removed in areas where the blocks are most porous to allow for openings

View at the Second Level


37

View looking upward from the courtyard


39

Statistics

The structure was only 30.73% the volume of this structure with traditional blocks.

Staircase Core

Type Volume (cm 3 ) Quanity Type Total (cm 3 )

1 356.99 610 217,764.92

2 384.27 190 73,010.76

3 480.49 253 121,563.16

4 487.27 231 112,558.70

5 537.29 372

199,873.20

6 463.41 357

165,438.11

7 525.60 388

203,693.94

8 577.48 351

202,693.94

9 715.67 435

311315.83

10 809.52 1412

1,143,037.53

Corner 934.23 344

321,373.72

Total 3,318,564.24

Original Total 2,000 5,400

10,800,000

Percentage 30.73%


41

Shell Structure

Shell Model

The shell model analyzed and optimized a Catalan vault with its self-weight.

The geometry was generated through the draping of a chamfered square

which created the most efficient structure. Each anchor is one and one-half

meter in length. The openings are six and one-quarter meters wide and

three meters tall. The structures height is four meters.

4 meters

3 meters

6.25 meters

1.5 meters

FEA Model


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FEA Optimization

FEA Result Isometric (Stiffness)

The diagrams at right denote the stiffness map from the FEA optimization.

The white areas are where the most structural stiffness is desired while the

least is required in the black areas.

FEA Result Plan (Stiffness)


45

Brick Mapping

Brick Mapping Isometric

After trying a variety of different patterns of packing, this one was chosen as

it highlights the geometry the best and approximates the stiffness map well.

Brick Mapping Plan


47

Rendering of Block Mapping

Isometric

These are renderings of the block mapping results.

Plan


49

Close-up render of the mapped blocks. The structure is denser closer to the support and becomes more porous as it approaches the center.


51

The pavilion site was a park. It provides a space for visitors to stop and rest. The shadows cast by the trees and the pavilion interact well with one another.


53

The lighting pattern on the underside of the shell shows the structural density.


55


57

Statistics

The structure was only 23.48% the volume of this structure with traditional blocks.

Catalan Vault

Type Volume (cm 3 ) Quanity Type Total (cm 3 )

1 356.99 1066 380,553.12

2 384.27 503 193,286.38

3 480.49 515 247,450.70

4 487.27 326 158,849.08

5 537.29 271

145,606.55

6 463.41 208

96,389.71

7 525.60 158

83,045.44

8 577.48 129

74,494.36

9 715.67 96

68,704.18

10 809.52 260

210,474.33

Total 1,658,853.86

Original Total 2,000 3,532

7,064,000

Percentage 23.48%


59

Fabrication Block One

PVA Formwork

A small test block was created which measured twelve centimeters (length)

by six centimeters (width) by six centimeters (height). The project was

bound to a Lulzbot Mini 2 desktop Fused Deposition Modeling (FDM) 3D

printer. Its build volume is sixteen centimeters (X) by sixteen centimeters (Y)

by eighteen (Z) centimeters.

Rockite Cast


61

Dissolution Block One 11:00 AM 12:00 AM

Prior material research has shown that using heated water to dissolve the

Polyvinyl Alcohol (PVA) expediates the process. Therefore, a crockpot at low

heat was used to degrade the formwork. The dissolution process took three

hours.

1:00 PM 2:00 PM


63

Fabrication Issues Block One

As a result of the inability to integrate support material into the formwork

there were five locations where the printer could not accommodate the

material bridging this created holes and a marred surface finish on the

backside of the block.


65

New Fabrication Method

A new fabrication method was developed for the second fabrication

test. This method, allowed for the creation of multiple parts that could

be held together with wooden dowels. This new strategy eliminated the

material bridging and need for support structures as a result of where the

components were cut. This allowed for the blocks volume to increase since

the entire block was not being printed at once. The volume of the second

block was 20 centimeter (length) x 10 centimeter (width) x 10 centimeter

(height).

x6

x2

x2

x3

x2


67

New Fabrication Method

A new fabrication method was developed for the second fabrication

test. This method, allowed for the creation of multiple parts that could

be held together with wooden dowels. This new strategy eliminated the

material bridging and need for support structures as a result of where the

components were cut. This allowed for the blocks volume to increase since

the entire block was not being printed at once. The volume of the second

block was 20 centimeter (length) x 10 centimeter (width) x 10 centimeter

(height).

PVA Formwork Held with Wooden Dowels

PVA and PLA formworks in Working in Conjunction


69

Dissolution of Block Two

The block in vertical orientation in the crockpot allowed for one end of the

PVA to dissolve first as the other end mainly stayed intact. A tall pot was

used to retain heat within the crockpot. As the PVA dissolved the dowels

were carefully removed. The dowels were saved and used once more for the

fabrication of the next block. Once the PVA at one end was dissolved the

other end was submerged.


71

Resulting Rockite Cast


73

Fabrication Issues Block Two

The thinner portions of block had a few cracks, but it is unclear if this is a

result of the Rockite pour or if these areas of the block are too thin.


75

x2

x4

x2

x2

Rendering of the Formwork and its Components

Fabrication of Block Three

Another fabrication test was conducted. The thinnest element of this block

as well as the external boundary was five millimeter. As a result of the

increased material thickness, the final block had no cracks.

PVA Formwork Held with Wooden Dowels


77

Resulting Rockite Cast


79

In this image the two final fabricated blocks were stacked to show the possible variation in porosity.


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NuBlock Design Report by Erin Hunt and Yaxuan Liu

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